Science.gov

Sample records for affect heart rate

  1. Factors affecting heart rate variability in preterm infants.

    PubMed

    Cabal, L A; Siassi, B; Zanini, B; Hodgman, J E; Hon, E E

    1980-01-01

    Neonatal heart rate variability (NHRV) was studied in 92 preterm infants (birth weight, 750 to 2,500 gm; gestational age, 28 to 36 weeks). Each infant was monitored continuously during the first 6 hours and for one hour at 24, 48, and 168 hours of life. During each hour NHRV was quantified and related to the following parameters: sex, gestational age, postnatal age, heart rate, and the presence and severity of respiratory distress syndrome (RDS). NHRV in healthy preterm infants was inversely related to heart rate level and directly related to the infant's postnatal age. In healthy babies with gestations of 30 to 36 weeks there was no significant correlation between NHRV and gestation. Decrease in NHRV was significantly related to the severity of RDS, and the reappearance of NHRV in infants with RDS was associated with a good prognosis. Decreased NHRV significantly differentiated the infants with RDS who survived after the fifth hour of life. The data reveal that NHRV (1) should be corrected for heart rate level and postnatal age; (2) is decreased in RDS; and (3) can be used as an indicator of morbidity and mortality in preterm infants with RDS.

  2. Relationship between obesity, negative affect and basal heart rate in predicting heart rate reactivity to psychological stress among adolescents

    PubMed Central

    Park, Andres E.; Huynh, Pauline; Schell, Anne M.; Baker, Laura A.

    2015-01-01

    Reduced cardiovascular responses to psychological stressors have been found to be associated with both obesity and negative affect in adults, but have been less well studied in children and adolescent populations. These findings have most often been interpreted as reflecting reduced sympathetic nervous system response, perhaps associated with heightened baseline sympathetic activation among the obese and those manifesting negative affect. However, obesity and negative affect may themselves be correlated, raising the question of whether they both independently affect cardiovascular reactivity. The present study thus examined the separate effects of obesity and negative affect on both cardiovascular and skin conductance responses to stress (e.g., during a serial subtraction math task) in adolescents, while controlling for baseline levels of autonomic activity during rest. Both obesity and negative affect had independent and negative associations with cardiovascular reactivity, such that reduced stress responses were apparent for obese adolescents and those with high levels of negative affect. In contrast, neither obesity nor negative affect was related to skin conductance responses to stress, implicating specifically noradrenergic mechanisms rather than sympathetic mechanisms generally as being deficient. Moreover, baseline heart rate was unrelated to obesity in this sample, which suggests that heightened baseline of sympathetic activity is not necessary for the reduced cardiovascular reactivity to stress. PMID:26049136

  3. Relationship between obesity, negative affect and basal heart rate in predicting heart rate reactivity to psychological stress among adolescents.

    PubMed

    Park, Andres E; Huynh, Pauline; Schell, Anne M; Baker, Laura A

    2015-08-01

    Reduced cardiovascular responses to psychological stressors have been found to be associated with both obesity and negative affect in adults, but have been less well studied in children and adolescent populations. These findings have most often been interpreted as reflecting reduced sympathetic nervous system response, perhaps associated with heightened baseline sympathetic activation among the obese and those manifesting negative affect. However, obesity and negative affect may themselves be correlated, raising the question of whether they both independently affect cardiovascular reactivity. The present study thus examined the separate effects of obesity and negative affect on both cardiovascular and skin conductance responses to stress (e.g., during a serial subtraction math task) in adolescents, while controlling for baseline levels of autonomic activity during rest. Both obesity and negative affect had independent and negative associations with cardiovascular reactivity, such that reduced stress responses were apparent for obese adolescents and those with high levels of negative affect. In contrast, neither obesity nor negative affect was related to skin conductance responses to stress, implicating specifically noradrenergic mechanisms rather than sympathetic mechanisms generally as being deficient. Moreover, baseline heart rate was unrelated to obesity in this sample, which suggests that heightened baseline of sympathetic activity is not necessary for the reduced cardiovascular reactivity to stress.

  4. Heart Rate Variability – a Tool to Differentiate Positive and Negative Affective States in Pigs?

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The causal neurophysiological processes, such as autonomic nervous system activity, that mediate behavioral and physiological reactivity to an environment have largely been ignored. Heart rate variability (HRV) analysis is a clinical diagnostic tool used to assess affective states (stressful and ple...

  5. Attachment Status Affects Heart Rate Responses to Experimental Ostracism in Inpatients with Depression

    PubMed Central

    De Rubeis, Jannika; Sütterlin, Stefan; Lange, Diane; Pawelzik, Markus; van Randenborgh, Annette; Victor, Daniela; Vögele, Claus

    2016-01-01

    Depression is assumed to be both a risk factor for rejection and a result of it, and as such constitutes an important factor in rejection research. Attachment theory has been applied to understand psychological disorders, such as depression, and can explain individual differences in responses to rejection. Research on autonomic nervous system activity to rejection experiences has been contradictory, with opposing strings of argumentation (activating vs. numbing). We investigated autonomic nervous system-mediated peripheral physiological responses (heart rate) to experimentally manipulated ostracism (Cyberball) in 97 depressed patients with organized (n = 52) and disorganized attachment status (n = 45). Controlling for baseline mean heart rate levels, depressed patients with disorganized attachment status responded to ostracism with significantly higher increases in heart rate than depressed patients with organized attachment status (p = .029; ηp2 = .051). These results suggest that attachment status may be a useful indicator of autonomic responses to perceived social threat, which in turn may affect the therapeutic process and the patient-therapist relationship. PMID:26943924

  6. Attachment Status Affects Heart Rate Responses to Experimental Ostracism in Inpatients with Depression.

    PubMed

    De Rubeis, Jannika; Sütterlin, Stefan; Lange, Diane; Pawelzik, Markus; van Randenborgh, Annette; Victor, Daniela; Vögele, Claus

    2016-01-01

    Depression is assumed to be both a risk factor for rejection and a result of it, and as such constitutes an important factor in rejection research. Attachment theory has been applied to understand psychological disorders, such as depression, and can explain individual differences in responses to rejection. Research on autonomic nervous system activity to rejection experiences has been contradictory, with opposing strings of argumentation (activating vs. numbing). We investigated autonomic nervous system-mediated peripheral physiological responses (heart rate) to experimentally manipulated ostracism (Cyberball) in 97 depressed patients with organized (n = 52) and disorganized attachment status (n = 45). Controlling for baseline mean heart rate levels, depressed patients with disorganized attachment status responded to ostracism with significantly higher increases in heart rate than depressed patients with organized attachment status (p = .029; ηp2 = .051). These results suggest that attachment status may be a useful indicator of autonomic responses to perceived social threat, which in turn may affect the therapeutic process and the patient-therapist relationship.

  7. Attachment Status Affects Heart Rate Responses to Experimental Ostracism in Inpatients with Depression.

    PubMed

    De Rubeis, Jannika; Sütterlin, Stefan; Lange, Diane; Pawelzik, Markus; van Randenborgh, Annette; Victor, Daniela; Vögele, Claus

    2016-01-01

    Depression is assumed to be both a risk factor for rejection and a result of it, and as such constitutes an important factor in rejection research. Attachment theory has been applied to understand psychological disorders, such as depression, and can explain individual differences in responses to rejection. Research on autonomic nervous system activity to rejection experiences has been contradictory, with opposing strings of argumentation (activating vs. numbing). We investigated autonomic nervous system-mediated peripheral physiological responses (heart rate) to experimentally manipulated ostracism (Cyberball) in 97 depressed patients with organized (n = 52) and disorganized attachment status (n = 45). Controlling for baseline mean heart rate levels, depressed patients with disorganized attachment status responded to ostracism with significantly higher increases in heart rate than depressed patients with organized attachment status (p = .029; ηp2 = .051). These results suggest that attachment status may be a useful indicator of autonomic responses to perceived social threat, which in turn may affect the therapeutic process and the patient-therapist relationship. PMID:26943924

  8. Muscular contraction mode differently affects autonomic control during heart rate matched exercise.

    PubMed

    Weippert, Matthias; Behrens, Martin; Gonschorek, Ray; Bruhn, Sven; Behrens, Kristin

    2015-01-01

    The precise contributions of afferent feedback to cardiovascular and respiratory responses to exercise are still unclear. The aim of this crossover study was to assess whether and how autonomic cardiovascular and respiratory control differed in response to dynamic (DYN) and isometric contractions (ISO) at a similar, low heart rate (HR) level. Therefore, 22 healthy males (26.7 ± 3.6 yrs) performed two kinds of voluntary exercises at similar HR: ISO and DYN of the right quadriceps femoris muscle. Although HR was eqivalent (82 ± 8 bpm for DYN and ISO, respectively), rating of exertion, blood pressures, and rate pressure product were higher, whereas breathing frequency, minute ventilation, oxygen uptake and carbon dioxide output were significantly lower during ISO. Tidal volume, end-tidal partial pressures of O2 and CO2, respiratory exchange ratio and capillary blood lactate concentration were comparable between both contraction modes. Heart rate variability (HRV) indicators, SDNN, HF-Power and LF-Power, representing both vagal and sympathetic influences, were significantly higher during ISO. Sample entropy, a non-linear measure of HRV was also significantly affected by contraction mode. It can be concluded that, despite the same net effect on HR, the quality of cardiovascular control during low intensity exercise is significantly different between DYN and ISO. HRV analysis indicated a sympatho-vagal coactivation during ISO. Whether mechanoreceptor feedback alone, a change in central command, or the interaction of both mechanisms is the main contributor of the distinct autonomic responses to the different exercise modes remains to be elucidated.

  9. Ablation of swallowing-induced atrial tachycardia affects heart rate variability: a case report.

    PubMed

    Hojo, Rintaro; Fukamizu, Seiji; Ishikawa, Tae; Hayashi, Takekuni; Komiyama, Kota; Tanabe, Yasuhiro; Tejima, Tamotsu; Kobayashi, Yoichi; Sakurada, Harumizu

    2014-05-01

    A 47-year-old man underwent slow pathway ablation for slow-fast atrioventricular nodal reentrant tachycardia. Following the procedure, he felt palpitations while swallowing, and swallowing-induced atrial tachycardia was diagnosed. Swallowing-induced atrial tachycardia arose from the right atrium-superior vena cava junction and was cured by catheter ablation. After the procedure, the patient's heart rate variability changed significantly, indicating suppression of parasympathetic nerve activity. In this case, swallowing-induced atrial tachycardia was related to the vagal nerve reflex. Analysis of heart rate variability may be helpful in elucidating the mechanism of swallowing-induced atrial tachycardia.

  10. The Use of Heart Rate Variability as a Novel Method to Differentiate between Affective States

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The major goal of animal welfare scientists is to determine when animals are experiencing a state of good welfare or poor welfare. The goal of this research was to determine if measures of heart rate variability can be used to differentiate whether animals are experiencing ‘unpleasant’ versus ‘pleas...

  11. Do Bells Affect Behaviour and Heart Rate Variability in Grazing Dairy Cows?

    PubMed Central

    Johns, Julia; Patt, Antonia; Hillmann, Edna

    2015-01-01

    In alpine regions cows are often equipped with bells. The present study investigated the impact of wearing a bell on behaviour and heart rate variability in dairy cows. Nineteen non-lactating Brown-Swiss cows with bell experience were assigned to three different treatments. For 3 days each, cows were equipped with no bell (control), with a bell with inactivated clapper (silent bell) or with a functional bell (functional bell). The bells weighed 5.5 kg and had frequencies between 532 Hz and 2.8 kHz and amplitudes between 90 and 113 dB at a distance of 20 cm. Data were collected on either the first and third or on all 3 days of each treatment. Whereas duration of rumination was reduced with a functional bell and a silent bell compared with no bell, feeding duration was reduced with a silent bell and was intermediate with a functional bell. Head movements were reduced when wearing a silent bell compared with no bell and tended to be reduced when wearing a functional compared to no bell. With a functional bell, lying duration was reduced by almost 4 hours on the third day of treatment compared with the first day with a functional bell and compared with no bell or a silent bell. All additional behavioural measures are consistent with the hypothesis of a restriction in the behaviour of the cows wearing bells, although this pattern did not reach significance. There was no treatment effect on heart rate variability, suggesting that the bells did not affect vago-sympathetic balance. An effect of experimental day was found for only 1 out of 10 behavioural parameters, as shown by a decrease in lying with a functional bell on day 3. The results indicate behavioural changes in the cows wearing a bell over 3 days, without indication of habituation to the bell. Altogether, the behavioural changes suggest that the behaviour of the cows was disturbed by wearing a bell. If long-lasting, these effects may have implications for animal welfare. PMID:26110277

  12. Cybersickness provoked by head-mounted display affects cutaneous vascular tone, heart rate and reaction time.

    PubMed

    Nalivaiko, Eugene; Davis, Simon L; Blackmore, Karen L; Vakulin, Andrew; Nesbitt, Keith V

    2015-11-01

    Evidence from studies of provocative motion indicates that motion sickness is tightly linked to the disturbances of thermoregulation. The major aim of the current study was to determine whether provocative visual stimuli (immersion into the virtual reality simulating rides on a rollercoaster) affect skin temperature that reflects thermoregulatory cutaneous responses, and to test whether such stimuli alter cognitive functions. In 26 healthy young volunteers wearing head-mounted display (Oculus Rift), simulated rides consistently provoked vection and nausea, with a significant difference between the two versions of simulation software (Parrot Coaster and Helix). Basal finger temperature had bimodal distribution, with low-temperature group (n=8) having values of 23-29 °C, and high-temperature group (n=18) having values of 32-36 °C. Effects of cybersickness on finger temperature depended on the basal level of this variable: in subjects from former group it raised by 3-4 °C, while in most subjects from the latter group it either did not change or transiently reduced by 1.5-2 °C. There was no correlation between the magnitude of changes in the finger temperature and nausea score at the end of simulated ride. Provocative visual stimulation caused prolongation of simple reaction time by 20-50 ms; this increase closely correlated with the subjective rating of nausea. Lastly, in subjects who experienced pronounced nausea, heart rate was elevated. We conclude that cybersickness is associated with changes in cutaneous thermoregulatory vascular tone; this further supports the idea of a tight link between motion sickness and thermoregulation. Cybersickness-induced prolongation of reaction time raises obvious concerns regarding the safety of this technology. PMID:26340855

  13. Cybersickness provoked by head-mounted display affects cutaneous vascular tone, heart rate and reaction time.

    PubMed

    Nalivaiko, Eugene; Davis, Simon L; Blackmore, Karen L; Vakulin, Andrew; Nesbitt, Keith V

    2015-11-01

    Evidence from studies of provocative motion indicates that motion sickness is tightly linked to the disturbances of thermoregulation. The major aim of the current study was to determine whether provocative visual stimuli (immersion into the virtual reality simulating rides on a rollercoaster) affect skin temperature that reflects thermoregulatory cutaneous responses, and to test whether such stimuli alter cognitive functions. In 26 healthy young volunteers wearing head-mounted display (Oculus Rift), simulated rides consistently provoked vection and nausea, with a significant difference between the two versions of simulation software (Parrot Coaster and Helix). Basal finger temperature had bimodal distribution, with low-temperature group (n=8) having values of 23-29 °C, and high-temperature group (n=18) having values of 32-36 °C. Effects of cybersickness on finger temperature depended on the basal level of this variable: in subjects from former group it raised by 3-4 °C, while in most subjects from the latter group it either did not change or transiently reduced by 1.5-2 °C. There was no correlation between the magnitude of changes in the finger temperature and nausea score at the end of simulated ride. Provocative visual stimulation caused prolongation of simple reaction time by 20-50 ms; this increase closely correlated with the subjective rating of nausea. Lastly, in subjects who experienced pronounced nausea, heart rate was elevated. We conclude that cybersickness is associated with changes in cutaneous thermoregulatory vascular tone; this further supports the idea of a tight link between motion sickness and thermoregulation. Cybersickness-induced prolongation of reaction time raises obvious concerns regarding the safety of this technology.

  14. Effects of microgravity on interstitial muscle receptors affecting heart rate and blood pressure during static exercise.

    PubMed

    Essfeld, D; Baum, K; Hoffmann, U; Stegemann, J

    1993-09-01

    Afferent nerve fibers from receptors situated in the interstitium of skeletal muscles can induce cardiovascular reflexes. It has been shown that these interstitial muscle receptors are also sensitive to the local state of hydration: increased heart rates and blood pressure values were seen during dynamic and static exercise after local dehydration on earth. Since weightlessness leads to a persisting fluid loss in the lower part of the body, we hypothesized that leg exercise in space would augment heart rate and blood pressure responses to a similar extent as during local, interstitial dehydration on earth. Initial measurements during weightlessness were obtained in one subject after 6 days of space flight. Heart rate and blood pressure responses to light static foot plantar flexion (18% of maximal voluntary contraction) were recorded in two sessions. To eliminate the influence of muscle perfusion, exercise was performed during a period of arterial occlusion obtained by means of pneumatic cuffs at mid-thigh level. Identical protocols were used in the pre- and postflight controls, which were performed both in the sitting posture and in a -90 degrees tilted sitting posture assumed 30-40 min before arterial occlusion. During weightlessness the exercise responses of heart rate and systolic and diastolic blood pressure closely followed the tracings obtained with the tilted sitting posture on ground. The response amplitudes in these states of reduced lower limb volumes (about 20/min and 20 mmHg, respectively) exceeded the responses in the supine position by a factor of at least 2.(ABSTRACT TRUNCATED AT 250 WORDS)

  15. Target Heart Rate Calculator

    MedlinePlus

    ... My Saved Articles » My ACS » + - Text Size Target Heart Rate Calculator Compute your best workout Enter your age ... is your age? years. How to Check Your Heart Rate Right after you stop exercising, take your pulse: ...

  16. Changes in extracellular muscle volume affect heart rate and blood pressure responses to static exercise

    NASA Astrophysics Data System (ADS)

    Baum, K.; Essfeld, D.; Stegemann, J.

    To investigate the effect of μg-induced peripheral extracellular fluid reductions on heart rate and blood pressure during isometric exercise, six healthy male subjects performed three calf ergometer test with different extracellular volumes of working muscles. In all tests, body positions during exercise were identical (supine with the knee joint flexed to 900). After a pre-exercise period of 25 min, during which calf volumes were manipulated, subjects had to counteract an external force of 180 N for 5 min. During the pre-exercise period three different protocols were applied. Test A: Subjects rested in the exercise position; test B: Body position was the same as in A but calf volume was increased by venous congestion (cuffs inflated to 80 mm Hg); test C: Calf volumes were decreased by a negative hydrostatic pressure (calves about 40 cm above heart level with the subjects supine). To clamp the changed calf volumes in tests B and C, cuffs were inflated to 300 mm Hg 5 min before the onset of exercise. This occlusion was maintained until termination of exercise. Compared to tests A and B, the reduced volume of test C led to significant increases in heart rate and blood pressure during exercise. Oxygen uptake did not exceed resting levels in B and C until cuffs were deflated, indicating that exclusively calf muscles contributed to the neurogenic peripheral drive. It is concluded that changes in extracellular muscle volume have to be taken into account when comparing heart rate and blood pressure during lg- and μg- exercise.

  17. Heart Rate Monitors

    NASA Technical Reports Server (NTRS)

    1990-01-01

    Under a NASA grant, Dr. Robert M. Davis and Dr. William M. Portnoy came up with a new type of electrocardiographic electrode that would enable long term use on astronauts. Their invention was an insulated capacitive electrode constructed of a thin dielectric film. NASA subsequently licensed the electrode technology to Richard Charnitski, inventor of the VersaClimber, who founded Heart Rate, Inc., to further develop and manufacture personal heart monitors and to produce exercise machines using the technology for the physical fitness, medical and home markets. Same technology is on both the Home and Institutional Model VersaClimbers. On the Home Model an infrared heart beat transmitter is worn under exercise clothing. Transmitted heart rate is used to control the work intensity on the VersaClimber using the heart rate as the speedometer of the exercise. This offers advantages to a full range of users from the cardiac rehab patient to the high level physical conditioning of elite athletes. The company manufactures and markets five models of the 1*2*3 HEART RATE monitors that are used wherever people exercise to accurately monitor their heart rate. Company is developing a talking heart rate monitor that works with portable headset radios. A version of the heart beat transmitter will be available to the manufacturers of other aerobic exercise machines.

  18. Combined non-adaptive light and smell stimuli lowered blood pressure, reduced heart rate and reduced negative affect.

    PubMed

    Dong, Shan; Jacob, Tim J C

    2016-03-15

    Bright light therapy has been shown to have a positive impact on seasonal affective disorder (SAD), depression and anxiety. Smell has also has been shown to have effects on mood, stress, anxiety and depression. The objective of this study was to investigate the effect of the combination of light and smell in a non-adaptive cycle. Human subjects were given smell (lemon, lavender or peppermint) and light stimuli in a triangular wave (60scycle) for 15min. Blood pressure and heart rate were monitored before and after each session for 5 consecutive days and a Profile of Mood States (POMS) test was administered before and after the sensory stimulation on days 1, 3 and 5. The light-smell stimulus lowered blood pressure, both systolic and diastolic, and reduced heart rate for all odours compared to control. Of the two sensory stimuli, the odour stimulus contributed most to this effect. The different aromas in the light-smell combinations could be distinguished by their different effects on the mood factors with lemon inducing the greatest mood changes in Dejection-Depression, Anger-Hostility, Tension-Anxiety. In conclusion, combined light and smell stimulation was effective in lowering blood pressure, reducing heart rate and improving mood. The combination was more effective than either smell or light stimuli alone, suggesting that a light-smell combination would be a more robust and efficacious alternative treatment for depression, anxiety and stress. PMID:26780148

  19. Combined non-adaptive light and smell stimuli lowered blood pressure, reduced heart rate and reduced negative affect.

    PubMed

    Dong, Shan; Jacob, Tim J C

    2016-03-15

    Bright light therapy has been shown to have a positive impact on seasonal affective disorder (SAD), depression and anxiety. Smell has also has been shown to have effects on mood, stress, anxiety and depression. The objective of this study was to investigate the effect of the combination of light and smell in a non-adaptive cycle. Human subjects were given smell (lemon, lavender or peppermint) and light stimuli in a triangular wave (60scycle) for 15min. Blood pressure and heart rate were monitored before and after each session for 5 consecutive days and a Profile of Mood States (POMS) test was administered before and after the sensory stimulation on days 1, 3 and 5. The light-smell stimulus lowered blood pressure, both systolic and diastolic, and reduced heart rate for all odours compared to control. Of the two sensory stimuli, the odour stimulus contributed most to this effect. The different aromas in the light-smell combinations could be distinguished by their different effects on the mood factors with lemon inducing the greatest mood changes in Dejection-Depression, Anger-Hostility, Tension-Anxiety. In conclusion, combined light and smell stimulation was effective in lowering blood pressure, reducing heart rate and improving mood. The combination was more effective than either smell or light stimuli alone, suggesting that a light-smell combination would be a more robust and efficacious alternative treatment for depression, anxiety and stress.

  20. Posture and Gender Differentially Affect Heart Rate Variability of Symptomatic Mitral Valve Prolapse and Normal Adults

    PubMed Central

    Chang, Chien-Jung; Chen, Ya-Chu; Lee, Chih-Hsien; Yang, Ing-Fang; Yang, Ten-Fang

    2016-01-01

    Background Heart rate variability (HRV) has been shown to be a useful measure of autonomic activity in healthy and mitral valve prolapsed (MVP) subjects. However, the effects of posture and gender on HRV in symptomatic MVP and normal adults had not been elucidated in Taiwan. Methods A total of 118 MVP patients (7 males, 39 ± 7 years old; and 111 females, 42 ± 13 years old) and 148 healthy control (54 males, 28 ± 4 years old; and 94 females, 26 ± 6 years old) were investigated. The diagnosis of MVP was confirmed by cross-sectional echocardiography. A locally developed Taiwanese machine was used to record the HRV parameters for MVP and control groups in three stationary positions. Thereafter, the HRV time-domain parameters, and the frequency-domain parameters derived from fast Fourier transform or autoregressive methods were analyzed. Results The MVP group showed a decrease in time domain parameters and obtunded postural effects on frequency domain parameters moreso than the control group. Though the parasympathetic tone was dominant in female (higher RMSSD, nHF and lower nLF vs. male), the sympathetic outflow was higher in MVP female (lower SDNN, NN50 and higher nLF vs. normal female). While the parasympathetic activity was lower in male, sympathetic outflow was dominant in MVP male (lower nHF and higher nLF vs. normal male). Conclusions Both MVP female and male subjects had elevated levels of sympathetic outflow. The obtunded postural effects on frequency domain measures testified to the autonomic dysregulation of MVP subjects. PMID:27471360

  1. Heart rate turbulence.

    PubMed

    Cygankiewicz, Iwona

    2013-01-01

    Heart rate turbulence (HRT) is a baroreflex-mediated biphasic reaction of heart rate in response to premature ventricular beats. Heart rate turbulence is quantified by: turbulence onset (TO) reflecting the initial acceleration of heart rate following premature beat and turbulence slope (TS) describing subsequent deceleration of heart rate. Abnormal HRT identifies patients with autonomic dysfunction or impaired baroreflex sensitivity due to variety of disorders, but also may reflect changes in autonomic nervous system induced by different therapeutic modalities such as drugs, revascularization, or cardiac resynchronization therapy. More importantly, impaired HRT has been shown to identify patients at high risk of all-cause mortality and sudden death, particularly in postinfarction and congestive heart failure patients. It should be emphasized that abnormal HRT has a well-established role in stratification of postinfarction and heart failure patients with relatively preserved left ventricular ejection fraction. The ongoing clinical trials will document whether HRT can be used to guide implantation of cardioverter-defibrillators in this subset of patients, not covered yet by ICD guidelines. This review focuses on the current state-of-the-art knowledge regarding clinical significance of HRT in detection of autonomic dysfunction and regarding the prognostic significance of this parameter in predicting all-cause mortality and sudden death.

  2. Heart rate turbulence.

    PubMed

    Cygankiewicz, Iwona

    2013-01-01

    Heart rate turbulence (HRT) is a baroreflex-mediated biphasic reaction of heart rate in response to premature ventricular beats. Heart rate turbulence is quantified by: turbulence onset (TO) reflecting the initial acceleration of heart rate following premature beat and turbulence slope (TS) describing subsequent deceleration of heart rate. Abnormal HRT identifies patients with autonomic dysfunction or impaired baroreflex sensitivity due to variety of disorders, but also may reflect changes in autonomic nervous system induced by different therapeutic modalities such as drugs, revascularization, or cardiac resynchronization therapy. More importantly, impaired HRT has been shown to identify patients at high risk of all-cause mortality and sudden death, particularly in postinfarction and congestive heart failure patients. It should be emphasized that abnormal HRT has a well-established role in stratification of postinfarction and heart failure patients with relatively preserved left ventricular ejection fraction. The ongoing clinical trials will document whether HRT can be used to guide implantation of cardioverter-defibrillators in this subset of patients, not covered yet by ICD guidelines. This review focuses on the current state-of-the-art knowledge regarding clinical significance of HRT in detection of autonomic dysfunction and regarding the prognostic significance of this parameter in predicting all-cause mortality and sudden death. PMID:24215748

  3. Heart Rate Monitor

    NASA Technical Reports Server (NTRS)

    1984-01-01

    In the mid 70's, NASA saw a need for a long term electrocardiographic electrode suitable for use on astronauts. Heart Rate Inc.'s insulated capacitive electrode is constructed of thin dielectric film applied to stainless steel surface, originally developed under a grant by Texas Technical University. HRI, Inc. was awarded NASA license and continued development of heart rate monitor for use on exercise machines for physical fitness and medical markets.

  4. Modelling heart rate kinetics.

    PubMed

    Zakynthinaki, Maria S

    2015-01-01

    The objective of the present study was to formulate a simple and at the same time effective mathematical model of heart rate kinetics in response to movement (exercise). Based on an existing model, a system of two coupled differential equations which give the rate of change of heart rate and the rate of change of exercise intensity is used. The modifications introduced to the existing model are justified and discussed in detail, while models of blood lactate accumulation in respect to time and exercise intensity are also presented. The main modification is that the proposed model has now only one parameter which reflects the overall cardiovascular condition of the individual. The time elapsed after the beginning of the exercise, the intensity of the exercise, as well as blood lactate are also taken into account. Application of the model provides information regarding the individual's cardiovascular condition and is able to detect possible changes in it, across the data recording periods. To demonstrate examples of successful numerical fit of the model, constant intensity experimental heart rate data sets of two individuals have been selected and numerical optimization was implemented. In addition, numerical simulations provided predictions for various exercise intensities and various cardiovascular condition levels. The proposed model can serve as a powerful tool for a complete means of heart rate analysis, not only in exercise physiology (for efficiently designing training sessions for healthy subjects) but also in the areas of cardiovascular health and rehabilitation (including application in population groups for which direct heart rate recordings at intense exercises are not possible or not allowed, such as elderly or pregnant women).

  5. Modelling Heart Rate Kinetics

    PubMed Central

    Zakynthinaki, Maria S.

    2015-01-01

    The objective of the present study was to formulate a simple and at the same time effective mathematical model of heart rate kinetics in response to movement (exercise). Based on an existing model, a system of two coupled differential equations which give the rate of change of heart rate and the rate of change of exercise intensity is used. The modifications introduced to the existing model are justified and discussed in detail, while models of blood lactate accumulation in respect to time and exercise intensity are also presented. The main modification is that the proposed model has now only one parameter which reflects the overall cardiovascular condition of the individual. The time elapsed after the beginning of the exercise, the intensity of the exercise, as well as blood lactate are also taken into account. Application of the model provides information regarding the individual’s cardiovascular condition and is able to detect possible changes in it, across the data recording periods. To demonstrate examples of successful numerical fit of the model, constant intensity experimental heart rate data sets of two individuals have been selected and numerical optimization was implemented. In addition, numerical simulations provided predictions for various exercise intensities and various cardiovascular condition levels. The proposed model can serve as a powerful tool for a complete means of heart rate analysis, not only in exercise physiology (for efficiently designing training sessions for healthy subjects) but also in the areas of cardiovascular health and rehabilitation (including application in population groups for which direct heart rate recordings at intense exercises are not possible or not allowed, such as elderly or pregnant women). PMID:25876164

  6. Heart rate variability in isolated rabbit hearts.

    PubMed

    Frey, B; Heger, G; Mayer, C; Kiegler, B; Stöhr, H; Steurer, G

    1996-11-01

    The presence of heart rate variability (HRV) in patients with cardiac denervation after heart transplantation raised our interest in HRV of isolated, denervated hearts. Hearts from seven adult white ELCO rabbits were transferred to a perfusion apparatus. All hearts were perfused in the working mode and in the Langendorff mode for 20 minutes each. HRV was analyzed in the frequency domain. A computer simulated test ECG at a constant rate of 2 Hz was used for error estimation of the system. In the isolated, denervated heart, HRV was of random, broadband fluctuations, different from the well-characterized oscillations at specific frequencies in intact animals. Mean NN was 423 +/- 51 ms in the Langendorff mode, 406 +/- 33 ms in the working heart mode, and 500 ms in the test ECG. Total power was 663 +/- 207 ms2, 817 +/- 318 ms2, and 3.7 ms2, respectively. There was no significant difference in any measure of HRV between Langendorff and working heart modes. The data provide evidence for the presence of HRV in isolated, denervated rabbit hearts. Left atrial and ventricular filling, i.e., the working heart mode, did not alter HRV, indicating that left atrial or ventricular stretch did not influence the sinus nodal discharge rate.

  7. Using time-series intervention analysis to model cow heart rate affected by programmed audio and environmental/physiological

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This research is the first use of the Box-Jenkins time-series models to describe changes in heart rate (HR) of free-ranging crossbred cows (Bos taurus) receiving both programmed audio cues from directional virtual fencing (DVFTM) devices and non-programmed environmental/physiological cues. The DVFT...

  8. Using time-series intervention analysis to model cow heart rate affected by programmed audio and environmental/physiological cues

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This research is the first use of the Box-Jenkins time-series models to describe changes in heart rate (HR) of free-ranging crossbred cows (Bos taurus) receiving both programmed audio cues from directional virtual fencing (DVFTM) devices and non-programmed environmental/physiological cues. The DVFT...

  9. All about Heart Rate (Pulse)

    MedlinePlus

    ... Pressure High Blood Pressure Tools & Resources Stroke More All About Heart Rate (Pulse) Updated:Apr 19,2016 ... Sodium and Salt 3 Low Blood Pressure 4 All About Heart Rate (Pulse) 5 How to Eat ...

  10. Equestrian expertise affecting physical fitness, body compositions, lactate, heart rate and calorie consumption of elite horse riding players

    PubMed Central

    Sung, Bong-Ju; Jeon, Sang-Yong; Lim, Sung-Ro; Lee, Kyu-Eon; Jee, Hyunseok

    2015-01-01

    Horse riding (HR) is a sport harmonized with rider and horse. HR is renowned as an effective sport for young and old women and men. There is rare study regarding comparison between elite horse riders and amateurs. We aimed to investigate comprehensive ranges of parameters such as change of lactate, heart rate, calorie, VO2max, skeletal muscle mass, body water, body fat, etc between amateurs and professionals to emphasize HR not only as a sport training but also as a therapeutic aspect. We performed 3 experiments for comparing physical fitness, body compositions, lactate value, heart rate and calorie consumption change before and after riding between amateurs and elites. Around 3 yr riding experienced elites are preeminent at balance capability compared to 1 yr riding experienced amateurs. During 18 min horse riding, skeletal muscle mass and body fat were interestingly increased and decreased, respectively. Lactate response was more sensitive in elites rather than amateurs and its recovery was reversely reacted. Exercise intensity estimated from heart rate was significantly higher in elites (P<0.05). The similar pattern of calorie consumption during riding between amateurs and elites was shown. Horse riding possibly induces various physiological (muscle strength, balance, oxidative capability, flexibility, and metabolic control) changes within body and is thus highly recommended as combined exercise for women, children, and aged as therapeutic and leisure sport activity. PMID:26171385

  11. Time of day affects heart rate recovery and variability after maximal exercise in pre-hypertensive men.

    PubMed

    Brito, Leandro; Peçanha, Tiago; Tinucci, Taís; Silva-Junior, Natan; Costa, Luiz; Forjaz, Claudia

    2015-01-01

    Heart rate (HR) recovery (HRR) and variability (HRV) after exercise are non-invasive tools used to assess cardiac autonomic regulation and cardiovascular prognosis. Autonomic recovery is slower after evening than morning exercise in healthy individuals, but this influence is unknown in subjects with autonomic dysfunction, although it may affect prognostic evaluation. This study compared post-exercise HRR and HRV after maximal morning and evening exercise in pre-hypertensive men. Ten volunteers randomly underwent two maximal exercise tests conducted in the morning (8-10 a.m.) and evening (6-8 p.m.). HRR60s (HR reduction at 60 s of recovery - prognostic index), T30 (short-term time-constant of HRR - parasympathetic reactivation marker), rMSSD30s (square root of the mean of the sum of the squares of differences between adjacent R-R intervals on subsequent 30 s segments - parasympathetic reactivation marker), and HRRτ (time constant of the first order exponential fitting of HRR - marker of sympathetic withdraw and parasympathetic reactivation) were measured. Paired t-test and two-way ANOVA were used. HRR60s and HRRτ were similar after exercise in the morning and evening (27 ± 7 vs. 29 ± 7 bpm, p = 0.111, and 79 ± 14 vs. 96 ± 29 s, p = 0.119, respectively). T30 was significantly greater after evening exercise (405 ± 215 vs. 295 ± 119 s, p = 0.002) and rMSSD30s was lower in the evening (main factor session, p = 0.009). In conclusion, in pre-hypertensive men, the prognostic index of HRR, HRR60s, is not affected by the time of day when exercise is conducted. However, post-exercise parasympathetic reactivation, evaluated by T30 and rMSSD30s, is blunted after evening exercise. PMID:26588261

  12. Heart rate, body temperature and physical activity are variously affected during insulin treatment in alloxan-induced type 1 diabetic rat.

    PubMed

    Howarth, F C; Jacobson, M; Shafiullah, M; Ljubisavljevic, M; Adeghate, E

    2011-01-01

    Diabetes mellitus is associated with a variety of cardiovascular complications including impaired cardiac muscle function. The effects of insulin treatment on heart rate, body temperature and physical activity in the alloxan (ALX)-induced diabetic rat were investigated using in vivo biotelemetry techniques. The electrocardiogram, physical activity and body temperature were recorded in vivo with a biotelemetry system for 10 days before ALX treatment, for 20 days following administration of ALX (120 mg/kg) and thereafter, for 15 days whilst rats received daily insulin. Heart rate declined rapidly after administration of ALX. Pre-ALX heart rate was 321+/-9 beats per minute, falling to 285+/-12 beats per minute 15-20 days after ALX and recovering to 331+/-10 beats per minute 5-10 days after commencement of insulin. Heart rate variability declined and PQ, QRS and QT intervals were prolonged after administration of ALX. Physical activity and body temperature declined after administration of ALX. Pre-ALX body temperature was 37.6+/-0.1 °C, falling to 37.3+/-0.1 °C 15-20 days after ALX and recovering to 37.8+/-0.1 °C 5-10 days after commencement insulin. ALX-induced diabetes is associated with disturbances in heart rhythm, physical activity and body temperature that are variously affected during insulin treatment.

  13. Tachycardia | Fast Heart Rate

    MedlinePlus

    ... Prevention & Treatment of High Blood Pressure High Blood Pressure Tools & Resources ... signals in the heart's upper chambers fire abnormally, which interferes with electrical signals coming from ...

  14. Target Heart Rates

    MedlinePlus

    ... a Healthy Heart Healthy Kids Our Kids Programs Childhood Obesity What is childhood obesity? Overweight in Children BMI in Children Is Childhood Obesity an Issue in Your Home? Addressing your Child's ...

  15. Heart Rate, Life Expectancy and the Cardiovascular System: Therapeutic Considerations.

    PubMed

    Boudoulas, Konstantinos Dean; Borer, Jeffrey S; Boudoulas, Harisios

    2015-01-01

    It has long been known that life span is inversely related to resting heart rate in most organisms. This association between heart rate and survival has been attributed to the metabolic rate, which is greater in smaller animals and is directly associated with heart rate. Studies have shown that heart rate is related to survival in apparently healthy individuals and in patients with different underlying cardiovascular diseases. A decrease in heart rate due to therapeutic interventions may result in an increase in survival. However, there are many factors regulating heart rate, and it is quite plausible that these may independently affect life expectancy. Nonetheless, a fast heart rate itself affects the cardiovascular system in multiple ways (it increases ventricular work, myocardial oxygen consumption, endothelial stress, aortic/arterial stiffness, decreases myocardial oxygen supply, other) which, in turn, may affect survival. In this brief review, the effects of heart rate on the heart, arterial system and survival will be discussed.

  16. Loss of the AE3 Cl−/HCO−3 exchanger in mice affects rate-dependent inotropy and stress-related AKT signaling in heart

    PubMed Central

    Prasad, Vikram; Lorenz, John N.; Lasko, Valerie M.; Nieman, Michelle L.; Al Moamen, Nabeel J.; Shull, Gary E.

    2013-01-01

    Cl−/HCO−3 exchangers are expressed abundantly in cardiac muscle, suggesting that HCO−3 extrusion serves an important function in heart. Mice lacking Anion Exchanger Isoform 3 (AE3), a major cardiac Cl−/HCO−3 exchanger, appear healthy, but loss of AE3 causes decompensation in a hypertrophic cardiomyopathy (HCM) model. Using intra-ventricular pressure analysis, in vivo pacing, and molecular studies we identified physiological and biochemical changes caused by loss of AE3 that may contribute to decompensation in HCM. AE3-null mice had normal cardiac contractility under basal conditions and after β-adrenergic stimulation, but pacing of hearts revealed that frequency-dependent inotropy was blunted, suggesting that AE3-mediated HCO−3 extrusion is required for a robust force-frequency response (FFR) during acute biomechanical stress in vivo. Modest changes in expression of proteins that affect Ca2+-handling were observed, but Ca2+-transient analysis of AE3-null myocytes showed normal twitch-amplitude and Ca2+-clearance. Phosphorylation and expression of several proteins implicated in HCM and FFR, including phospholamban (PLN), myosin binding protein C, and troponin I were not altered in hearts of paced AE3-null mice; however, phosphorylation of Akt, which plays a central role in mechanosensory signaling, was significantly higher in paced AE3-null hearts than in wild-type controls and phosphorylation of AMPK, which is affected by Akt and is involved in energy metabolism and some cases of HCM, was reduced. These data show loss of AE3 leads to impaired rate-dependent inotropy, appears to affect mechanical stress-responsive signaling, and reduces activation of AMPK, which may contribute to decompensation in heart failure. PMID:24427143

  17. Modality of fear cues affects acoustic startle potentiation but not heart-rate response in patients with dental phobia.

    PubMed

    Wannemüller, André; Sartory, Gudrun; Elsesser, Karin; Lohrmann, Thomas; Jöhren, Hans P

    2015-01-01

    The acoustic startle response (SR) has consistently been shown to be enhanced by fear-arousing cross-modal background stimuli in phobics. Intra-modal fear-potentiation of acoustic SR was rarely investigated and generated inconsistent results. The present study compared the acoustic SR to phobia-related sounds with that to phobia-related pictures in 104 dental phobic patients and 22 controls. Acoustic background stimuli were dental treatment noises and birdsong and visual stimuli were dental treatment and neutral control pictures. Background stimuli were presented for 4 s, randomly followed by the administration of the startle stimulus. In addition to SR, heart-rate (HR) was recorded throughout the trials. Irrespective of their content, background pictures elicited greater SR than noises in both groups with a trend for phobic participants to show startle potentiation to phobia-related pictures but not noises. Unlike controls, phobics showed HR acceleration to both dental pictures and noises. HR acceleration of the phobia group was significantly positively correlated with SR in the noise condition only. The acoustic SR to phobia-related noises is likely to be inhibited by prolonged sensorimotor gating.

  18. Modality of fear cues affects acoustic startle potentiation but not heart-rate response in patients with dental phobia

    PubMed Central

    Wannemüller, André; Sartory, Gudrun; Elsesser, Karin; Lohrmann, Thomas; Jöhren, Hans P.

    2015-01-01

    The acoustic startle response (SR) has consistently been shown to be enhanced by fear-arousing cross-modal background stimuli in phobics. Intra-modal fear-potentiation of acoustic SR was rarely investigated and generated inconsistent results. The present study compared the acoustic SR to phobia-related sounds with that to phobia-related pictures in 104 dental phobic patients and 22 controls. Acoustic background stimuli were dental treatment noises and birdsong and visual stimuli were dental treatment and neutral control pictures. Background stimuli were presented for 4 s, randomly followed by the administration of the startle stimulus. In addition to SR, heart-rate (HR) was recorded throughout the trials. Irrespective of their content, background pictures elicited greater SR than noises in both groups with a trend for phobic participants to show startle potentiation to phobia-related pictures but not noises. Unlike controls, phobics showed HR acceleration to both dental pictures and noises. HR acceleration of the phobia group was significantly positively correlated with SR in the noise condition only. The acoustic SR to phobia-related noises is likely to be inhibited by prolonged sensorimotor gating. PMID:25774142

  19. Blood Pressure vs. Heart Rate

    MedlinePlus

    ... High Blood Pressure Tools & Resources Stroke More Blood Pressure vs. Heart Rate Updated:Aug 30,2016 Blood ... last reviewed on 08/04/2014. High Blood Pressure • Home • About High Blood Pressure (HBP) Introduction What ...

  20. Dimensional analysis of heart rate variability in heart transplant recipients

    SciTech Connect

    Zbilut, J.P.; Mayer-Kress, G.; Geist, K.

    1987-01-01

    We discuss periodicities in the heart rate in normal and transplanted hearts. We then consider the possibility of dimensional analysis of these periodicities in transplanted hearts and problems associated with the record.

  1. Heart Rate Sensor for Freshwater Mussels

    NASA Astrophysics Data System (ADS)

    Just, C. L.; Vial, D. P.; Kruger, A.; Niemeier, J. J.; Lee, H. W.; Schroer, H. W.

    2014-12-01

    Researchers have long been interested the cardiac activity of mollusks. First, it is important as a basic measure of the animal's metabolism. Further, activities such as feeding and burrowing affect heart rate, as do environmental factors such as water salinity, water temperature, exposure, and predation. We have developed a small, noninvasive sensor for measuring freshwater mussel heart rate. Its working principle is as follows. An infrared (IR) light-emitting diode is placed in contact with the mussel shell. Some of the IR penetrates through the shell, reflects off internal organs, and traverses back. A photodetector detects this IR, and electronics condition the signal. The heartbeat of the animal modulates the IR, allowing one to measure the heart rate. The technique is widely-used in finger heart-rate monitors in humans. The sensors do not have to be positioned above the heart and several locations on the mussel shell work well. The sensor is small (8 mm × 10 mm) and consumes less than 1 mA, and has a simple one-wire interface that allows for easy integration into data acquisition hardware. We present heart rate measurements for the common pocketbook (lampsilis cardium) freshwater mussel.

  2. The mitochondrial uniporter controls fight or flight heart rate increases.

    PubMed

    Wu, Yuejin; Rasmussen, Tyler P; Koval, Olha M; Joiner, Mei-Ling A; Hall, Duane D; Chen, Biyi; Luczak, Elizabeth D; Wang, Qiongling; Rokita, Adam G; Wehrens, Xander H T; Song, Long-Sheng; Anderson, Mark E

    2015-01-01

    Heart rate increases are a fundamental adaptation to physiological stress, while inappropriate heart rate increases are resistant to current therapies. However, the metabolic mechanisms driving heart rate acceleration in cardiac pacemaker cells remain incompletely understood. The mitochondrial calcium uniporter (MCU) facilitates calcium entry into the mitochondrial matrix to stimulate metabolism. We developed mice with myocardial MCU inhibition by transgenic expression of a dominant-negative (DN) MCU. Here, we show that DN-MCU mice had normal resting heart rates but were incapable of physiological fight or flight heart rate acceleration. We found that MCU function was essential for rapidly increasing mitochondrial calcium in pacemaker cells and that MCU-enhanced oxidative phoshorylation was required to accelerate reloading of an intracellular calcium compartment before each heartbeat. Our findings show that MCU is necessary for complete physiological heart rate acceleration and suggest that MCU inhibition could reduce inappropriate heart rate increases without affecting resting heart rate. PMID:25603276

  3. The mitochondrial uniporter controls fight or flight heart rate increases.

    PubMed

    Wu, Yuejin; Rasmussen, Tyler P; Koval, Olha M; Joiner, Mei-Ling A; Hall, Duane D; Chen, Biyi; Luczak, Elizabeth D; Wang, Qiongling; Rokita, Adam G; Wehrens, Xander H T; Song, Long-Sheng; Anderson, Mark E

    2015-01-20

    Heart rate increases are a fundamental adaptation to physiological stress, while inappropriate heart rate increases are resistant to current therapies. However, the metabolic mechanisms driving heart rate acceleration in cardiac pacemaker cells remain incompletely understood. The mitochondrial calcium uniporter (MCU) facilitates calcium entry into the mitochondrial matrix to stimulate metabolism. We developed mice with myocardial MCU inhibition by transgenic expression of a dominant-negative (DN) MCU. Here, we show that DN-MCU mice had normal resting heart rates but were incapable of physiological fight or flight heart rate acceleration. We found that MCU function was essential for rapidly increasing mitochondrial calcium in pacemaker cells and that MCU-enhanced oxidative phoshorylation was required to accelerate reloading of an intracellular calcium compartment before each heartbeat. Our findings show that MCU is necessary for complete physiological heart rate acceleration and suggest that MCU inhibition could reduce inappropriate heart rate increases without affecting resting heart rate.

  4. Heart Rate and Respiratory Rate Influence on Heart Rate Variability Repeatability: Effects of the Correction for the Prevailing Heart Rate

    PubMed Central

    Gąsior, Jakub S.; Sacha, Jerzy; Jeleń, Piotr J.; Zieliński, Jakub; Przybylski, Jacek

    2016-01-01

    Background: Since heart rate variability (HRV) is associated with average heart rate (HR) and respiratory rate (RespRate), alterations in these parameters may impose changes in HRV. Hence the repeatability of HRV measurements may be affected by differences in HR and RespRate. The study aimed to evaluate HRV repeatability and its association with changes in HR and RespRate. Methods: Forty healthy volunteers underwent two ECG examinations 7 days apart. Standard HRV indices were calculated from 5-min ECG recordings. The ECG-derived respiration signal was estimated to assess RespRate. To investigate HR impact on HRV, HRV parameters were corrected for prevailing HR. Results: Differences in HRV parameters between the measurements were associated with the changes in HR and RespRate. However, in multiple regression analysis only HR alteration proved to be independent determinant of the HRV differences—every change in HR by 1 bpm changed HRV values by 16.5% on average. After overall removal of HR impact on HRV, coefficients of variation of the HRV parameters significantly dropped on average by 26.8% (p < 0.001), i.e., by the same extent HRV reproducibility improved. Additionally, the HRV correction for HR decreased association between RespRate and HRV. Conclusions: In stable conditions, HR but not RespRate is the most powerful factor determining HRV reproducibility and even a minimal change of HR may considerably alter HRV. However, the removal of HR impact may significantly improve HRV repeatability. The association between HRV and RespRate seems to be, at least in part, HR dependent. PMID:27588006

  5. Heart rate reduction in coronary artery disease and heart failure.

    PubMed

    Ferrari, Roberto; Fox, Kim

    2016-08-01

    Elevated heart rate is known to induce myocardial ischaemia in patients with coronary artery disease (CAD), and heart rate reduction is a recognized strategy to prevent ischaemic episodes. In addition, clinical evidence shows that slowing the heart rate reduces the symptoms of angina by improving microcirculation and coronary flow. Elevated heart rate is an established risk factor for cardiovascular events in patients with CAD and in those with chronic heart failure (HF). Accordingly, reducing heart rate improves prognosis in patients with HF, as demonstrated in SHIFT. By contrast, data from SIGNIFY indicate that heart rate is not a modifiable risk factor in patients with CAD who do not also have HF. Heart rate is also an important determinant of cardiac arrhythmias; low heart rate can be associated with atrial fibrillation, and high heart rate after exercise can be associated with sudden cardiac death. In this Review, we critically assess these clinical findings, and propose hypotheses for the variable effect of heart rate reduction in cardiovascular disease.

  6. Multifractality and heart rate variability

    NASA Astrophysics Data System (ADS)

    Sassi, Roberto; Signorini, Maria Gabriella; Cerutti, Sergio

    2009-06-01

    In this paper, we participate to the discussion set forth by the editor of Chaos for the controversy, "Is the normal heart rate chaotic?" Our objective was to debate the question, "Is there some more appropriate term to characterize the heart rate variability (HRV) fluctuations?" We focused on the ≈24 h RR series prepared for this topic and tried to verify with two different techniques, generalized structure functions and wavelet transform modulus maxima, if they might be described as being multifractal. For normal and congestive heart failure subjects, the hq exponents showed to be decreasing for increasing q with both methods, as it should be for multifractal signals. We then built 40 surrogate series to further verify such hypothesis. For most of the series (≈75%-80% of cases) multifractality stood the test of the surrogate data employed. On the other hand, series coming from patients in atrial fibrillation showed a small, if any, degree of multifractality. The population analyzed is too small for definite conclusions, but the study supports the use of multifractal series to model HRV. Also it suggests that the regulatory action of autonomous nervous system might play a role in the observed multifractality.

  7. Circadian variation of heart rate is affected by environment: a study of continuous electrocardiographic monitoring in members of a symphony orchestra.

    PubMed

    Mulcahy, D; Keegan, J; Fingret, A; Wright, C; Park, A; Sparrow, J; Curcher, D; Fox, K M

    1990-12-01

    Twenty four hour ambulatory ST segment monitoring was performed on 48 members (43 players and five members of the management/technical team) of the British Broadcasting Corporation (BBC) symphony orchestra without a history of cardiac disease. This period included final rehearsals and live performances (for audience and radio) of music by Richard Strauss and Mozart at the Royal Festival Hall (n = 36) and Rachmaninov and Tchaikovsky at the Barbican Arts Centre (n = 21). During the period of monitoring one person (2%) had transient ST segment changes. Mean heart rates were significantly higher during the live performances than during the rehearsals. Mean heart rates during the live performance of Rachmaninov and Tchaikovsky were significantly higher than during Strauss and Mozart in those (n = 6) who were monitored on both occasions. Mean heart rates in the management and technical team were higher than those of the players. The recognised circadian pattern of heart rate, with a peak in the morning waking hours, was altered similarly during both concert days, with a primary peak occurring in the evening hours and a lesser peak in the morning for both musicians and management/technical staff. This study showed that environmental factors are of primary importance in defining the circadian pattern of heart rate. This has important implications when identifying peak periods of cardiovascular stress and tailoring drug treatment for patients with angina pectoris.

  8. Circadian variation of heart rate is affected by environment: a study of continuous electrocardiographic monitoring in members of a symphony orchestra.

    PubMed Central

    Mulcahy, D; Keegan, J; Fingret, A; Wright, C; Park, A; Sparrow, J; Curcher, D; Fox, K M

    1990-01-01

    Twenty four hour ambulatory ST segment monitoring was performed on 48 members (43 players and five members of the management/technical team) of the British Broadcasting Corporation (BBC) symphony orchestra without a history of cardiac disease. This period included final rehearsals and live performances (for audience and radio) of music by Richard Strauss and Mozart at the Royal Festival Hall (n = 36) and Rachmaninov and Tchaikovsky at the Barbican Arts Centre (n = 21). During the period of monitoring one person (2%) had transient ST segment changes. Mean heart rates were significantly higher during the live performances than during the rehearsals. Mean heart rates during the live performance of Rachmaninov and Tchaikovsky were significantly higher than during Strauss and Mozart in those (n = 6) who were monitored on both occasions. Mean heart rates in the management and technical team were higher than those of the players. The recognised circadian pattern of heart rate, with a peak in the morning waking hours, was altered similarly during both concert days, with a primary peak occurring in the evening hours and a lesser peak in the morning for both musicians and management/technical staff. This study showed that environmental factors are of primary importance in defining the circadian pattern of heart rate. This has important implications when identifying peak periods of cardiovascular stress and tailoring drug treatment for patients with angina pectoris. PMID:2271347

  9. Wearable sensor for heart rate detection

    NASA Astrophysics Data System (ADS)

    Shi, Cong; Liu, Xiaohua; Kong, Lingqin; Wu, Jizhe; Liu, Ming; Dong, Liquan; Hui, Mei; Zhao, Yuejin

    2015-08-01

    In recent years heart and blood vessel diseases kill more people than everything else combined. The daily test of heart rate for the prevention and treatment of the heart head blood-vessel disease has the vital significance. In order to adapt the transformation of medical model and solve the low accuracy problem of the traditional method of heart rate measuring, we present a new method to monitor heart rate in this paper. The heart rate detection is designed for daily heart rate detection .The heart rate signal is collected by the heart rate sensor. The signal through signal processing circuits converts into sine wave and square wave in turn. And then the signal is transmitted to the computer by data collection card. Finally, we use LABVIEW and MATLAB to show the heart rate wave and calculate the heart rate. By doing contrast experiment with medical heart rate product, experimental results show that the system can realize rapidly and accurately measure the heart rate value. A measurement can be completed within 10 seconds and the error is less than 3beat/min. And the result shows that the method in this paper has a strong anti-interference ability. It can effectively suppress the movement interference. Beyond that the result is insensitive to light.

  10. [Resting heart rate and cardiovascular disease].

    PubMed

    Brito Díaz, Buenaventura; Alemán Sánchez, José Juan; Cabrera de León, Antonio

    2014-07-01

    Heart rate reflects autonomic nervous system activity. Numerous studies have demonstrated that an increased heart rate at rest is associated with cardiovascular morbidity and mortality as an independent risk factor. It has been shown a link between cardiac autonomic balance and inflammation. Thus, an elevated heart rate produces a micro-inflammatory response and is involved in the pathogenesis of endothelial dysfunction. In turn, decrease in heart rate produces benefits in congestive heart failure, myocardial infarction, atrial fibrillation, obesity, hyperinsulinemia, insulin resistance, and atherosclerosis. Alteration of other heart rate-related parameters, such as their variability and recovery after exercise, is associated with risk of cardiovascular events. Drugs reducing the heart rate (beta-blockers, calcium antagonists and inhibitors of If channels) have the potential to reduce cardiovascular events. Although not recommended in healthy subjects, interventions for reducing heart rate constitute a reasonable therapeutic goal in certain pathologies.

  11. How to Take Your Heart Rate

    MedlinePlus

    ... Page 1 of 2 The chart illustrates target heart rate ranges for exercise based on the maximal heart rate for selected ... to the next older age listed. - Compare your heart rate to the target exercise range. • If you are doing moderate exercise, your ...

  12. Increased heteroscedasticity of heart rate in fatal heart failure

    NASA Astrophysics Data System (ADS)

    Struzik, Z. R.; Kiyono, K.; Hayano, J.; Watanabe, E.; Yamamoto, Y.

    2008-04-01

    Healthy human heart rate is known to fluctuate in a highly complex manner, displaying complexity characteristics such as those shared by physical systems at a critical state. It is, however, widely believed that chronic heart failure reduces this complexity and that heart rate data from chronic-heart-failure patients can be used for the validation of complexity measures and paradigms applicable both to heart rate and more generally to assess any system's complexity. Here, we counter the above belief, showing an increase in fluctuations and in complexity of heart rate in chronic-heart-failure patients, in particular those at risk of death. This is supported by evidence of increased non-Gaussianity and heteroscedasticity resulting from the emergence of a characteristic correlation scale in the magnitude correlation landscape.

  13. Continuous positive airway pressure treatment for obstructive sleep apnoea reduces resting heart rate but does not affect dysrhythmias: a randomised controlled trial.

    PubMed

    Craig, Sonya; Pepperell, Justin C T; Kohler, Malcolm; Crosthwaite, Nicky; Davies, Robert J O; Stradling, John R

    2009-09-01

    Obstructive sleep apnoea (OSA) is associated with cardiovascular morbidity and may precipitate cardiac dysrhythmias. Uncontrolled reports suggest that continuous positive airway pressure (CPAP) may reduce dysrhythmia frequency and resting heart rate. We undertook a randomised controlled trial of therapeutic CPAP and compared with a subtherapeutic control which included an exploration of changes in dysrhythmia frequency and heart rate. Values are expressed as mean (SD). Eighty-three men [49.5 (9.6) years] with moderate-severe OSA [Oxygen Desaturation Index, 41.2 (24.3) dips per hour] underwent 3-channel 24-h electrocardiograms during normal daily activities, before and after 1 month of therapeutic (n = 43) or subtherapeutic (n = 40) CPAP. Recordings were manually analysed for mean heart rate, pauses, bradycardias, supraventricular and ventricular dysrhythmias. The two groups were well matched for age, body mass index, OSA severity, cardiovascular risk factors and history. Supraventricular ectopics and ventricular ectopics were frequently found in 95.2% and 85.5% of patients, respectively. Less common were sinus pauses (42.2%), episodes of bradycardia (12%) and ventricular tachycardias (4.8%). Compared with subtherapeutic control, CPAP reduced mean 24-h heart rate from 83.0 (11.5) to 79.7 (9.8) (P < 0.002) in the CPAP group compared with a non-significant rise (P = 0.18) from 79.0 (10.4) to 79.9 (10.4) in the subtherapeutic group; this was also the case for the day period analysed separately. There was no significant change in the frequencies of dysrhythmias after CPAP. Four weeks of CPAP therapy reduces mean 24-h heart rate possibly due to reduced sympathetic activation but did not result in a significant decrease in dysrhythmia frequency.

  14. Heart rate reduction and longevity in mice.

    PubMed

    Gent, Sabine; Kleinbongard, Petra; Dammann, Philip; Neuhäuser, Markus; Heusch, Gerd

    2015-03-01

    Heart rate correlates inversely with life span across all species, including humans. In patients with cardiovascular disease, higher heart rate is associated with increased mortality, and such patients benefit from pharmacological heart rate reduction. However, cause-and-effect relationships between heart rate and longevity, notably in healthy individuals, are not established. We therefore prospectively studied the effects of a life-long pharmacological heart rate reduction on longevity in mice. We hypothesized, that the total number of cardiac cycles is constant, and that a 15% heart rate reduction might translate into a 15% increase in life span. C57BL6/J mice received either placebo or ivabradine at a dose of 50 mg/kg/day in drinking water from 12 weeks to death. Heart rate and body weight were monitored. Autopsy was performed on all non-autolytic cadavers, and parenchymal organs were evaluated macroscopically. Ivabradine reduced heart rate by 14% (median, interquartile range 12-15%) throughout life, and median life span was increased by 6.2% (p = 0.01). Body weight and macroscopic findings were not different between placebo and ivabradine. Life span was not increased to the same extent as heart rate was reduced, but nevertheless significantly prolonged by 6.2%.

  15. CNS-disease affecting the heart: brain-heart disorders.

    PubMed

    Finsterer, Josef; Wahbi, Karim

    2014-10-15

    There are a number of hereditary and non-hereditary central nervous system (CNS) disorders, which directly or indirectly affect the heart (brain-heart disorders). The most well-known of these CNS-disorders are epilepsy, stroke, subarachanoid bleeding, bacterial meningitis, and head injury. In addition, a number of hereditary and non-hereditary neurodegenerative disorders may impair cardiac functions. Affection of the heart may manifest as arrhythmias, cardiomyopathy, or autonomic dysfunction. Rarer cardiac complications of CNS disorders include heart failure, systolic or diastolic dysfunction, myocardial infarction, arterial hypertension, or pulmonary hypertension. Cardiomyopathy induced by hereditary CNS disease mainly include stress-induced myocardial dysfunction, known as Takotsubo syndrome (TTS). CNS disease triggering TTS includes epilepsy, ischemic stroke, subarachnoid bleeding, or PRES syndrome. Arrhythmias induced by hereditary CNS disease include supraventricular or ventricular arrhythmias leading to palpitations, dizziness, vertigo, fainting, syncope, (near) sudden cardiac death, or sudden unexplained death in epilepsy (SUDEP). Appropriate management of cardiac involvement in CNS-disorders is essential to improve outcome of affected patients. PMID:25034054

  16. Heart-Rate and Breath-Rate Monitor

    NASA Technical Reports Server (NTRS)

    Cooper, T. G.

    1983-01-01

    Circuit requiring only four integrated circuits (IC's) measures both heart rate and breath rate. Phase-locked loops lock on heart-rate and respiration-rate input signals. Each loop IC contains two phase comparators. Positive-edge-triggered circuit used in making monitors insensitive to dutycycle variations.

  17. Effects of biofeedback training on voluntary heart rate control during dynamic exercise.

    PubMed

    Alvarez Moleiro, M; Villamaín Cid, F

    2001-12-01

    The aims of this study were to (1) compare the effect of biofeedback with that of verbal instructions on the control of heart rate during exercise on a treadmill, (2) test the possible effect of workload on this control, and (3) examine the effect of workload on baseline heart rate at rest and during exercise. The study involved 35 participants who were randomly assigned to each of 4 experimental conditions generated by combining the 2 independent variables: training strategy for heart rate control (heart rate biofeedback or verbal control instructions) and work level (30 or 50% of maximal heart rate). By the end of 5 experimental sessions, participants trained with heart rate biofeedback showed a greater attenuation of the increase in heart rate produced by exercise than participants trained with verbal control instructions. The workload did not influence the voluntary control of heart rate, nor did it affect resting baseline heart rate, but it did affect exercise baseline heart rate. PMID:11802677

  18. Heart Rate and Reinforcement Sensitivity in ADHD

    ERIC Educational Resources Information Center

    Luman, Marjolein; Oosterlaan, Jaap; Hyde, Christopher; van Meel, Catharina S.; Sergeant, Joseph A.

    2007-01-01

    Background: Both theoretical and clinical accounts of attention-deficit/hyperactivity disorder (ADHD) implicate a dysfunctional reinforcement system. This study investigated heart rate parameters in response to feedback associated with reward and response cost in ADHD children and controls aged 8 to 12. Methods: Heart rate responses (HRRs)…

  19. Heart rates of participants in wheelchair sports.

    PubMed

    Coutts, K D

    1988-02-01

    The relative stress of participation in wheelchair basketball, volleyball, tennis, and racquetball were determined by monitoring the heart rates of wheelchair athletes. Heart rates were recorded for 5 seconds every 30 seconds during monitoring sessions of 10 min or longer under game or practice conditions. Subjects were volunteer paraplegic athletes with lesions below T5 or with equivalent disability according to an international sport classification system. Average heart rates were 89 beats/min for tennis 'practice', 96 for racquetball 'practice' 107 for volleyball 'practice', 114 for volleyball 'game', 127 for tennis 'game', 129 for basketball 'practice', 135 for racquetball 'game', and 149 for basketball 'game' conditions. The percentage of time when heart rates were above 140 beats/min, followed the same pattern as the average heart rates and ranged from 0 to 62%.

  20. Volitional control of the heart rate.

    PubMed

    Abukonna, Ahmed; Yu, Xiaolin; Zhang, Chong; Zhang, Jianbao

    2013-11-01

    The heart rate is largely under control of the autonomic nervous system. The aim of the present study is to investigate the interactions between the brain and heart underlying volitional control of the heart and to explore the effectiveness of volition as a strategy to control the heart rate without biofeedback. Twenty seven healthy male subjects voluntarily participated in the study and were instructed to decrease and increase their heart beats according to rhythmic, computer generated sound either 10% faster or slower than the subjects' measured heart rate. Sympathetic and parasympathetic activities were estimated with the heart rate variability (HRV) obtained by power spectral analysis of RR intervals. Functional coupling patterns of cerebral cortex with the heart were determined by Partial directed coherence (PDC). In HR(slow) task; HR and sympathetic activity significantly decreased. However parasympathetic activity and power spectral density of EEG in low Alpha (8-10.5 Hz) band significantly increased. Moreover information flow from parietal area (P3 and P4) to RR interval significantly increased. During HR(quick) task; HR, sympathetic activity and power spectral density of EEG in low Beta (14-24 Hz) band significantly increased. Parasympathetic activity significantly decreased. Information flow from FT8, CZ and T8 electrodes to RR interval significantly increased. Our findings suggested that the heart beat can be controlled by volition and is related to some special areas in the cortex.

  1. FPGA Implementation of Heart Rate Monitoring System.

    PubMed

    Panigrahy, D; Rakshit, M; Sahu, P K

    2016-03-01

    This paper describes a field programmable gate array (FPGA) implementation of a system that calculates the heart rate from Electrocardiogram (ECG) signal. After heart rate calculation, tachycardia, bradycardia or normal heart rate can easily be detected. ECG is a diagnosis tool routinely used to access the electrical activities and muscular function of the heart. Heart rate is calculated by detecting the R peaks from the ECG signal. To provide a portable and the continuous heart rate monitoring system for patients using ECG, needs a dedicated hardware. FPGA provides easy testability, allows faster implementation and verification option for implementing a new design. We have proposed a five-stage based methodology by using basic VHDL blocks like addition, multiplication and data conversion (real to the fixed point and vice-versa). Our proposed heart rate calculation (R-peak detection) method has been validated, using 48 first channel ECG records of the MIT-BIH arrhythmia database. It shows an accuracy of 99.84%, the sensitivity of 99.94% and the positive predictive value of 99.89%. Our proposed method outperforms other well-known methods in case of pathological ECG signals and successfully implemented in FPGA.

  2. FPGA Implementation of Heart Rate Monitoring System.

    PubMed

    Panigrahy, D; Rakshit, M; Sahu, P K

    2016-03-01

    This paper describes a field programmable gate array (FPGA) implementation of a system that calculates the heart rate from Electrocardiogram (ECG) signal. After heart rate calculation, tachycardia, bradycardia or normal heart rate can easily be detected. ECG is a diagnosis tool routinely used to access the electrical activities and muscular function of the heart. Heart rate is calculated by detecting the R peaks from the ECG signal. To provide a portable and the continuous heart rate monitoring system for patients using ECG, needs a dedicated hardware. FPGA provides easy testability, allows faster implementation and verification option for implementing a new design. We have proposed a five-stage based methodology by using basic VHDL blocks like addition, multiplication and data conversion (real to the fixed point and vice-versa). Our proposed heart rate calculation (R-peak detection) method has been validated, using 48 first channel ECG records of the MIT-BIH arrhythmia database. It shows an accuracy of 99.84%, the sensitivity of 99.94% and the positive predictive value of 99.89%. Our proposed method outperforms other well-known methods in case of pathological ECG signals and successfully implemented in FPGA. PMID:26643079

  3. Fetal Heart Rate Response to Maternal Exercise.

    PubMed

    Monga, Manju

    2016-09-01

    Current guidelines regarding recommended exercise in pregnancy appear consistent with reported research regarding fetal heart changes in response to maternal exercise. Fetal heart rate increases during pregnancy, but maternal exercise appears well tolerated if performed in uncomplicated pregnancies and not in the supine position. Maximal levels of exercise that are well tolerated by the fetus have not yet been well defined; however, recent literature suggests that sustained exercise during pregnancy may have beneficial effects on autonomic control of fetal heart rate and variability that may lead to long-term health benefits. PMID:27388963

  4. Elevated heart rate and nondipping heart rate as potential targets for melatonin: a review.

    PubMed

    Simko, Fedor; Baka, Tomas; Paulis, Ludovit; Reiter, Russel J

    2016-09-01

    Elevated heart rate is a risk factor for cardiovascular and all-cause mortalities in the general population and various cardiovascular pathologies. Insufficient heart rate decline during the night, that is, nondipping heart rate, also increases cardiovascular risk. Abnormal heart rate reflects an autonomic nervous system imbalance in terms of relative dominance of sympathetic tone. There are only a few prospective studies concerning the effect of heart rate reduction in coronary heart disease and heart failure. In hypertensive patients, retrospective analyses show no additional benefit of slowing down the heart rate by beta-blockade to blood pressure reduction. Melatonin, a secretory product of the pineal gland, has several attributes, which predict melatonin to be a promising candidate in the struggle against elevated heart rate and its consequences in the hypertensive population. First, melatonin production depends on the sympathetic stimulation of the pineal gland. On the other hand, melatonin inhibits the sympathetic system in several ways representing potentially the counter-regulatory mechanism to normalize excessive sympathetic drive. Second, administration of melatonin reduces heart rate in animals and humans. Third, the chronobiological action of melatonin may normalize the insufficient nocturnal decline of heart rate. Moreover, melatonin reduces the development of endothelial dysfunction and atherosclerosis, which are considered a crucial pathophysiological disorder of increased heart rate and pulsatile blood flow. The antihypertensive and antiremodeling action of melatonin along with its beneficial effects on lipid profile and insulin resistance may be of additional benefit. A clinical trial investigating melatonin actions in hypertensive patients with increased heart rate is warranted.

  5. Influence of basic heart rate and sex on heart rate turbulence in healthy subjects.

    PubMed

    Schwab, Jörg O; Eichner, Gerrit; Veit, Gudrun; Schmitt, Heiko; Lewalter, Thorsten; Lüderitz, Berndt

    2004-12-01

    Acceleration and deceleration of the heart rate after the occurrence of a ventricular premature complex is characterized as heart rate turbulence (HRT). Two parameters quantify heart rate turbulence: onset and slope. The physiological properties have not been clarified in a large cohort of persons yet. This study evaluated properties of HRT, and focused on the influence of basic heart rate and sex on HRT. Using a special protocol, 95 persons were studied prospectively. HRT and its physiological properties were determined in 95 persons using Holter ECGs. The authors found 24% with a turbulence onset 0% and 5% with a turbulence slope <2.5 ms/RRI. Mean heart rate during Holter differed significantly between women and men (745 vs 817 ms, P < 0.0001). A linear, weighted regression model revealed that an increased heart rate before a ventricular premature complex is associated with a decreased turbulence onset (P < 0.0001). Turbulence slope was attenuated by basic heart rate only in men (P = 0.0022). On the contrary, the study detected no influence of the basic heart rate on turbulence slope in women (P = 0.0015 for the comparison between women and men). Basic heart rate and sex show an influence on HRT and should be considered when using HRT for noninvasive risk stratification.

  6. Heart Disease Affects Women of All Ages

    MedlinePlus

    ... 64 have a heart attack. About half of women who have a heart attack before age 65 die within 8 years. Heart ... have another within 6 years. About half of women who have a heart attack will be disabled with heart failure within 6 ...

  7. [Hypoxaemia, peripheral chemoreceptors and fetal heart rate].

    PubMed

    Secourgeon, J-F

    2012-02-01

    The perinatal results of the widespread adoption of the continuous electronic fetal heart rate monitoring during labor remain rather disappointing. This is due in part to a lack of consistent interpretation of the fetal heart tracings. Despite efforts by referral agencies over the past decade the situation has not improved. In defense of practitioners the heterogeneity and complexity of definitions and classifications patterns especially morphological currently proposed should be noted. Whereas with the recent advances in the field of neuroscience, it is now possible to visualize the chain of pathophysiological events that lead from the hypoxemic stimulus of the glomus cell to changes in the morphology of the fetal heart rate tracing. Thus by taking some examples of real situations, we propose a method of analysis that dissects the fetal heart tracing and take into account the functional specifications of the chemoreceptor when exposed to a hypoxic environment. Furthermore we can identify tracings with a "threshold effect" and also "sensitization and desensitization effects" according to the intensity, duration and recurrence of hypoxaemic episodes. This new approach based upon specific research into the mechanism behind the fetal heart rate abnormalities may be useful to complement the morphological study of the fetal heart tracing, to provide a better idea of the fetal status and to better define the indications of fetal blood sampling procedures.

  8. Stochastic model for heart-rate fluctuations

    NASA Astrophysics Data System (ADS)

    Kuusela, Tom; Shepherd, Tony; Hietarinta, Jarmo

    2003-06-01

    A normal human heart rate shows complex fluctuations in time, which is natural, because the heart rate is controlled by a large number of different feedback control loops. These unpredictable fluctuations have been shown to display fractal dynamics, long-term correlations, and 1/f noise. These characterizations are statistical and they have been widely studied and used, but much less is known about the detailed time evolution (dynamics) of the heart-rate control mechanism. Here we show that a simple one-dimensional Langevin-type stochastic difference equation can accurately model the heart-rate fluctuations in a time scale from minutes to hours. The model consists of a deterministic nonlinear part and a stochastic part typical to Gaussian noise, and both parts can be directly determined from the measured heart-rate data. Studies of 27 healthy subjects reveal that in most cases, the deterministic part has a form typically seen in bistable systems: there are two stable fixed points and one unstable one.

  9. Bupivacaine Mandibular Nerve Block Affects Intraoperative Blood Pressure and Heart Rate in a Yucatan Miniature Swine Mandibular Condylectomy Model: A Pilot Study

    PubMed Central

    Bova, Jonathan F.; da Cunha, Anderson F.; Stout, Rhett W.; Bhumiratana, Sarindr; Alfi, David M.; Eisig, Sidney B.; Vunjak-Novakovic, Gordana; Lopez, Mandi J.

    2015-01-01

    Purpose/Aim The primary objective was to evaluate the effect of a bupivacaine mandibular nerve block on intraoperative blood pressure (BP) and heart rate (HR) in response to surgical stimulation and the need for systemic analgesics postoperatively. We hypothesized that a mandibular nerve block would decrease the need for systemic analgesics both intraoperatively and postoperatively. Materials and Methods Fourteen adult male Yucatan pigs were purchased. Pigs were chemically restrained with ketamine, midazolam, and dexmedetomidine and anesthesia was maintained with isoflurane inhalant anesthesia. Pigs were randomized to receive a mandibular block with either bupivacaine (bupivacaine group) or saline (control group). A nerve stimulator was used for administration of the block with observation of masseter muscle twitch to indicate the injection site. Invasive BP and HR were measured with the aid of an arterial catheter in eight pigs. A rescue analgesic protocol consisting of fentanyl and lidocaine was administered if HR or BP values increased 20% from baseline. Postoperative pain was quantified with a customized ethogram. HR and BP were evaluated at base line, pre-rescue, 10 and 20 min post-rescue. Results Pre-rescue mean BP was significantly increased (p = .001) for the bupivacaine group. Mean intraoperative HR was significantly lower (p = .044) in the bupivacaine versus saline group. All other parameters were not significant. Conclusion Addition of a mandibular nerve block to the anesthetic regimen in the miniature pig condylectomy model may improve variations in intraoperative BP and HR. This study establishes the foundation for future studies with larger animal numbers to confirm these preliminary findings. PMID:25394295

  10. Heart-rate pulse-shift detector

    NASA Technical Reports Server (NTRS)

    Anderson, M.

    1974-01-01

    Detector circuit accurately separates and counts phase-shift pulses over wide range of basic pulse-rate frequency, and also provides reasonable representation of full repetitive EKG waveform. Single telemeter implanted in small animal monitors not only body temperature but also animal movement and heart rate.

  11. Resting Heart Rate and Auditory Evoked Potential

    PubMed Central

    Fiuza Regaçone, Simone; Baptista de Lima, Daiane Damaris; Engrácia Valenti, Vitor; Figueiredo Frizzo, Ana Cláudia

    2015-01-01

    The objective of this study was to evaluate the association between rest heart rate (HR) and the components of the auditory evoked-related potentials (ERPs) at rest in women. We investigated 21 healthy female university students between 18 and 24 years old. We performed complete audiological evaluation and measurement of heart rate for 10 minutes at rest (heart rate monitor Polar RS800CX) and performed ERPs analysis (discrepancy in frequency and duration). There was a moderate negative correlation of the N1 and P3a with rest HR and a strong positive correlation of the P2 and N2 components with rest HR. Larger components of the ERP are associated with higher rest HR. PMID:26504838

  12. Heart Rate Conditioning in Newborn Infants: Relationships Among Conditionability, Heart Rate Variability, and Sex

    ERIC Educational Resources Information Center

    Stamps, Leighton E.; Porges, Stephen W.

    1975-01-01

    Trace conditioning was evaluated in newborn infants by measurements of heart rate responses to a conditioned stimulus in anticipation of or in absence of the unconditioned stimulus. Data suggest females have higher levels of heart rate variability than males, which parallels their greater conditionability. (GO)

  13. Estimation of heart rate and heart rate variability from pulse oximeter recordings using localized model fitting.

    PubMed

    Wadehn, Federico; Carnal, David; Loeliger, Hans-Andrea

    2015-08-01

    Heart rate variability is one of the key parameters for assessing the health status of a subject's cardiovascular system. This paper presents a local model fitting algorithm used for finding single heart beats in photoplethysmogram recordings. The local fit of exponentially decaying cosines of frequencies within the physiological range is used to detect the presence of a heart beat. Using 42 subjects from the CapnoBase database, the average heart rate error was 0.16 BPM and the standard deviation of the absolute estimation error was 0.24 BPM. PMID:26737125

  14. Infant Heart Rate: A Review of Research and Methodology.

    ERIC Educational Resources Information Center

    Von Bargen, Donna M.

    1983-01-01

    Reviews literature on children up to age one to determine whether heart rate (HR) is a reliable, stable, and valid measure. Considers factors influencing resting HR and the Law of Initial Values, discusses information about response to stimulation and infant perception and affect obtained by using HR measures, and describes HR use in risk…

  15. Heart rate variability in Chinchilla rabbits.

    PubMed

    Nadareishvili, K Sh; Meskhishvili, I I; Kakhiani, D D; Ormotsadze, G L; Nazarishvili, G T; Gvasalia, M G; Khvedelidze, M T; Sandodze, V Ya

    2002-12-01

    Temporal and spectral parameters of heart rate variability were studied as criteria for classification of mature Chinchilla rabbit population according to their basal neurovegetative status. The absolute values of total spectral power density and individual frequency bands differed significantly in vagotonics and sympathotonics. However, standardized spectral power distributions in high-, low- and very low-frequency ranges were similar in both groups. Our results suggest that the intensity of regulatory influences on the heart at all levels of regulation, which can be evaluated by spectral analysis, is similarly distributed in both groups. Hence, the observed differences in the heart rate variability can not be explained by peculiarities in sympathovagal balance, but are determined by more universal mechanisms. PMID:12660841

  16. Current clinical applications of heart rate variability.

    PubMed

    Stys, A; Stys, T

    1998-10-01

    Heart rate variability (HRV) has become a popular method for the studies of physiologic mechanisms responsible for the control of heart rate fluctuations, in which the autonomic nervous system appears to play a primary role. Depression of HRV has been observed in many clinical scenarios, including autonomic neuropathy, heart transplantation, congestive heart failure, myocardial infarction (MI), and other cardiac and noncardiac diseases. However, it is important to realize that clinical implication of HRV analysis has been clearly recognized in only two clinical conditions: (1) as a predictor of risk of arrhythmic events or sudden cardiac death after acute MI, and (2) as a clinical marker of evolving diabetic neuropathy. Recently, its role in evaluation and management of heart failure has also been recognized. It is pertinent to recognize the limitations of HRV as far as its clinical utility at present is concerned. The methodology of HRV had remained poorly standardized until the recent publication of the Special Report of the Task Force of ESC/NASPE, and thus has been presenting difficulty in comparing earlier existing data. Also, determination of the exact sensitivity, specificity, and predictive value of HRV, as well as the normal values of standard measures in the general population, still require further investigation before better standards can be set for existing and future clinical applications. This article reviews the major concepts of HRV measurements, their clinical relevance, and the recent advances in this field. PMID:9789691

  17. Heart rate and heart rate variability modification in chronic insomnia patients.

    PubMed

    Farina, Benedetto; Dittoni, Serena; Colicchio, Salvatore; Testani, Elisa; Losurdo, Anna; Gnoni, Valentina; Di Blasi, Chiara; Brunetti, Riccardo; Contardi, Anna; Mazza, Salvatore; Della Marca, Giacomo

    2014-01-01

    Chronic insomnia is highly prevalent in the general population, provoking personal distress and increased risk for psychiatric and medical disorders. Autonomic hyper-arousal could be a pathogenic mechanism of chronic primary insomnia. The aim of this study was to investigate autonomic activity in patients with chronic primary insomnia by means of heart rate variability (HRV) analysis. Eighty-five consecutive patients affected by chronic primary insomnia were enrolled (38 men and 47 women; mean age: 53.2 ± 13.6). Patients were compared with a control group composed of 55 healthy participants matched for age and gender (23 men and 32 women; mean age: 54.2 ± 13.9). Patients underwent an insomnia study protocol that included subjective sleep evaluation, psychometric measures, and home-based polysomnography with evaluation of HRV in wake before sleep, in all sleep stages, and in wake after final awakening. Patients showed modifications of heart rate and HRV parameters, consistent with increased sympathetic activity, while awake before sleep and during Stage-2 non-REM sleep. No significant differences between insomniacs and controls could be detected during slow-wave sleep, REM sleep, and post-sleep wake. These results are consistent with the hypothesis that autonomic hyper-arousal is a major pathogenic mechanism in primary insomnia, and confirm that this condition is associated with an increased cardiovascular risk.

  18. Heart rate detection from plantar bioimpedance measurements.

    PubMed

    González Landaeta, R; Casas, O; Pallàs-Areny, R

    2006-01-01

    The heart rate is a basic health indicator, useful in both clinical measurements and home health care. Current home care systems often require the attachment of electrodes or other sensors to the body, which can be cumbersome to the patient. Moreover, some measurements are sensitive to movement artifacts, are not user-friendly and require a specialized supervision. In this paper, a novel technique for heart rate measurement for a standing subject is proposed, which is based on plantar bioimpedance measurements, such as those performed by some bathroom weighting scales for body composition analysis. Because of the low level of heart-related impedance variations, the measurement system has a gain of 1400. We have implemented a fully differential AC amplifier with a common-mode rejection ratio (CMRR) of 105 dB at 10 kHz. Coherent demodulation based on synchronous sampling yields a signal-to-noise ratio (SNR) of 55 dB. The system has a sensitivity of 1.9 V/Omega. The technique has been demonstrated on 18 volunteers, whose bioimpedance signal and ECG were simultaneously measured to validate the results. The average cross-correlation coefficient between the heart rates determined from these two signals was 0.998 (std. dev. 0.001). PMID:17946677

  19. Reliability of spectral analysis of fetal heart rate variability.

    PubMed

    Warmerdam, G J J; Vullings, R; Bergmans, J W M; Oei, S G

    2014-01-01

    Spectral analysis of fetal heart rate variability could provide information on fetal wellbeing. Unfortunately, fetal heart rate recordings are often contaminated by artifacts. Correction of these artifacts affects the outcome of spectral analysis, but it is currently unclear what level of artifact correction facilitates reliable spectral analysis. In this study, a method is presented that estimates the error in spectral powers due to artifact correction, based on the properties of the Continuous Wavelet Transformation. The results show that it is possible to estimate the error in spectral powers. The information about this error makes it possible for clinicians to assess the reliability of spectral analysis of fetal heart rate recordings that are contaminated by artifacts. PMID:25570577

  20. Lessons from the Heart: Individualizing Physical Education with Heart Rate Monitors.

    ERIC Educational Resources Information Center

    Kirkpatrick, Beth; Birnbaum, Burton H.

    Learning about the relationship between heart rate and physical activity is an important aspect of fitness education. Use of a heart rate monitor (HRM) helps a student to understand how stretching and large muscle movements gradually increase the heart rate and blood flow, and enables students to measure their exercise heart rates and set goals…

  1. Music structure determines heart rate variability of singers

    PubMed Central

    Vickhoff, Björn; Malmgren, Helge; Åström, Rickard; Nyberg, Gunnar; Ekström, Seth-Reino; Engwall, Mathias; Snygg, Johan; Nilsson, Michael; Jörnsten, Rebecka

    2013-01-01

    Choir singing is known to promote wellbeing. One reason for this may be that singing demands a slower than normal respiration, which may in turn affect heart activity. Coupling of heart rate variability (HRV) to respiration is called Respiratory sinus arrhythmia (RSA). This coupling has a subjective as well as a biologically soothing effect, and it is beneficial for cardiovascular function. RSA is seen to be more marked during slow-paced breathing and at lower respiration rates (0.1 Hz and below). In this study, we investigate how singing, which is a form of guided breathing, affects HRV and RSA. The study comprises a group of healthy 18 year olds of mixed gender. The subjects are asked to; (1) hum a single tone and breathe whenever they need to; (2) sing a hymn with free, unguided breathing; and (3) sing a slow mantra and breathe solely between phrases. Heart rate (HR) is measured continuously during the study. The study design makes it possible to compare above three levels of song structure. In a separate case study, we examine five individuals performing singing tasks (1–3). We collect data with more advanced equipment, simultaneously recording HR, respiration, skin conductance and finger temperature. We show how song structure, respiration and HR are connected. Unison singing of regular song structures makes the hearts of the singers accelerate and decelerate simultaneously. Implications concerning the effect on wellbeing and health are discussed as well as the question how this inner entrainment may affect perception and behavior. PMID:23847555

  2. Heart Rate Variability – A Historical Perspective

    PubMed Central

    Billman, George E.

    2011-01-01

    Heart rate variability (HRV), the beat-to-beat variation in either heart rate or the duration of the R–R interval – the heart period, has become a popular clinical and investigational tool. The temporal fluctuations in heart rate exhibit a marked synchrony with respiration (increasing during inspiration and decreasing during expiration – the so called respiratory sinus arrhythmia, RSA) and are widely believed to reflect changes in cardiac autonomic regulation. Although the exact contributions of the parasympathetic and the sympathetic divisions of the autonomic nervous system to this variability are controversial and remain the subject of active investigation and debate, a number of time and frequency domain techniques have been developed to provide insight into cardiac autonomic regulation in both health and disease. It is the purpose of this essay to provide an historical overview of the evolution in the concept of HRV. Briefly, pulse rate was first measured by ancient Greek physicians and scientists. However, it was not until the invention of the “Physician’s Pulse Watch” (a watch with a second hand that could be stopped) in 1707 that changes in pulse rate could be accurately assessed. The Rev. Stephen Hales (1733) was the first to note that pulse varied with respiration and in 1847 Carl Ludwig was the first to record RSA. With the measurement of the ECG (1895) and advent of digital signal processing techniques in the 1960s, investigation of HRV and its relationship to health and disease has exploded. This essay will conclude with a brief description of time domain, frequency domain, and non-linear dynamic analysis techniques (and their limitations) that are commonly used to measure HRV. PMID:22144961

  3. Heart rate variability - a historical perspective.

    PubMed

    Billman, George E

    2011-01-01

    Heart rate variability (HRV), the beat-to-beat variation in either heart rate or the duration of the R-R interval - the heart period, has become a popular clinical and investigational tool. The temporal fluctuations in heart rate exhibit a marked synchrony with respiration (increasing during inspiration and decreasing during expiration - the so called respiratory sinus arrhythmia, RSA) and are widely believed to reflect changes in cardiac autonomic regulation. Although the exact contributions of the parasympathetic and the sympathetic divisions of the autonomic nervous system to this variability are controversial and remain the subject of active investigation and debate, a number of time and frequency domain techniques have been developed to provide insight into cardiac autonomic regulation in both health and disease. It is the purpose of this essay to provide an historical overview of the evolution in the concept of HRV. Briefly, pulse rate was first measured by ancient Greek physicians and scientists. However, it was not until the invention of the "Physician's Pulse Watch" (a watch with a second hand that could be stopped) in 1707 that changes in pulse rate could be accurately assessed. The Rev. Stephen Hales (1733) was the first to note that pulse varied with respiration and in 1847 Carl Ludwig was the first to record RSA. With the measurement of the ECG (1895) and advent of digital signal processing techniques in the 1960s, investigation of HRV and its relationship to health and disease has exploded. This essay will conclude with a brief description of time domain, frequency domain, and non-linear dynamic analysis techniques (and their limitations) that are commonly used to measure HRV. PMID:22144961

  4. Modeling heart rate variability by stochastic feedback

    NASA Technical Reports Server (NTRS)

    Amaral, L. A.; Goldberger, A. L.; Stanley, H. E.

    1999-01-01

    We consider the question of how the cardiac rhythm spontaneously self-regulates and propose a new mechanism as a possible answer. We model the neuroautonomic regulation of the heart rate as a stochastic feedback system and find that the model successfully accounts for key characteristics of cardiac variability, including the 1/f power spectrum, the functional form and scaling of the distribution of variations of the interbeat intervals, and the correlations in the Fourier phases which indicate nonlinear dynamics.

  5. Multiscale power analysis for heart rate variability

    NASA Astrophysics Data System (ADS)

    Zeng, Peng; Liu, Hongxing; Ni, Huangjing; Zhou, Jing; Xia, Lan; Ning, Xinbao

    2015-06-01

    We first introduce multiscale power (MSP) method to assess the power distribution of physiological signals on multiple time scales. Simulation on synthetic data and experiments on heart rate variability (HRV) are tested to support the approach. Results show that both physical and psychological changes influence power distribution significantly. A quantitative parameter, termed power difference (PD), is introduced to evaluate the degree of power distribution alteration. We find that dynamical correlation of HRV will be destroyed completely when PD>0.7.

  6. Phase asymmetry of heart rate variability signal.

    PubMed

    Karmakar, C K; Khandoker, A H; Palaniswami, M

    2015-02-01

    Heart rate asymmetry (HRA) is considered as a physiological phenomenon in healthy subjects. In this article, we propose a novel HRA index, Slope Index (SI), to quantify phase asymmetry of heart rate variability (HRV) system. We assessed the performance of proposed index in comparison with conventional (Guzik's Index (GI) and Porta's Index (PI)) HRA indices. As illustrative examples, we used two case studies: (i) differentiate physiologic RR series from synthetic RR series; and (ii) discriminate arrhythmia subjects from Healthy using beat-to-beat heart rate time series. The results showed that SI is a superior parameter than GI and PI for both case studies with maximum ROC area of 0.84 and 0.82 respectively. In contrast, GI and PI had ROC areas {0.78, 0.61} and {0.50, 0.56} in two case studies respectively. We also performed surrogate analysis to show that phase asymmetry is caused by a physiologic phenomena rather than a random nature of the signal. In conclusion, quantification of phase asymmetry of HRV provides additional information on HRA, which might have a potential clinical use to discriminate pathological HRV in future.

  7. [Music and heart rate variability. Study of the effect of music on heart rate variability in healthy adolescents].

    PubMed

    Escher, J; Evéquoz, D

    1999-05-20

    The effect of trophotropic (relaxing) music on heart rate and heart rate variability has been investigated in 23 healthy young individuals by means of 24-hour Holter-ECG. Relaxing music (Bach, Vivaldi, Mozart) resulted in significant reduction of heart rate and also significant reduction of heart rate variability. The significance of these results for the use of music in coronary heart disease is discussed.

  8. Bluetooth Heart Rate Monitors for Spaceflight

    NASA Technical Reports Server (NTRS)

    Buxton, R. E.; West, M. R.; Kalogera, K. L.; Hanson, A. M.

    2016-01-01

    Heart rate monitoring is required for crewmembers during exercise aboard the International Space Station (ISS) and will be for future exploration missions. The cardiovascular system must be sufficiently stressed throughout a mission to maintain the ability to perform nominal and contingency/emergency tasks. High quality heart rate data are required to accurately determine the intensity of exercise performed by the crewmembers and show maintenance of VO2max. The quality of the data collected on ISS is subject to multiple limitations and is insufficient to meet current requirements. PURPOSE: To evaluate the performance of commercially available Bluetooth heart rate monitors (BT HRM) and their ability to provide high quality heart rate data to monitor crew health aboard the ISS and during future exploration missions. METHODS: Nineteen subjects completed 30 data collection sessions of various intensities on the treadmill and/or cycle. Subjects wore several BT HRM technologies for each testing session. One electrode-based chest strap (CS) was worn, while one or more optical sensors (OS) were worn. Subjects were instrumented with a 12-lead ECG to compare the heart rate data from the Bluetooth sensors. Each BT HRM data set was time matched to the ECG data and a +/-5bpm threshold was applied to the difference between the 2 data sets. Percent error was calculated based on the number of data points outside the threshold and the total number of data points. RESULTS: The electrode-based chest straps performed better than the optical sensors. The best performing CS was CS1 (1.6% error), followed by CS4 (3.3% error), CS3 (6.4% error), and CS2 (9.2% error). The OS resulted in 10.4% error for OS1 and 14.9% error for OS2. CONCLUSIONS: The highest quality data came from CS1, but unfortunately it has been discontinued by the manufacturer. The optical sensors have not been ruled out for use, but more investigation is needed to determine how to obtain the best quality data. CS2 will be

  9. Bluetooth Heart Rate Monitors For Spaceflight

    NASA Technical Reports Server (NTRS)

    Buxton, R. E.; West, M. R.; Kalogera, K. L.; Hanson, A. M.

    2016-01-01

    Heart rate monitoring is required for crewmembers during exercise aboard the International Space Station (ISS) and will be for future exploration missions. The cardiovascular system must be sufficiently stressed throughout a mission to maintain the ability to perform nominal and contingency/emergency tasks. High quality heart rate data are required to accurately determine the intensity of exercise performed by the crewmembers and show maintenance of VO2max. The quality of the data collected on ISS is subject to multiple limitations and is insufficient to meet current requirements. PURPOSE: To evaluate the performance of commercially available Bluetooth heart rate monitors (BT_HRM) and their ability to provide high quality heart rate data to monitor crew health aboard the ISS and during future exploration missions. METHODS: Nineteen subjects completed 30 data collection sessions of various intensities on the treadmill and/or cycle. Subjects wore several BT_HRM technologies for each testing session. One electrode-based chest strap (CS) was worn, while one or more optical sensors (OS) were worn. Subjects were instrumented with a 12-lead ECG to compare the heart rate data from the Bluetooth sensors. Each BT_HRM data set was time matched to the ECG data and a +/-5bpm threshold was applied to the difference between the 2 data sets. Percent error was calculated based on the number of data points outside the threshold and the total number of data points. RESULTS: The electrode-based chest straps performed better than the optical sensors. The best performing CS was CS1 (1.6% error), followed by CS4 (3.3% error), CS3 (6.4% error), and CS2 (9.2% error). The OS resulted in 10.4% error for OS1 and 14.9% error for OS2. CONCLUSIONS: The highest quality data came from CS1, but unfortunately it has been discontinued by the manufacturer. The optical sensors have not been ruled out for use, but more investigation is needed to determine how to obtain the best quality data. CS2 will be

  10. Passive fetal heart rate monitoring apparatus and method with enhanced fetal heart beat discrimination

    NASA Technical Reports Server (NTRS)

    Zahorian, Stephen A. (Inventor); Livingston, David L. (Inventor); Pretlow, III, Robert A. (Inventor)

    1996-01-01

    An apparatus for acquiring signals emitted by a fetus, identifying fetal heart beats and determining a fetal heart rate. Multiple sensor signals are outputted by a passive fetal heart rate monitoring sensor. Multiple parallel nonlinear filters filter these multiple sensor signals to identify fetal heart beats in the signal data. A processor determines a fetal heart rate based on these identified fetal heart beats. The processor includes the use of a figure of merit weighting of heart rate estimates based on the identified heart beats from each filter for each signal. The fetal heart rate thus determined is outputted to a display, storage, or communications channel. A method for enhanced fetal heart beat discrimination includes acquiring signals from a fetus, identifying fetal heart beats from the signals by multiple parallel nonlinear filtering, and determining a fetal heart rate based on the identified fetal heart beats. A figure of merit operation in this method provides for weighting a plurality of fetal heart rate estimates based on the identified fetal heart beats and selecting the highest ranking fetal heart rate estimate.

  11. A role for BK channels in heart rate regulation in rodents.

    PubMed

    Imlach, Wendy L; Finch, Sarah C; Miller, John H; Meredith, Andrea L; Dalziel, Julie E

    2010-01-14

    The heart generates and propagates action potentials through synchronized activation of ion channels allowing inward Na(+) and Ca(2+) and outward K(+) currents. There are a number of K(+) channel types expressed in the heart that play key roles in regulating the cardiac cycle. Large conductance calcium-activated potassium (BK) ion channels are not thought to be directly involved in heart function. Here we present evidence that heart rate can be significantly reduced by inhibiting the activity of BK channels. Agents that specifically inhibit BK channel activity, including paxilline and lolitrem B, slowed heart rate in conscious wild-type mice by 30% and 42%, respectively. Heart rate of BK channel knock-out mice (Kcnma1(-/-)) was not affected by these BK channel inhibitors, suggesting that the changes to heart rate were specifically mediated through BK channels. The possibility that these effects were mediated through BK channels peripheral to the heart was ruled out with experiments using isolated, perfused rat hearts, which showed a significant reduction in heart rate when treated with the BK channel inhibitors paxilline (1 microM), lolitrem B (1 microM), and iberiotoxin (0.23 microM), of 34%, 60%, and 42%, respectively. Furthermore, paxilline was shown to decrease heart rate in a dose-dependent manner. These results implicate BK channels located in the heart to be directly involved in the regulation of heart rate.

  12. BIOPHYSICAL CHARACTERISATION OF THE UNDER-APPRECIATED AND IMPORTANT RELATIONSHIP BETWEEN HEART RATE VARIABILITY AND HEART RATE

    PubMed Central

    Monfredi, Oliver; Lyashkov, Alexey E; Johnsen, Anne-Berit; Inada, Shin; Schneider, Heiko; Wang, Ruoxi; Nirmalan, Mahesh; Wisloff, Ulrik; Maltsev, Victor A; Lakatta, Edward G; Zhang, Henggui; Boyett, Mark R

    2014-01-01

    Heart rate variability (beat-to-beat changes in the RR interval) has attracted considerable attention over the last 30+ years (PubMed currently lists >17,000 publications). Clinically, a decrease in heart rate variability is correlated to higher morbidity and mortality in diverse conditions, from heart disease to foetal distress. It is usually attributed to fluctuation in cardiac autonomic nerve activity. We calculated heart rate variability parameters from a variety of cardiac preparations (including humans, living animals, Langendorff-perfused heart and single sinoatrial nodal cell) in diverse species, combining this with data from previously published papers. We show that regardless of conditions, there is a universal exponential decay-like relationship between heart rate variability and heart rate. Using two biophysical models, we develop a theory for this, and confirm that heart rate variability is primarily dependent on heart rate and cannot be used in any simple way to assess autonomic nerve activity to the heart. We suggest that the correlation between a change in heart rate variability and altered morbidity and mortality is substantially attributable to the concurrent change in heart rate. This calls for re-evaluation of the findings from many papers that have not adjusted properly or at all for heart rate differences when comparing heart rate variability in multiple circumstances. PMID:25225208

  13. Acoustically based fetal heart rate monitor

    NASA Technical Reports Server (NTRS)

    Baker, Donald A.; Zuckerwar, Allan J.

    1991-01-01

    The acoustically based fetal heart rate monitor permits an expectant mother to perform the fetal Non-Stress Test in her home. The potential market would include the one million U.S. pregnancies per year requiring this type of prenatal surveillance. The monitor uses polyvinylidene fluoride (PVF2) piezoelectric polymer film for the acoustic sensors, which are mounted in a seven-element array on a cummerbund. Evaluation of the sensor ouput signals utilizes a digital signal processor, which performs a linear prediction routine in real time. Clinical tests reveal that the acoustically based monitor provides Non-Stress Test records which are comparable to those obtained with a commercial ultrasonic transducer.

  14. Mental workload classification using heart rate metrics.

    PubMed

    Henelius, Andreas; Hirvonen, Kati; Holm, Anu; Korpela, Jussi; Muller, Kiti

    2009-01-01

    The ability of different short-term heart rate variability metrics to classify the level of mental workload (MWL) in 140 s segments was studied. Electrocardiographic data and event related potentials (ERPs), calculated from electroencephalographic data, were collected from 13 healthy subjects during the performance of a computerised cognitive multitask test with different task load levels. The amplitude of the P300 component of the ERPs was used as an objective measure of MWL. Receiver operating characteristics analysis (ROC) showed that the time domain metric of average interbeat interval length was the best-performing metric in terms of classification ability.

  15. Heart rate discrimination and heart rate control: a test of Brener's theory.

    PubMed

    Grigg, L; Ashton, R

    1984-12-01

    Three experiments were conducted to examine predictions from Brener's theory regarding the relationship between autonomic discrimination and autonomic control. Experiment 1 examined the possibility that training subjects to discriminate their heart rates would enhance their skill at controlling that response. Twenty subjects participated in two sessions during which one group of 10 subjects received training (knowledge of results) on the Ashton discrimination technique. The second group performed the discrimination task but received no training. All subjects then took part in a third session of heart rate (HR) control (both increase and decrease) where half of each of the aforementioned groups received feedback during the control task, while the other half performed the HR control task without feedback. Results indicated that for the control of both HR increases and decreases, there was no significant difference between those subjects trained to discriminate their HR, and those who had received no training to discriminate HR. The second experiment investigated the hypothesis that training subjects with feedback to control their HR would enhance their capacity to discriminate their heart activity. Ten subjects participated in two sessions of HR control during which half the subjects received feedback training to increase HR. During a third session, all subjects underwent a test of discrimination ability using the Ashton technique, and no knowledge of results regarding performance was provided. Results confirmed the hypothesis. The final experiment in the series investigated the discrimination/control relationship within a problem-solving framework and used 20 subjects. Results confirmed the hypothesis that subjects forewarned at the time of discrimination training that a heart rate control task was to follow would perform better than 10 subjects receiving no forewarning of the task objective. This effect took place independently of cardiac discrimination ability. A

  16. Model-based Heart rate prediction during Lokomat walking.

    PubMed

    Koenig, Alexander C; Somaini, Luca; Pulfer, Michael; Holenstein, Thomas; Omlin, Ximena; Wieser, Martin; Riener, Robert

    2009-01-01

    We implemented a model for prediction of heart rate during Lokomat walking. Using this model, we can predict potential overstressing of the patient and adapt the physical load accordingly. Current models for treadmill based heart rate control neglect the fact that the interaction torques between Lokomat and human can have a significant effect on heart rate. Tests with five healthy subjects lead to a model of sixth order with walking speed and power expenditure as inputs and heart rate prediction as output. Recordings with five different subjects were used for model validation. Future work includes model identification and predictive heart rate control with spinal cord injured and stroke patients. PMID:19963765

  17. Electroencephalogram and Heart Rate Regulation to Familiar and Unfamiliar People in Children with Autism Spectrum Disorders

    ERIC Educational Resources Information Center

    Van Hecke, Amy Vaughan; Lebow, Jocelyn; Bal, Elgiz; Lamb, Damon; Harden, Emily; Kramer, Alexis; Denver, John; Bazhenova, Olga; Porges, Stephen W.

    2009-01-01

    Few studies have examined whether familiarity of partner affects social responses in children with autism. This study investigated heart rate regulation (respiratory sinus arrhythmia [RSA]: The myelinated vagus nerve's regulation of heart rate) and temporal-parietal electroencephalogram (EEG) activity while nineteen 8- to 12-year-old children with…

  18. Aerobic Fitness, Heart Rate Recovery and Heart Rate Recovery Time in Indian School Children.

    PubMed

    Fernando, Rajesh Jeniton; Ravichandran, K; Vaz, Mario

    2015-01-01

    Data on aerobic fitness and heart rate recovery in children are limited. This study was done to evaluate the relation between them in Indian school going children. Three hundred children of 7 to 10.5 years were recruited and their aerobic fitness was predicted using modified Harvard's step test (VO₂max) and 20 meter shuttle test (VO₂peak). The heart rate was monitored for 12 minutes post modified Harvard's step test. The difference between the maximum and the 1st minute HR was noted as HRR1 and the time taken to reach the resting heart rate was also recorded. VO₂max was inversely correlated with HRR1 (r = -0.64, p<0.001). However, the partial correlation of the two was not significant (r(partial) = -0.037, p = 0.55), indicating children with higher basal HR had higher HRR1 and that accounted for the observed association with aerobic fitness. Cox regression analysis showed that the recovery rate per unit time was 3% greater with increasing VO₂max (HR = 1.03, 95% CI:1.01 to 1.05, p = 0.013). The heart rate parameters did not show any associat with VO₂peak This study demonstrates that there is no relation between VO₂max and HRR1 after 3 minutes of modified Harvard's step test in Indian children of 7 to 10.5 years. However, aerobic fitness is a positive predictor of heart rate recovery time in this group. PMID:27530008

  19. Children's Heart Rate Reactivity Responses to Three School Tasks.

    ERIC Educational Resources Information Center

    Sharpley, Christopher F.; And Others

    1989-01-01

    Investigated effects of 3 routine classroom arithmetic and reading tasks upon the heart rate reactivity of 30 fifth grade children. Results indicated that some children showed large increases in heart rates during the three tasks, and that these children should be considered at risk for coronary heart disease. (Author/TE)

  20. Heart Rate Changes in Electroacupuncture Treated Polycystic Ovary in Rats

    PubMed Central

    Ramadoss, Mukilan; Subbiah, Angelie Jessica; Natrajan, Chidambaranathan

    2016-01-01

    Introduction Polycystic Ovary Syndrome (PCOS) is a common metabolic disorder, it affects both humans and animals. It may induce coronary heart disease, obesity and hyperandrogenism. Previous studies show that Low frequency Electroacupuncture (EA) have an effect on PCOS, however the exact pathway is unclear. Aim To find the effect of EA on autonomic activity of the heart in Estradiol Valerate (EV) induced PCOS rats. Materials and Methods Heart rate variability (HRV) was assessed in 3 groups: 1) Control; 2) PCOS rats; and 3) PCOS rats after EA treatment (n=8 in each group). From the time domain analysis and frequency domain analysis (linear measures) HRV analysis was done. EA stimulation was given at low frequency of 2Hz for 15 min on alternate days for 4-5 weeks. Collected data were statistically analysed using One-Way Analysis of Variance with the application of multiple comparisons of Tukey test. Results EA treatment group shows significant reduction in Heart Rate (HR) and low frequency, high frequency ratio (LF/HF); and increase in RR interval, Total Power (TP) when compared to PCOS group. Conclusion The study concludes that EA treatment has a significant effect on reducing sympathetic tone and decreasing HR in PCOS. PMID:27134868

  1. Quantitative analysis of heart rate variability

    NASA Astrophysics Data System (ADS)

    Kurths, J.; Voss, A.; Saparin, P.; Witt, A.; Kleiner, H. J.; Wessel, N.

    1995-03-01

    In the modern industrialized countries every year several hundred thousands of people die due to sudden cardiac death. The individual risk for this sudden cardiac death cannot be defined precisely by common available, noninvasive diagnostic tools like Holter monitoring, highly amplified ECG and traditional linear analysis of heart rate variability (HRV). Therefore, we apply some rather unconventional methods of nonlinear dynamics to analyze the HRV. Especially, some complexity measures that are based on symbolic dynamics as well as a new measure, the renormalized entropy, detect some abnormalities in the HRV of several patients who have been classified in the low risk group by traditional methods. A combination of these complexity measures with the parameters in the frequency domain seems to be a promising way to get a more precise definition of the individual risk. These findings have to be validated by a representative number of patients.

  2. Ordinal pattern statistics for the assessment of heart rate variability

    NASA Astrophysics Data System (ADS)

    Graff, G.; Graff, B.; Kaczkowska, A.; Makowiec, D.; Amigó, J. M.; Piskorski, J.; Narkiewicz, K.; Guzik, P.

    2013-06-01

    The recognition of all main features of a healthy heart rhythm (the so-called sinus rhythm) is still one of the biggest challenges in contemporary cardiology. Recently the interesting physiological phenomenon of heart rate asymmetry has been observed. This phenomenon is related to unbalanced contributions of heart rate decelerations and accelerations to heart rate variability. In this paper we apply methods based on the concept of ordinal pattern to the analysis of electrocardiograms (inter-peak intervals) of healthy subjects in the supine position. This way we observe new regularities of the heart rhythm related to the distribution of ordinal patterns of lengths 3 and 4.

  3. Inverse Correlation between Heart Rate Variability and Heart Rate Demonstrated by Linear and Nonlinear Analysis

    PubMed Central

    Zhang, Henggui; Aziz, Wajid; Monfredi, Oliver; Abbas, Syed Ali; Shah, Saeed Arif; Kazmi, Syeda Sobia Hassan; Butt, Wasi Haider

    2016-01-01

    The dynamical fluctuations in the rhythms of biological systems provide valuable information about the underlying functioning of these systems. During the past few decades analysis of cardiac function based on the heart rate variability (HRV; variation in R wave to R wave intervals) has attracted great attention, resulting in more than 17000-publications (PubMed list). However, it is still controversial about the underling mechanisms of HRV. In this study, we performed both linear (time domain and frequency domain) and nonlinear analysis of HRV data acquired from humans and animals to identify the relationship between HRV and heart rate (HR). The HRV data consists of the following groups: (a) human normal sinus rhythm (n = 72); (b) human congestive heart failure (n = 44); (c) rabbit sinoatrial node cells (SANC; n = 67); (d) conscious rat (n = 11). In both human and animal data at variant pathological conditions, both linear and nonlinear analysis techniques showed an inverse correlation between HRV and HR, supporting the concept that HRV is dependent on HR, and therefore, HRV cannot be used in an ordinary manner to analyse autonomic nerve activity of a heart. PMID:27336907

  4. Inverse Correlation between Heart Rate Variability and Heart Rate Demonstrated by Linear and Nonlinear Analysis.

    PubMed

    Kazmi, Syed Zaki Hassan; Zhang, Henggui; Aziz, Wajid; Monfredi, Oliver; Abbas, Syed Ali; Shah, Saeed Arif; Kazmi, Syeda Sobia Hassan; Butt, Wasi Haider

    2016-01-01

    The dynamical fluctuations in the rhythms of biological systems provide valuable information about the underlying functioning of these systems. During the past few decades analysis of cardiac function based on the heart rate variability (HRV; variation in R wave to R wave intervals) has attracted great attention, resulting in more than 17000-publications (PubMed list). However, it is still controversial about the underling mechanisms of HRV. In this study, we performed both linear (time domain and frequency domain) and nonlinear analysis of HRV data acquired from humans and animals to identify the relationship between HRV and heart rate (HR). The HRV data consists of the following groups: (a) human normal sinus rhythm (n = 72); (b) human congestive heart failure (n = 44); (c) rabbit sinoatrial node cells (SANC; n = 67); (d) conscious rat (n = 11). In both human and animal data at variant pathological conditions, both linear and nonlinear analysis techniques showed an inverse correlation between HRV and HR, supporting the concept that HRV is dependent on HR, and therefore, HRV cannot be used in an ordinary manner to analyse autonomic nerve activity of a heart. PMID:27336907

  5. Heart rate and blood lactate responses during competitive Olympic boardsailing.

    PubMed

    Guével, A; Maïsetti, O; Prou, E; Dubois, J J; Marini, J F

    1999-02-01

    The rules of competitive boardsailing events were changed before the Atlanta Olympic Games. Pumping the sail (pulling repeatedly on the rig) is now allowed and the duration of races has been shortened. Eight members of the French national team (mean age 23+/-2.7 years) participated in this study. Their cardiac and metabolic responses were assessed by measuring heart rate and blood lactate concentration during various competitive events in two strengths of wind (light vs. moderate). Heart rate was higher in light (87.4+/-4.3% HRmax; mean racing time 37 min) than in moderate wind conditions (82.9+/-5.3% HRmax; mean racing time 33 min). The mean post-race blood lactate concentration (5.2+/-1.0 mmol x l(-1)) was not affected by the wind conditions. Mean heart rate was highest during downwind legs (88.0+/-3.1% HRmax; duration 7-10 min). The races consisted of two laps, the first of which induced significantly higher cardiac demands than the second. We conclude that the changes to the rules of competitive boardsailing have increased the cardiac and metabolic efforts involved. PMID:10069270

  6. Modeling heart rate variability including the effect of sleep stages

    NASA Astrophysics Data System (ADS)

    Soliński, Mateusz; Gierałtowski, Jan; Żebrowski, Jan

    2016-02-01

    We propose a model for heart rate variability (HRV) of a healthy individual during sleep with the assumption that the heart rate variability is predominantly a random process. Autonomic nervous system activity has different properties during different sleep stages, and this affects many physiological systems including the cardiovascular system. Different properties of HRV can be observed during each particular sleep stage. We believe that taking into account the sleep architecture is crucial for modeling the human nighttime HRV. The stochastic model of HRV introduced by Kantelhardt et al. was used as the initial starting point. We studied the statistical properties of sleep in healthy adults, analyzing 30 polysomnographic recordings, which provided realistic information about sleep architecture. Next, we generated synthetic hypnograms and included them in the modeling of nighttime RR interval series. The results of standard HRV linear analysis and of nonlinear analysis (Shannon entropy, Poincaré plots, and multiscale multifractal analysis) show that—in comparison with real data—the HRV signals obtained from our model have very similar properties, in particular including the multifractal characteristics at different time scales. The model described in this paper is discussed in the context of normal sleep. However, its construction is such that it should allow to model heart rate variability in sleep disorders. This possibility is briefly discussed.

  7. Modeling heart rate variability including the effect of sleep stages.

    PubMed

    Soliński, Mateusz; Gierałtowski, Jan; Żebrowski, Jan

    2016-02-01

    We propose a model for heart rate variability (HRV) of a healthy individual during sleep with the assumption that the heart rate variability is predominantly a random process. Autonomic nervous system activity has different properties during different sleep stages, and this affects many physiological systems including the cardiovascular system. Different properties of HRV can be observed during each particular sleep stage. We believe that taking into account the sleep architecture is crucial for modeling the human nighttime HRV. The stochastic model of HRV introduced by Kantelhardt et al. was used as the initial starting point. We studied the statistical properties of sleep in healthy adults, analyzing 30 polysomnographic recordings, which provided realistic information about sleep architecture. Next, we generated synthetic hypnograms and included them in the modeling of nighttime RR interval series. The results of standard HRV linear analysis and of nonlinear analysis (Shannon entropy, Poincaré plots, and multiscale multifractal analysis) show that-in comparison with real data-the HRV signals obtained from our model have very similar properties, in particular including the multifractal characteristics at different time scales. The model described in this paper is discussed in the context of normal sleep. However, its construction is such that it should allow to model heart rate variability in sleep disorders. This possibility is briefly discussed. PMID:26931582

  8. Allometric estimation of metabolic rate from heart rate in penguins.

    PubMed

    Green, J A; White, C R; Butler, P J

    2005-12-01

    Studies of the relationship between heart rate (f(H)) and rate of oxygen consumption (V(.) (O(2))), which are then used to predict field metabolic rate, frequently fail to incorporate body mass as a predictive variable. This is a potentially important omission in the study of animals whose body mass fluctuates substantially during their annual cycle. In an attempt further to improve estimates of field metabolic rate from f(H), we re-evaluated data on M(b), f(H) and V(.) (O(2)) from previous studies of macaroni penguins (Eudyptes chrysolophus) and king penguins (Aptenodytes patagonicus) and derived a new relationship to integrate these three quantities. This relationship is at least as accurate and precise as previously determined relationships. We applied this same principle to published data on 11 of the 20 recognised penguin taxa to derive a relationship to predict V(.) (O(2)) from f(H) and M(b) in penguins of any species. This result has interesting implications in terms of reducing the logistical burden in studies of field metabolic rate. PMID:16297646

  9. Correlation of heart rate and radionuclide index of left ventricular contraction and relaxation.

    PubMed

    Adachi, H; Sugihara, H; Nakagawa, H; Inagaki, S; Kubota, Y; Nakagawa, M

    1990-11-01

    Since the cardiac function indices derived from radionuclide ventriculography (RNV) are considered to depend on the heart rate, we studied the relationship between systolic or diastolic indices and heart rates in patients with normal RNV and devised a method of correcting these indices according to the heart rate. For the systolic indices, the heart rate showed significant correlation with ET (r = -0.640), PER (r = 0.791) and TPE (r = -0.401) but not with EF, 1/3 EF, MNSER or 1/3 MNSER. For the diastolic indices, the heart rate correlated with FT (r = -0.938), RFT (r = -0.736), SFT (r = -0.803), 1/3 FF (r = -0.758), PFR (r = 0.759), 1/3 PFR (r = 0.742) and TPF (r = -0.389) but not with AFT, 1/3 MNDFR or AFF. These results indicate that many systolic and diastolic indices derived from RNV are affected by the heart rate. So when cardiac function is evaluated with the use of radionuclide indices, those which are independent of the heart rate should be used, or they should be corrected for the heart rate. As a method of correction, we proposed a rotating method obtained by manipulation of the regression equation of heart rates and indices. This new method is certain and easier to use when the correcting equations are set into a computer program.

  10. Interaction of a commercial heart rate monitor with implanted pacemakers.

    PubMed

    Joglar, J A; Hamdan, M H; Welch, P J; Page, R L

    1999-03-01

    Dry-electrode heart rate monitors allow display of heart rate by transmitting a signal to the receiving device, which typically is on the wrist or exercise machine, but due to the potential for electromagnetic interference, their use has been contraindicated in patients with pacemakers. In 12 patients, we found no adverse effect on pacemaker function; in addition, the monitors generally were accurate in measuring heart rate during pacing.

  11. Unconstrained Evaluation System for Heart Rate Using Ultrasonic Vibrograph

    NASA Astrophysics Data System (ADS)

    Nagamune, Kouki; Kobashi, Syoji; Kondo, Katsuya; Hata, Yutaka; Taniguchi, Kazuhiko; Sawayama, Toshiyuki

    2004-05-01

    Unconstrained health monitoring systems have received much considerable attention in medical applications, because such system can examine a subject without constraint. In this study, we propose a detection method based on a fuzzy logic for evaluating heart rate using our ultrasonic vibrograph. In the experiment for confirming heart rate, our method has been successfully used to detect the heart rates of four subjects, compared with a method using an electrocardiograph.

  12. Controlling the emotional heart: heart rate biofeedback improves cardiac control during emotional reactions.

    PubMed

    Peira, Nathalie; Fredrikson, Mats; Pourtois, Gilles

    2014-03-01

    When regulating negative emotional reactions, one goal is to reduce physiological reactions. However, not all regulation strategies succeed in doing that. We tested whether heart rate biofeedback helped participants reduce physiological reactions in response to negative and neutral pictures. When viewing neutral pictures, participants could regulate their heart rate whether the heart rate feedback was real or not. In contrast, when viewing negative pictures, participants could regulate heart rate only when feedback was real. Ratings of task success paralleled heart rate. Participants' general level of anxiety, emotion awareness, or cognitive emotion regulation strategies did not influence the results. Our findings show that accurate online heart rate biofeedback provides an efficient way to down-regulate autonomic physiological reactions when encountering negative stimuli. PMID:24373886

  13. A Bayesian classification of heart rate variability data

    NASA Astrophysics Data System (ADS)

    Muirhead, R. J.; Puff, R. D.

    2004-05-01

    We propose a simple Bayesian method for the classification of time series signals originating from mutually exclusive sources. In particular, the method is used to address the question of whether a 24-h recording of human heart rate data is produced by a normally functioning heart or by one exhibiting symptoms of congestive heart failure. Our method correctly classifies 18 of 18 normal heart data sets, and 38 of 44 congestive failure data sets.

  14. Critical Scale Invariance in a Healthy Human Heart Rate

    NASA Astrophysics Data System (ADS)

    Kiyono, Ken; Struzik, Zbigniew R.; Aoyagi, Naoko; Sakata, Seiichiro; Hayano, Junichiro; Yamamoto, Yoshiharu

    2004-10-01

    We demonstrate the robust scale-invariance in the probability density function (PDF) of detrended healthy human heart rate increments, which is preserved not only in a quiescent condition, but also in a dynamic state where the mean level of the heart rate is dramatically changing. This scale-independent and fractal structure is markedly different from the scale-dependent PDF evolution observed in a turbulentlike, cascade heart rate model. These results strongly support the view that a healthy human heart rate is controlled to converge continually to a critical state.

  15. How Does Heart Disease Affect Women?

    MedlinePlus

    ... Human Services. Rate This Content: NEXT >> Featured Video All of Our Stories Are Red: Yaskary's Story 04/ ... part of the National Institutes of Health (NIH). All of Our Stories Are Red: Eileen's Story 04/ ...

  16. Drowsiness detection using heart rate variability.

    PubMed

    Vicente, José; Laguna, Pablo; Bartra, Ariadna; Bailón, Raquel

    2016-06-01

    It is estimated that 10-30 % of road fatalities are related to drowsy driving. Driver's drowsiness detection based on biological and vehicle signals is being studied in preventive car safety. Autonomous nervous system activity, which can be measured noninvasively from the heart rate variability (HRV) signal obtained from surface electrocardiogram, presents alterations during stress, extreme fatigue and drowsiness episodes. We hypothesized that these alterations manifest on HRV and thus could be used to detect driver's drowsiness. We analyzed three driving databases in which drivers presented different sleep-deprivation levels, and in which each driving minute was annotated as drowsy or awake. We developed two different drowsiness detectors based on HRV. While the drowsiness episodes detector assessed each minute of driving as "awake" or "drowsy" with seven HRV derived features (positive predictive value 0.96, sensitivity 0.59, specificity 0.98 on 3475 min of driving), the sleep-deprivation detector discerned if a driver was suitable for driving or not, at driving onset, as function of his sleep-deprivation state. Sleep-deprivation state was estimated from the first three minutes of driving using only one HRV feature (positive predictive value 0.80, sensitivity 0.62, specificity 0.88 on 30 drivers). Incorporating drowsiness assessment based on HRV signal may add significant improvements to existing car safety systems.

  17. Drowsiness detection using heart rate variability.

    PubMed

    Vicente, José; Laguna, Pablo; Bartra, Ariadna; Bailón, Raquel

    2016-06-01

    It is estimated that 10-30 % of road fatalities are related to drowsy driving. Driver's drowsiness detection based on biological and vehicle signals is being studied in preventive car safety. Autonomous nervous system activity, which can be measured noninvasively from the heart rate variability (HRV) signal obtained from surface electrocardiogram, presents alterations during stress, extreme fatigue and drowsiness episodes. We hypothesized that these alterations manifest on HRV and thus could be used to detect driver's drowsiness. We analyzed three driving databases in which drivers presented different sleep-deprivation levels, and in which each driving minute was annotated as drowsy or awake. We developed two different drowsiness detectors based on HRV. While the drowsiness episodes detector assessed each minute of driving as "awake" or "drowsy" with seven HRV derived features (positive predictive value 0.96, sensitivity 0.59, specificity 0.98 on 3475 min of driving), the sleep-deprivation detector discerned if a driver was suitable for driving or not, at driving onset, as function of his sleep-deprivation state. Sleep-deprivation state was estimated from the first three minutes of driving using only one HRV feature (positive predictive value 0.80, sensitivity 0.62, specificity 0.88 on 30 drivers). Incorporating drowsiness assessment based on HRV signal may add significant improvements to existing car safety systems. PMID:26780463

  18. Significance, prognostic value and management of heart rate in hypertension.

    PubMed

    Courand, Pierre-Yves; Lantelme, Pierre

    2014-01-01

    Many epidemiological studies have demonstrated that resting heart rate is a risk marker but also a risk factor in patients with coronary artery disease and heart failure. In hypertensive subjects free from overt cardiac disease, the question has been less frequently addressed. A few cohort studies have shown that hypertensive patients with a high resting heart rate have an increased risk of all-cause and cardiovascular death. However, intervention trials have not demonstrated that lowering the heart rate is beneficial in hypertensive subjects. Studies with an assessment of ambulatory heart rate tend to demonstrate a better association between cardiovascular outcomes and variables, including nighttime heart rate. Clinical trials comparing beta-blockers with non-slowing antihypertensive drugs have not demonstrated the superiority of the former. Finally, an elevated resting heart rate in hypertensive subjects free from overt cardiac disease seems to be more a risk marker than a risk factor. Although these patients are at high risk, no scientific data exist to support targeting heart rate. In this review, we describe the pathophysiological effects of heart rate, including vascular cell signalling, link with sympathetic activity and influence on central blood pressure, and the prognostic value and management of HR in hypertensive patients free from overt cardiac diseases.

  19. Heart Rate and Risk of Cancer Death in Healthy Men

    PubMed Central

    Jouven, Xavier; Escolano, Sylvie; Celermajer, David; Empana, Jean-Philippe; Bingham, Annie; Hermine, Olivier; Desnos, Michel; Perier, Marie-Cécile; Marijon, Eloi; Ducimetière, Pierre

    2011-01-01

    Background Data from several previous studies examining heart-rate and cardiovascular risk have hinted at a possible relationship between heart-rate and non-cardiac mortality. We thus systematically examined the predictive value of heart-rate variables on the subsequent risk of death from cancer. Methods In the Paris Prospective Study I, 6101 asymptomatic French working men aged 42 to 53 years, free of clinically detectable cardiovascular disease and cancer, underwent a standardized graded exercise test between 1967 and 1972. Resting heart-rate, heart-rate increase during exercise, and decrease during recovery were measured. Change in resting heart-rate over 5 years was also available in 5139 men. Mortality including 758 cancer deaths was assessed over the 25 years of follow-up. Findings There were strong, graded and significant relationships between all heart-rate parameters and subsequent cancer deaths. After adjustment for age and tobacco consumption and, compared with the lowest quartile, those with the highest quartile for resting heart-rate had a relative risk of 2.4 for cancer deaths (95% confidence interval: 1.9–2.9, p<0.0001) This was similar after adjustment for traditional cardiovascular risk factors and was observed for the commonest malignancies (respiratory and gastrointestinal). Similarly, significant relationships with cancer death were observed between poor heart rate increase during exercise, poor decrease during recovery and greater heart-rate increase over time (p<0.0001 for all). Interpretation Resting and exercise heart rate had consistent, graded and highly significant associations with subsequent cancer mortality in men. PMID:21826196

  20. Parasympathetic heart rate modulation during parabolic flights.

    PubMed

    Beckers, F; Seps, B; Ramaekers, D; Verheyden, B; Aubert, A E

    2003-09-01

    During parabolic flight short periods of microgravity and hypergravity are created. These changes influence cardiovascular function differently according to posture. During the 29th parabolic flight campaign of the European Space Agency (ESA), the electrocardiogram (ECG) was recorded continuously in seven healthy volunteers in two positions (standing and supine). Five different phases were differentiated: 1 g (1 g=9.81 m/s(2)) before and after each parabola, 1.8 g at the ascending leg of the parabola (hypergravity), 0 g at the apex, 1.6 g at the descending leg (hypergravity). We assessed heart rate variability (HRV) by indices of temporal analysis [mean RR interval (meanRR), the standard deviation of the intervals (SDRR), and the square root of the mean squared differences of successive intervals (rMSSD) and coefficient of variation (CV)]. In the supine position no significant differences were shown between different gravity phases for all HRV indices. In the standing position the 0 g phase showed a tendency towards higher values of meanRR compared to the control and to the other phases ( p=NS). SDRR, rMSSD and CV were significantly higher compared to control ( p<0.05). Significantly higher values for meanRR in the supine position at 1 g and hypergravity ( p<0.05) were found when compared to standing. SDRR was significantly higher at 0 g in the standing position compared to supine [95 (44) ms vs. 50 (15) ms; p<0.05] and lower in other phases. rMSSD and CV showed the same trend ( p=NS). We confirm that, during parabolic flights, position matters for cardiovascular measurements. Time domain indices of HRV during different gravity phases showed: (1) higher vagal modulation of the autonomic nervous system in microgravity, when compared with normo- or hypergravity in standing subjects; and (2) no differences in supine subjects between different g phases.

  1. Using Target Heart-Rate Zones in Your Class

    ERIC Educational Resources Information Center

    Gilbert, Jennie A.

    2005-01-01

    Should teachers teach the calculation of target heart rate to students? And when is it appropriate to engage students in the attainment of these heart rates during physical education class activities? The answers to these questions are not easy. One might be tempted to state a simple yes or no and to identify a specific age to begin using training…

  2. Neuronal control of heart rate in isolated mouse atria.

    PubMed

    Choate, J K; Feldman, R

    2003-09-01

    A novel mouse isolated atrial preparation with intact postganglionic autonomic innervation was used to investigate the neuronal control of heart rate. To establish whether autonomic activation was likely to alter heart rate by modulating the hyperpolarization-activated current (If), the L-type Ca2+ current (ICa,L), or the ACh-activated K+ current (IK,ACh), the effects of nerve stimulation (right stellate ganglion or right vagus, 1-30 Hz) and autonomic agonists (0.1 microM norepinephrine or 0.3 microM carbachol) on heart rate were investigated in the presence of inhibitors of these currents, cesium chloride (Cs+, 1 mM), nifedipine (200 nM), and barium chloride (Ba2+, 0.1 mM), respectively. The positive chronotropic response to stellate ganglion stimulation was reduced by approximately 20% with Cs+ and nifedipine (P < 0.05), whereas the heart rate response to norepinephrine was only reduced with Cs+ (P < 0.05). Ba2+ attenuated the decrease in heart rate with vagal stimulation and carbachol by approximately 60% (P < 0.05). These results are consistent with the idea that sympathetic nerve stimulation modulates If to increase heart rate in the mouse. Activation of ICa,L also appears to contribute to the sympathetic heart rate response. However, the decrease in heart rate with vagal stimulation or carbachol is likely to result primarily from the activation of IK,ACh.

  3. Effect of Age and Other Factors on Maximal Heart Rate.

    ERIC Educational Resources Information Center

    Londeree, Ben R.; Moeschberger, Melvin L.

    1982-01-01

    To reduce confusion regarding reported effects of age on maximal exercise heart rate, a comprehensive review of the relevant English literature was conducted. Data on maximal heart rate after exercising with a bicycle, a treadmill, and after swimming were analyzed with regard to physical fitness and to age, sex, and racial differences. (Authors/PP)

  4. Assessing Heart Rate in Physical Education. Assessment Series: K-12 Physical Education.

    ERIC Educational Resources Information Center

    Buck, Marilyn M.

    This guide discusses the assessment of heart rate and, in particular, the assessment of heart rate using a heart monitor. Part 1, "Foundation for the Use of Heart Rate," reviews literature about heart rate assessment and heart rate monitors, offering an overview of national guidelines for physical activity. It focuses on the importance of physical…

  5. Effects of different training amplitudes on heart rate and heart rate variability in young rowers.

    PubMed

    Vaz, Marcelo S; Picanço, Luan M; Del Vecchio, Fabrício B

    2014-10-01

    The aim of this study was to investigate the autonomic nervous system recovery and the psychological response as a result of 3 training amplitudes on heart rate (HR), heart rate variability (HRV), and rate of perceived exertion (RPE) in rowing. Eight young rowers (16.8 ± 1.4 years) performed, in a randomized fashion, 2 sessions of high-intensity interval training, with high and low amplitude and a continuous training (CT) session, with the same exercise duration (10 minutes) and mean intensity (60% of maximal stroke test). The data of HR, HRV, and RPE were collected 5 minutes before, immediately after each session, and 24 hours later. High amplitude promoted higher impact in maximum HR (p ≤ 0.05) and RPE (p < 0.001) when compared with CT. For the time domain HRV variable, there was a statistically significant difference between moments of rest (pretraining or post 24 hours) and posttraining in all training sessions. Originally, we conclude that training with higher load variation between effort and recovery impacts HRV, HR, and RPE with greater intensity, but the younger rowers were ready for new training sessions 24 hours after either training method. Coaches can use the polarized training method, observing the stimulus nature and time required for recovery, because it may be an adequate strategy for the development of rower's conditioning. PMID:24736775

  6. Effects of Tai Chi exercise on heart rate variability.

    PubMed

    Cole, Aimee R; Wijarnpreecha, Karn; Chattipakorn, Siriporn C; Chattipakorn, Nipon

    2016-05-01

    Tai Chi is a callisthenic exercise form that incorporates aerobic exercise with diaphragmatic breathing. These two aspects alone have been shown to enhance the heart rate variability, warranting research into the effects of Tai Chi on autonomic nervous system modulation and heart rate variability. A low heart rate variability has been shown to be indicative of compromised health. Any methods to enhance the heart rate variability, in particular, non-pharmacological methods, are therefore seen as beneficial to health and are sought after. The aim of this review was to comprehensively summarize the currently published studies regarding the effects of Tai Chi on heart rate variability. Both consistent and inconsistent findings are presented and discussed, and an overall conclusion attained which could benefit future clinical studies.

  7. The Effect of Exertion on Heart Rate and Rating of Perceived Exertion in Acutely Concussed Individuals

    PubMed Central

    Hinds, Andrea; Leddy, John; Freitas, Michael; Czuczman, Natalie; Willer, Barry

    2016-01-01

    Objective Research suggests that one physiological effect of concussion is a disruption in regulation of autonomic nervous system control that affects the balance between parasympathetic and sympathetic output. While changes in heart rate after concussion have been observed, the nature of the heart rate change during progressive exercise has not been well evaluated in acutely symptomatic patients. Additionally, little is known about the relationship between HR and RPE in this population. Methods We compared changes in heart rate and perceived effort during graded treadmill exertion in recently concussed patients to elucidate the effect of brain injury on cardiovascular response to exercise. Resting HR, HR on exercise initiation, and changes in HR and RPE during the Buffalo Concussion Treadmill Test (BCTT) were compared on two test visits: When patients were symptomatic (acute) and after recovery. Results were compared with the test-retest results obtained from a control group consisting of healthy, non-concussed individuals. Results Patients had a significantly lower HR at onset of exercise when acutely concussed as compared to when recovered and reported greater perceived exertion at every exercise intensity level when symptomatic, despite exercising at lower workloads, than when recovered. Sympathetic response to increased exertion was not affected by concussion - HR increased in response to exercise at a comparable rate in both tests. These differences observed in response to exercise between the first BCTT and follow-up evaluation in initially concussed patients were not present in non-concussed individuals. Conclusion Our results suggest that during the acute phase after concussion, acutely concussed patients demonstrated an impaired ability to shift from parasympathetic to sympathetic control over heart rate at the onset of exercise. Changes in the autonomic nervous system after concussion may be more complex than previously reported. Continued evaluation of

  8. The effect of heart rate on the heart rate variability response to autonomic interventions.

    PubMed

    Billman, George E

    2013-01-01

    Heart rate variability (HRV), the beat-to-beat variation in either heart rate (HR) or heart period (R-R interval), has become a popular clinical and investigational tool to quantify cardiac autonomic regulation. However, it is not widely appreciated that, due to the inverse curvilinear relationship between HR and R-R interval, HR per se can profoundly influence HRV. It is, therefore, critical to correct HRV for the prevailing HR particularly, as HR changes in response to autonomic neural activation or inhibition. The present study evaluated the effects of HR on the HRV response to autonomic interventions that either increased (submaximal exercise, n = 25 or baroreceptor reflex activation, n = 20) or reduced (pharmacological blockade: β-adrenergic receptor, muscarinic receptor antagonists alone and in combination, n = 25, or bilateral cervical vagotomy, n = 9) autonomic neural activity in a canine model. Both total (RR interval standard deviation, RRSD) and the high frequency (HF) variability (HF, 0.24-1.04 Hz) were determined before and in response to an autonomic intervention. All interventions that reduced or abolished cardiac parasympathetic regulation provoked large reductions in HRV even after HR correction [division by mean RRsec or (mean RRsec)(2) for RRSD and HF, respectively] while interventions that reduced HR yielded mixed results. β-adrenergic receptor blockade reduced HRV (RRSD but not HF) while both RRSD and HF increased in response to increases in arterial blood (baroreceptor reflex activation) even after HR correction. These data suggest that the physiological basis for HRV is revealed after correction for prevailing HR and, further, that cardiac parasympathetic activity is responsible for a major portion of the HRV in the dog.

  9. Learning by Heart: Students Use Heart Rate Patterns To Identify Nervous System Imbalances.

    ERIC Educational Resources Information Center

    Ackerly, Spafford C.

    2001-01-01

    Introduces a science unit on heart rate variability (HVR) patterns. Uses spectral analysis to determine the effects of environmental stimulants such as music and emotional stress on heart rate. Observes relaxation techniques and their effects on the autonomous nervous system. (Contains 12 references.) (YDS)

  10. Opportunity for information search and the effect of false heart rate feedback.

    PubMed

    Barefoot, John C; Straub, Ronald B

    2005-01-01

    The role of information search in the attribution of physiological states was investigated by manipulating the subject's opportunity for information search following the presentation of false information about his heart-rate reactions to photographs of female nudes. Consistent with the self-persuasion hypothesis proposed by Valins, the rated attractiveness of the slides was not affected by the false heart-rate feedback for those subjects who were prevented from visually searching the slides. Those subjects who had ample opportunity to view the slides rated those slides accompanied by false information of a heart-rate change as more attractive than those slides which were not paired with a change in heart rate. PMID:17477208

  11. Remote measurement of cognitive stress via heart rate variability.

    PubMed

    McDuff, Daniel; Gontarek, Sarah; Picard, Rosalind

    2014-01-01

    Remote detection of cognitive load has many powerful applications, such as measuring stress in the workplace. Cognitive tasks have an impact on breathing and heart rate variability (HRV). We show that changes in physiological parameters during cognitive stress can be captured remotely (at a distance of 3m) using a digital camera. A study (n=10) was conducted with participants at rest and under cognitive stress. A novel five band digital camera was used to capture videos of the face of the participant. Significantly higher normalized low frequency HRV components and breathing rates were measured in the stress condition when compared to the rest condition. Heart rates were not significantly different between the two conditions. We built a person-independent classifier to predict cognitive stress based on the remotely detected physiological parameters (heart rate, breathing rate and heart rate variability). The accuracy of the model was 85% (35% greater than chance). PMID:25570611

  12. Thermal Acclimation of Heart Rates in Reptilian Embryos

    PubMed Central

    Du, Wei-Guo; Ye, Hua; Zhao, Bo; Warner, Daniel A.; Shine, Richard

    2010-01-01

    In many reptiles, the thermal regimes experienced by eggs in natural nests vary as a function of ambient weather and location, and this variation has important impacts on patterns of embryonic development. Recent advances in non-invasive measurement of embryonic heart rates allow us to answer a long-standing puzzle in reptilian developmental biology: Do the metabolic and developmental rates of embryos acclimate to local incubation regimes, as occurs for metabolic acclimation by post-hatching reptiles? Based on a strong correlation between embryonic heart rate and oxygen consumption, we used heart rates as a measure of metabolic rate. We demonstrate acclimation of heart rates relative to temperature in embryos of one turtle, one snake and one lizard species that oviposit in relatively deep nests, but found no acclimation in another lizard species that uses shallow (and hence, highly thermally variable) nests. Embryonic thermal acclimation thus is widespread, but not ubiquitous, within reptiles. PMID:21179473

  13. [Association between level of intelligence and heart rate variability].

    PubMed

    Mukhin, V N; Iakovlev, N M

    2011-08-01

    Earlier we discovered that heart rate variability was associated with the level of intelligence. The purpose of this study is to confirm this association using more reliable method and to define more precisely the frequency band within which the amplitude of the heart rate modulations is related to intelligence. 13 males (aged 14 to 17) were the study subjects. The total score of the computer game Tetris was taken as a general measure of the intelligence level. Heart rate was recorded electrocardiographically both at rest and during playing Tetris. Frequency analysis of heart rate was carried out with digital Fourier transformation. Correlation analysis showed that there was positive association between the level of intelligence and the amplitude of heart rate modulation at the frequencies 0.30 and 0.15 modulations per RR interval. This association is closer for the heart rate at rest than for the heart rate during mental work and for the frequency 0.30 than for the 0.15 modulations per RR interval.

  14. Dynamic heart rate estimation using principal component analysis.

    PubMed

    Yu, Yong-Poh; Raveendran, P; Lim, Chern-Loon; Kwan, Ban-Hoe

    2015-11-01

    In this paper, facial images from various video sequences are used to obtain a heart rate reading. In this study, a video camera is used to capture the facial images of eight subjects whose heart rates vary dynamically, between 81 and 153 BPM. Principal component analysis (PCA) is used to recover the blood volume pulses (BVP) which can be used for the heart rate estimation. An important consideration for accuracy of the dynamic heart rate estimation is to determine the shortest video duration that realizes it. This video duration is chosen when the six principal components (PC) are least correlated amongst them. When this is achieved, the first PC is used to obtain the heart rate. The results obtained from the proposed method are compared to the readings obtained from the Polar heart rate monitor. Experimental results show the proposed method is able to estimate the dynamic heart rate readings using less computational requirements when compared to the existing method. The mean absolute error and the standard deviation of the absolute errors between experimental readings and actual readings are 2.18 BPM and 1.71 BPM respectively.

  15. Fractal and complexity measures of heart rate variability.

    PubMed

    Perkiömäki, Juha S; Mäkikallio, Timo H; Huikuri, Heikki V

    2005-01-01

    Heart rate variability has been analyzed conventionally with time and frequency domain methods, which measure the overall magnitude of RR interval fluctuations around its mean value or the magnitude of fluctuations in some predetermined frequencies. Analysis of heart rate dynamics by methods based on chaos theory and nonlinear system theory has gained recent interest. This interest is based on observations suggesting that the mechanisms involved in cardiovascular regulation likely interact with each other in a nonlinear way. Furthermore, recent observational studies suggest that some indexes describing nonlinear heart rate dynamics, such as fractal scaling exponents, may provide more powerful prognostic information than the traditional heart rate variability indexes. In particular, the short-term fractal scaling exponent measured by the detrended fluctuation analysis method has predicted fatal cardiovascular events in various populations. Approximate entropy, a nonlinear index of heart rate dynamics, that describes the complexity of RR interval behavior, has provided information on the vulnerability to atrial fibrillation. Many other nonlinear indexes, e.g., Lyapunov exponent and correlation dimensions, also give information on the characteristics of heart rate dynamics, but their clinical utility is not well established. Although concepts of chaos theory, fractal mathematics, and complexity measures of heart rate behavior in relation to cardiovascular physiology or various cardiovascular events are still far away from clinical medicine, they are a fruitful area for future research to expand our knowledge concerning the behavior of cardiovascular oscillations in normal healthy conditions as well as in disease states.

  16. Dynamic heart rate estimation using principal component analysis

    PubMed Central

    Yu, Yong-Poh; Raveendran, P.; Lim, Chern-Loon; Kwan, Ban-Hoe

    2015-01-01

    In this paper, facial images from various video sequences are used to obtain a heart rate reading. In this study, a video camera is used to capture the facial images of eight subjects whose heart rates vary dynamically, between 81 and 153 BPM. Principal component analysis (PCA) is used to recover the blood volume pulses (BVP) which can be used for the heart rate estimation. An important consideration for accuracy of the dynamic heart rate estimation is to determine the shortest video duration that realizes it. This video duration is chosen when the six principal components (PC) are least correlated amongst them. When this is achieved, the first PC is used to obtain the heart rate. The results obtained from the proposed method are compared to the readings obtained from the Polar heart rate monitor. Experimental results show the proposed method is able to estimate the dynamic heart rate readings using less computational requirements when compared to the existing method. The mean absolute error and the standard deviation of the absolute errors between experimental readings and actual readings are 2.18 BPM and 1.71 BPM respectively. PMID:26601022

  17. Stochastic heart-rate model can reveal pathologic cardiac dynamics

    NASA Astrophysics Data System (ADS)

    Kuusela, Tom

    2004-03-01

    A simple one-dimensional Langevin-type stochastic difference equation can simulate the heart-rate fluctuations in a time scale from minutes to hours. The model consists of a deterministic nonlinear part and a stochastic part typical of Gaussian noise, and both parts can be directly determined from measured heart-rate data. Data from healthy subjects typically exhibit the deterministic part with two or more stable fixed points. Studies of 15 congestive heart-failure subjects reveal that the deterministic part of pathologic heart dynamics has no clear stable fixed points. Direct simulations of the stochastic model for normal and pathologic cases can produce statistical parameters similar to those of real subjects. Results directly indicate that pathologic situations simplify the heart-rate control system.

  18. Mercury Exposure and Heart Rate Variability: A Systematic Review

    PubMed Central

    Gribble, Matthew O.; Cheng, Alan; Berger, Ronald D.; Rosman, Lori; Guallar, Eliseo

    2015-01-01

    Background Mercury affects the nervous system and has been implicated in altering heart rhythm and function. We sought to better define its role in modulating heart rate variability, a well-known marker of cardiac autonomic function. Design Systematic review. Methods We searched PubMed, Embase, TOXLINE and DART databases without language restriction. We report findings as a qualitative systematic review because heterogeneity in study design and assessment of exposures and outcomes across studies, as well as other methodological limitations of the literature, precluded a quantitative meta-analysis. Results We identified 12 studies of mercury exposure and heart rate variability in human populations (10 studies involving primarily environmental methylmercury exposure and two studies involving occupational exposure to inorganic mercury) conducted in Japan, the Faroe Islands, Canada, Korea, French Polynesia, Finland and Egypt. The association of prenatal mercury exposure with lower high-frequency band scores (thought to reflect parasympathetic activity) in several studies, in particular the inverse association of cord blood mercury levels with the coefficient of variation of the R-R intervals and with low frequency and high frequency bands at 14 years of age in the Faroe Islands birth cohort study, suggests that early mercury exposure could have a long-lasting effect on cardiac parasympathetic activity. Studies with later environmental exposures to mercury in children or in adults were heterogeneous and did not show consistent associations. Conclusions The evidence was too limited to draw firm causal inferences. Additional research is needed to elucidate the effects of mercury on cardiac autonomic function, particularly as early-life exposures might have lasting impacts on cardiac parasympathetic function. PMID:26231507

  19. Heart Rate Turbulence as Risk-Predictor after Myocardial Infarction

    PubMed Central

    Zuern, Christine S.; Barthel, Petra; Bauer, Axel

    2011-01-01

    Heart rate turbulence (HRT) is the baroreflex-mediated short-term oscillation of cardiac cycle lengths after spontaneous ventricular premature complexes. HRT is composed of a brief heart rate acceleration followed by a gradual heart rate deceleration. In high risk patients after myocardial infarction (MI) HRT is blunted or diminished. Since its first description in 1999 HRT emerged as one of the most potent risk factors after MI. Predictive power of HRT has been studied in more than 10,000 post-infarction patients. This review is intended to provide an overview of HRT as risk-predictor after MI. PMID:22180744

  20. Phase Transition in a Healthy Human Heart Rate

    NASA Astrophysics Data System (ADS)

    Kiyono, Ken; Struzik, Zbigniew R.; Aoyagi, Naoko; Togo, Fumiharu; Yamamoto, Yoshiharu

    2005-07-01

    A healthy human heart rate displays complex fluctuations which share characteristics of physical systems in a critical state. We demonstrate that the human heart rate in healthy individuals undergoes a dramatic breakdown of criticality characteristics, reminiscent of continuous second order phase transitions. By studying the germane determinants, we show that the hallmark of criticality—highly correlated fluctuations—is observed only during usual daily activity, and a breakdown of these characteristics occurs in prolonged, strenuous exercise and sleep. This finding is the first reported discovery of the dynamical phase transition phenomenon in a biological control system and will be a key to understanding the heart rate control system in health and disease.

  1. Scaling Behaviour and Memory in Heart Rate of Healthy Human

    NASA Astrophysics Data System (ADS)

    Cai, Shi-Min; Peng, Hu; Yang, Hui-Jie; Zhou, Tao; Zhou, Pei-Ling; Wang, Bing-Hong

    2007-10-01

    We investigate a set of complex heart rate time series from healthy human in different behaviour states with the detrended fluctuation analysis and diffusion entropy (DE) method. It is proposed that the scaling properties are influenced by behaviour states. The memory detected by DE exhibits an approximately same pattern after a detrending procedure. Both of them demonstrate the long-range strong correlations in heart rate. These findings may be helpful to understand the underlying dynamical evolution process in the heart rate control system, as well as to model the cardiac dynamic process.

  2. Accurate heart rate estimation from camera recording via MUSIC algorithm.

    PubMed

    Fouladi, Seyyed Hamed; Balasingham, Ilangko; Ramstad, Tor Audun; Kansanen, Kimmo

    2015-01-01

    In this paper, we propose an algorithm to extract heart rate frequency from video camera using the Multiple SIgnal Classification (MUSIC) algorithm. This leads to improved accuracy of the estimated heart rate frequency in cases the performance is limited by the number of samples and frame rate. Monitoring vital signs remotely can be exploited for both non-contact physiological and psychological diagnosis. The color variation recorded by ordinary cameras is used for heart rate monitoring. The orthogonality between signal space and noise space is used to find more accurate heart rate frequency in comparison with traditional methods. It is shown via experimental results that the limitation of previous methods can be overcome by using subspace methods. PMID:26738015

  3. A comparison between heart rate and heart rate variability as indicators of cardiac health and fitness.

    PubMed

    Grant, Catharina C; Murray, Carien; Janse van Rensburg, Dina C; Fletcher, Lizelle

    2013-01-01

    Quantification of cardiac autonomic activity and control via heart rate (HR) and heart rate variability (HRV) is known to provide prognostic information in clinical populations. Issues with regard to standardization and interpretation of HRV data make the use of the more easily accessible HR on its own as an indicator of autonomic cardiac control very appealing. The aim of this study was to investigate the strength of associations between an important cardio vascular health metric such as VO2max and the following: HR, HRV indicators, and HR normalized HRV indicators. A cross sectional descriptive study was done including 145 healthy volunteers aged between 18 and 22 years. HRV was quantified by time domain, frequency domain and Poincaré plot analysis. Indirect VO2max was determined using the Multistage Coopers test. The Pearson correlation coefficient was calculated to quantify the strength of the associations. Both simple linear and multiple stepwise regressions were performed to be able to discriminate between the role of the individual indicators as well as their combined association with VO2max. Only HR, RR interval, and pNN50 showed significant (p < 0.01, p < 0.01, and p = 0.03) correlations with VO2max. Stepwise multiple regression indicated that, when combining all HRV indicators the most important predictor of cardio vascular fitness as represented by VO2max, is HR. HR explains 17% of the variation, while the inclusion of HF (high frequency HRV indicator) added only an additional 3.1% to the coefficient of determination. Results also showed when testing the normalized indicators, HR explained of the largest percentage of the changes in VO2max (16.5%). Thus, HR on its own is the most important predictor of changes in an important cardiac health metric such as VO2max. These results may indicate that during investigation of exercise ability (VO2max) phenomena, quantification of HRV may not add significant value. PMID:24312058

  4. Interaction Between Heart Rate Variability and Heart Rate in Pediatric Population

    PubMed Central

    Gąsior, Jakub S.; Sacha, Jerzy; Jeleń, Piotr J.; Pawłowski, Mariusz; Werner, Bożena; Dąbrowski, Marek J.

    2015-01-01

    Background: Heart rate variability (HRV) is primarily heart rate (HR) dependent, and therefore, different HR may exert different impact on HRV. The objectives of the study were to evaluate the effect of HR on HRV in children and to determine whether HRV indices normalized to HR are sex- and age-related. Methods: Short-term ECG recordings were performed in 346 healthy children. Standard time and frequency domain HRV parameters and HR were analyzed in four age subgroups (6–7, 8–9, 10–11, and 12–13 years old). To investigate the HR impact on HRV, standard HRV parameters were normalized to prevailing HR. Results: Standard HRV measures did not differ between age subgroups, however, HR significantly decreased with subjects age and turned out to be the strongest determinant of HRV. The normalization of HRV to prevailing HR allowed to show that sex-related differences in standard HRV resulted from differences in HR between boys and girls. The normalized HRV significantly decreased with age—before the normalization this effect was masked by age-related HR alterations. Conclusions: HR significantly impacts HRV in pediatric population and turns out to be the strongest determinant of all standard HRV indices. The differences in standard HRV between boys and girls result from differences in their HR. The normalized HRV is decreasing with age in healthy children and it is accompanied by the reduction of HR—as a net result, the standard HRV is constant in children at different ages. This may reflect the maturation of the autonomic nervous system. PMID:26733878

  5. Heart rate, startle response, and intrusive trauma memories

    PubMed Central

    Chou, Chia-Ying; Marca, Roberto La; Steptoe, Andrew; Brewin, Chris R

    2014-01-01

    The current study adopted the trauma film paradigm to examine potential moderators affecting heart rate (HR) as an indicator of peritraumatic psychological states and as a predictor of intrusive memories. We replicated previous findings that perifilm HR decreases predicted the development of intrusive images and further showed this effect to be specific to images rather than thoughts, and to detail rather than gist recognition memory. Moreover, a group of individuals showing both an atypical sudden reduction in HR after a startle stimulus and higher trait dissociation was identified. Only among these individuals was lower perifilm HR found to indicate higher state dissociation, fear, and anxiety, along with reduced vividness of intrusions. The current findings emphasize how peritraumatic physiological responses relate to emotional reactions and intrusive memory. The moderating role of individual difference in stress defense style was highlighted. PMID:24397333

  6. Chronomics of heart rate variability on earth and in space.

    PubMed

    Otsuka, K; Izumi, R; Ishioka, N; Ohshima, H; Mukai, C

    2009-10-01

    Chronomes are time structures consisting of multifrequency rhythms, elements of chaos, and trends in chaotic and rhythmic endpoints. Chronomics maps the dynamics of organisms' broad interactions with the environment near and far, rather than merely the daily routines. We introduced the chronomics of heart rate variability (HRV), characterized by a broad time structure, that includes the prominent circadians and also ultradian (notably about 8h and about 12h) and infradian (notably about-weekly, about-yearly, and about 10-yearly) changes, in addition to undergoing trends with aging. Alterations in these HRV chronomes are known to predict the presence of disease in the near future. Thus, for the health and safety of astronauts, HRV chronomes should be assessed before, during and after the mission in the International Space Station to check for any alteration. Future work should focus on how phenomena in the cosmos, including helio- and geomagnetics, can affect physiological chronomes, those of the HRV in particular.

  7. Signal processing methodologies for an acoustic fetal heart rate monitor

    NASA Technical Reports Server (NTRS)

    Pretlow, Robert A., III; Stoughton, John W.

    1992-01-01

    Research and development is presented of real time signal processing methodologies for the detection of fetal heart tones within a noise-contaminated signal from a passive acoustic sensor. A linear predictor algorithm is utilized for detection of the heart tone event and additional processing derives heart rate. The linear predictor is adaptively 'trained' in a least mean square error sense on generic fetal heart tones recorded from patients. A real time monitor system is described which outputs to a strip chart recorder for plotting the time history of the fetal heart rate. The system is validated in the context of the fetal nonstress test. Comparisons are made with ultrasonic nonstress tests on a series of patients. Comparative data provides favorable indications of the feasibility of the acoustic monitor for clinical use.

  8. SCUBA-dive-related changes in heart rate in children.

    PubMed

    Winkler, Bernd E; Tetzlaff, Kay; Muth, Claus-Martin; Paulat, Klaus; Hebestreit, Helge

    2011-08-01

    The purpose of this study was to monitor heart rate (HR) and rhythm during open water SCUBA dives. Nine children performed 25-min open water SCUBA dives to 8 m depth. Before, during and after these dives, ECG was recorded. Compared with predive heart rate, heart rate declined by -24 ± 8% (range -36%; -15%) during the dive. In some children a further decline in HR was observed within the last minutes of the dive. Older and taller subjects and those with a high initial HR showed a more pronounced decline in HR. Furthermore singular supraventricular and ventricular extrasystoles were observed in some children. Immersion as well as facial and skin cooling presumably account for the initial decline in heart rate. A further drop in HR within the last minutes of the dive might be related to mild hypothermia. Single supraventricular and ventricular extrasystoles might occur in healthy children during dives.

  9. Heart Rate Response and Lactic Acid Concentration in Squash Players.

    ERIC Educational Resources Information Center

    Beaudin, Paula; And Others

    1978-01-01

    It was concluded that playing squash is an activity that results in heart rate responses of sufficient intensity to elicit aerobic training effects without producing high lactic acid concentration in the blood. (MM)

  10. Electrocardiogram, heart movement and heart rate in the awake gecko (Hemidactylus mabouia).

    PubMed

    Germer, Carina M; Tomaz, Juliana M; Carvalho, Ana F; Bassani, Rosana A; Bassani, José W M

    2015-01-01

    The electrocardiogram (ECG) is the simplest and most effective non-invasive method to assess the electrical activity of the heart and to obtain information on the heart rate (HR) and rhythm. Because information on the HR of very small reptiles (body mass <10 g) is still scarce in the literature, in the present work we describe a procedure for recording the ECG in non-anesthetized geckos (Hemidactylus mabouia, Moreau de Jonnès, 1818) under different conditions, namely manual restraint (MR), spontaneous tonic immobility (TI), and in the non-restrained condition (NR). In the gecko ECG, the P, QRS and T waves were clearly distinguishable. The HR was 2.83 ± 0.02 Hz under MR, which was significantly greater (p < 0.001) than the HR under the TI (1.65 ± 0.09 Hz) and NR (1.60 ± 0.10 Hz) conditions. Spontaneously beating isolated gecko hearts contracted at 0.84 ± 0.03 Hz. The in vitro beating rate was affected in a concentration-dependent fashion by adrenoceptor stimulation with noradrenaline, as well as by the muscarinic cholinergic agonist carbachol, which produced significant positive and negative chronotropic effects, respectively (p < 0.001). To our knowledge, this is the first report on the ECG morphology and HR values in geckos, particularly under TI. The methodology and instrumentation developed here are useful for non-invasive in vivo physiological and pharmacological studies in small reptiles without the need of physical restraint or anesthesia.

  11. Accuracy of Heart Rate Watches: Implications for Weight Management

    PubMed Central

    2016-01-01

    Background Wrist-worn monitors claim to provide accurate measures of heart rate and energy expenditure. People wishing to lose weight use these devices to monitor energy balance, however the accuracy of these devices to measure such parameters has not been established. Aim To determine the accuracy of four wrist-worn devices (Apple Watch, Fitbit Charge HR, Samsung Gear S and Mio Alpha) to measure heart rate and energy expenditure at rest and during exercise. Methods Twenty-two healthy volunteers (50% female; aged 24 ± 5.6 years) completed ~1-hr protocols involving supine and seated rest, walking and running on a treadmill and cycling on an ergometer. Data from the devices collected during the protocol were compared with reference methods: electrocardiography (heart rate) and indirect calorimetry (energy expenditure). Results None of the devices performed significantly better overall, however heart rate was consistently more accurate than energy expenditure across all four devices. Correlations between the devices and reference methods were moderate to strong for heart rate (0.67–0.95 [0.35 to 0.98]) and weak to strong for energy expenditure (0.16–0.86 [-0.25 to 0.95]). All devices underestimated both outcomes compared to reference methods. The percentage error for heart rate was small across the devices (range: 1–9%) but greater for energy expenditure (9–43%). Similarly, limits of agreement were considerably narrower for heart rate (ranging from -27.3 to 13.1 bpm) than energy expenditure (ranging from -266.7 to 65.7 kcals) across devices. Conclusion These devices accurately measure heart rate. However, estimates of energy expenditure are poor and would have implications for people using these devices for weight loss. PMID:27232714

  12. Heart rate variability in natural time and 1/f "noise"

    NASA Astrophysics Data System (ADS)

    Sarlis, N. V.; Skordas, E. S.; Varotsos, P. A.

    2009-07-01

    Several studies have shown that heart rate fluctuations exhibit the ubiquitous 1/f behavior which is altered in desease. Furthermore, the analysis of electrocardiograms in natural time reveals that important malfunctions in the complex system of the human heart can be identified. Here, we present a simple evolution model in natural time that exhibits the 1/fa behavior with a close to unity. The results of this model are consistent with a progressive modification of heart rate variability in healthy children and adolescents. The model results in complexity measures that separate healthy dynamics from patients as well as from sudden cardiac death individuals.

  13. Digital heart rate measurement based on Atmega16L

    NASA Astrophysics Data System (ADS)

    Zhang, Xiaoqing; Feng, Lishuang; Wang, Jiqiang

    2008-02-01

    The photoelectric heart rate meter reported in this paper picks up heart rate signals with a photoelectric cell, converts them into standard TTL pulse signal, and sends them into the input capture interface of a single-chip computer Atmega16L. Its input capture register can capture the Timer/Counter value at a given external (edge triggered) event on the input capture pin (ICP1) of T/C1. The counter number is sent into T/C1's input capture register ICR1 after the voltage of the input capture pin ICP1 jumped according to the program setting. The single-chip computer catches the input pulse signal as some numerical values of Timer/Counter (T/C1) and works out a single heart rate cycle and displays by three seven segment tubes, which are the peripheral equipments of the single-chip computer. ICCAVR integrated compiler is applied to assemble and compile the software programs of the heart rate meter. After the programs compiled successfully, a HEX file is produced and downloaded into the single chip computer by software SLISP. This photoelectric heart rate meter can measure the people heart rate efficiently with measurement range of 10-200 times per minute, precision of +/- 1%, low cost and reliable performance.

  14. Facial electromyogram and heart-rate correlates of a paradoxical attitude change to antinuclear war information

    SciTech Connect

    Vigne, J.J.; Dale, J.A.; Klions, H.L.

    1988-12-01

    The effects of film images versus film descriptions of the effects of nuclear explosions (versus a no-film control) on corrugator muscle tension, heart rate, attitude and mood were investigated. The last 5 min. of the images were associated with more corrugator tension for that condition when compared to the last 5 min. of the description condition. The groups did not differ in heart rate but women in both groups showed an increase in heart rate whereas men in both groups showed a decrease in heart rate. Film groups did not differ in their significant increases in anxiety, hostility, and depression on the Multiple Adjective Affect Checklist. On the pretest there was no significant correlation between scores on Betts' Questionnaire Upon Mental Imagery and scores on Goldenring and Doctor's index of concern for nuclear war. The vivid-image film group showed a decrease in concern for nuclear war when compared to the descriptive film group and the no-film control.

  15. 1/f scaling in heart rate requires antagonistic autonomic control

    NASA Astrophysics Data System (ADS)

    Struzik, Zbigniew R.; Hayano, Junichiro; Sakata, Seiichiro; Kwak, Shin; Yamamoto, Yoshiharu

    2004-11-01

    We present systematic evidence for the origins of 1/f -type temporal scaling in human heart rate. The heart rate is regulated by the activity of two branches of the autonomic nervous system: the parasympathetic (PNS) and the sympathetic (SNS) nervous systems. We examine alterations in the scaling property when the balance between PNS and SNS activity is modified, and find that the relative PNS suppression by congestive heart failure results in a substantial increase in the Hurst exponent H towards random-walk scaling 1/f2 and a similar breakdown is observed with relative SNS suppression by primary autonomic failure. These results suggest that 1/f scaling in heart rate requires the intricate balance between the antagonistic activity of PNS and SNS.

  16. Adaptive beat-to-beat heart rate estimation in ballistocardiograms.

    PubMed

    Brüser, Christoph; Stadlthanner, Kurt; de Waele, Stijn; Leonhardt, Steffen

    2011-09-01

    A ballistocardiograph records the mechanical activity of the heart. We present a novel algorithm for the detection of individual heart beats and beat-to-beat interval lengths in ballistocardiograms (BCGs) from healthy subjects. An automatic training step based on unsupervised learning techniques is used to extract the shape of a single heart beat from the BCG. Using the learned parameters, the occurrence of individual heart beats in the signal is detected. A final refinement step improves the accuracy of the estimated beat-to-beat interval lengths. Compared to many existing algorithms, the new approach offers heart rate estimates on a beat-to-beat basis. The agreement of the proposed algorithm with an ECG reference has been evaluated. A relative beat-to-beat interval error of 1.79% with a coverage of 95.94% was achieved on recordings from 16 subjects.

  17. Assessing positive emotional states in dogs using heart rate and heart rate variability.

    PubMed

    Zupan, Manja; Buskas, Julia; Altimiras, Jordi; Keeling, Linda J

    2016-03-01

    Since most animal species have been recognized as sentient beings, emotional state may be a good indicator of welfare in animals. The goal of this study was to manipulate the environment of nine beagle research dogs to highlight physiological responses indicative of different emotional experiences. Stimuli were selected to be a more or a less positive food (meatball or food pellet) or social reward (familiar person or less familiar person). That all the stimuli were positive and of different reward value was confirmed in a runway motivation test. Dogs were tested individually while standing facing a display theatre where the different stimuli could be shown by lifting a shutter. The dogs approached and remained voluntarily in the test system. They were tested in four sessions (of 20s each) for each of the four stimuli. A test session consisted of four presentation phases (1st exposure to stimulus, post exposure, 2nd exposure, and access to reward). Heart rate (HR) and heart rate variability (HRV) responses were recorded during testing in the experimental room and also when lying resting in a quiet familiar room. A new method of 'stitching' short periods of HRV data together was used in the analysis. When testing different stimuli, no significant differences were observed in HR and LF:HF ratio (relative power in low frequency (LF) and the high-frequency (HF) range), implying that the sympathetic tone was activated similarly for all the stimuli and may suggest that dogs were in a state of positive arousal. A decrease of HF was associated with the meatball stimulus compared to the food pellet and the reward phase (interacting with the person or eating the food) was associated with a decrease in HF and RMSSD (root mean square of successive differences of inter-beat intervals) compared to the preceding phase (looking at the person or food). This suggests that parasympathetic deactivation is associated with a more positive emotional state in the dog. A similar reduction

  18. Heart Rate Variability and Arrhythmic Burden in Pulmonary Hypertension.

    PubMed

    Witte, C; Meyer Zur Heide Genannt Meyer-Arend, J U; Andrié, R; Schrickel, J W; Hammerstingl, C; Schwab, J O; Nickenig, G; Skowasch, D; Pizarro, C

    2016-01-01

    A growing body of evidence indicates that sudden cardiac death constitutes a major cause of mortality in pulmonary hypertension (PH). As validated method to evaluate cardiac autonomic system dysfunction, alterations in heart rate variability (HRV) are predictive of arrhythmic events, particularly in left ventricular disease. Here, we sought to determine the clinical value of HRV assessment in PH. Sixty-four patients were allocated to different PH-subgroups in this prospectively conducted trial: 25 patients with pulmonary arterial hypertension (PAH), 11 patients with chronic thromboembolic PH (CTEPH), and 28 patients with COPD-induced PH. All patients underwent 24-h Holter electrocardiogram for HRV assessment by time- and frequency-domain analysis. Arrhythmic burden was evaluated by manual analysis and complementary automatic measurement of premature atrial and ventricular contractions. The results were compared to 31 healthy controls. The PAH patients offered a significantly higher mean heart rate (78.6 ± 10.4 bpm vs. 70.1 ± 10.3 bpm, p = 0.04), a higher burden of premature ventricular contractions (p < 0.01), and decreases in HRV (SDNN: p < 0.01; SDANN: p < 0.01; very low frequency: p < 0.01; low frequency/high frequency ratio: p < 0.01; total power: p = 0.02). In CTEPH patients, only the amount of premature ventricular contractions differed from controls (p < 0.01), whereas in COPD both premature atrial contraction count and frequency-domain-based HRV manifested significant differences. In conclusion, PAH appears to be primarily affected by HRV alterations and ventricular arrhythmic burden, indicating a high risk for malignant arrhythmic events. PMID:27241509

  19. Impact of age and basic heart rate on heart rate turbulence in healthy persons.

    PubMed

    Schwab, Jörg Otto; Eichner, Gerrit; Shlevkov, Nikolay; Schrickel, Jan; Yang, Alexander; Balta, Osman; Lewalter, Thorsten; Lüderitz, Berndt

    2005-01-01

    Postextrasystolic acceleration of heart rate (HR), known as HR turbulence (HRT) is attenuated in patients with coronary artery disease at increased risk of adverse events. The influence of age and basic HR on HRT have not been evaluated in a large cohort of persons. In 95 healthy individuals, HRT onset (TO) and slope (TS) were calculated from 24-hour ambulatory electrocardiograms, as well as the turbulence timing (TT). Gender specific differences in TO and TS were compared in simple, linear, weighted regression model. The influence of age and the basic HR preceding ventricular premature contractions on HRT were examined. We found that, in men and women, TO decreases as basic HR increases (P < 0.01). In contrast, in men, TS decreased as basic HR increases, whereas in women, basic HR influenced TS only slightly (P < 0.01). A multiple, linear regression model revealed a decrease in HRT with increasing age in men. In conclusion, physiological acceleration of the HR within the first 11 beats after premature ventricular complex (VPC) was observed in >75% of healthy individuals. An accelerating HR preceding the VPC influenced HRT in men. An increasing age was associated with a decrease in HRT in men and a decrease in TO in women. These results illustrate the importance of physiological modulations of HRT when used for risk stratification, especially in older populations.

  20. Transfer of heart rate feedback training to reduce heart rate response to laboratory tasks.

    PubMed

    Goodie, Jeffrey L; Larkin, Kevin T

    2006-09-01

    To examine whether transfer of heart rate (HR) feedback training to tasks not used during training could be improved by using multiple tasks during training, a modified multiple baseline across tasks, single subject design study was conducted using six high HR-reactive young adults. Participants received HR feedback training during the presentation of a videogame, and transfer of training was assessed to a mental arithmetic challenge and handgrip task. Transfer of training was next assessed following training with the mental arithmetic challenge and handgrip task. HR responses to each training task with no HR feedback were assessed during a pre-treatment session, an immediate post-training period following training on each task, a short delay (1-2 days) post-training session, and a long delay (1-2 weeks) post-training session. HR response to a novel speech task was assessed at pre-treatment and during short delay and long delay post-training sessions. Results revealed that participants reduced HR during training and generally maintained this reduction in HR during the immediate post-training assessment when HR feedback was not present. Participants were not able to reduce HR responses to tasks during short delay and long delay post-training sessions, and they were unable to transfer HR reduction skills to the speech task. Transfer of HR feedback training to new tasks was limited in nature and efforts to train across multiple stressors did not appear to improve transfer of training.

  1. Building trust: Heart rate synchrony and arousal during joint action increased by public goods game.

    PubMed

    Mitkidis, Panagiotis; McGraw, John J; Roepstorff, Andreas; Wallot, Sebastian

    2015-10-01

    The physiological processes underlying trust are subject of intense interest in the behavioral sciences. However, very little is known about how trust modulates the affective link between individuals. We show here that trust has an effect on heart rate arousal and synchrony, a result consistent with research on joint action and experimental economics. We engaged participants in a series of joint action tasks which, for one group of participants, was interleaved with a PGG, and measured their heart synchrony and arousal. We found that the introduction of the economic game shifted participants' attention to the dynamics of the interaction. This was followed by increased arousal and synchrony of heart rate profiles. Also, the degree of heart rate synchrony was predictive of participants' expectations regarding their partners in the economic game. We conclude that the above changes in physiology and behavior are shaped by the valuation of other people's social behavior, and ultimately indicate trust building process.

  2. Effects of middle cerebral artery occlusion on baroreceptor reflex control of heart rate in the rat.

    PubMed

    Saad, M A; Huerta, F; Trancard, J; Elghozi, J L

    1989-07-01

    Neurons in the insular cortex have recently been shown to innervate medullary autonomic nuclei such as the nucleus tractus solitarii (NTS). The present study examines the effect of lesioning the insular cortex on baroreceptor-heart rate reflex in conscious rats. We did this by occluding the stem of the left proximal middle cerebral artery which causes a lesion of the insular and adjacent lateral frontoparietal cortices. Nine and 10 days after lesioning or sham operation, reflex heart rate responses were recorded following i.v. doses of the pressor agent phenylephrine and the depressor agent sodium nitroprusside. Baroreceptor reflex parameters were determined by computerized sigmoidal curve-fitting. The overall contribution of the sympathetic and the cardiac vagus were assessed by using peripherally acting muscarinic and beta-adrenoceptor antagonists, respectively. Lesioned rats were compared to sham-operated rats. Lesioning the insular cortex did not affect mean blood pressure and heart rate. However, the lesion selectively enhanced reflex vagal bradycardia that occurred when mean blood pressure was artificially elevated. A greater vagal bradycardia with no change in the upper plateau indicated that ischemia was acting entirely on the baroreflex-dependent vagal cardiac motoneurons. There was no effect on the sympathetic heart rate range but the normalized gain of the sympathetic component was increased in those lesioned rats. These observations suggest that the unilateral cortical lesion chronically affected the baroreceptor control of heart rate through mechanisms differentially affecting the vagus and the cardiac sympathetic nerves. PMID:2778268

  3. Quantification of fetal heart rate regularity using symbolic dynamics

    NASA Astrophysics Data System (ADS)

    van Leeuwen, P.; Cysarz, D.; Lange, S.; Geue, D.; Groenemeyer, D.

    2007-03-01

    Fetal heart rate complexity was examined on the basis of RR interval time series obtained in the second and third trimester of pregnancy. In each fetal RR interval time series, short term beat-to-beat heart rate changes were coded in 8bit binary sequences. Redundancies of the 28 different binary patterns were reduced by two different procedures. The complexity of these sequences was quantified using the approximate entropy (ApEn), resulting in discrete ApEn values which were used for classifying the sequences into 17 pattern sets. Also, the sequences were grouped into 20 pattern classes with respect to identity after rotation or inversion of the binary value. There was a specific, nonuniform distribution of the sequences in the pattern sets and this differed from the distribution found in surrogate data. In the course of gestation, the number of sequences increased in seven pattern sets, decreased in four and remained unchanged in six. Sequences that occurred less often over time, both regular and irregular, were characterized by patterns reflecting frequent beat-to-beat reversals in heart rate. They were also predominant in the surrogate data, suggesting that these patterns are associated with stochastic heart beat trains. Sequences that occurred more frequently over time were relatively rare in the surrogate data. Some of these sequences had a high degree of regularity and corresponded to prolonged heart rate accelerations or decelerations which may be associated with directed fetal activity or movement or baroreflex activity. Application of the pattern classes revealed that those sequences with a high degree of irregularity correspond to heart rate patterns resulting from complex physiological activity such as fetal breathing movements. The results suggest that the development of the autonomic nervous system and the emergence of fetal behavioral states lead to increases in not only irregular but also regular heart rate patterns. Using symbolic dynamics to

  4. [Analysis of scalp potential activity and heart rate variability during volitional control of heart beat].

    PubMed

    Yu, Xiao-Lin; Zhang, Jian-Bao; Wang, Jue

    2009-07-01

    In the study the changes of scalp potential and cardiac autonomic nervous system during volitional control of heart beat are explored with the wavelet packet parameters and approximate entropy (ApEn) of Electroencephalogram (EEG) and heart rate variability. The results show that volition can control heart beat and the changes of brain activity are earlier than that of autonomic activity. But its control of heart beat is very different from the motor nervous system because different cortical positions are respectively concerned during the quick and slow control of heart beat. The pre-central areas of brain are correlated with parasympathetic activity by which HR is controlled to slow down. The post-central areas of brain are correlated with sympathetic activity by which HR is controlled to accelerate.

  5. AUTONOMIC CONTROL OF HEART RATE AFTER EXERCISE IN TRAINED WRESTLERS

    PubMed Central

    Báez, San Martín E.; Von Oetinger, A.; Cañas, Jamett R.; Ramírez, Campillo R.

    2013-01-01

    The objective of this study was to establish differences in vagal reactivation, through heart rate recovery and heart rate variability post exercise, in Brazilian jiu-jitsu wrestlers (BJJW). A total of 18 male athletes were evaluated, ten highly trained (HT) and eight moderately trained (MT), who performed a maximum incremental test. At the end of the exercise, the R-R intervals were recorded during the first minute of recovery. We calculated heart rate recovery (HRR60s), and performed linear and non-linear (standard deviation of instantaneous beat-to-beat R-R interval variability – SD1) analysis of heart rate variability (HRV), using the tachogram of the first minute of recovery divided into four segments of 15 s each (0-15 s, 15-30 s, 30-45 s, 45-60 s). Between HT and MT individuals, there were statistically significant differences in HRR60s (p <0.05) and in the non linear analysis of HRV from SD130-45s (p <0.05) and SD145-60s (p <0.05). The results of this research suggest that heart rate kinetics during the first minute after exercise are related to training level and can be used as an index for autonomic cardiovascular control in BJJW. PMID:24744476

  6. Autonomic control of heart rate after exercise in trained wrestlers.

    PubMed

    Henríquez, Olguín C; Báez, San Martín E; Von Oetinger, A; Cañas, Jamett R; Ramírez, Campillo R

    2013-06-01

    The objective of this study was to establish differences in vagal reactivation, through heart rate recovery and heart rate variability post exercise, in Brazilian jiu-jitsu wrestlers (BJJW). A total of 18 male athletes were evaluated, ten highly trained (HT) and eight moderately trained (MT), who performed a maximum incremental test. At the end of the exercise, the R-R intervals were recorded during the first minute of recovery. We calculated heart rate recovery (HRR60s), and performed linear and non-linear (standard deviation of instantaneous beat-to-beat R-R interval variability - SD1) analysis of heart rate variability (HRV), using the tachogram of the first minute of recovery divided into four segments of 15 s each (0-15 s, 15-30 s, 30-45 s, 45-60 s). Between HT and MT individuals, there were statistically significant differences in HRR60s (p <0.05) and in the non linear analysis of HRV from SD130-45s (p <0.05) and SD145-60s (p <0.05). The results of this research suggest that heart rate kinetics during the first minute after exercise are related to training level and can be used as an index for autonomic cardiovascular control in BJJW.

  7. Heart rate measurement based on face video sequence

    NASA Astrophysics Data System (ADS)

    Xu, Fang; Zhou, Qin-Wu; Wu, Peng; Chen, Xing; Yang, Xiaofeng; Yan, Hong-jian

    2015-03-01

    This paper proposes a new non-contact heart rate measurement method based on photoplethysmography (PPG) theory. With this method we can measure heart rate remotely with a camera and ambient light. We collected video sequences of subjects, and detected remote PPG signals through video sequences. Remote PPG signals were analyzed with two methods, Blind Source Separation Technology (BSST) and Cross Spectral Power Technology (CSPT). BSST is a commonly used method, and CSPT is used for the first time in the study of remote PPG signals in this paper. Both of the methods can acquire heart rate, but compared with BSST, CSPT has clearer physical meaning, and the computational complexity of CSPT is lower than that of BSST. Our work shows that heart rates detected by CSPT method have good consistency with the heart rates measured by a finger clip oximeter. With good accuracy and low computational complexity, the CSPT method has a good prospect for the application in the field of home medical devices and mobile health devices.

  8. Concurrent validity of the Armour39 heart rate monitor strap.

    PubMed

    Flanagan, Shawn D; Comstock, Brett A; Dupont, William H; Sterczala, Adam R; Looney, Dave P; Dombrowski, Dylan H; McDermott, Danielle M; Bryce, Alexander; Maladouangdock, Jesse; Dunn-Lewis, Courtenay; Luk, Hui-Ying; Szivak, Tunde K; Hooper, David R; Kraemer, William J

    2014-03-01

    New technology offers potential advantages in physically demanding environments where convenience and comfort are important and accurate and reliable data collection is challenging. Nevertheless, it is important to validate the accuracy and reliability of such biological monitoring systems (BMS) before they are adopted. The purpose of this investigation was to assess the concurrent validity of a new heart rate monitor across a range of exercise intensities and with a large and diverse group of male subjects in a large cohort with diverse physical fitness characteristics. Seventy-five men (age, 23 ± 4 years; height, 181 ± 8 cm; body mass, 83 ± 12 kg; estimated V[Combining Dot Above]O2peak, 3.16 ± 0.63 [L·min]) volunteered and completed a graded cycle ergometer exercise protocol while heart rate was continuously monitored before, during, and after exercise with the new device (Armour39) and the gold standard (electrocardiogram). The 2-minute stages included sitting, standing, and cycling with 35 W increments until volitional fatigue. The coefficient of determination between mean heart rate values at each stage was R = 0.99, whereas Pearson correlations (r) at each stage were ≥ 0.99. Heart rates during exercise were typically within 1 beat of each other. The Armour39 BMS, therefore, is an acceptable means for the valid and reliable determination of heart rate under various bodily positions and levels of exertion, including maximal exercise intensity. PMID:23860286

  9. Dual-source computed tomographic coronary angiography: image quality and stenosis diagnosis in patients with high heart rates.

    PubMed

    Zheng, Minwen; Li, Jiayi; Xu, Jian; Chen, Kang; Zhao, Hongliang; Huan, Yi

    2009-01-01

    We sought to evaluate prospectively the effects of heart rate and heart-rate variability on dual-source computed tomographic coronary image quality in patients whose heart rates were high, and to determine retrospectively the accuracy of dual-source computed tomographic diagnosis of coronary artery stenosis in the same patients.We compared image quality and diagnostic accuracy in 40 patients whose heart rates exceeded 70 beats/min with the same data in 40 patients whose heart rates were 70 beats/min or slower. In both groups, we analyzed 1,133 coronary arterial segments. Five hundred forty-five segments (97.7%) in low-heart-rate patients and 539 segments (93.7%) in high-heart-rate patients were of diagnostic image quality. We considered P < 0.05 to be statistically significant. No statistically significant differences between the groups were found in diagnostic-image quality scores of total segments or of any coronary artery, nor were any significant differences found between the groups in the accurate diagnosis of angiographically significant stenosis.Calcification was the chief factor that affected diagnostic accuracy. In high-heart-rate patients, heart-rate variability was significantly related to the diagnostic image quality of all segments (P = 0.001) and of the left circumflex coronary artery (P = 0.016). Heart-rate variability of more than 5 beats/min most strongly contributed to an inability to evaluate segments in both groups. When heart rates rose, the optimal reconstruction window shifted from diastole to systole.The image quality of dual-source computed tomographic coronary angiography at high heart rates enables sufficient diagnosis of stenosis, although variability of heart rates significantly deteriorates image quality. PMID:19436804

  10. The Use of Heart Rate Monitors in Physical Education

    ERIC Educational Resources Information Center

    Nichols, Randall; Davis, Kathryn L.; McCord, Tim; Schmidt, Dave; Slezak, Alex M.

    2009-01-01

    The ever-rising rate of obesity and the need for increased physical activity for young children is well documented. Data suggests that today's youth are not participating in enough quality health-enhancing physical activity either in or outside of school. Heart rate monitors have been used by adult exercisers for many years to monitor and assess…

  11. Effects of two newly synthesized analogues of lidocaine on rat arterial blood pressure and heart rate.

    PubMed

    Al Rasheed, N M; Al Sayed, M I; Al Zuhair, H H; Al Obaid, A R; Fatani, A J

    2001-04-01

    Two new analogues of lidocaine were synthesized at the College of Pharmacy, King Saud University: compound I (Methyl-2-[2-(N,N-diethylamino) acetamido]-3-cyano-4,5-dimethylbenzoate) and compound II (Methyl-2-[2-(piperidino) acetamido]-3-cyano-4,5-dimethylbenzoate). Their influence on the arterial blood pressure and the heart rate of urethane-anaesthetized rats was studied and compared with the actions of lidocaine. Compounds I, II and lidocaine induced significant dose-dependent decreases in the arterial blood pressure and heart rate, which usually returned to basal values within 3-5 min. There were significant differences in the potency of the three compounds in producing their effects on blood pressure and heart rate (P< 0.0001, ANOVA). Compound II was 14 and 6 times more potent in reducing blood pressure and 8 and 2 times more capable of reducing the heart rate than lidocaine and compound I, respectively. The results of this study also indicated the ineffectiveness of antagonists of autonomic, histaminergic and 5-HT receptor, and various vasodilators in blocking the actions of the three compounds on blood pressure and heart rate. Pretreatment with CaCl(2)significantly reduced the hypotension and bradycardia induced by the three compounds, suggesting the involvement of calcium channels, probably of the L type. Several possible mechanisms are postulated. In conclusion, the results direct attention to the capability of the two new compounds to decrease blood pressure and heart rate; affects that may have clinical potential.

  12. Relationship between self-reported activity levels and actual heart rates in teenagers

    SciTech Connect

    Terblanche, A.P.S.; Ozkaynak, H.; Spengler, J.D.; Butler, D.A. )

    1991-08-01

    A study was designed to explore the relationship between self-reported activity levels and actual heart rate (HR) as measured by a portable heart rate monitor. Twenty-two teenagers (8 boys, 14 girls, median age of 16) from Watertown High School, Massachusetts participated in this pilot study which involved continuous monitoring of HR during normal daily activities and simultaneous completion of a time-activity diary. There were 31 successful monitoring sessions ranging from 1.9 to 17 hours with a median monitoring time of 12.6 hours. Four unsuccessful monitoring sessions were experienced due to equipment failure. Apart from participant cooperation, the single most important factor affecting the feasibility of continuous heart rate monitoring was found to be equipment design. Th overall average heart rate observed was 88.4 bpm (SD = 24.3). An individual's correlation coefficient for perceived activity level (documented in half-hour intervals) and heart rate (averaged over the half-hour intervals) varied from 0.24 to 0.89. More than half of the correlation coefficients were below 0.40. There was a significant difference between average heart rate for time spent indoors (90 bpm) versus outdoors (103 bpm) even after correcting for sleeping time. It is concluded that continuous HR monitoring with simultaneous completion of a time/activity dairy is feasible and is a promising source of information for studies on exposure to air pollutants.

  13. Heart rate and heart rate variability in pregnant dairy cows and their fetuses determined by fetomaternal electrocardiography.

    PubMed

    Trenk, Lisa; Kuhl, Juliane; Aurich, Jörg; Aurich, Christine; Nagel, Christina

    2015-11-01

    In this study, fetomaternal electrocardiograms were recorded once weekly in cattle during the last 14 weeks of gestation. From the recorded beat-to-beat (RR) intervals, heart rate and heart rate variability (HRV) variables standard deviation of the RR interval (SDRR) and root mean square of successive RR differences (RMSSD) were calculated. To differentiate between effects of lactation and gestation, pregnant lactating (PL) cows (n = 7) and pregnant nonlactating (PNL) heifers (n = 8) were included. We hypothesized that lactation is associated with stress detectable by HRV analysis. We also followed the hypothesis that heart rate and HRV are influenced by growth and maturation of the fetus toward term. Maternal heart rate changed over time in both groups, and in PL cows, it decreased with drying-off. During the last 5 weeks of gestation, maternal heart rate increased in both groups but was lower in PL cows than in PNL heifers. Maternal HRV did not change over time, but SDRR was significantly higher in PL cows than in PNL heifers, and significant interactions of group × time existed. On the basis of HRV, undisturbed pregnancies are thus no stressor for the dam in cattle. Fetal heart rate decreased from week 14 to week 1 before birth with no difference between groups. Gestational age thus determines heart rate in the bovine fetus. The HRV variables SDRR and RMSSD increased toward the end of gestation in fetuses carried by cows but not in those carried by heifers. The increase in HRV indicates maturation of fetal cardiac regulation which may be overrun by high sympathoadrenal activity in fetuses carried by heifers as suggested by their low HRV. PMID:26279313

  14. Continuous positive airway pressure increases heart rate variability in heart failure patients with obstructive sleep apnoea.

    PubMed

    Gilman, Matthew P; Floras, John S; Usui, Kengo; Kaneko, Yasuyuki; Leung, Richard S T; Bradley, T Douglas

    2008-02-01

    Patients with heart failure or OSA (obstructive sleep apnoea) have reduced HF-HRV (high-frequency heart rate variability), indicating reduced cardiac vagal modulation, a marker of poor prognosis. CPAP (continuous positive airway pressure) abolishes OSA in patients with heart failure, but effects on daytime HF-HRV have not been determined. We hypothesized that, in patients with heart failure, treatment of coexisting OSA by CPAP would increase morning HF-HRV. In 19 patients with heart failure (left ventricular ejection fraction <45%) and OSA (>/=20 apnoeas and hypopnoeas/h of sleep), HF-HRV was quantified before and 1 month after randomization to a control or CPAP-treated group. In the control group (n=7), there were no changes in HF-HRV over the 1 month study during wakefulness in the morning. In the CPAP-treated group (n=12) HF-HRV increased significantly during wakefulness in the morning [from 2.43+/-0.55 to 2.82+/-0.50 log(ms(2)/Hz); P=0.002] due to an increase in transfer function between changes in lung volume and changes in HF-HRV (92.37+/-96.03 to 219.07+/-177.14 ms/l; P=0.01). In conclusion, treatment of coexisting OSA by nocturnal CPAP in patients with heart failure increases HF-HRV during morning wakefulness, indicating improved vagal modulation of heart rate. This may contribute to improved prognosis.

  15. Neuroanatomical substrates for the volitional regulation of heart rate

    PubMed Central

    Jones, Catherine L.; Minati, Ludovico; Nagai, Yoko; Medford, Nick; Harrison, Neil A.; Gray, Marcus; Ward, Jamie; Critchley, Hugo D.

    2015-01-01

    The control of physiological arousal can assist in the regulation of emotional state. A subset cortical and subcortical brain regions are implicated in autonomic control of bodily arousal during emotional behaviors. Here, we combined human functional neuroimaging with autonomic monitoring to identify neural mechanisms that support the volitional regulation of heart rate, a process that may be assisted by visual feedback. During functional magnetic resonance imaging (fMRI), 15 healthy adults performed an experimental task in which they were prompted voluntarily to increase or decrease cardiovascular arousal (heart rate) during true, false, or absent visual feedback. Participants achieved appropriate changes in heart rate, without significant modulation of respiratory rate, and were overall not influenced by the presence of visual feedback. Increased activity in right amygdala, striatum and brainstem occurred when participants attempted to increase heart rate. In contrast, activation of ventrolateral prefrontal and parietal cortices occurred when attempting to decrease heart rate. Biofeedback enhanced activity within occipito-temporal cortices, but there was no significant interaction with task conditions. Activity in regions including pregenual anterior cingulate and ventral striatum reflected the magnitude of successful task performance, which was negatively related to subclinical anxiety symptoms. Measured changes in respiration correlated with posterior insula activation and heart rate, at a more lenient threshold, change correlated with insula, caudate, and midbrain activity. Our findings highlight a set of brain regions, notably ventrolateral prefrontal cortex, supporting volitional control of cardiovascular arousal. These data are relevant to understanding neural substrates supporting interaction between intentional and interoceptive states related to anxiety, with implications for biofeedback interventions, e.g., real-time fMRI, that target emotional

  16. Neuroanatomical substrates for the volitional regulation of heart rate.

    PubMed

    Jones, Catherine L; Minati, Ludovico; Nagai, Yoko; Medford, Nick; Harrison, Neil A; Gray, Marcus; Ward, Jamie; Critchley, Hugo D

    2015-01-01

    The control of physiological arousal can assist in the regulation of emotional state. A subset cortical and subcortical brain regions are implicated in autonomic control of bodily arousal during emotional behaviors. Here, we combined human functional neuroimaging with autonomic monitoring to identify neural mechanisms that support the volitional regulation of heart rate, a process that may be assisted by visual feedback. During functional magnetic resonance imaging (fMRI), 15 healthy adults performed an experimental task in which they were prompted voluntarily to increase or decrease cardiovascular arousal (heart rate) during true, false, or absent visual feedback. Participants achieved appropriate changes in heart rate, without significant modulation of respiratory rate, and were overall not influenced by the presence of visual feedback. Increased activity in right amygdala, striatum and brainstem occurred when participants attempted to increase heart rate. In contrast, activation of ventrolateral prefrontal and parietal cortices occurred when attempting to decrease heart rate. Biofeedback enhanced activity within occipito-temporal cortices, but there was no significant interaction with task conditions. Activity in regions including pregenual anterior cingulate and ventral striatum reflected the magnitude of successful task performance, which was negatively related to subclinical anxiety symptoms. Measured changes in respiration correlated with posterior insula activation and heart rate, at a more lenient threshold, change correlated with insula, caudate, and midbrain activity. Our findings highlight a set of brain regions, notably ventrolateral prefrontal cortex, supporting volitional control of cardiovascular arousal. These data are relevant to understanding neural substrates supporting interaction between intentional and interoceptive states related to anxiety, with implications for biofeedback interventions, e.g., real-time fMRI, that target emotional

  17. Heart rate dynamics in different levels of Zen meditation.

    PubMed

    Peressutti, Caroline; Martín-González, Juan M; M García-Manso, Juan; Mesa, Denkô

    2010-11-01

    The dynamic interactions among physiological rhythms imbedded in the heart rate signal can give valuable insights into autonomic modulation in conditions of reduced outward attention. Therefore, in this study we analyzed the heart rate variability (HRV) in different levels of practice in Zen meditation (Zazen). Nineteen subjects with variable experience took part in this study. In four special cases we collected both HRV and respiration data. The time series were analyzed in frequency domain and also using the Continuous Wavelet Transform, which detects changes in the time domain and in the frequency domain simultaneously. The shifts in the respiratory modulation of heart rate, or respiratory sinus arrhythmia (RSA), reflect the different levels of practice among practitioners with variable experience in Zazen; in turn the modulation of the RSA may reflect changes in the breathing pattern as in the parasympathetic outflow related to the quality and focus of attention in each stage.

  18. Exaggerated heart rate oscillations during two meditation techniques.

    PubMed

    Peng, C K; Mietus, J E; Liu, Y; Khalsa, G; Douglas, P S; Benson, H; Goldberger, A L

    1999-07-31

    We report extremely prominent heart rate oscillations associated with slow breathing during specific traditional forms of Chinese Chi and Kundalini Yoga meditation techniques in healthy young adults. We applied both spectral analysis and a novel analytic technique based on the Hilbert transform to quantify these heart rate dynamics. The amplitude of these oscillations during meditation was significantly greater than in the pre-meditation control state and also in three non-meditation control groups: i) elite athletes during sleep, ii) healthy young adults during metronomic breathing, and iii) healthy young adults during spontaneous nocturnal breathing. This finding, along with the marked variability of the beat-to-beat heart rate dynamics during such profound meditative states, challenges the notion of meditation as only an autonomically quiescent state.

  19. Universal structures of normal and pathological heart rate variability

    PubMed Central

    Gañán-Calvo, Alfonso M.; Fajardo-López, Juan

    2016-01-01

    The circulatory system of living organisms is an autonomous mechanical system softly tuned with the respiratory system, and both developed by evolution as a response to the complex oxygen demand patterns associated with motion. Circulatory health is rooted in adaptability, which entails an inherent variability. Here, we show that a generalized N-dimensional normalized graph representing heart rate variability reveals two universal arrhythmic patterns as specific signatures of health one reflects cardiac adaptability, and the other the cardiac-respiratory rate tuning. In addition, we identify at least three universal arrhythmic profiles whose presences raise in proportional detriment of the two healthy ones in pathological conditions (myocardial infarction; heart failure; and recovery from sudden death). The presence of the identified universal arrhythmic structures together with the position of the centre of mass of the heart rate variability graph provide a unique quantitative assessment of the health-pathology gradient. PMID:26912108

  20. Universal structures of normal and pathological heart rate variability.

    PubMed

    Gañán-Calvo, Alfonso M; Fajardo-López, Juan

    2016-02-25

    The circulatory system of living organisms is an autonomous mechanical system softly tuned with the respiratory system, and both developed by evolution as a response to the complex oxygen demand patterns associated with motion. Circulatory health is rooted in adaptability, which entails an inherent variability. Here, we show that a generalized N-dimensional normalized graph representing heart rate variability reveals two universal arrhythmic patterns as specific signatures of health one reflects cardiac adaptability, and the other the cardiac-respiratory rate tuning. In addition, we identify at least three universal arrhythmic profiles whose presences raise in proportional detriment of the two healthy ones in pathological conditions (myocardial infarction; heart failure; and recovery from sudden death). The presence of the identified universal arrhythmic structures together with the position of the centre of mass of the heart rate variability graph provide a unique quantitative assessment of the health-pathology gradient.

  1. [An Algorithm for Correcting Fetal Heart Rate Baseline].

    PubMed

    Li, Xiaodong; Lu, Yaosheng

    2015-10-01

    Fetal heart rate (FHR) baseline estimation is of significance for the computerized analysis of fetal heart rate and the assessment of fetal state. In our work, a fetal heart rate baseline correction algorithm was presented to make the existing baseline more accurate and fit to the tracings. Firstly, the deviation of the existing FHR baseline was found and corrected. And then a new baseline was obtained finally after treatment with some smoothing methods. To assess the performance of FHR baseline correction algorithm, a new FHR baseline estimation algorithm that combined baseline estimation algorithm and the baseline correction algorithm was compared with two existing FHR baseline estimation algorithms. The results showed that the new FHR baseline estimation algorithm did well in both accuracy and efficiency. And the results also proved the effectiveness of the FHR baseline correction algorithm.

  2. Universal structures of normal and pathological heart rate variability.

    PubMed

    Gañán-Calvo, Alfonso M; Fajardo-López, Juan

    2016-01-01

    The circulatory system of living organisms is an autonomous mechanical system softly tuned with the respiratory system, and both developed by evolution as a response to the complex oxygen demand patterns associated with motion. Circulatory health is rooted in adaptability, which entails an inherent variability. Here, we show that a generalized N-dimensional normalized graph representing heart rate variability reveals two universal arrhythmic patterns as specific signatures of health one reflects cardiac adaptability, and the other the cardiac-respiratory rate tuning. In addition, we identify at least three universal arrhythmic profiles whose presences raise in proportional detriment of the two healthy ones in pathological conditions (myocardial infarction; heart failure; and recovery from sudden death). The presence of the identified universal arrhythmic structures together with the position of the centre of mass of the heart rate variability graph provide a unique quantitative assessment of the health-pathology gradient. PMID:26912108

  3. Randomised controlled trial of intrapartum fetal heart rate monitoring.

    PubMed Central

    Mahomed, K.; Nyoni, R.; Mulambo, T.; Kasule, J.; Jacobus, E.

    1994-01-01

    OBJECTIVE--To compare effectiveness of different methods of monitoring intrapartum fetal heart rate. DESIGN--Prospective randomised controlled trial. SETTING--Referral maternity hospital, Harare, Zimbabwe. SUBJECTS--1255 women who were 37 weeks or more pregnant with singleton cephalic presentation and normal fetal heart rate before entry into study. INTERVENTIONS--Intermittent monitoring of fetal heart rate by electronic monitoring, Doppler ultrasound, use of Pinard stethoscope by a research midwife, or routine use of Pinard stethoscope by attending midwife. MAIN OUTCOME MEASURES--Abnormal fetal heart rate patterns, need for operative delivery for fetal distress, neonatal mortality, Apgar scores, admission to neonatal unit, neonatal seizures, and hypoxic ischaemic encephalopathy. RESULTS--Abnormalities in fetal heart rate were detected in 54% (172/318) of the electronic monitoring group, 32% (100/312) of the ultrasonography group, 15% (47/310) of the Pinard stethoscope group, and 9% (28/315) of the routine monitoring group. Caesarean sections were performed for 28% (89%), 24% (76), 10% (32), and 15% (46) of the four groups respectively. Neonatal outcome was best in the ultrasonography group: hypoxic ischaemic encephalopathy occurred in two, one, seven, and 10 cases in the four groups respectively; neonatal seizures occurred only in the last two groups (six and nine cases respectively); and deaths occurred in eight, two, five, and nine cases respectively. CONCLUSIONS--Abnormalities in fetal heart rate were more reliably detected by Doppler ultrasonography than with Pinard stethoscope, and its use resulted in good perinatal outcome. The use of relatively cheap ultrasound monitors should be further evaluated and promoted in obstetric units caring for high risk pregnancies in developing countries with scarce resources. PMID:8136665

  4. Motivated behavioral outcomes affect ratings of attractiveness.

    PubMed

    Bernard, Larry C; Hardy, David J

    2014-12-01

    A relatively new theory of motivation posits that purposeful human behavior may be partly explained by multidimensional individual differences "traits of action" (motives). Its 15 motives can be characterized according to their purpose: individual integrity, competitiveness, and cooperativeness. Existing evidence supports the model on which the motives are based and the reliability and validity of strategies to assess them. This experiment tested whether the hypothetical results of consistent, motivated cooperative and competitive behavior could affect ratings of attractiveness. Male and female participants (N = 98; M age = 18.8, SD = 1.4) were shown 24 opposite-sex facial photos ranging in attractiveness. The photos were paired with one of three conditions representing theoretical outcomes that would result from low, control, and high levels of cooperative and competitive motives. As predicted, outcome descriptions representing high motive strength of six motives statistically significantly affected ratings of attractiveness. This result was independent of sex of participant and consistent with the theory. PMID:25457092

  5. Diving behaviour and heart rate in tufted ducks (Aythya fuligula).

    PubMed

    Stephenson, R; Butler, P J; Woakes, A J

    1986-11-01

    Diving behaviour and heart rate were monitored in tufted ducks diving under circumstances which simulated various environmental conditions such as feeding under ice in winter. When distance to food was increased on a covered outdoor pond, dive duration increased proportionately, but it was calculated that time available for feeding was reduced during the longer-distance 'extended' dives. There was a gradual reduction in heart rate to 77.3 +/- 13.8 beats min-1, which is significantly lower than the resting value of 121.1 +/- 14.1 beats min-1, during the course of extended dives, suggesting that the ducks could gradually switch over to a 'classical' oxygen-conserving response during these prolonged voluntary dives. The duration of the pre-dive preparatory period was positively correlated with dive distance. When the ducks were briefly unable to resurface during an otherwise normal feeding dive in an indoor tank, a situation which may occur if they become disoriented under ice, there was an immediate switch to a full bradycardia. Reduction in heart rate during these 'enclosed' dives occurred only when the ducks were apparently aware of the situation and the rate of onset of bradycardia was very similar to that previously observed during involuntary submersion of tufted ducks. Minimum heart rate was the same at 46 beats min-1 after 15 s of enclosed dives and after 30 s of involuntary submersions, despite the differences in levels of activity in the two situations. PMID:3805996

  6. Diving behaviour and heart rate in tufted ducks (Aythya fuligula).

    PubMed

    Stephenson, R; Butler, P J; Woakes, A J

    1986-11-01

    Diving behaviour and heart rate were monitored in tufted ducks diving under circumstances which simulated various environmental conditions such as feeding under ice in winter. When distance to food was increased on a covered outdoor pond, dive duration increased proportionately, but it was calculated that time available for feeding was reduced during the longer-distance 'extended' dives. There was a gradual reduction in heart rate to 77.3 +/- 13.8 beats min-1, which is significantly lower than the resting value of 121.1 +/- 14.1 beats min-1, during the course of extended dives, suggesting that the ducks could gradually switch over to a 'classical' oxygen-conserving response during these prolonged voluntary dives. The duration of the pre-dive preparatory period was positively correlated with dive distance. When the ducks were briefly unable to resurface during an otherwise normal feeding dive in an indoor tank, a situation which may occur if they become disoriented under ice, there was an immediate switch to a full bradycardia. Reduction in heart rate during these 'enclosed' dives occurred only when the ducks were apparently aware of the situation and the rate of onset of bradycardia was very similar to that previously observed during involuntary submersion of tufted ducks. Minimum heart rate was the same at 46 beats min-1 after 15 s of enclosed dives and after 30 s of involuntary submersions, despite the differences in levels of activity in the two situations.

  7. Voluntary heart rate reduction following yoga using different strategies

    PubMed Central

    Raghavendra, BR; Telles, S; Manjunath, NK; Deepak, KK; Naveen, KV; Subramanya, P

    2013-01-01

    Background/Aims: One month of yoga training has been shown to reduce the pulse rate voluntarily without using external cues. Hence, the present study was designed to understand the strategies used by yoga practitioners and autonomic changes associated with voluntary heart rate reduction. Materials and Methods: Fifty volunteers (group mean age ± S.D., 25.4 ± 4.8 years; 25 males) were assessed in two trials on separate days. Each trial was for 12 minutes, with a ‘pre’ state and ‘during’ state of 6 minutes each. For both trials the ‘pre’ state was relaxation with eyes closed. In the ‘during’ state of Trial I, subjects were asked to voluntarily reduce their heart rate using a strategy of their choice. From their responses to specific questions it was determined that 22 out of 50 persons used breath regulation as a strategy. Hence, in the ‘during’ state of Trial II, subjects were asked to voluntarily reduce their heart rate by breath regulation. Results: In the first trial, the heart rate was reduced by an average of 19.6 beats per minute and in the second trial (with breath regulation exclusively) an average decrease of 22.2 beats per minute was achieved. Conclusions: Hence, the strategy used did not markedly alter the outcome. PMID:23440267

  8. The Effects of Televised Consequences of Aggression upon Physiological Arousal (Heart Rate).

    ERIC Educational Resources Information Center

    Wotring, C. Edward; Porter, D. Thomas

    1978-01-01

    Describes a study using heart rate as an index of autonomic arousal to measure the effects on television viewers of depicting the consequences of violence, violence with no consequence, and nonviolence. Supports the conclusion that specific content manipulations of aggressive stimuli affect levels of arousal. (JMF)

  9. A healthy heart is not a metronome: an integrative review of the heart's anatomy and heart rate variability.

    PubMed

    Shaffer, Fred; McCraty, Rollin; Zerr, Christopher L

    2014-01-01

    Heart rate variability (HRV), the change in the time intervals between adjacent heartbeats, is an emergent property of interdependent regulatory systems that operate on different time scales to adapt to challenges and achieve optimal performance. This article briefly reviews neural regulation of the heart, and its basic anatomy, the cardiac cycle, and the sinoatrial and atrioventricular pacemakers. The cardiovascular regulation center in the medulla integrates sensory information and input from higher brain centers, and afferent cardiovascular system inputs to adjust heart rate and blood pressure via sympathetic and parasympathetic efferent pathways. This article reviews sympathetic and parasympathetic influences on the heart, and examines the interpretation of HRV and the association between reduced HRV, risk of disease and mortality, and the loss of regulatory capacity. This article also discusses the intrinsic cardiac nervous system and the heart-brain connection, through which afferent information can influence activity in the subcortical and frontocortical areas, and motor cortex. It also considers new perspectives on the putative underlying physiological mechanisms and properties of the ultra-low-frequency (ULF), very-low-frequency (VLF), low-frequency (LF), and high-frequency (HF) bands. Additionally, it reviews the most common time and frequency domain measurements as well as standardized data collection protocols. In its final section, this article integrates Porges' polyvagal theory, Thayer and colleagues' neurovisceral integration model, Lehrer et al.'s resonance frequency model, and the Institute of HeartMath's coherence model. The authors conclude that a coherent heart is not a metronome because its rhythms are characterized by both complexity and stability over longer time scales. Future research should expand understanding of how the heart and its intrinsic nervous system influence the brain.

  10. A healthy heart is not a metronome: an integrative review of the heart's anatomy and heart rate variability

    PubMed Central

    Shaffer, Fred; McCraty, Rollin; Zerr, Christopher L.

    2014-01-01

    Heart rate variability (HRV), the change in the time intervals between adjacent heartbeats, is an emergent property of interdependent regulatory systems that operate on different time scales to adapt to challenges and achieve optimal performance. This article briefly reviews neural regulation of the heart, and its basic anatomy, the cardiac cycle, and the sinoatrial and atrioventricular pacemakers. The cardiovascular regulation center in the medulla integrates sensory information and input from higher brain centers, and afferent cardiovascular system inputs to adjust heart rate and blood pressure via sympathetic and parasympathetic efferent pathways. This article reviews sympathetic and parasympathetic influences on the heart, and examines the interpretation of HRV and the association between reduced HRV, risk of disease and mortality, and the loss of regulatory capacity. This article also discusses the intrinsic cardiac nervous system and the heart-brain connection, through which afferent information can influence activity in the subcortical and frontocortical areas, and motor cortex. It also considers new perspectives on the putative underlying physiological mechanisms and properties of the ultra-low-frequency (ULF), very-low-frequency (VLF), low-frequency (LF), and high-frequency (HF) bands. Additionally, it reviews the most common time and frequency domain measurements as well as standardized data collection protocols. In its final section, this article integrates Porges' polyvagal theory, Thayer and colleagues' neurovisceral integration model, Lehrer et al.'s resonance frequency model, and the Institute of HeartMath's coherence model. The authors conclude that a coherent heart is not a metronome because its rhythms are characterized by both complexity and stability over longer time scales. Future research should expand understanding of how the heart and its intrinsic nervous system influence the brain. PMID:25324790

  11. Remote measurements of heart and respiration rates for telemedicine.

    PubMed

    Zhao, Fang; Li, Meng; Qian, Yi; Tsien, Joe Z

    2013-01-01

    Non-contact and low-cost measurements of heart and respiration rates are highly desirable for telemedicine. Here, we describe a novel technique to extract blood volume pulse and respiratory wave from a single channel images captured by a video camera for both day and night conditions. The principle of our technique is to uncover the temporal dynamics of heart beat and breathing rate through delay-coordinate transformation and independent component analysis-based deconstruction of the single channel images. Our method further achieves robust elimination of false positives via applying ratio-variation probability distributions filtering approaches. Moreover, it enables a much needed low-cost means for preventing sudden infant death syndrome in new born infants and detecting stroke and heart attack in elderly population in home environments. This noncontact-based method can also be applied to a variety of animal model organisms for biomedical research.

  12. Direct observation of homoclinic orbits in human heart rate variability

    NASA Astrophysics Data System (ADS)

    Żebrowski, J. J.; Baranowski, R.

    2003-05-01

    Homoclinic trajectories of the interbeat intervals between contractions of ventricles of the human heart are identified. The interbeat intervals are extracted from 24-h Holter ECG recordings. Three such recordings are discussed in detail. Mappings of the measured consecutive interbeat intervals are constructed. In the second and in some cases in the fourth iterate of the map of interbeat intervals homoclinic trajectories associated with a hyperbolic saddle are found. The homoclinic trajectories are often persistent for many interbeat intervals, sometimes spanning many thousands of heartbeats. Several features typical for homoclinic trajectories found in other systems were identified, including a signature of the gluing bifurcation. The homoclinic trajectories are present both in recordings of heart rate variability obtained from patients with an increased number of arrhythmias and in cases in which the sinus rhythm is dominant. The results presented are a strong indication of the importance of deterministic nonlinear instabilities in human heart rate variability.

  13. Remote Measurements of Heart and Respiration Rates for Telemedicine

    PubMed Central

    Qian, Yi; Tsien, Joe Z.

    2013-01-01

    Non-contact and low-cost measurements of heart and respiration rates are highly desirable for telemedicine. Here, we describe a novel technique to extract blood volume pulse and respiratory wave from a single channel images captured by a video camera for both day and night conditions. The principle of our technique is to uncover the temporal dynamics of heart beat and breathing rate through delay-coordinate transformation and independent component analysis-based deconstruction of the single channel images. Our method further achieves robust elimination of false positives via applying ratio-variation probability distributions filtering approaches. Moreover, it enables a much needed low-cost means for preventing sudden infant death syndrome in new born infants and detecting stroke and heart attack in elderly population in home environments. This noncontact-based method can also be applied to a variety of animal model organisms for biomedical research. PMID:24115996

  14. Ambulatory heart rate range predicts mode-specific mortality and hospitalisation in chronic heart failure

    PubMed Central

    Cubbon, Richard M; Ruff, Naomi; Groves, David; Eleuteri, Antonio; Denby, Christine; Kearney, Lorraine; Ali, Noman; Walker, Andrew M N; Jamil, Haqeel; Gierula, John; Gale, Chris P; Batin, Phillip D; Nolan, James; Shah, Ajay M; Fox, Keith A A; Sapsford, Robert J; Witte, Klaus K; Kearney, Mark T

    2016-01-01

    Objective We aimed to define the prognostic value of the heart rate range during a 24 h period in patients with chronic heart failure (CHF). Methods Prospective observational cohort study of 791 patients with CHF associated with left ventricular systolic dysfunction. Mode-specific mortality and hospitalisation were linked with ambulatory heart rate range (AHRR; calculated as maximum minus minimum heart rate using 24 h Holter monitor data, including paced and non-sinus complexes) in univariate and multivariate analyses. Findings were then corroborated in a validation cohort of 408 patients with CHF with preserved or reduced left ventricular ejection fraction. Results After a mean 4.1 years of follow-up, increasing AHRR was associated with reduced risk of all-cause, sudden, non-cardiovascular and progressive heart failure death in univariate analyses. After accounting for characteristics that differed between groups above and below median AHRR using multivariate analysis, AHRR remained strongly associated with all-cause mortality (HR 0.991/bpm increase in AHRR (95% CI 0.999 to 0.982); p=0.046). AHRR was not associated with the risk of any non-elective hospitalisation, but was associated with heart-failure-related hospitalisation. AHRR was modestly associated with the SD of normal-to-normal beats (R2=0.2; p<0.001) and with peak exercise-test heart rate (R2=0.33; p<0.001). Analysis of the validation cohort revealed AHRR to be associated with all-cause and mode-specific death as described in the derivation cohort. Conclusions AHRR is a novel and readily available prognosticator in patients with CHF, which may reflect autonomic tone and exercise capacity. PMID:26674986

  15. Effect of ethanol of heart rate and blood pressure in nonstressed and stressed rats

    SciTech Connect

    Sparrow, M.G.; Roggendorf, H.; Vogel, W.H.

    1987-06-29

    The effect of ethanol on the cardiovascular system (ECG, heart rate, blood pressure) was studied in anesthetized, nonstressed or stressed rats. In anesthetized rats, ethanol showed no effect on heart rate or ECG. In nonstressed rats, ethanol sedated the animals but increased heart rate significantly. This ethanol induced tachycardia seemed the result of a direct stimulation of the sympathetic nerves to the heart. Blood pressure was not significantly affected by ethanol in these nonstressed rats. In stressed rats, marked behavioral excitation and significant increases in heart rate and blood pressure were noted. Ethanol pretreatment calmed the animals considerably during restraint. Ethanol did reduce slightly the stress-induced tachycardia but markedly reduced or antagonized stress-induced blood pressure increases. No major changes in the ECG were noted during these studies with the exception of a few individual animals which showed pathologic ECG responses to ethanol. These data show that ethanol affects cardiovascular functions differently in anesthetized, non stressed or stressed rats, and that ethanol can significantly reduce or antagonize stress-induced behavioral excitation, tachycardia and hypertension. 32 references, 4 tables.

  16. Does Baseline Heart Rate Variability Reflect Stable Positive Emotionality?

    PubMed

    Silvia, Paul J; Jackson, Bryonna A; Sopko, Rachel S

    2014-11-01

    Several recent studies have found significant correlations, medium in effect size, between baseline heart rate variability (HRV) and measures of positive functioning, such as extraversion, agreeableness, and trait positive affectivity. Other research, however, has suggested an optimal level of HRV and found nonlinear effects. In the present study, a diverse sample of 239 young adults completed a wide range of measures that reflect positive psychological functioning, including personality traits, an array of positive emotions (measured with the Dispositional Positive Emotions Scale), and depression, anxiety, and stress symptoms (measured with the DASS and CESD). HRV was measured with a 6-minute baseline period and quantified using many common HRV metrics (e.g., respiratory sinus arrhythmia, root mean square of successive differences, and others), and potentially confounding behavioral and lifestyle variables (e.g., BMI, caffeine and nicotine use, sleep quality) were assessed. Neither linear nor non-linear effects were found, and the effect sizes were small and near zero. The findings suggest that the cross-sectional relationship between HRV and positive experience deserves more attention and meta-analytic synthesis. PMID:25147421

  17. A systematic review on heart rate variability in Bulimia Nervosa.

    PubMed

    Peschel, Stephanie K V; Feeling, Nicole R; Vögele, Claus; Kaess, Michael; Thayer, Julian F; Koenig, Julian

    2016-04-01

    Eating disorders are associated with alterations of the autonomic nervous system (ANS). Among other indices, heart rate variability (HRV) provides a readily available index of ANS function. While ANS dysfunction indexed by HRV in Anorexia Nervosa has been addressed in previous reviews, here we aimed to review the current evidence on HRV in Bulimia Nervosa (BN). A systematic literature search in Web of Science, PsycInfo, Scopus, and PubMed identified 17 studies reporting HRV in patients with BN. Studies described (i) differences in resting state HRV in patients compared to controls, (ii) alterations in the stress response in BN indexed by HRV, and (iii) treatment effects on HRV in patients with BN. Despite a number of conflicting results, we conclude that BN is characterized by increased resting state vagally-mediated HRV and an impaired stress-response. Intervention-studies suggest that altered ANS-activity in BN is at least partially reversible. Future studies on the complex relation between BN and HRV should investigate the effect of comorbid disorders, subtypes of BN, and mechanisms affecting treatment outcome. PMID:26828568

  18. Heart Rate Variability During Early Adaptation to Space

    NASA Technical Reports Server (NTRS)

    Toscano, W. B.; Cowings, P. S.

    1994-01-01

    A recent report hypothesized that episodes of space motion sickness (SMS) were reliably associated with low frequency oscillations (less than 0.03 to less than 0.01 Hz) in heart rate variability. This paper archives a large data set for review of investigators in this field which may facilitate the evaluation of this hypothesis. Continuous recording of Electro-cardiography (ECG) and other measures were made for 6 to 12 hours per day (waking hours) of six Shuttle crewmembers for the first 3 mission days of two separate Shuttle flights. Spectral analyses of heart rate variability during approximately 200 hours of inflight is presented. In addition, nearly 200 hours of data collected on these same individuals during ground tests prior to the mission are presented. The Purpose of this Publication is to document the incidence of low frequency oscillations of heart rate in 4 people exposed to microgravity over a period of five days. In addition, this report contains spectral analyses of heart rate data collected on these same individuals during ground-based mission simulations. By archiving these data in this manner, it is our intention to make this information available to other investigators interested in studying this phenomena.

  19. Phase plane based identification of fetal heart rate patterns

    PubMed Central

    Vairavan, Srinivasan; Sriram, Bhargavi; Wilson, James D.; Preissl, Hubert; Eswaran, Hari

    2012-01-01

    Using a phase plane analysis (PPA) of the spatial spread of trajectories of the fetal heart rate and its time-derivative we characterize the fetal heart rate patterns (fHRP) as defined by Nijhuis. For this purpose, we collect 22 fetal magnetocardiogram using a 151 SQUID system from 22 low-risk fetuses in gestational ages ranging from 30 to 37 weeks. Each study lasted for 30 minutes. After the attenuation of the maternal cardiac signals, we identify the R waves using an adaptive Hilbert transform approach and calculate the fetal heart rate. On these datasets, we apply the proposed approach and the traditionally used approaches such as standard deviation of the normal to normal intervals (SDNN) and root mean square of the successive difference (RMSSD). Heart rate patterns are scored by an expert using Nijhuis criteria and revealed A, B, and D patterns. A receiver operator characteristic (ROC) curve is used to assess the performance of the metric to differentiate the different patterns. Results showed that only PPA was able to differentiate all pairs of fHRP with high performance. PMID:22254593

  20. Heart Rate and Stress in a College Setting

    ERIC Educational Resources Information Center

    Elwess, Nancy L.; Vogt, F. Daniel

    2005-01-01

    Conditions producing stress are present in all colleges and universities. In this paper we report on an investigation utilizing heart rate as an indicator of stress in students when participating in activities encountered in a college classroom or laboratory. The activities included presenting an oral report, taking an exam, and participating in a…

  1. Fetal heart rate changes associated with general anesthesia.

    PubMed

    Fedorkow, D M; Stewart, T J; Parboosingh, J

    1989-07-01

    Decreased fetal heart rate variability was noted 90 seconds after the induction of general anesthesia with sodium thiopentone and fentanyl in a patient undergoing basket extraction of a renal calculus at 30 weeks' gestation. The fetal sleep pattern lasted for 105 minutes after the anesthetic was discontinued, 45 minutes after the mother was fully awake.

  2. Transfer entropy analysis of maternal and fetal heart rate coupling.

    PubMed

    Marzbanrad, Faezeh; Kimura, Yoshitaka; Endo, Miyuki; Palaniswami, Marimuthu; Khandoker, Ahsan H

    2015-01-01

    Although evidence of the short term relationship between maternal and fetal heart rates has been found in previous model-based studies, knowledge about the mechanism and patterns of the coupling during gestation is still limited. In this study, a model-free method based on Transfer Entropy (TE) was applied to quantify the maternal-fetal heart rate couplings in both directions. Furthermore, analysis of the lag at which TE was maximum and its changes throughout gestation, provided more information about the mechanism of coupling and its latency. Experimental results based on fetal electrocardiograms (fECGs) and maternal ECG showed the evidence of coupling for 62 out of 65 healthy mothers and fetuses in each direction, by statistically validating against the surrogate pairs. The fetuses were divided into three gestational age groups: early (16-25 weeks), mid (26-31 weeks) and late (32-41 weeks) gestation. The maximum TE from maternal to fetal heart rate significantly increased from early to mid gestation, while the coupling delay on both directions decreased significantly from mid to late gestation. These changes occur concomitant with the maturation of the fetal sensory and autonomic nervous systems with advancing gestational age. In conclusion, the application of TE with delays revealed detailed information about the changes in fetal-maternal heart rate coupling strength and latency throughout gestation, which could provide novel clinical markers of fetal development and well-being.

  3. Volitional Control of Heart Rate During Exercise Stress.

    ERIC Educational Resources Information Center

    LeFevers, Victoria A.

    Thirty five volunteer college women were divided into three groups to determine if heart rate could be conditioned instrumentally and lowered during exercise stress on the treadmill. The three groups were a) experimental group I, 15 subjects who received instrumental conditioning with visual feedback; b) instrumental group II, 9 subjects who…

  4. Heart Rate Variability and Drawing Impairment in Hypoxemic COPD

    ERIC Educational Resources Information Center

    Incalzi, Raffaele Antonelli; Corsonello, Andrea; Trojano, Luigi; Pedone, Claudio; Acanfora, Domenico; Spada, Aldo; D'Addio, Gianni; Maestri, Roberto; Rengo, Franco; Rengo, Giuseppe

    2009-01-01

    We studied 54 patients with hypoxemic chronic obstructive pulmonary disease (COPD). The Mini Mental State Examination and the Mental Deterioration Battery were used for neuropsychological assessment. Heart rate variability (HRV) was assessed based on 24-h Holter ECG recording. Mann-Whitney test was used to compare HRV parameters of patients…

  5. Heart Rate Monitors Promote Physical Education for Children

    ERIC Educational Resources Information Center

    Tipton, Jan; Sander, Allan N.

    2004-01-01

    National health and fitness data suggests that a significant percentage of children are not on a pathway to leading healthy, physically active lifestyles. Many children are leading sedentary lifestyles due to a lack of opportunity, success, or self-motivation in physical activity. Programs that highlight the use of heart rate monitors offer a…

  6. A PC-aided optical foetal heart rate detection system.

    PubMed

    Oweis, Rami J; As'ad, Hala; Aldarawsheh, Amany; Al-Khdeirat, Rawan; Lwissy, Kaldoun

    2014-01-01

    Safe monitoring of foetal heart rate is a valuable tool for the healthy evolution and wellbeing of both foetus and mother. This paper presents a non-invasive optical technique that allows for foetal heart rate detection using a photovoltaic infrared (IR) detector placed on the mother's abdomen. The system presented here consists of a photoplethysmography (PPG) circuit, abdomen circuit and a personal computer equipped with MATLAB. A near IR beam having a wavelength of 880 nm is transmitted through the mother's abdomen and foetal tissue. The received abdominal signal that conveys information pertaining to the mother and foetal heart rate is sensed by a low noise photodetector. The PC receives the signal through the National Instrumentation Data Acquisition Card (NIDAQ). After synchronous detection of the abdominal and finger PPG signals, the designed MATLAB-based software saves, analyses and extracts information related to the foetal heart rate. Extraction is carried out using recursive least squares adaptive filtration. Measurements on eight pregnant women with gestational periods ranging from 35-39 weeks were performed using the proposed system and CTG. Results show a correlation coefficient of 0.978 and a correlation confidence interval between 88-99.6%. The t test results in a p value of 0.034, which is less than 0.05. Low power, low cost, high signal-to-noise ratio, reduction of ambient light effect and ease of use are the main characteristics of the proposed system. PMID:24195701

  7. Exploring the Relationship between Fetal Heart Rate and Cognition

    ERIC Educational Resources Information Center

    Kisilevsky, Barbara S.; Hains, Sylvia M. J.

    2010-01-01

    A relationship between fetal heart rate (HR) and cognition is explored within the context of infant, child and adult studies where the association is well established. Lack of direct access to the fetus and maturational changes limit research paradigms and response measures for fetal studies. Nevertheless, neural regulation of HR shows a number of…

  8. Heart Rate Variability: Effect of Exercise Intensity on Postexercise Response

    ERIC Educational Resources Information Center

    James, David V. B.; Munson, Steven C.; Maldonado-Martin, Sara; De Ste Croix, Mark B. A.

    2012-01-01

    The purpose of the present study was to investigate the influence of two exercise intensities (moderate and severe) on heart rate variability (HRV) response in 16 runners 1 hr prior to (-1 hr) and at +1 hr, +24 hr, +48 hr, and +72 hr following each exercise session. Time domain indexes and a high frequency component showed a significant decrease…

  9. Role of feedback in voluntary control of heart rate.

    PubMed

    Manuck, S B; Levenson, R W; Hinrichsen, J J; Gryll, S L

    1975-06-01

    The relative effectiveness of biofeedback techniques on the voluntary control of heart rate was examined by randomly assigning 32 Ss to one of four feedback conditions in a bi-directional heart-rate control task: (1) no feedback, (2) binary feedback--S was signaled when an interbeat interval had changed in the correct direction, (3) "real-time," proportional feedback--S was provided information about the relative duration of successive interbeat intervals, and (4) numerical, proportional feedback--each interbeat interval was represented as a numeral indicating its relationship to pre-trial mean by direction and magnitude. Significant over-all heart-rate changes were evidenced for both increase and decrease directions, but no differences were found between the feedback conditions. While these data suggest that feedback may be a relatively insignificant factor in voluntary heart-rate control, it was recommended that further investigation examine the role of feedback within the context of other training, mediating and motivational variables.

  10. Relationship between Exercise Heart Rate and Music Tempo Preference

    ERIC Educational Resources Information Center

    Karageorghis, Costas I.; Jones, Leighton; Low, Daniel C.

    2006-01-01

    The present study examined the predicted positive and linear relationship (Iwanaga, 1995a, 1995b) between exercise heart rate and music tempo preference. Initially, 128 undergraduate students (M age = 20.0 years, SD = 0.9) were surveyed to establish their three favorite music artists. A separate experimental group of 29 undergraduates (M age =…

  11. Modelling and control for heart rate regulation during treadmill exercise.

    PubMed

    Su, Steven W; Wang, Lu; Celler, Branko G; Savkin, Andrey V; Guo, Ying

    2006-01-01

    This paper proposes a novel integrated approach for the identification and control of Hammerstein systems to achieve desired heart rate tracking performance for an automated treadmill system. The pseudo-random binary sequence input is employed to decouple the identification of dynamic linear part from static nonlinearity. The powerful e-insensitivity support vector regression is adopted to obtain sparse representations of the inversion of static nonlinearity in order to obtain an approximated linear model of the Hammerstein system. An H(infinity) controller is designed for the approximated linear model to achieve robust tracking performance. This new approach is applied to the design of a computer-controlled treadmill system for the regulation of heart rate during treadmill exercise. Minimizing deviations of heart rate from a preset profile is achieved by controlling the speed of the treadmill. Both conventional proportional-integral-derivative (PID) control and the proposed approaches have been employed for the controller design. The proposed algorithm achieves much better heart rate tracking performance.

  12. Identification and control for heart rate regulation during treadmill exercise.

    PubMed

    Su, Steven W; Wang, Lu; Celler, Branko G; Savkin, Andrey V; Guo, Ying

    2007-07-01

    This paper proposes a novel integrated approach for the identification and control of Hammerstein systems to achieve desired heart rate profile tracking performance for an automated treadmill system. For the identification of Hammerstein systems, the pseudorandom binary sequence input is employed to decouple the identification of dynamic linear part from input nonlinearity. The powerful epsilon-insensitivity support vector regression method is adopted to obtain sparse representations of the inverse of static nonlinearity in order to obtain an approximate linear model of the Hammerstein system. An Hinfinity controller is designed for the approximated linear model to achieve robust tracking performance. This new approach is successfully applied to the design of a computer-controlled treadmill system for the regulation of heart rate during treadmill exercise. Minimizing deviations of heart rate from a preset profile is achieved by controlling the speed of the treadmill. Both conventional proportional-integral-derivative (PID) control and the proposed approaches have been employed for the controller design. The proposed algorithm achieves much better heart rate tracking performance.

  13. An improved method of measuring heart rate using a webcam

    NASA Astrophysics Data System (ADS)

    Liu, Yi; Ouyang, Jianfei; Yan, Yonggang

    2014-09-01

    Measuring heart rate traditionally requires special equipment and physical contact with the subject. Reliable non-contact and low-cost measurements are highly desirable for convenient and comfortable physiological self-assessment. Previous work has shown that consumer-grade cameras can provide useful signals for remote heart rate measurements. In this paper a simple and robust method of measuring the heart rate using low-cost webcam is proposed. Blood volume pulse is extracted by proper Region of Interest (ROI) and color channel selection from image sequences of human faces without complex computation. Heart rate is subsequently quantified by spectrum analysis. The method is successfully applied under natural lighting conditions. Results of experiments show that it takes less time, is much simpler, and has similar accuracy to the previously published and widely used method of Independent Component Analysis (ICA). Benefitting from non-contact, convenience, and low-costs, it provides great promise for popularization of home healthcare and can further be applied to biomedical research.

  14. An exploration of heart rate response to differing music rhythm and tempos.

    PubMed

    da Silva, Ariany G; Guida, Heraldo L; Antônio, Ana Márcia Dos S; Marcomini, Renata S; Fontes, Anne M G G; Carlos de Abreu, Luiz; Roque, Adriano L; Silva, Sidney B; Raimundo, Rodrigo D; Ferreira, Celso; Valenti, Vitor E

    2014-05-01

    The aim of this study was to investigate acute cardiac response and heart rate variability (HRV) when listening to differing forms of music. Eleven healthy men aged between 18 and 25 years old were included in the study. HRV was recorded at rest for ten minutes with no music, then were asked to listen to classical baroque or heavy metal music for a period of 20 min. It was noted that heart rate variability did not affect HRV indices for time and frequency. In conclusion, music with different tempos does not influence cardiac autonomic regulation in men. However more studies are suggested to explore this topic in greater detail. PMID:24767959

  15. An exploration of heart rate response to differing music rhythm and tempos.

    PubMed

    da Silva, Ariany G; Guida, Heraldo L; Antônio, Ana Márcia Dos S; Marcomini, Renata S; Fontes, Anne M G G; Carlos de Abreu, Luiz; Roque, Adriano L; Silva, Sidney B; Raimundo, Rodrigo D; Ferreira, Celso; Valenti, Vitor E

    2014-05-01

    The aim of this study was to investigate acute cardiac response and heart rate variability (HRV) when listening to differing forms of music. Eleven healthy men aged between 18 and 25 years old were included in the study. HRV was recorded at rest for ten minutes with no music, then were asked to listen to classical baroque or heavy metal music for a period of 20 min. It was noted that heart rate variability did not affect HRV indices for time and frequency. In conclusion, music with different tempos does not influence cardiac autonomic regulation in men. However more studies are suggested to explore this topic in greater detail.

  16. [Parameters of heart rate variability during bicycle ergometry test].

    PubMed

    Parnes, E Ia; Koshkina, E V; Krasnoselskiĭ, M Ia

    2003-01-01

    Short-term (5 min) heart rate variability (HRV) was studied before and during submaximal bicycle exercise tests in 27 patients with ischemic heart disease, 23 patients with hypertension and 9 healthy subjects. Low-frequency (0.04 to 0.15 Hz) and high-frequency (0.15 to 0.40 Hz) power components of HRV were significantly decreased during submaximal exercise. The level of load at which abrupt decrease of low-frequency components below 40 ms(2) occurred possibly reflected individual exercise tolerance. Episodes of myocardial ischemia were associated with pronounced decreases of low - frequency HRV components.

  17. Analysis of heart rate control to assess thermal sensitivity responses in Brazilian toads.

    PubMed

    Natali, J E S; Santos, B T; Rodrigues, V H; Chauí-Berlinck, J G

    2015-01-01

    In anurans, changes in ambient temperature influence body temperature and, therefore, energy consumption. These changes ultimately affect energy supply and, consequently, heart rate (HR). Typically, anurans living in different thermal environments have different thermal sensitivities, and these cannot be distinguished by changes in HR. We hypothesized that Rhinella jimi (a toad from a xeric environment that lives in a wide range of temperatures) would have a lower thermal sensitivity regarding cardiac control than R. icterica (originally from a tropical forest environment with a more restricted range of ambient temperatures). Thermal sensitivity was assessed by comparing animals housed at 15° and 25°C. Cardiac control was estimated by heart rate variability (HRV) and heart rate complexity (HRC). Differences in HRV between the two temperatures were not significant (P=0.214 for R. icterica and P=0.328 for R. jimi), whereas HRC differences were. All specimens but one R. jimi had a lower HRC at 15°C (all P<0.01). These results indicate that R. jimi has a lower thermal sensitivity and that cardiac control is not completely dependent on the thermal environment because HRC was not consistently different between temperatures in all R. jimi specimens. This result indicates a lack of evolutive trade-offs among temperatures given that heart rate control at 25°C is potentially not a constraint to heart rate control at 15°C.

  18. Analysis of heart rate control to assess thermal sensitivity responses in Brazilian toads.

    PubMed

    Natali, J E S; Santos, B T; Rodrigues, V H; Chauí-Berlinck, J G

    2014-10-24

    In anurans, changes in ambient temperature influence body temperature and, therefore, energy consumption. These changes ultimately affect energy supply and, consequently, heart rate (HR). Typically, anurans living in different thermal environments have different thermal sensitivities, and these cannot be distinguished by changes in HR. We hypothesized that Rhinella jimi (a toad from a xeric environment that lives in a wide range of temperatures) would have a lower thermal sensitivity regarding cardiac control than R. icterica (originally from a tropical forest environment with a more restricted range of ambient temperatures). Thermal sensitivity was assessed by comparing animals housed at 15° and 25°C. Cardiac control was estimated by heart rate variability (HRV) and heart rate complexity (HRC). Differences in HRV between the two temperatures were not significant (P=0.214 for R. icterica and P=0.328 for R. jimi), whereas HRC differences were. All specimens but one R. jimi had a lower HRC at 15°C (all P<0.01). These results indicate that R. jimi has a lower thermal sensitivity and that cardiac control is not completely dependent on the thermal environment because HRC was not consistently different between temperatures in all R. jimi specimens. This result indicates a lack of evolutive trade-offs among temperatures given that heart rate control at 25°C is potentially not a constraint to heart rate control at 15°C.

  19. Nonlinear control of heart rate variability in human infants.

    PubMed Central

    Sugihara, G; Allan, W; Sobel, D; Allan, K D

    1996-01-01

    Nonlinear analyses of infant heart rhythms reveal a marked rise in the complexity of the electrocardiogram with maturation. We find that normal mature infants (gestation greater than or equal to 35 weeks) have complex and distinctly nonlinear heart rhythms (consistent with recent reports for healthy adults) but that such nonlinearity is lacking in preterm infants (gestation > or = to 27 weeks) where parasympathetic-sympathetic interaction and function are presumed to be less well developed. Our study further shows that infants with clinical brain death and those treated with atropine exhibit a similar lack of nonlinear feedback control. These three lines of evidence support the hypothesis championed by Goldberger et al. [Goldberger, A.L., Rigney, D.R. & West, B.J. (1990) Sci. Am. 262, 43-49] that autonomic nervous system control underlies the nonlinearity and possible chaos of normal heart rhythms. This report demonstrates the acquisition of nonlinear heart rate dynamics and possible chaos in developing human infants and its loss in brain death and with the administration of atropine. It parallels earlier work documenting changes in the variability of heart rhythms in each of these cases and suggests that nonlinearity may provide additional power in characterizing physiological states. PMID:8637921

  20. Nonlinear Control of Heart Rate Variability in Human Infants

    NASA Astrophysics Data System (ADS)

    Sugihara, George; Allan, Walter; Sobel, Daniel; Allan, Kenneth D.

    1996-03-01

    Nonlinear analyses of infant heart rhythms reveal a marked rise in the complexity of the electrocardiogram with maturation. We find that normal mature infants (gestation >= 35 weeks) have complex and distinctly nonlinear heart rhythms (consistent with recent reports for healthy adults) but that such nonlinearity is lacking in preterm infants (gestation <= 27 weeks) where parasympathetic-sympathetic interaction and function are presumed to be less well developed. Our study further shows that infants with clinical brain death and those treated with atropine exhibit a similar lack of nonlinear feedback control. These three lines of evidence support the hypothesis championed by Goldberger et al. [Goldberger, A. L., Rigney, D. R. & West, B. J. (1990) Sci. Am. 262, 43-49] that autonomic nervous system control underlies the nonlinearity and possible chaos of normal heart rhythms. This report demonstrates the acquisition of nonlinear heart rate dynamics and possible chaos in developing human infants and its loss in brain death and with the administration of atropine. It parallels earlier work documenting changes in the variability of heart rhythms in each of these cases and suggests that nonlinearity may provide additional power in characterizing physiological states.

  1. Pulse transducer with artifact signal attenuator. [heart rate sensors

    NASA Technical Reports Server (NTRS)

    Cash, W. H., Jr.; Polhemus, J. T. (Inventor)

    1980-01-01

    An artifact signal attenuator for a pulse rate sensor is described. The circuit for attenuating background noise signals is connected with a pulse rate transducer which has a light source and a detector for light reflected from blood vessels of a living body. The heart signal provided consists of a modulated dc signal voltage indicative of pulse rate. The artifact signal resulting from light reflected from the skin of the body comprises both a constant dc signal voltage and a modulated dc signal voltage. The amplitude of the artifact signal is greater and the frequency less than that of the heart signal. The signal attenuator circuit includes an operational amplifier for canceling the artifact signal from the output signal of the transducer and has the capability of meeting packaging requirements for wrist-watch-size packages.

  2. Do organic ligands affect calcite dissolution rates?

    NASA Astrophysics Data System (ADS)

    Oelkers, Eric H.; Golubev, Sergey V.; Pokrovsky, Oleg S.; Bénézeth, Pascale

    2011-04-01

    Steady state Iceland-spar calcite dissolution rates were measured at 25 °C in aqueous solutions containing 0.1 M NaCl and up to 0.05 M dissolved bicarbonate at pH from 7.9 to 9.1 in the presence of 13 distinct dissolved organic ligands in mixed-flow reactors. The organic ligands considered in this study include those most likely to be present in either (1) aquifers at the conditions pertinent to CO 2 sequestration or (2) soil/early diagenetic environments: acetate, phthalate, citrate, EDTA 4-, succinate, D-glucosaminate, L-glutamate, D-gluconate, 2,4-dihydroxybenzoate, 3,4-dihydroxybenzoate, fumarate, malonate, and gallate. Results show that the presence of <0.05 mol/kg of these organic anions changes calcite dissolution rates by less than a factor of 2.5 with the exception of citrate and EDTA 4-. The presence of 0.05 mol/kg citrate and EDTA 4- increases calcite dissolution rates by as much as a factor of 35 and 500, respectively, compared to rates in organic anion-free solutions. Further calcite dissolution experiments were performed in the presence of organic polymers similar to bacterial exudates, cell exopolysaccharides, and analogs of microbial cell envelopes: alginate, lichen extract, humic acid, pectin, and gum xanthan. In no case did the presence of <100 ppm of these organics change calcite dissolution rates by more than a factor of 2.5. Results obtained in this study suggest that the presence of aqueous organic anions negligibly affects calcite forward dissolution rates in most natural environments. Some effect on calcite reactivity may be observed, however, by the presence of organic anions if they change substantially the chemical affinity of the fluid with respect to calcite.

  3. Sleep Apnea in Heart Failure Increases Heart Rate Variability and Sympathetic Dominance

    PubMed Central

    Szollosi, Irene; Krum, Henry; Kaye, David; Naughton, Matthew T.

    2007-01-01

    Aims: Sleep disordered breathing (SDB) is common in heart failure and ventilation is known to influence heart rate. Our aims were to assess the influence of SDB on heart rate variability (HRV) and to determine whether central sleep apnea (CSA) and obstructive sleep apnea (OSA) produced different patterns of HRV. Methods and Results: Overnight polysomnography was performed in 21 patients with heart failure and SDB. Two 10-minute segments each of SDB and stable breathing from each patient were visually identified and ECG signal exported for HRV analysis. SDB increased total power (TP) with very low frequency (VLF) power accounting for the greatest increase (1.89±0.54 vs 2.96±0.46 ms2, P <0.001); LF/HF ratio increased during SDB (1.2±1.0 vs 2.7±2.1, P <0.001). Compared to OSA, CSA was associated with lower absolute LF (2.10±0.47 vs 2.52±0.55 ms2, P = 0.049) and HF power (1.69±0.41 vs 2.34±0.58 ms2, P = 0.004), increased VLF% (78.9%±13.4% vs 60.9%±19.2%, P = 0.008), decreased HF% (6.9%±7.8% vs 16.0%±11.7%, P = 0.046) with a trend to higher LF/HF ratio. Conclusions: SDB increases HRV in the setting of increased sympathetic dominance. HRV in CSA and OSA have unique HRV patterns which are likely to reflect the different pathophysiological mechanisms involved. Citation: Szollosi I; Krum H; Kaye D; Naughton MT. Sleep apnea in heart failure increases heart rate variability and sympathetic dominance. SLEEP 2007;30(11):1509-1514. PMID:18041483

  4. Heart Rate and Heart Rate Variability in Dairy Cows with Different Temperament and Behavioural Reactivity to Humans

    PubMed Central

    Tőzsér, János; Szenci, Ottó; Póti, Péter; Pajor, Ferenc

    2015-01-01

    From the 1990s, extensive research was started on the physiological aspects of individual traits in animals. Previous research has established two extreme (proactive and reactive) coping styles in several animal species, but the means of reactivity with the autonomic nervous system (ANS) activity has not yet been investigated in cattle. The aim of this study was the characterization of cardiac autonomic activity under different conditions in cows with different individual characteristics. For this purpose, we investigated heart rate and ANS-related heart rate variability (HRV) parameters of dairy cows (N = 282) on smaller- and larger-scale farms grouped by (1) temperament and (2) behavioural reactivity to humans (BRH). Animals with high BRH scores were defined as impulsive, while animals with low BRH scores were defined as reserved. Cardiac parameters were calculated for undisturbed lying (baseline) and for milking bouts, the latter with the presence of an unfamiliar person (stressful situation). Sympathetic tone was higher, while vagal activity was lower in temperamental cows than in calm animals during rest both on smaller- and larger-scale farms. During milking, HRV parameters were indicative of a higher sympathetic and a lower vagal activity of temperamental cows as compared to calm ones in farms of both sizes. Basal heart rate did not differ between BRH groups either on smaller- or larger-scale farms. Differences between basal ANS activity of impulsive and reserved cows reflected a higher resting vagal and lower sympathetic activity of reserved animals compared to impulsive ones both on smaller- and larger-scale farms. There was no difference either in heart rate or in HRV parameters between groups during milking neither in smaller- nor in larger-scale farms. These two groupings allowed to draw possible parallels between personality and cardiac autonomic activity during both rest and milking in dairy cows. Heart rate and HRV seem to be useful for

  5. Heart rate and heart rate variability in multiparous dairy cows with unassisted calvings in the periparturient period.

    PubMed

    Kovács, L; Tőzsér, J; Kézér, F L; Ruff, F; Aubin-Wodala, M; Albert, E; Choukeir, A; Szelényi, Z; Szenci, O

    2015-02-01

    Behavioural changes before calving can be monitored on farms; however, predicting the onset of calving is sometimes difficult based only on clinical signs. Heart rate (HR) and heart rate variability (HRV) as non-invasive measures of autonomic nervous system (ANS) activity were investigated in Holstein-Friesian cows (N=20) with unassisted calvings in the periparturient period to predict the onset of calving and assess the stress associated with calving. R-R-intervals were analysed in 5-min time windows during the following three main periods of measurement: 1) between 0 and 96 h before the onset of calving restlessness (prepartum period); 2) during four stages of calving: (I) early first stage; between the onset of calving restlessness and the first abdominal contractions; (II) late first stage (between the first abdominal contractions and the appearance of the amniotic sac); (III) early second stage (between the appearance of the amniotic sac and the appearance of the foetal hooves); (IV) late second stage (between the appearance of the foetal hooves and delivery of the calf), and 3) over 48 h following calving (postpartum period). Data collected between 72 and 96 h before calving restlessness was used as baseline. Besides HR, Poincaré measures [standard deviation 1 (SD1) and 2 (SD2) and SD2/SD1 ratio], the root mean square of successive differences (RMSSD) in R-R intervals, the high-frequency (HF) component of HRV and the ratio between the low-frequency (LF) and the HF components (LF/HF ratio) were calculated. Heart rate increased only following the onset of the behavioural signs, peaked before delivery of the calf, then decreased immediately after calving. Parasympathetic indices of HRV (RMSSD, HFnorm and SD1) decreased, whereas sympathovagal indices (LF/HF ratio and SD2/SD1 ratio) increased significantly from baseline between 12 and 24 before the onset of calving restlessness. The same pattern was observed between 0 and 1h before calving restlessness. Following

  6. General anesthesia suppresses normal heart rate variability in humans

    NASA Astrophysics Data System (ADS)

    Matchett, Gerald; Wood, Philip

    2014-06-01

    The human heart normally exhibits robust beat-to-beat heart rate variability (HRV). The loss of this variability is associated with pathology, including disease states such as congestive heart failure (CHF). The effect of general anesthesia on intrinsic HRV is unknown. In this prospective, observational study we enrolled 100 human subjects having elective major surgical procedures under general anesthesia. We recorded continuous heart rate data via continuous electrocardiogram before, during, and after anesthesia, and we assessed HRV of the R-R intervals. We assessed HRV using several common metrics including Detrended Fluctuation Analysis (DFA), Multifractal Analysis, and Multiscale Entropy Analysis. Each of these analyses was done in each of the four clinical phases for each study subject over the course of 24 h: Before anesthesia, during anesthesia, early recovery, and late recovery. On average, we observed a loss of variability on the aforementioned metrics that appeared to correspond to the state of general anesthesia. Following the conclusion of anesthesia, most study subjects appeared to regain their normal HRV, although this did not occur immediately. The resumption of normal HRV was especially delayed on DFA. Qualitatively, the reduction in HRV under anesthesia appears similar to the reduction in HRV observed in CHF. These observations will need to be validated in future studies, and the broader clinical implications of these observations, if any, are unknown.

  7. Heart rate as an indicator of oxygen consumption: influence of body condition in the king penguin.

    PubMed

    Froget, G; Butler, P J; Handrich, Y; Woakes, A J

    2001-06-01

    The use of heart rate to estimate field metabolic rate has become a more widely used technique. However, this method also has some limitations, among which is the possible impact that several variables such as sex, body condition (i.e. body fat stores) and/or inactivity might have on the relationship between heart rate and rate of oxygen consumption. In the present study, we investigate the extent to which body condition can affect the use of heart rate as an indicator of the rate of oxygen consumption. Twenty-two breeding king penguins (Aptenodytes patagonicus) were exercised on a variable-speed treadmill. These birds were allocated to four groups according to their sex and whether or not they had been fasting. Linear regression equations were used to describe the relationship between heart rate and the rate of oxygen consumption for each group. There were significant differences between the regression equations for the four groups. Good relationships were obtained between resting and active oxygen pulses and an index of the body condition of the birds. Validation experiments on six courting king penguins showed that the use of a combination of resting oxygen pulse and active oxygen pulse gave the best estimate of the rate of oxygen consumption V(O2). The mean percentage error between predicted and measured V(O2) was only +0.81% for the six birds. We conclude that heart rate can be used to estimate rate of oxygen consumption in free-ranging king penguins even over a small time scale (30 min). However, (i) the type of activity of the bird must be known and (ii) the body condition of the bird must be accurately determined. More investigations on the impact of fasting and/or inactivity on this relationship are required to refine these estimates further. PMID:11441055

  8. Effect of Qi-training on blood pressure, heart rate and respiration rate.

    PubMed

    Lee, M S; Kim, B G; Huh, H J; Ryu, H; Lee, H S; Chung, H T

    2000-05-01

    To examine the physiological effects of Korean traditional Qi-training, we investigated the changes in blood pressure, heart and respiratory rates before, during and after ChunDoSunBup (CDSB) Qi-training. Twelve normal healthy CDSB Qi-trainees (19-37 years old; trained for 1.3 +/- 0.2 years; 9 men and 3 women) volunteered to participate in this study. Heart rate, respiratory rate, systolic blood pressure and rate-pressure product were significantly decreased during Qi-training. From these results, we suggest that CDSB Qi-training has physiological effects that indicate stabilization of cardiovascular system.

  9. Heart Rate and Energy Expenditure During Aqua Dynamics.

    PubMed

    Vickery, S R; Cureton, K J; Langstaff, J L

    1983-03-01

    In brief: The heart rate, oxygen uptake, and energy expenditure of three young women were measured during 20-minute low-gear, 30-minute middle-gear, and 60-minute high-gear aqua dynamics workouts. All three workouts were moderate in intensity, eliciting average heart rates of 132 to 143 beats min(-1) (70% to 77% HR max), average oxygen uptakes of 1.2 to 1.3 liters min(-1) (51% to 57% VO2 max), and average energy expenditures of 5.9 to 6.5 kcals min(-1) The findings indicate that aqua dynamics could be a beneficial conditioning program for people who have relatively low physical work capacity and enjoy swimming but cannot conveniently engage in lap swimming. PMID:27409547

  10. Association between oral variables and heart rate variability.

    PubMed

    Santana, Milana Drumond Ramos; de Souza, Ana Cecilia Amorim; de Abreu, Luiz Carlos; Valenti, Vitor E

    2013-12-27

    The heart rate variability is a useful method to assess cardiac autonomic modulation in patients undergoing dental procedures, because knowledge of physiological conditions provides greater security to the professional as well as the possibility of a better plan treatment to patient benefit. The aim of our study was to describe the association between cardiac autonomic control and dental variables. We consulted the databases Medline, SciELO, Lilacs and Cochrane, using the terms "autonomic", "dentistry", "heart rate variability", "cardiovascular physiology." The selected studies indicated a strong relationship between dental variables and HRV. There was an association between malocclusion, TMD, dental procedures cirugia and low HRV. Thus, they become more studies that relate to HRV in dental science, especially in clinical practice.

  11. Real-time signal processing for fetal heart rate monitoring.

    PubMed

    Ibrahimy, Muhammad I; Ahmed, Firoz; Mohd Ali, M A; Zahedi, Edmond

    2003-02-01

    An algorithm based on digital filtering, adaptive thresholding, statistical properties in the time domain, and differencing of local maxima and minima has been developed for the simultaneous measurement of the fetal and maternal heart rates from the maternal abdominal electrocardiogram during pregnancy and labor for ambulatory monitoring. A microcontroller-based system has been used to implement the algorithm in real-time. A Doppler ultrasound fetal monitor was used for statistical comparison on five volunteers with low risk pregnancies, between 35 and 40 weeks of gestation. Results showed an average percent root mean square difference of 5.32% and linear correlation coefficient from 0.84 to 0.93. The fetal heart rate curves remained inside a +/- 5-beats-per-minute limit relative to the reference ultrasound method for 84.1% of the time. PMID:12665042

  12. Respiration and heart rate in exercising land crabs.

    PubMed

    Herreid, C F; Lee, L W; Shah, G M

    1979-05-01

    Land Crabs, Cardisoma guanhumi, were fitted with respiratory masks and E.C.G. electrodes and run for 10 or 20 min on a treadmill at speeds of 150 and 300 cm/min. Aerobic metabolism increased linearly with the speed of locomotion. The recovery period was characterized by a large oxygen debt. The primary respiratory adjustment to exercise was an increased ventilation volume; only a minor increase in oxygen extraction occurred. The respiratory exchange ratio increased during exercise and during recovery, presumably correlated with a metabolic acidosis. These results are similar to data collected for exercising vertebrates and the net cost of locomotion of crabs appears similar to quadrupeds. However, the heart rate in exercising crabs changed in an unexpected way: during moderate exercise no change was noted, but during heavy exercise a bradycardia developed. The reduction in rate resulted from an increase in interbeat interval and frequent pauses in the heart beat.

  13. Prognostic significance of heart rate variability in centenarians.

    PubMed

    Shimizu, Kenichiro; Arai, Yasumichi; Hirose, Nobuyoshi; Yonemoto, Takayuki; Wakida, Yasushi

    2002-01-01

    We studied the significance for further survival of heart rate variability and other variables in the very elderly. In 1992, we assessed activities of daily living, cognitive function, and nutritional status in 27 centenarians with no disease, in addition to the power of the heart rate variability in the ultralow, very low, low (LF), and high frequency (HF) bands. In 1996, we assessed survival in these centenarians; 17 had died and 10 were still living. Logistic regression analysis using backward elimination detected three factors, dementia, LF/HF, and age, that independently influenced mortality. Mortality risk increased with greater age in 1992, more severe dementia, or lower LF/HF. Sympathetic nerve activity, represented as LF/HF, may be associated with prognosis for survival in centenarians.

  14. Heart rate dynamics preceding hemorrhage in the intensive care unit.

    PubMed

    Moss, Travis J; Clark, Matthew T; Lake, Douglas E; Moorman, J Randall; Calland, J Forrest

    2015-01-01

    Occult hemorrhage in surgical/trauma intensive care unit (STICU) patients is common and may lead to circulatory collapse. Continuous electrocardiography (ECG) monitoring may allow for early identification and treatment, and could improve outcomes. We studied 4,259 consecutive admissions to the STICU at the University of Virginia Health System. We collected ECG waveform data captured by bedside monitors and calculated linear and non-linear measures of the RR interbeat intervals. We tested the hypothesis that a transfusion requirement of 3 or more PRBC transfusions in a 24 hour period is preceded by dynamical changes in these heart rate measures and performed logistic regression modeling. We identified 308 hemorrhage events. A multivariate model including heart rate, standard deviation of the RR intervals, detrended fluctuation analysis, and local dynamics density had a C-statistic of 0.62. Earlier detection of hemorrhage might improve outcomes by allowing earlier resuscitation in STICU patients.

  15. gHRV: Heart rate variability analysis made easy.

    PubMed

    Rodríguez-Liñares, L; Lado, M J; Vila, X A; Méndez, A J; Cuesta, P

    2014-08-01

    In this paper, the gHRV software tool is presented. It is a simple, free and portable tool developed in python for analysing heart rate variability. It includes a graphical user interface and it can import files in multiple formats, analyse time intervals in the signal, test statistical significance and export the results. This paper also contains, as an example of use, a clinical analysis performed with the gHRV tool, namely to determine whether the heart rate variability indexes change across different stages of sleep. Results from tests completed by researchers who have tried gHRV are also explained: in general the application was positively valued and results reflect a high level of satisfaction. gHRV is in continuous development and new versions will include suggestions made by testers.

  16. Heart rate variability (HRV): an indicator of stress

    NASA Astrophysics Data System (ADS)

    Kaur, Balvinder; Durek, Joseph J.; O'Kane, Barbara L.; Tran, Nhien; Moses, Sophia; Luthra, Megha; Ikonomidou, Vasiliki N.

    2014-05-01

    Heart rate variability (HRV) can be an important indicator of several conditions that affect the autonomic nervous system, including traumatic brain injury, post-traumatic stress disorder and peripheral neuropathy [3], [4], [10] & [11]. Recent work has shown that some of the HRV features can potentially be used for distinguishing a subject's normal mental state from a stressed one [4], [13] & [14]. In all of these past works, although processing is done in both frequency and time domains, few classification algorithms have been explored for classifying normal from stressed RRintervals. In this paper we used 30 s intervals from the Electrocardiogram (ECG) time series collected during normal and stressed conditions, produced by means of a modified version of the Trier social stress test, to compute HRV-driven features and subsequently applied a set of classification algorithms to distinguish stressed from normal conditions. To classify RR-intervals, we explored classification algorithms that are commonly used for medical applications, namely 1) logistic regression (LR) [16] and 2) linear discriminant analysis (LDA) [6]. Classification performance for various levels of stress over the entire test was quantified using precision, accuracy, sensitivity and specificity measures. Results from both classifiers were then compared to find an optimal classifier and HRV features for stress detection. This work, performed under an IRB-approved protocol, not only provides a method for developing models and classifiers based on human data, but also provides a foundation for a stress indicator tool based on HRV. Further, these classification tools will not only benefit many civilian applications for detecting stress, but also security and military applications for screening such as: border patrol, stress detection for deception [3],[17], and wounded-warrior triage [12].

  17. Baroreflex control of heart rate during sleep in severe obstructive sleep apnoea: effects of acute CPAP.

    PubMed

    Bonsignore, M R; Parati, G; Insalaco, G; Castiglioni, P; Marrone, O; Romano, S; Salvaggio, A; Mancia, G; Bonsignore, G; Di Rienzo, M

    2006-01-01

    Baroreflex control of heart rate during sleep (baroreflex sensitivity; BRS) has been shown to be depressed in obstructive sleep apnoea (OSA), and improved after treatment with continuous positive airway pressure (CPAP). Whether CPAP also acutely affects BRS during sleep in uncomplicated severe OSA is still debatable. Blood pressure was monitored during nocturnal polysomnography in 18 patients at baseline and during first-time CPAP application. Spontaneous BRS was analysed by the sequence method, and estimated as the mean sequence slope. CPAP did not acutely affect mean blood pressure or heart rate but decreased cardiovascular variability during sleep. Mean BRS increased slightly during CPAP application (from 6.5+/-2.4 to 7.5+/-2.9 ms x mmHg(-1)), mostly in response to decreasing blood pressure. The change in BRS did not correlate with changes in arterial oxygen saturation or apnoea/hypopnoea index. The small change in baroreflex control of heart rate during sleep at first application of continuous positive airway pressure in severe obstructive sleep apnoea was unrelated to the acute resolution of nocturnal hypoxaemia, and might reflect autonomic adjustments to positive intrathoracic pressure, and/or improved sleep architecture. The small increase in baroreflex control of heart rate during sleep may be of clinical relevance as it was accompanied by reduced cardiovascular variability, which is acknowledged as an independent cardiovascular risk factor.

  18. Cholesterol enhances classical conditioning of the rabbit heart rate response

    PubMed Central

    Schreurs, Bernard G.; Smith-Bell, Carrie A.; Darwish, Deya S.; Wang, Desheng; Burhans, Lauren B.; Gonzales-Joekes, Jimena; Deci, Stephen; Stankovic, Goran; Sparks, D. Larry

    2007-01-01

    The cholesterol-fed rabbit is a model of atherosclerosis and has been proposed as an animal model of Alzheimer's disease. Feeding rabbits cholesterol has been shown to increase the number of beta amyloid immunoreactive neurons in the cortex. Addition of copper to the drinking water of cholesterol-fed rabbits can increase this number still further and may lead to plaque-like structures. Classical conditioning of the nictitating membrane response in cholesterol-fed rabbits is retarded in the presence of these plaque-like structures but may be facilitated in their absence. In a factorial design, rabbits fed 2% cholesterol or a normal diet (0% cholesterol) for 8 weeks with or without copper added to the drinking water were given trace classical conditioning using a tone and periorbital electrodermal stimulation to study the effects of cholesterol and copper on classical conditioning of heart rate and the nictitating membrane response. Cholesterol-fed rabbits showed significant facilitation of heart rate conditioning and conditioning-specific modification of heart rate relative to normal diet controls. Consistent with previous research, cholesterol had minimal effects on classical conditioning of the nictitating membrane response when periorbital electrodermal stimulation was used as the unconditioned stimulus. Immunohistochemical analysis showed a significant increase in the number of beta amyloid positive neurons in the cortex, hippocampus and amygdala of the cholesterol-fed rabbits. Supplementation of drinking water with copper increased the number of beta amyloid positive neurons in the cortex of cholesterol-fed rabbits but did not produce plaque-like structures or have a significant effect on heart rate conditioning. The data provide additional support for our finding that, in the absence of plaques, dietary cholesterol may facilitate learning and memory. PMID:17466388

  19. Changes in heart rate variability during concentration meditation.

    PubMed

    Phongsuphap, Sukanya; Pongsupap, Yongyuth; Chandanamattha, Pakorn; Lursinsap, Chidchanok

    2008-11-28

    This study aims at investigating changes in heart rate variability (HRV) measured during meditation. The statistical and spectral measures of HRV from the RR intervals were analyzed. Results indicate that meditation may have different effects on health depending on frequency of the resonant peak that each meditator can achieve. The possible effects may concern resetting baroreflex sensitivity, increasing the parasympathetic tone, and improving efficiency of gas exchange in the lung.

  20. Spectral photoplethysmographic imaging sensor fusion for enhanced heart rate detection

    NASA Astrophysics Data System (ADS)

    Amelard, Robert; Clausi, David A.; Wong, Alexander

    2016-03-01

    Continuous heart rate monitoring can provide important context for quantitative clinical assessment in scenarios such as long-term health monitoring and disability prevention. Photoplethysmographic imaging (PPGI) systems are particularly useful for such monitoring scenarios as contact-based devices pose problems related to comfort and mobility. Each pixel can be regarded as a virtual PPG sensor, thus enabling simultaneous measurements of multiple skin sites. Existing PPGI systems analyze temporal PPGI sensor uctuations related to hemodynamic pulsations across a region of interest to extract the blood pulse signal. However, due to spatially varying optical properties of the skin, the blood pulse signal may not be consistent across all PPGI sensors, leading to inaccurate heart rate monitoring. To increase the hemodynamic signal-to-noise ratio (SNR), we propose a novel spectral PPGI sensor fusion method for enhanced estimation of the true blood pulse signal. Motivated by the observation that PPGI sensors with high hemodynamic SNR exhibit a spectral energy peak at the heart rate frequency, an entropy-based fusion model was formulated to combine PPGI sensors based on the sensors' spectral energy distribution. The optical PPGI device comprised a near infrared (NIR) sensitive camera and an 850 nm LED. Spatially uniform irradiance was achieved by placing optical elements along the LED beam, providing consistent illumination across the skin area. Dual-mode temporally coded illumination was used to negate the temporal effect of ambient illumination. Experimental results show that the spectrally weighted PPGI method can accurately and consistently extract heart rate information where traditional region-based averaging fails.

  1. The effects of hypnosis on heart rate variability.

    PubMed

    Yüksel, Ramazan; Ozcan, Osman; Dane, Senol

    2013-01-01

    Uslu et al. (2012 ) suggested that hypnotic status can modulate cerebral blood flow. The authors investigated the effects of hypnosis on heart rate variability (HRV). In women, HRV decreased during hypnosis. Posthypnotic values were higher compared to prehypnotic and hypnotic values. Women had highest HRV parameters in the posthypnotic condition. It appears that hypnosis can produce cardiac and cognitive activations. Hypnotherapy may be useful in some cardiac clinical conditions characterized by an autonomic imbalance or some cardiac arrhythmias.

  2. Heart rate variability and sympathovagal balance: pharmacological validation

    PubMed Central

    Bootsma, M.; Swenne, C.A.; Janssen, M.J.A.; Cats, V. Manger; Schalij, M.J.

    2003-01-01

    Rationale We validated heart rate (HR) and six time and six frequency domain measures of heart rate variability (HRV) as estimators of autonomic outflow in 44 young healthy male subjects. Gold standards for autonomic outflow were the Rosenblueth-Simeone factors m (sympathetic tone) and n (vagal tone), and the sympathovagal balance m·n, determined by two-stage complete autonomic blockade. Methods Rank correlations were computed between HR and the HRV measures obtained before autonomic blockade, and m, n and m·n. Also, the maximal mean performances (averaged sensitivity and specificity) for HR and HRV as discriminators between low and high values of m, n or m·n were computed. Results The spectral HRV measures showed less good correlations and performances than the time domain HRV measures. Correlations with sympathetic tone were all below 0.31. Respiratory sinus arrhythmia during 15 cycles/min metronome breathing was superior in estimating vagal tone and sympathovagal balance (correlations -0.71/-0.73; both performances 0.82), heart rate scored similarly for assessing the sympathovagal balance (correlation 0.71; performance 0.82). Conclusions It does not appear justified to evaluate HR or HRV in terms of sympathetic tone, vagal tone, or sympathovagal balance. HR and HRV are specifically weak in assessing sympathetic tone. Respiratory sinus arrhythmia during 15 cycles/min metronome breathing is superior in assessing vagal tone. Current HRV analysis techniques offer no advantages compared with HR in assessing the sympathovagal balance. PMID:25696224

  3. Impaired heart rate recovery in patients with endemic fluorosis.

    PubMed

    Adali, M Koray; Varol, Ercan; Aksoy, Fatih; Icli, Atilla; Ersoy, I Hakki; Ozaydin, Mehmet; Erdogan, Dogan; Dogan, Abdullah

    2013-06-01

    The objective of the present study was to determine the heart rate recovery index (HRRI), a marker of autonomic nervous system function in patients with endemic fluorosis. Forty patients with endemic fluorosis (16 men/24 women) and 40 age-, sex-, and body mass index-matched healthy controls (16 men/24 women) with normal fluoride intake were enrolled in this study. HRRI was calculated by subtracting the heart rate values at the first, second, and third minutes of the recovery phase from the peak heart rate (HRRI 1, HRRI 2, HRRI 3). Urine fluoride levels of fluorosis patients were significantly (P < 0.001) higher than control subjects as expected. HRRI 2 was significantly lower in fluorosis patients than in the controls. The incidence of abnormal HRRI 1 was significantly higher in fluorosis patients than in the controls (P < 0.05). We observed that HRRI, a marker of autonomic nervous system function, is impaired in patients with chronic fluorosis.

  4. Experimental heart rate regulation in cycle-ergometer exercises.

    PubMed

    Paradiso, Michele; Pietrosanti, Stefano; Scalzi, Stefano; Tomei, Patrizio; Verrelli, Cristiano Maria

    2013-01-01

    The heart rate can be effectively used as a measure of the exercise intensity during long duration cycle-ergometer exercises: precisely controlling the heart rate (HR) becomes crucial especially for athletes or patients with cardiovascular/obesity problems. The aim of this letter is to experimentally show how the nonlocal and nonswitching nonlinear control that has been recently proposed in the literature for the HR regulation in treadmill exercises can be effectively applied to cycle-ergometer exercises at constant cycling speed. The structure of the involved nonlinear model for the HR dynamics in cycle-ergometer exercises is mathematically inspired by the structure of a recently identified and experimentally validated nonlinear model for the HR dynamics in treadmill exercises: the role played by the treadmill speed is played here by the work load while the zero speed case for the treadmill exercise is here translated into the cycling operation under zero work load. Experimental results not only validate the aforementioned nonlinear model but also demonstrate the effectiveness--in terms of precise HR regulation--of an approach which simply generalizes to the nonlinear framework the classical proportional-integral control design. The possibility of online modifying the HR reference on the basis of the heart rate variability (HRV) is also suggested and experimentally motivated.

  5. Heart rate & blood lactate response in amateur competitive boxing.

    PubMed

    Ghosh, A K; Goswami, A; Ahuja, A

    1995-10-01

    The heart rate (HR) and blood lactate response were studied on 26 senior national level boxers in competitive bouts to explore the aerobic-anaerobic metabolism as well as the training status of the players. The aerobic capacity (VO2 max) of the players were determined using graded running protocol on a treadmill. Heart rate and blood lactate concentration were measured during warm up and boxing rounds. The mean relative VO2 max of the heavy weight category boxers was lower (P < 0.05) than the other two weight categories. No interweight category as well as inter-round differences were observed in the heart rate and blood lactate concentration of the boxers, excepting in the 48-57 kg category, the mean lactate levels in the second and third rounds were higher (P < 0.05) than in the first round. When all weight categories were pooled the mean HR and blood lactate levels were 178 beats/min and 8.24 mMol/l respectively. The study highlights that in amateur boxing, irrespective of the weight category and aerobic capacity, the anaerobic adaptability of the boxers was the same. The training requirements of the boxers demand that they should be also to tolerate a high blood lactate level (approx. 9.0 mMol/l) and a high HR (approx. 180 beats/min) over a total duration of one bout.

  6. Local dynamics of heart rate: detection and prognostic implications.

    PubMed

    Moss, Travis J; Lake, Douglas E; Moorman, J Randall

    2014-10-01

    The original observation that reduced heart rate variability (HRV) confers poor prognosis after myocardial infarction has been followed by many studies of heart rate dynamics. We tested the hypothesis that an entropy-based local dynamics measure gave prognostic information in ambulatory patients undergoing 24-h electrocardiography. In this context, entropy is the probability that short templates will find matches in the time series. We studied RR interval time series from 24-h Holter monitors of 1564 consecutive patients over age 39. We generated histograms of the count of templates as a function of the number of templates matches in short RR interval time series, and found characteristic appearance of histograms for atrial fibrillation, sinus rhythm with normal HRV, and sinus rhythm with reduced HRV and premature ventricular contractions (PVCs). We developed statistical models to detect the abnormal dynamic phenotype of reduced HRV with PVCs and fashioned a local dynamics score (LDs) that, after controlling for age, added more prognostic information than other standard risk factors and common HRV metrics, including, to our surprise, the PVC count and the HRV of normal-to-normal intervals. Addition of the LDs to a predictive model using standard risk factors significantly increased the ROC area and the net reclassification improvement was 27%. We conclude that abnormal local dynamics of heart rate confer adverse prognosis in patients undergoing 24-h ambulatory electrocardiography.

  7. Mesenchymal Stem Cells Improve Heart Rate Variability and Baroreflex Sensitivity in Rats with Chronic Heart Failure

    PubMed Central

    de Morais, Sharon Del Bem Velloso; da Silva, Luiz Eduardo Virgilio; Lataro, Renata Maria; Silva, Carlos Alberto Aguiar; de Oliveira, Luciano Fonseca Lemos; de Carvalho, Eduardo Elias Vieira; Simões, Marcus Vinicius; da Silva Meirelles, Lindolfo; Fazan, Rubens

    2015-01-01

    Heart failure induced by myocardial infarct (MI) attenuates the heart rate variability (HRV) and baroreflex sensitivity, which are important risk factors for life-threatening cardiovascular events. Therapies with mesenchymal stem cells (MSCs) have shown promising results after MI. However, the effects of MSCs on hemodynamic (heart rate and arterial pressure) variability and baroreflex sensitivity in chronic heart failure (CHF) following MI have not been evaluated thus far. Male Wistar rats received MSCs or saline solution intravenously 1 week after ligation of the left coronary artery. Control (noninfarcted) rats were also evaluated. MI size was assessed using single-photon emission computed tomography (SPECT). The left ventricular ejection fraction (LVEF) was evaluated using radionuclide ventriculography. Four weeks after MSC injection, the animals were anesthetized and instrumented for chronic ECG recording and catheters were implanted in the femoral artery to record arterial pressure. Arterial pressure and HRVs were determined in time and frequency domain (spectral analysis) while HRV was also examined using nonlinear methods: DFA (detrended fluctuation analysis) and sample entropy. The initial MI size was the same among all infarcted rats but was reduced by MSCs. CHF rats exhibited increased myocardial interstitial collagen and sample entropy combined with the attenuation of the following cardiocirculatory parameters: DFA indices, LVEF, baroreflex sensitivity, and HRV. Nevertheless, MSCs hampered all these alterations, except the LVEF reduction. Therefore, 4 weeks after MSC therapy was applied to CHF rats, MI size and myocardial interstitial fibrosis decreased, while baroreflex sensitivity and HRV improved. PMID:26059001

  8. Skeletal muscle electrical stimulation improves baroreflex sensitivity and heart rate variability in heart failure rats.

    PubMed

    Lazzarotto Rucatti, Ananda; Jaenisch, Rodrigo Boemo; Rossato, Douglas Dalcin; Bonetto, Jéssica Hellen Poletto; Ferreira, Janaína; Xavier, Leder Leal; Sonza, Anelise; Dal Lago, Pedro

    2015-12-01

    The goal of the current study was to evaluate the effects of electrical stimulation (ES) on the arterial baroreflex sensitivity (BRS) and cardiovascular autonomic control in rats with chronic heart failure (CHF). Male Wistar rats were designated to one of four groups: placebo sham (P-Sham, n=9), ES sham (ES-Sham, n=9), placebo CHF (P-CHF, n=9) or ES CHF (ES-CHF, n=9). The ES was adjusted at a low frequency (30 Hz), duration of 250 μs, with hold and rest time of 8s (4 weeks, 30 min/day, 5 times/week). It was applied on the gastrocnemius muscle with intensity to produce a visible muscle contraction. The rats assigned to the placebo groups performed the same procedures with the equipment turned off. The two-way ANOVA and the post hoc Student-Newman-Keuls tests (P<0.05) were used to data comparison. The BRS was higher in ES-Sham group compared to the P-Sham group and the ES-CHF group compared to the P-CHF group. ES was able to decrease heart rate sympatho-vagal modulation and peripheral sympathetic modulation in ES-CHF compared to P-CHF group. Interestingly, heart rate sympatho-vagal modulation was similar between ES-CHF and P-Sham groups. Thus, ES enhances heart rate parasympathetic modulation on heart failure (ES-CHF) compared to placebo (P-CHF), with consequent decrease of sympatho-vagal balance in the ES-CHF group compared to the P-CHF. The results show that a 4 week ES protocol in CHF rats enhances arterial BRS and cardiovascular autonomic control.

  9. Bluetooth(Registered Trademark) Heart Rate Monitors for Spaceflight

    NASA Technical Reports Server (NTRS)

    Buxton, Roxanne E.; West, Michael R.; Kalogera, Kent L.; Hanson, Andrea M.

    2016-01-01

    Heart rate monitoring is required during exercise for crewmembers aboard the International Space Station (ISS) and will be for future exploration missions. The cardiovascular system must be sufficiently stressed throughout a mission to maintain the ability to perform nominal and contingency/emergency tasks. High quality heart rate data is required to accurately determine the intensity of exercise performed by the crewmembers and show maintenance of VO2max. The quality of the data collected on ISS is subject to multiple limitations and is insufficient to meet current requirements. PURPOSE: To evaluate the performance of commercially available Bluetooth® heart rate monitors (BT_HRM) and their ability to provide high quality heart rate data to monitor crew health on board ISS and during future exploration missions. METHODS: Nineteen subjects completed 30 data collection sessions of various intensities on the treadmill and/or cycle. Subjects wore several BT_HRM technologies for each testing session. One electrode-based chest strap (CS) was worn, while one or more optical sensors (OS) was worn. Subjects were instrumented with a 12-lead ECG to compare the heart rate data from the Bluetooth sensors. Each BT_RHM data set was time matched to the ECG data and a +/-5bpm threshold was applied to the difference between the two data sets. Percent error was calculated based on the number of data points outside the threshold and the total number of data points. REULTS: The electrode-based chest straps performed better than the optical sensors. The best performing CS was CS1 (1.6%error), followed by CS4 (3.3%error), CS3 (6.4%error), and CS2 (9.2%error). The OS resulted in 10.4% error for OS1 and 14.9% error for OS2. CONCLUSIONS: The highest quality data came from CS1, unfortunately it has been discontinued by the manufacturer. The optical sensors have not been ruled out for use, but more investigation is needed to determine how to get the best quality data. CS2 will be used in an

  10. Classifying work rate from heart rate measurements using an adaptive neuro-fuzzy inference system.

    PubMed

    Kolus, Ahmet; Imbeau, Daniel; Dubé, Philippe-Antoine; Dubeau, Denise

    2016-05-01

    In a new approach based on adaptive neuro-fuzzy inference systems (ANFIS), field heart rate (HR) measurements were used to classify work rate into four categories: very light, light, moderate, and heavy. Inter-participant variability (physiological and physical differences) was considered. Twenty-eight participants performed Meyer and Flenghi's step-test and a maximal treadmill test, during which heart rate and oxygen consumption (VO2) were measured. Results indicated that heart rate monitoring (HR, HRmax, and HRrest) and body weight are significant variables for classifying work rate. The ANFIS classifier showed superior sensitivity, specificity, and accuracy compared to current practice using established work rate categories based on percent heart rate reserve (%HRR). The ANFIS classifier showed an overall 29.6% difference in classification accuracy and a good balance between sensitivity (90.7%) and specificity (95.2%) on average. With its ease of implementation and variable measurement, the ANFIS classifier shows potential for widespread use by practitioners for work rate assessment. PMID:26851475

  11. Blood volume, heart rate, and left ventricular ejection fraction changes in dogs before and after exercise during endurance training

    SciTech Connect

    Mackintosh, I.C.; Dormehl, I.C.; van Gelder, A.L.; du Plessis, M.

    1983-10-01

    In Beagles after 7 weeks' endurance training, resting blood volume increased by an average of 13.1%. Resting heart rates were not significantly affected, but heart rates measured 2 minutes after exercise were significantly lower after the endurance training than before. Left ventricular ejection fractions determined by radionuclide angiography from 2 minutes after exercise showed no significant changes in response to a single exercise period or over the 50 days' training.

  12. Skinfold thickness is related to cardiovascular autonomic control as assessed by heart rate variability and heart rate recovery.

    PubMed

    Esco, Michael R; Williford, Henry N; Olson, Michele S

    2011-08-01

    The purpose of this study was to determine if heart rate recovery (HRR) and heart rate variability (HRV) are related to maximal aerobic fitness and selected body composition measurements. Fifty men (age = 21.9 ± 3.0 years, height = 180.8 ± 7.2 cm, weight = 80.4 ± 9.1 kg, volunteered to participate in this study. For each subject, body mass index (BMI), waist circumference (WC), and the sum of skinfolds across the chest, abdomen, and thigh regions (SUMSF) were recorded. Heart rate variability (HRV) was assessed during a 5-minute period while the subjects rested in a supine position. The following frequency domain parameters of HRV were recorded: normalized high-frequency power (HFnu), and low-frequency to high-frequency power ratio (LF:HF). To determine maximal aerobic fitness (i.e., VO2max), each subject performed a maximal graded exercise test on a treadmill. Heart rate recovery was recorded 1 (HRR1) and 2 (HRR2) minutes during a cool-down period. Mean VO2max and BMI for all the subjects were 49.5 ± 7.5 ml·kg(-1)·min(-1) and 24.7 ± 2.2 kg·m(-2), respectively. Although VO2max, WC, and SUMSF was each significantly correlated to HRR and HRV, only SUMSF had a significant independent correlation to HRR1, HRR2, HFnu, LF:HF (p < 0.01). The results of the regression procedure showed that SUMSF accounted for the greatest variance in HRR1, HRR2, HFnu, and LF:HF (p < 0.01). The results of this study suggest that cardiovascular autonomic modulation is significantly related to maximal aerobic fitness and body composition. However, SUMSF appears to have the strongest independent relationship with HRR and HRV, compared to other body composition parameters and VO2max.

  13. Neural control of heart rate: the role of neuronal networking.

    PubMed

    Kember, G; Armour, J A; Zamir, M

    2011-05-21

    Neural control of heart rate, particularly its sympathetic component, is generally thought to reside primarily in the central nervous system, though accumulating evidence suggests that intrathoracic extracardiac and intrinsic cardiac ganglia are also involved. We propose an integrated model in which the control of heart rate is achieved via three neuronal "levels" representing three control centers instead of the conventional one. Most importantly, in this model control is effected through networking between neuronal populations within and among these layers. The results obtained indicate that networking serves to process demands for systemic blood flow before transducing them to cardiac motor neurons. This provides the heart with a measure of protection against the possibility of "overdrive" implied by the currently held centrally driven system. The results also show that localized networking instabilities can lead to sporadic low frequency oscillations that have the characteristics of the well-known Mayer waves. The sporadic nature of Mayer waves has been unexplained so far and is of particular interest in clinical diagnosis.

  14. Respiratory modulation and baroreflex control of heart rate in space

    NASA Astrophysics Data System (ADS)

    Verheyden, Bart; Couckuyt, Kurt; Liu, Jiexin; Aubert, Andre

    During everyday life, gravity constantly stresses the human circulation by diminishing venous return in the upright position. This induces baroreflex-mediated cardiovascular adjustments that are aimed to prevent the blood pressure from falling. In weightlessness, gravitational pressure gradients do not arise in the circulation so that baroreflex function remains chronically unchallenged. This may contribute to the development of post spaceflight orthostatic intolerance. The purpose of this study was to evaluate respiratory modulation and baroreflex control of heart rate after a week of weightlessness in space. We tested the hypothesis that cardiovascular control in space will be similar to the baseline supine condition on Earth. We studied nine male cosmonauts during seven different space missions aboard the ISS (age 40 - 52 yrs, height 1.69 - 1.85 m, weight 67 - 90 kg). Data collection was performed between 30 and 45 days before launch in the standing and supine positions, and after 8 days in space. Cosmonauts were carefully trained to perform in-flight data collection by themselves. They were instructed to pace their breathing to a fixed rate of 12 breaths per minute (0.2 Hz) for a total duration of 3 minutes. The electrocardiogram and beat-by-beat finger arterial blood pressure were recorded at 1-kHz sample rate. Respiratory rate was evaluated using an abdominal pressure sensor. We used power spectral analysis to calculate respiratory sinus arrhythmia (RSA) as well as the low-frequency (0.04 - 0.15 Hz) powers of spontaneous oscillations in heart rate and systolic blood pressure. Baroreflex sensitivity (BRS) was estimated in the time domain using cross-correlation analysis. As expected, there was a rise in heart rate upon assuming the standing position before space- flight (59 ± 6 to 79 ± 11 beats per min; p ¡ 0.001). This was accompanied by an increase in mean arterial blood pressure (84 ± 6 to 93 ± 6 mmHg; p ¡ 0.001). Standing up further induced a marked

  15. Characterizing heart rate variability by scale-dependent Lyapunov exponent

    NASA Astrophysics Data System (ADS)

    Hu, Jing; Gao, Jianbo; Tung, Wen-wen

    2009-06-01

    Previous studies on heart rate variability (HRV) using chaos theory, fractal scaling analysis, and many other methods, while fruitful in many aspects, have produced much confusion in the literature. Especially the issue of whether normal HRV is chaotic or stochastic remains highly controversial. Here, we employ a new multiscale complexity measure, the scale-dependent Lyapunov exponent (SDLE), to characterize HRV. SDLE has been shown to readily characterize major models of complex time series including deterministic chaos, noisy chaos, stochastic oscillations, random 1/f processes, random Levy processes, and complex time series with multiple scaling behaviors. Here we use SDLE to characterize the relative importance of nonlinear, chaotic, and stochastic dynamics in HRV of healthy, congestive heart failure, and atrial fibrillation subjects. We show that while HRV data of all these three types are mostly stochastic, the stochasticity is different among the three groups.

  16. Heart dimensions may influence the occurrence of the heart rate deflection point in highly trained cyclists

    PubMed Central

    Lucia, A.; Carvajal, A.; Boraita, A.; Serratosa, L.; Hoyos, J.; Chicharro, J. L.

    1999-01-01

    OBJECTIVES: To determine whether the heart rate (HR) response to exercise in 21 highly trained cyclists (mean (SD) age 25 (3) years) was related to their heart dimensions. METHODS: Before performing an incremental exercise test involving a ramp protocol with workload increases of 25 W/min, each subject underwent echocardiographic evaluation of the following variables: left ventricular end diastolic internal diameter (LVIDd), left ventricular posterior wall thickness at end diastole (LVPWTd), interventricular septal wall thickness at end diastole (IVSTd), left ventricular mass index (LVMI), left atrial dimension (LAD), longitudinal left atrial (LLAD) and right atrial (LRAD) dimensions, and the ratio of early to late (E/A) diastolic flow velocity. RESULTS: The HR response showed a deflection point (HRd) at about 85% VO2MAX in 66.7% of subjects (D group; n = 14) and was linear in 33.3% (NoD group; n = 7). Several echocardiographic variables (LVMI, LAD, LLAD, LRAD) indicative of heart dimensions were similar in each group. However, mean LPWTd (p<0.01) and IVSTd (p<0.05) values were significantly higher in the D group. Finally, no significant difference between groups was found with respect to the E/A. CONCLUSIONS: The HR response is curvilinear during incremental exercise in a considerable number of highly trained endurance athletes-that is, top level cyclists. The departure of HR increase from linearity may predominantly occur in athletes with thicker heart walls. 


 PMID:10597846

  17. Heart rate responses to autonomic challenges in obstructive sleep apnea.

    PubMed

    Macey, Paul M; Kumar, Rajesh; Woo, Mary A; Yan-Go, Frisca L; Harper, Ronald M

    2013-01-01

    Obstructive sleep apnea (OSA) is accompanied by structural alterations and dysfunction in central autonomic regulatory regions, which may impair dynamic and static cardiovascular regulation, and contribute to other syndrome pathologies. Characterizing cardiovascular responses to autonomic challenges may provide insights into central nervous system impairments, including contributions by sex, since structural alterations are enhanced in OSA females over males. The objective was to assess heart rate responses in OSA versus healthy control subjects to autonomic challenges, and, separately, characterize female and male patterns. We studied 94 subjects, including 37 newly-diagnosed, untreated OSA patients (6 female, age mean ± std: 52.1 ± 8.1 years; 31 male aged 54.3 ± 8.4 years), and 57 healthy control subjects (20 female, 50.5 ± 8.1 years; 37 male, 45.6 ± 9.2 years). We measured instantaneous heart rate with pulse oximetry during cold pressor, hand grip, and Valsalva maneuver challenges. All challenges elicited significant heart rate differences between OSA and control groups during and after challenges (repeated measures ANOVA, p<0.05). In post-hoc analyses, OSA females showed greater impairments than OSA males, which included: for cold pressor, lower initial increase (OSA vs. control: 9.5 vs. 7.3 bpm in females, 7.6 vs. 3.7 bpm in males), OSA delay to initial peak (2.5 s females/0.9 s males), slower mid-challenge rate-of-increase (OSA vs. control: -0.11 vs. 0.09 bpm/s in females, 0.03 vs. 0.06 bpm/s in males); for hand grip, lower initial peak (OSA vs. control: 2.6 vs. 4.6 bpm in females, 5.3 vs. 6.0 bpm in males); for Valsalva maneuver, lower Valsalva ratio (OSA vs. control: 1.14 vs. 1.30 in females, 1.29 vs. 1.34 in males), and OSA delay during phase II (0.68 s females/1.31 s males). Heart rate responses showed lower amplitude, delayed onset, and slower rate changes in OSA patients over healthy controls, and impairments may be more pronounced in females. The

  18. Humoral regulation of heart rate during digestion in pythons (Python molurus and Python regius).

    PubMed

    Enok, Sanne; Simonsen, Lasse Stærdal; Pedersen, Signe Vesterskov; Wang, Tobias; Skovgaard, Nini

    2012-05-15

    Pythons exhibit a doubling of heart rate when metabolism increases several times during digestion. Pythons, therefore, represent a promising model organism to study autonomic cardiovascular regulation during the postprandial state, and previous studies show that the postprandial tachycardia is governed by a release of vagal tone as well as a pronounced stimulation from nonadrenergic, noncholinergic (NANC) factors. Here we show that infusion of plasma from digesting donor pythons elicit a marked tachycardia in fasting snakes, demonstrating that the NANC factor resides in the blood. Injections of the gastrin and cholecystokinin receptor antagonist proglumide had no effect on double-blocked heart rate or blood pressure. Histamine has been recognized as a NANC factor in the early postprandial period in pythons, but the mechanism of its release has not been identified. Mast cells represent the largest repository of histamine in vertebrates, and it has been speculated that mast cells release histamine during digestion. Treatment with the mast cell stabilizer cromolyn significantly reduced postprandial heart rate in pythons compared with an untreated group but did not affect double-blocked heart rate. While this study indicates that histamine induces postprandial tachycardia in pythons, its release during digestion is not stimulated by gastrin or cholecystokinin nor is its release from mast cells a stimulant of postprandial tachycardia.

  19. Optimum Heart Rate to Minimize Pulsatile External Cardiac Power

    NASA Astrophysics Data System (ADS)

    Pahlevan, Niema; Gharib, Morteza

    2011-11-01

    The workload on the left ventricle is composed of steady and pulsatile components. Clinical investigations have confirmed that an abnormal pulsatile load plays an important role in the pathogenesis of left ventricular hypertrophy (LVH) and progression of LVH to congestive heart failure (CHF). The pulsatile load is the result of the complex dynamics of wave propagation and reflection in the compliant arterial vasculature. We hypothesize that aortic waves can be optimized to reduce the left ventricular (LV) pulsatile load. We used an in-vitro experimental approach to investigate our hypothesis. A unique hydraulic model was used for in-vitro experiments. This model has physical and dynamical properties similar to the heart-aorta system. Different compliant models of the artificial aorta were used to test the hypothesis under various aortic rigidities. Our results indicate that: i) there is an optimum heart rate that minimizes LV pulsatile power (this is in agreement with our previous computational study); ii) introducing an extra reflection site at the specific location along the aorta creates constructive wave conditions that reduce the LV pulsatile power.

  20. Circadian blood pressure and heart rate rhythms in mice.

    PubMed

    Li, P; Sur, S H; Mistlberger, R E; Morris, M

    1999-02-01

    The circadian pattern of mean arterial pressure (MAP) and heart rate (HR) was measured in C57BL mice with carotid arterial catheters. Cardiovascular parameters were recorded continuously with a computerized monitoring system at a sampling rate of 100 Hz. The tethered animals were healthy, showing stabilized drinking and eating patterns within 2 days of surgery and little loss of body weight. Analysis of the 24-h pattern of MAP and HR was conducted using data from 3-6 consecutive days of recording. A daily rhythm of MAP was evident in all mice, with group mean dark and light values of 101.4 +/- 7.3 and 93.1 +/- 2.9 mmHg, respectively. The group mean waveform was bimodal, with peak values evident early and late in the dark period, and a trough during the middle of the light period. The phase of maximum and minimum values showed low within-group variance. Mean heart rate was greater at night than during the day (561.9 +/- 22.7 vs. 530.3 +/- 22.3 beats/min). Peak values generally occurred at dark onset, and minimum values during the middle of both the dark and the light periods. We conclude that it is possible to perform measurements of circadian cardiovascular parameters in the mouse, providing new avenues for the investigation of genetic models.

  1. Heart rate variability biofeedback: how and why does it work?

    PubMed Central

    Lehrer, Paul M.; Gevirtz, Richard

    2014-01-01

    In recent years there has been substantial support for heart rate variability biofeedback (HRVB) as a treatment for a variety of disorders and for performance enhancement (Gevirtz, 2013). Since conditions as widely varied as asthma and depression seem to respond to this form of cardiorespiratory feedback training, the issue of possible mechanisms becomes more salient. The most supported possible mechanism is the strengthening of homeostasis in the baroreceptor (Vaschillo et al., 2002; Lehrer et al., 2003). Recently, the effect on the vagal afferent pathway to the frontal cortical areas has been proposed. In this article, we review these and other possible mechanisms that might explain the positive effects of HRVB. PMID:25101026

  2. Heart rate and estimated energy expenditure during ballroom dancing.

    PubMed Central

    Blanksby, B A; Reidy, P W

    1988-01-01

    Ten competitive ballroom dance couples performed simulated competitive sequences of Modern and Latin American dance. Heart rate was telemetered during the dance sequences and related to direct measures of oxygen uptake and heart rate obtained while walking on a treadmill. Linear regression was employed to estimate gross and net energy expenditures of the dance sequences. A multivariate analysis of variance with repeated measures on the dance factor was applied to the data to test for interaction and main effects on the sex and dance factors. Overall mean heart rate values for the Modern dance sequence were 170 beats.min-1 and 173 beats.min-1 for males and females respectively. During the Latin American sequence mean overall heart rate for males was 168 beats.min-1 and 177 beats.min-1 for females. Predicted mean gross values of oxygen consumption for the males were 42.8 +/- 5.7 ml.kg-1 min-1 and 42.8 +/- 6.9 ml.kg-1 min-1 for the Modern and Latin American sequences respectively. Corresponding gross estimates of oxygen consumption for the females were 34.7 +/- 3.8 ml.kg-1 min-1 and 36.1 +/- 4.1 ml.kg-1 min-1. Males were estimated to expand 54.1 +/- 8.1 kJ.min-1 of energy during the Modern sequence and 54.0 +/- 9.6 kJ.min-1 during the Latin American sequence, while predicted energy expenditure for females was 34.7 +/- 3.8 kJ.min-1 and 36.1 +/- 4.1 kJ.min-1 for Modern and Latin American dance respectively. The results suggested that both males and females were dancing at greater than 80% of their maximum oxygen consumption. A significant difference between males and females was observed for predicted gross and net values of oxygen consumption (in L.min-1 and ml.kg-1 min-1). PMID:3167503

  3. Making the Most of the "Daphnia" Heart Rate Lab: Optimizing the Use of Ethanol, Nicotine & Caffeine

    ERIC Educational Resources Information Center

    Corotto, Frank; Ceballos, Darrel; Lee, Adam; Vinson, Lindsey

    2010-01-01

    Students commonly test the effects of chemical agents on the heart rate of the crustacean "Daphnia" magna, but the procedure has never been optimized. We determined the effects of three concentrations of ethanol, nicotine, and caffeine and of a control solution on heart rate in "Daphnia." Ethanol at 5% and 10% (v/v) reduced mean heart rate to…

  4. Heart Rates of High School Physical Education Students during Team Sports, Individual Sports, and Fitness Activities

    ERIC Educational Resources Information Center

    Laurson, Kelly R.; Brown, Dale D.; Cullen, Robert W.; Dennis, Karen K.

    2008-01-01

    This study examined how activity type influenced heart rates and time spent in target heart rate zones of high school students participating in physical education classes. Significantly higher average heart rates existed for fitness (142 plus or minus 24 beats per minute [bpm]) compared to team (118 plus or minus 24 bpm) or individual (114 plus or…

  5. Comparison of Traditional and Alternative Fitness Teaching Formats on Heart Rate Intensity and Perceived Enjoyment.

    ERIC Educational Resources Information Center

    Ha, Amy Sau-ching; Heung-Sang Wong, Stephen

    2002-01-01

    Compared a traditional and an alternative (skill-fitness- music) fitness teaching format to determine whether there would be differences on Hong Kong middle school students' heart rate intensity and perceived enjoyment. Data from heart rate monitors and student surveys indicated that the two formats did not produce differences in heart rates.…

  6. The Relationship between Heart Rate Reserve and Oxygen Uptake Reserve in Children and Adolescents

    ERIC Educational Resources Information Center

    Hui, Stanley Sai-chuen; Chan, Janus Wan-sze

    2006-01-01

    The purpose of the present study was to examine the relationship between oxygen uptake (VO[subscript 2]) and heart rate (HR) responses during rest and exercise in Chinese children and youth and to evaluate the relationships between maximal heart rate (%HRmax), heart rate reserve (%HRR), peak oxygen uptake (%VO[subscript 2]peak), and oxygen uptake…

  7. Dynamic analysis of heart rate may predict subsequent ventricular tachycardia after myocardial infarction

    NASA Technical Reports Server (NTRS)

    Makikallio, T. H.; Seppanen, T.; Airaksinen, K. E.; Koistinen, J.; Tulppo, M. P.; Peng, C. K.; Goldberger, A. L.; Huikuri, H. V.

    1997-01-01

    Dynamics analysis of RR interval behavior and traditional measures of heart rate variability were compared between postinfarction patients with and without vulnerability to ventricular tachyarrhythmias in a case-control study. Short-term fractal correlation of heart rate dynamics was better than traditional measures of heart rate variability in differentiating patients with and without life-threatening arrhythmias.

  8. Heart Rate and Lactate Levels during Weight-Training Exercise in Trained and Untrained Men.

    ERIC Educational Resources Information Center

    Stone, Michael H.; And Others

    1987-01-01

    A study of effects of squatting exercise on heart rate and blood lactate levels in trained and untrained males indicated that trained subjects performed more work and had higher heart rates and lactate levels at exhaustion untrained subjects, though heart rate and lactate levels were lower for trained subjects at a given bar mass or submaximal…

  9. Electroencephalogram and heart rate regulation to familiar and unfamiliar people in children with autism spectrum disorders.

    PubMed

    Vaughan Van Hecke, Amy; Lebow, Jocelyn; Bal, Elgiz; Lamb, Damon; Harden, Emily; Kramer, Alexis; Denver, John; Bazhenova, Olga; Porges, Stephen W

    2009-01-01

    Few studies have examined whether familiarity of partner affects social responses in children with autism. This study investigated heart rate regulation (respiratory sinus arrhythmia [RSA]: The myelinated vagus nerve's regulation of heart rate) and temporal-parietal electroencephalogram (EEG) activity while nineteen 8- to 12-year-old children with autism and 14 controls viewed videos of a familiar and an unfamiliar person reading a story. Children with autism had lower overall RSA levels and exhibited decreased RSA to the unfamiliar person, versus control children. Both groups decreased temporal-parietal EEG activity to the unfamiliar person. Higher RSA was related to higher social skill ratings and fewer problem behaviors. Thus, the social difficulties of children with autism may be characterized by specific mobilization to unfamiliar people. PMID:19630897

  10. Impact of pubertal development and physical activity on heart rate variability in overweight and obese children in Taiwan.

    PubMed

    Chen, Su-Ru; Chiu, Hung-Wen; Lee, Yann-Jinn; Sheen, Tzong-Chi; Jeng, Chii

    2012-08-01

    Child obesity is frequently associated with dysfunction of autonomic nervous system. Children in pubertal development were suggested to be vulnerable to autonomic nervous system problems such as decrease of heart rate variability from dysregulation of metabolic control. This study explored the influence of pubertal development on autonomic nervous system function in overweight and obese children and the concurrent effects of their physical activity. Eighty-four overweight or obese children and 87 normal weighted controls were recruited. Autonomic nervous system function was studied by measuring heart rate variability. Results showed that the overweight/obese children had significantly lower heart rate variability. Overweight/obese children in puberty had significantly lower heart rate variability which was positively correlated with their physical activity levels. In conclusion, overweight/obesity adversely affects the autonomic nervous system function of children especially during their pubertal development. Overweight/obese children should be encouraged to engage in physical activities during puberty to improve their autonomic nervous system function.

  11. Deletion of neurturin impairs development of cholinergic nerves and heart rate control in postnatal mouse hearts.

    PubMed

    Downs, Anthony M; Jalloh, Hawa B; Prater, Kayla J; Fregoso, Santiago P; Bond, Cherie E; Hampton, Thomas G; Hoover, Donald B

    2016-05-01

    The neurotrophic factor neurturin is required for normal cholinergic innervation of adult mouse heart and bradycardic responses to vagal stimulation. Our goals were to determine effects of neurturin deletion on development of cardiac chronotropic and dromotropic functions, vagal baroreflex response, and cholinergic nerve density in nodal regions of postnatal mice. Experiments were performed on postnatal C57BL/6 wild-type (WT) and neurturin knockout (KO) mice. Serial electrocardiograms were recorded noninvasively from conscious pups using an ECGenie apparatus. Mice were treated with atenolol to evaluate and block sympathetic effects on heart rate (HR) and phenylephrine (PE) to stimulate the baroreflex. Immunohistochemistry was used to label cholinergic nerves in paraffin sections. WT and KO mice showed similar age-dependent increases in HR and decreases in PR interval between postnatal days (P) 2.5 and 21. Treatment with atenolol reduced HR significantly in WT and KO pups at P7.5. PE caused a reflex bradycardia that was significantly smaller in KO pups. Cholinergic nerve density was significantly less in nodal regions of P7.5 KO mice. We conclude that cholinergic nerves have minimal influence on developmental changes in HR and PR, QRS, and QTc intervals in mouse pups. However, cholinergic nerves mediate reflex bradycardia by 1 week postnatally. Deletion of neurturin impairs cholinergic innervation of the heart and the vagal efferent component of the baroreflex early during postnatal development.

  12. Heart rate effects of intraosseous injections using slow and fast rates of anesthetic solution deposition.

    PubMed

    Susi, Louis; Reader, Al; Nusstein, John; Beck, Mike; Weaver, Joel; Drum, Melissa

    2008-01-01

    The authors, using a crossover design, randomly administered, in a single-blind manner, 3 primary intraosseous injections to 61 subjects using: the Wand local anesthetic system at a deposition rate of 45 seconds (fast injection); the Wand local anesthetic system at a deposition rate of 4 minutes and 45 seconds (slow injection); a conventional syringe injection at a deposition rate of 4 minutes and 45 seconds (slow injection), in 3 separate appointments spaced at least 3 weeks apart. A pulse oximeter measured heart rate (pulse). The results demonstrated the mean maximum heart rate was statistically higher with the fast intraosseous injection (average 21 to 28 beats/min increase) than either of the 2 slow intraosseous injections (average 10 to 12 beats/min increase). There was no statistically significant difference between the 2 slow injections. We concluded that an intraosseous injection of 1.4 mL of 2% lidocaine with 1 : 100,000 epinephrine with the Wand at a 45-second rate of anesthetic deposition resulted in a significantly higher heart rate when compared with a 4-minute and 45-second anesthetic solution deposition using either the Wand or traditional syringe.

  13. Heart-rate variability and precompetitive anxiety in swimmers.

    PubMed

    Cervantes Blásquez, Julio César; Rodas Font, Gil; Capdevila Ortís, Lluís

    2009-11-01

    The aim of this study was to test the utility of heart-rate variability (HRV) analyses as a noninvasive means of quantifying cardiac autonomic regulation during precompetitive anxiety situations in swimmers. Psychophysiological state evaluation of 10 volunteer swimmers (6 women and 4 men) was obtained by comparing baseline training condition (TC) with competition condition (CC). Self-evaluation of precompetitive somatic anxiety measured by CSAI-2 showed significant increase from the TC to CC. Analysis showed that during higher precompetitive anxiety level, a significant reduction in the timing (RMSSD), frequency (HFms2 and HFnu) and Poincaré plot (SD1) of heart-rate variability was observed, and a significant increase in the low frequency to high frequency ratio (LF/HF %). The results indicate a shift towards sympathetic predominance as a result of parasympathetic withdrawal. Our results provide an HRV analysis in a valid, useful and non-invasive way to evaluate the change of sympathovagal balance in presence of precompetitive stress.

  14. Heart rate variability (HRV) during virtual reality immersion.

    PubMed

    Malińska, Marzena; Zużewicz, Krystyna; Bugajska, Joanna; Grabowski, Andrzej

    2015-01-01

    The goal of the study was assessment of the hour-long training involving handling virtual environment (sVR) and watching a stereoscopic 3D movie on the mechanisms of autonomic heart rate (HR) regulation among the subjects who were not predisposed to motion sickness. In order to exclude predispositions to motion sickness, all the participants (n=19) underwent a Coriolis test. During an exposure to 3D and sVR the ECG signal was continuously recorded using the Holter method. For the twelve consecutive 5-min epochs of ECG signal, the analysis of heart rate variability (HRV) in time and frequency domains was conducted. After 30 min from the beginning of the training in handling the virtual workstation a significant increase in LF spectral power was noted. The values of the sympathovagal LF/HF index while sVR indicated a significant increase in sympathetic predominance in four time intervals, namely between the 5th and the 10th minute, between the 15th and the 20th minute, between the 35th and 40th minute and between the 55th and the 60th minute of exposure.

  15. Abnormal intermittency of heart rate in patients with neurocardiogenic syncope

    NASA Astrophysics Data System (ADS)

    Yum, Myung-Kul; Kim, Kyung-Sik; Kim, June-Soo

    2002-03-01

    Introduction: We aim to test our hypothesis that, during daily activity, though not as prominent as during HUT test, the patients may show different degree of intermittency in heart rates compared to healthy persons. METHOD AND RESULTS: Thirty patients with neurocardiogenic syncope who showed a positive HUT test and thirty healthy controls without history of syncope were included. Their twenty-four hour ambulatory electrocardiograms were digitized and RR interval (RRI) data of six-hour interval were analyzed. To quantify the intermittency (C1) behavior, The intermittency analysis was performed using Mexican hat wavelet. For the syncope group, the values of C1 were significantly higher at 6AM-6PM and lower at 6AM-midnight, respectively. However, the values were not different at midnight-6AM. The significant night-day circadian change shown in the control group was lost in C1. CONCLUSION: When compared to healthy control, the patients with neurocardiogenic syncope shows increased intermittency of heart rates in daytime during daily activity, and abnormal circadian rhythms of the index. These new findings may be useful for investigating the pathophysiology of neurocardiogenic syncope and early identification of the patients.

  16. Human heart rate variability relation is unchanged during motion sickness

    NASA Technical Reports Server (NTRS)

    Mullen, T. J.; Berger, R. D.; Oman, C. M.; Cohen, R. J.

    1998-01-01

    In a study of 18 human subjects, we applied a new technique, estimation of the transfer function between instantaneous lung volume (ILV) and instantaneous heart rate (HR), to assess autonomic activity during motion sickness. Two control recordings of ILV and electrocardiogram (ECG) were made prior to the development of motion sickness. During the first, subjects were seated motionless, and during the second they were seated rotating sinusoidally about an earth vertical axis. Subjects then wore prism goggles that reverse the left-right visual field and performed manual tasks until they developed moderate motion sickness. Finally, ILV and ECG were recorded while subjects maintained a relatively constant level of sickness by intermittent eye closure during rotation with the goggles. Based on analyses of ILV to HR transfer functions from the three conditions, we were unable to demonstrate a change in autonomic control of heart rate due to rotation alone or due to motion sickness. These findings do not support the notion that moderate motion sickness is manifested as a generalized autonomic response.

  17. Heart rate variability (HRV) during virtual reality immersion

    PubMed Central

    Malińska, Marzena; Zużewicz, Krystyna; Bugajska, Joanna; Grabowski, Andrzej

    2015-01-01

    The goal of the study was assessment of the hour-long training involving handling virtual environment (sVR) and watching a stereoscopic 3D movie on the mechanisms of autonomic heart rate (HR) regulation among the subjects who were not predisposed to motion sickness. In order to exclude predispositions to motion sickness, all the participants (n=19) underwent a Coriolis test. During an exposure to 3D and sVR the ECG signal was continuously recorded using the Holter method. For the twelve consecutive 5-min epochs of ECG signal, the analysis of heart rate variability (HRV) in time and frequency domains was conducted. After 30 min from the beginning of the training in handling the virtual workstation a significant increase in LF spectral power was noted. The values of the sympathovagal LF/HF index while sVR indicated a significant increase in sympathetic predominance in four time intervals, namely between the 5th and the 10th minute, between the 15th and the 20th minute, between the 35th and 40th minute and between the 55th and the 60th minute of exposure. PMID:26327262

  18. Motion-compensated non-contact detection of heart rate

    NASA Astrophysics Data System (ADS)

    Yang, Lei; Liu, Ming; Dong, Liquan; Zhao, Yuejin; Liu, Xiaohua

    2015-12-01

    A new non-contact heart rate detection method based on the dual-wavelength technique is proposed and demonstrated experimentally. It is a well-known fact that the differences in the circuits of two detection modules result in different responses of two modules for motion artifacts. This poses a great challenge to compensate the motion artifacts during measurements. In order to circumvent this problem, we have proposed the amplitude spectrum and phase spectrum adaptive filter. Comparing with the time-domain adaptive filter and independent component analysis, the amplitude spectrum and phase spectrum adaptive filter can suppress the interference caused by the two circuit differences and effectively compensate the motion artifacts. To make the device is much compact and portable, a photoelectric probe is designed. The measurement distance is from several centimeters up to several meters. Moreover, the data obtained by using this non-contact detection system is compared with those of the conventional finger blood volume pulse (BVP) sensor by simultaneously measuring the heart rate of the subject. The data obtained from the proposed non-contact system are consistent and comparable with that of the BVP sensor.

  19. Autonomic functions in acrocyanosis assessed by heart rate variability

    PubMed Central

    Yılmaz, Sedat; Yokuşoğlu, Mehmet; Çınar, Muhammet; Şimşek, İsmail; Baysan, Oben; Öz, Bilgehan Savaş; Erdem, Hakan; Pay, Salih; Dinç, Ayhan

    2014-01-01

    Objective To evaluate the autonomic activity of patients with acrocyanosis by using heart rate variability indices. Material and Methods The study group consisted of 24 patients with acrocyanosis and the control group contained 22 sex- and age-matched healthy subjects. All subjects underwent 24-hour Holter monitoring. Among the heart rate variability (HRV) parameters, time-domain and frequency-domain indices were analysed. Results The time-domain indices of HRV indicating global autonomic functions were found to be increased, and indices indicating parasympathetic activity showed a significant decrease in the patient group. Power-spectral analysis of HRV revealed that the low frequency and high frequency power were higher in the patient group than in controls. However, the ratio of Low Frequency/High Frequency was found to be lower in the patient group than in controls. Conclusion In acrocyanosis, both sympathetic and parasympathetic systems seem to be disrupted. Therefore, we may conclude that acrocyanosis may be resulted of systemic autonomic imbalance rather than pure sympathetic over-activation. Also, these results suggest that acrocyanosis is not a localised disorder; on the contrary, it is associated with various abnormalities of the systemic autonomic nervous system.

  20. Heart rate monitoring and control in altered gravity conditions.

    PubMed

    Di Rienzo, M; Parati, G; Rizzo, F; Meriggi, P; Merati, G; Faini, A; Castiglioni, P

    2007-01-01

    On the basis of indirect evidences it has been hypothesized that during space missions the almost complete absence of gravity might impair the baroreflex control of circulation. In the first part of this paper we report results obtained from a series of experiments carried out to directly verify this hypothesis during the 16-day STS 107 Shuttle flight. Spontaneous baroreflex sensitivity was assessed in four astronauts before flight (baseline) and at days 0-1, 6-7 and 12-13 during flight, both at rest and while performing moderate exercise. Our results indicate that at rest the baroreflex sensitivity significantly increased in the early flight phase, as compared to pre-flight values and tended to return to baseline in the mid-late phase of flight. During exercise, baroreflex sensitivity was lower than at rest, without any difference among pre-flight and in-flight values. These findings seem to exclude the hypothesis of an impairment of the baroreflex control of heart rate during exposure to microgravity, at least over a time window of 16 days. In the second part of the paper we propose a novel textile-based methodology for heart rate and other vital signs monitoring during gravity stress. The positive results obtained from its use during parachute jumps support the use of smart garments for the unobtrusive assessment of physiological parameters in extreme environments. PMID:18003559

  1. Heart rate variability in children with type 1 diabetes mellitus

    PubMed Central

    Gardim, Camila Balsamo; de Oliveira, Bruno Affonso P.; Bernardo, Aline Fernanda B.; Gomes, Rayana Loch; Pacagnelli, Francis Lopes; Lorençoni, Roselene Modolo R.; Vanderlei, Luiz Carlos M.

    2014-01-01

    OBJECTIVE: To gather current information about the effects of type 1 diabetes mellitus on children's cardiac autonomic behavior. DATA SOURCES: The search of articles was conducted on PubMed, Ibecs, Medline, Cochrane, Lilacs, SciELO and PEDro databases using the MeSH terms: "autonomic nervous system", "diabetes mellitus", "child", "type 1 diabetes mellitus", "sympathetic nervous system" and "parasympathetic nervous system", and their respective versions in Portuguese (DeCS). Articles published from January 2003 to February 2013 that enrolled children with 9-12 years old with type 1 diabetes mellitus were included in the review. DATA SYNTHESIS: The electronic search resulted in four articles that approached the heart rate variability in children with type 1 diabetes mellitus, showing that, in general, these children present decreased global heart rate variability and vagal activity. The practice of physical activity promoted benefits for these individuals. CONCLUSIONS: Children with type 1 diabetes mellitus present changes on autonomic modulation, indicating the need for early attention to avoid future complications in this group. PMID:25119762

  2. Heart rate variability (HRV) during virtual reality immersion.

    PubMed

    Malińska, Marzena; Zużewicz, Krystyna; Bugajska, Joanna; Grabowski, Andrzej

    2015-01-01

    The goal of the study was assessment of the hour-long training involving handling virtual environment (sVR) and watching a stereoscopic 3D movie on the mechanisms of autonomic heart rate (HR) regulation among the subjects who were not predisposed to motion sickness. In order to exclude predispositions to motion sickness, all the participants (n=19) underwent a Coriolis test. During an exposure to 3D and sVR the ECG signal was continuously recorded using the Holter method. For the twelve consecutive 5-min epochs of ECG signal, the analysis of heart rate variability (HRV) in time and frequency domains was conducted. After 30 min from the beginning of the training in handling the virtual workstation a significant increase in LF spectral power was noted. The values of the sympathovagal LF/HF index while sVR indicated a significant increase in sympathetic predominance in four time intervals, namely between the 5th and the 10th minute, between the 15th and the 20th minute, between the 35th and 40th minute and between the 55th and the 60th minute of exposure. PMID:26327262

  3. High frequency chest compression effects heart rate variability.

    PubMed

    Lee, Jongwon; Lee, Yong W; Warwick, Warren J

    2007-01-01

    High frequency chest compression (HFCC) supplies a sequence of air pulses through a jacket worn by a patient to remove excessive mucus for the treatment or prevention of lung disease patients. The air pulses produced from the pulse generator propagates over the thorax delivering the vibration and compression energy. A number of studies have demonstrated that the HFCC system increases the ability to clear mucus and improves lung function. Few studies have examined the change in instantaneous heart rate (iHR) and heart rate variability (HRV) during the HFCC therapy. The purpose of this study is to measure the change of HRV with four experimental protocols: (a) without HFCC, (b) during Inflated, (c)HFCC at 6Hz, and (d) HFCC at 21Hz. The nonlinearity and regularity of HRV was assessed by approximate entropy (ApEn), a method used to quantify the complexities and randomness. To compute the ApEn, we sectioned with a total of eight epochs and displayed the ApEn over the each epoch. Our results show significant differences in the both the iHR and HRV between the experimental protocols. The iHR was elevated at both the (c) 6Hz and (d) 21Hz condition from without HFCC (10%, 16%, respectively). We also found that the HFCC system tends to increase the HRV. Our study suggests that monitoring iHR and HRV are very important physiological indexes during HFCC therapy.

  4. Prognostic significance of heart rate turbulence parameters in patients with chronic heart failure

    PubMed Central

    2014-01-01

    Background This study is aimed to evaluate the clinical significance of heart rate turbulence (HRT) parameters in predicting the prognosis in patients with chronic heart failure (CHF). Methods From June 2011 to December 2012, a total of 104 CHF patients and 30 healthy controls were enrolled in this study. We obtained a 24-hour Holter ECG recording to assess the HRT parameters, included turbulence onset (TO), turbulence slope (TS), standard deviation of N-N intervals (SDNN), and resting heart rate (RHR). The relationships between HRT parameters and the prognosis of CHF patients were determined. Results The assessment follow-up period lasted until January 31, 2013. The overall mortality of CHF patients was 9.6% (10/104). Our results revealed that CHF patients had higher levels of TO than those of healthy subjects, but the TS levels of CHF patients were lower than that of the control group. CHF patients with NYHA grade IV had higher HRT1/2 rate than those with NYHA grade II/III. There were statistical differences in TS, LVEF, SDNN and RHR between the non-deteriorating group and the non-survivor group. Significant differences in TS among the three groups were also found. Furthermore, CHF patients in the non-survivor group had lower levels of TS than those in the deteriorating group. Correlation analyses indicated that TO negatively correlate with SDNN, while TS positively correlated with SDNN and left ventricular ejection fraction (LVEF). We also observed negative correlations between TS and left ventricular end-diastolic cavity dimension (LVEDD), RHR, homocysteine (Hcy) and C-reactive protein (CRP). Multivariate Cox regression analysis further confirmed that LVEF (≤30%), HRT2, SDNN and RHR were independent risk factors which can indicate poor prognosis in CHF patients. Conclusions Our findings indicate that HRT may have good clinical predictive value in patients with CHF. Thus, quantifying HRT parameters could be a useful tool for predicting mortality in CHF

  5. Effects of Vibration and G-Loading on Heart Rate, Breathing Rate, and Response Time

    NASA Technical Reports Server (NTRS)

    Godinez, Angelica; Ayzenberg, Ruthie; Liston, Dorian B.; Stone, Leland S.

    2013-01-01

    Aerospace and applied environments commonly expose pilots and astronauts to G-loading and vibration, alone and in combination, with well-known sensorimotor (Cohen, 1970) and performance consequences (Adelstein et al., 2008). Physiological variables such as heart rate (HR) and breathing rate (BR) have been shown to increase with G-loading (Yajima et al., 1994) and vibration (e.g. Guignard, 1965, 1985) alone. To examine the effects of G-loading and vibration, alone and in combination, we measured heart rate and breathing rate under aerospace-relevant conditions (G-loads of 1 Gx and 3.8 Gx; vibration of 0.5 gx at 8, 12, and 16 Hz).

  6. Assessment of cardiac autonomic functions by heart rate recovery, heart rate variability and QT dynamicity parameters in patients with acromegaly.

    PubMed

    Dural, Muhammet; Kabakcı, Giray; Cınar, Neşe; Erbaş, Tomris; Canpolat, Uğur; Gürses, Kadri Murat; Tokgözoğlu, Lale; Oto, Ali; Kaya, Ergün Barış; Yorgun, Hikmet; Sahiner, Levent; Dağdelen, Selçuk; Aytemir, Kudret

    2014-04-01

    Cardiovascular complications are the most common causes of morbidity and mortality in acromegaly. However, there is little data regarding cardiac autonomic functions in these patients. Herein, we aimed to investigate several parameters of cardiac autonomic functions in patients with acromegaly compared to healthy subjects. We enrolled 20 newly diagnosed acromegalic patients (55% female, age:45.7 ± 12.6 years) and 32 age- and gender-matched healthy subjects. All participants underwent 24 h Holter recording. Heart rate recovery (HRR) indices were calculated by subtracting 1st, 2nd and 3rd minute heart rates from maximal heart rate. All patients underwent heart rate variability (HRV) and QT dynamicity analysis. Baseline characteristics were similar except diabetes mellitus and hypertension among groups. Mean HRR1 (29.2 ± 12.3 vs 42.6 ± 6.5, p = 0.001), HRR2 (43.5 ± 15.6 vs 61.1 ± 10.8, p = 0.001) and HRR3 (46.4 ± 16.2 vs 65.8 ± 9.8, p = 0.001) values were significantly higher in control group. HRV parameters as, SDNN [standard deviation of all NN intervals] (p = 0.001), SDANN [SD of the 5 min mean RR intervals] (p = 0.001), RMSSD [root square of successive differences in RR interval] (p = 0.001), PNN50 [proportion of differences in successive NN intervals >50 ms] (p = 0.001) and high-frequency [HF] (p = 0.001) were significantly decreased in patients with acromegaly; but low frequency [LF] (p = 0.046) and LF/HF (p = 0.001) were significantly higher in acromegaly patients. QTec (p = 0.009), QTac/RR slope (p = 0.017) and QTec/RR slope (p = 0.01) were significantly higher in patients with acromegaly. Additionally, there were significant negative correlation of disease duration with HRR2, HRR3, SDNN, PNN50, RMSSD, variability index. Our study results suggest that cardiac autonomic functions are impaired in patients with acromegaly. Further large scale studies are needed to exhibit the prognostic significance of impaired autonomic functions in patients with

  7. Puerperal endometritis and intrauterine fetal heart rate monitoring.

    PubMed

    Rehu, M; Haukkamaa, M

    1980-08-01

    The incidence of puerperal endometritis in 5058 patients who were delivered during a one year study period was recorded prospectively. Caesarean section was performed in 774 cases (15.3%) and intrauterine fetal heart rate monitoring was used in 2016 cases (39.9%). After vaginal delivery, the incidence of endometritis was 1.5% in those monitored externally and 2.4% in those monitored internally (P less than 0.05). After Caesarean section, endometritis occurred in 8.0% of those monitored externally and in 16.4% of those monitored internally for varying times (P less than 0.01). The duration of monitoring had no significant effect on these infection rates. The risk of puerperal endometritis after internal fetal monitoring seemed to be the same as after one vaginal examination. PMID:7259077

  8. Contact-free heart rate measurement using multiple video data

    NASA Astrophysics Data System (ADS)

    Hung, Pang-Chan; Lee, Kual-Zheng; Tsai, Luo-Wei

    2013-10-01

    In this paper, we propose a contact-free heart rate measurement method by analyzing sequential images of multiple video data. In the proposed method, skin-like pixels are firstly detected from multiple video data for extracting the color features. These color features are synchronized and analyzed by independent component analysis. A representative component is finally selected among these independent component candidates to measure the HR, which achieves under 2% deviation on average compared with a pulse oximeter in the controllable environment. The advantages of the proposed method include: 1) it uses low cost and high accessibility camera device; 2) it eases users' discomfort by utilizing contact-free measurement; and 3) it achieves the low error rate and the high stability by integrating multiple video data.

  9. How to avoid misinterpretation of heart rate variability power spectra?

    PubMed

    Cammann, Henning; Michel, Josef

    2002-04-01

    Spectral analysis of R-R Interval time series is increasingly used to determine periodic components of heart rate variability (HRV). Particular diagnostic relevance is assigned to a low-frequency (LF) component, associated with blood pressure regulation, and a high-frequency (HF) component, also referred to as respiratory sinus arrhythmia (RSA) in the HRV power spectra. Frequency ranges for parametrisation of power spectra have been defined for either component in numerous publications.Results obtained from examinations with standardised psychic load in which ECG and respiratory signal are continuously recorded and adequately processed have shown that the true individual frequency range of the HF component can be reliably determined only by means of characteristics of respiration (respiratory rate (RR), range and median value of RR, tidal depth). Respiratory rhythms are interindividually extremely differentiated and of individual-specific nature. In many cases LF and HF components may be totally superimposed on each other and, consequently, cannot be diagnostically evaluated.

  10. Abortion Rates Rising in Zika-Affected Countries, Study Shows

    MedlinePlus

    ... page: https://medlineplus.gov/news/fullstory_159500.html Abortion Rates Rising in Zika-Affected Countries, Study Shows ... from mosquito-borne Zika may be driving up abortion rates in Latin American countries affected by the ...

  11. Hierarchical Structure of Heart Rate Variability in Humans

    NASA Astrophysics Data System (ADS)

    Gao, X. Z.; Ching, E. S. C.; Lin, D. C.

    2004-03-01

    We show a hierarchical structure (HS) of the She-Leveque form in the beat-to-beat RR intervals of heart rate variability (HRV) in humans. This structure, first found as an empirical law in turbulent fluid flows, implies further details in the HRV multifractal scaling. We tested HS using daytime RRi data from healthy subjects and heart diseased patients with congestive heart failure and found a universal law C(b) where b characterizes the multifractality of HRV and C is related to a co-dimension parameter of the most violent events in the fluctuation. The potential of diagnosis is discussed based on the characteristics of this finding. To model the HRV phenomenology, we propose a local-feedback-global-cascade (LFGC) model based on the She-Waymire (SW) cascade solution to the HS in fluid turbulence. This model extends from the previous work in that it integrates additive law multiplicatively into the cascade structure. It is an attempt to relate to the cardiovascular physiology which consists of numerous feedback controls that function primarily on the principle of additive law. In particular, the model is based on the same philosophy as the SW cascade that its multifractal dynamics consists of a singular and a modulating component. In the LFGC model, we introduce local feedback to model the dynamics of the modulating effect. The novelty of our model is to incorporate the cascade structure in the scheduling for the feedback control. This model also represents an alternative solution to the HS. We will present the simulation results by the LFGC model and discuss its implication in physiology terms.

  12. Heart rates increase after hatching in two species of natricine snakes

    PubMed Central

    Aubret, Fabien

    2013-01-01

    Experimental studies have shown heart rates to decrease from embryo to hatchling stage in turtles, remain steady in skinks, and increase in birds. However, no snake species has been studied in this regard. I recorded heart rate evolution trajectories from embryo to juvenile stage in 78 eggs from two species of European Natricine snakes. Unexpectedly, snakes behaved more like birds than turtles or lizards: heart rates increased after hatching in both N. maura and N. natrix, respectively by 43.92 ± 22.84% and 35.92 ± 24.52%. Heart rate shift was not related to an abrupt elevation of metabolism per se (snakes that increased their heart rates the most sharply grew the least after birth), but rather due to a number of smaller eggs that experienced lower than normal heart rates throughout the incubation and recovered a normal heart rate post-birth. This finding is discussed in the light of hatching synchrony benefits. PMID:24287712

  13. Heart rates increase after hatching in two species of Natricine snakes.

    PubMed

    Aubret, Fabien

    2013-11-29

    Experimental studies have shown heart rates to decrease from embryo to hatchling stage in turtles, remain steady in skinks, and increase in birds. However, no snake species has been studied in this regard. I recorded heart rate evolution trajectories from embryo to juvenile stage in 78 eggs from two species of European Natricine snakes. Unexpectedly, snakes behaved more like birds than turtles or lizards: heart rates increased after hatching in both N. maura and N. natrix, respectively by 43.92 ± 22.84% and 35.92 ± 24.52%. Heart rate shift was not related to an abrupt elevation of metabolism per se (snakes that increased their heart rates the most sharply grew the least after birth), but rather due to a number of smaller eggs that experienced lower than normal heart rates throughout the incubation and recovered a normal heart rate post-birth. This finding is discussed in the light of hatching synchrony benefits.

  14. Unobtrusive heart rate monitor based on a fiber specklegram sensor and a single-board computer

    NASA Astrophysics Data System (ADS)

    Benevides, Alessandro B.; Frizera, Anselmo; Cotrina, Anibal; Ribeiro, Moisés. R. N.; Segatto, Marcelo E. V.; Pontes, Maria José

    2015-09-01

    This paper proposes a portable and unobtrusive heart rate monitor based on fiber specklegram sensors. The proposed module uses the Raspberry Pi module to perform the image acquisition and the fiber specklegram sensor, which is based on multimode plastic optical fibers. The heart rate is obtained by welch power spectral density estimate and the heart beats are identified by means of a threshold analysis.

  15. Problem Behavior and Heart Rate Reactivity in Adopted Adolescents: Longitudinal and Concurrent Relations

    ERIC Educational Resources Information Center

    Bimmel, Nicole; van IJzendoorn, Marinus H.; Bakermans-Kranenburg, Marian J.; Juffer, Femmie; De Geus, Eco J. C.

    2008-01-01

    The present longitudinal study examined resting heart rate and heart rate variability and reactivity to a stressful gambling task in adopted adolescents with aggressive, delinquent, or internalizing behavior problems and adopted adolescents without behavior problems (total N=151). Early-onset delinquent adolescents showed heart rate…

  16. Comparison of pulse rate variability with heart rate variability during obstructive sleep apnea.

    PubMed

    Khandoker, Ahsan H; Karmakar, Chandan K; Palaniswami, Marimuthu

    2011-03-01

    We investigate whether pulse rate variability (PRV) extracted from finger photo-plethysmography (Pleth) waveforms can be the substitute of heart rate variability (HRV) from RR intervals of ECG signals during obstructive sleep apnea (OSA). Simultaneous measurements (ECG and Pleth) were taken from 29 healthy subjects during normal (undisturbed sleep) breathing and 22 patients with OSA during OSA events. Highly significant (p<0.01) correlations (1.0>r>0.95) were found between heart rate (HR) and pulse rate (PR). Bland-Altman plot of HR and PR shows good agreement (<5% difference). Comparison of 2 min recording epochs demonstrated significant differences (p<0.01) in time, frequency domains and complexity analysis, between normal and OSA events using PRV as well as HRV measures. Results suggest that both HRV and PRV indices could be used to distinguish OSA events from normal breathing during sleep. However, several variability measures (SDNN, RMSSD, HF power, LF/HF and sample entropy) of PR and HR were found to be significantly (p<0.01) different during OSA events. Therefore, we conclude that PRV provides accurate inter-pulse variability to measure heart rate variability under normal breathing in sleep but does not precisely reflect HRV in sleep disordered breathing.

  17. Heart rate variability in risk stratification of cardiac patients.

    PubMed

    Huikuri, Heikki V; Stein, Phyllis K

    2013-01-01

    Heart rate (HR) variability has been extensively studied in cardiac patients, especially in patients surviving an acute myocardial infarction (AMI) and also in patients with congestive heart failure (CHF) or left ventricular (LV) dysfunction. The majority of studies have shown that patients with reduced or abnormal HR variability have an increased risk of mortality within a few years after an AMI or after a diagnosis of CHF/LV dysfunction. Various measures of HR dynamics, such as time-domain, spectral, and non-linear measures of HR variability have been used in risk stratification. The prognostic power of various measures, except of those reflecting rapid R-R interval oscillations, has been almost identical, albeit some non-linear HR variability measures, such as short-term fractal scaling exponent have provided somewhat better prognostic information than the others. Abnormal HR variability predicts both sudden and non-sudden cardiac death. Because of remodeling of the arrhythmia substrate after AMI, early measurement of HR variability to identify those at high risk should likely be repeated later in order to assess the risk of fatal arrhythmia events. Future randomized trials using HR variability/turbulence as one of the pre-defined inclusion criteria will show whether routine measurement of HR variability/turbulence will become a routine clinical tool for risk stratification of cardiac patients.

  18. Resting high frequency heart rate variability selectively predicts cooperative behavior.

    PubMed

    Beffara, Brice; Bret, Amélie G; Vermeulen, Nicolas; Mermillod, Martial

    2016-10-01

    This study explores whether the vagal connection between the heart and the brain is involved in prosocial behaviors. The Polyvagal Theory postulates that vagal activity underlies prosocial tendencies. Even if several results suggest that vagal activity is associated with prosocial behaviors, none of them used behavioral measures of prosociality to establish this relationship. We recorded the resting state vagal activity (reflected by High Frequency Heart Rate Variability, HF-HRV) of 48 (42 suitale for analysis) healthy human adults and measured their level of cooperation during a hawk-dove game. We also manipulated the consequence of mutual defection in the hawk-dove game (severe vs. moderate). Results show that HF-HRV is positively and linearly related to cooperation level, but only when the consequence of mutual defection is severe (compared to moderate). This supports that i) prosocial behaviors are likely to be underpinned by vagal functioning ii) physiological disposition to cooperate interacts with environmental context. We discuss these results within the theoretical framework of the Polyvagal Theory. PMID:27343804

  19. Resting high frequency heart rate variability selectively predicts cooperative behavior.

    PubMed

    Beffara, Brice; Bret, Amélie G; Vermeulen, Nicolas; Mermillod, Martial

    2016-10-01

    This study explores whether the vagal connection between the heart and the brain is involved in prosocial behaviors. The Polyvagal Theory postulates that vagal activity underlies prosocial tendencies. Even if several results suggest that vagal activity is associated with prosocial behaviors, none of them used behavioral measures of prosociality to establish this relationship. We recorded the resting state vagal activity (reflected by High Frequency Heart Rate Variability, HF-HRV) of 48 (42 suitale for analysis) healthy human adults and measured their level of cooperation during a hawk-dove game. We also manipulated the consequence of mutual defection in the hawk-dove game (severe vs. moderate). Results show that HF-HRV is positively and linearly related to cooperation level, but only when the consequence of mutual defection is severe (compared to moderate). This supports that i) prosocial behaviors are likely to be underpinned by vagal functioning ii) physiological disposition to cooperate interacts with environmental context. We discuss these results within the theoretical framework of the Polyvagal Theory.

  20. Modulation of parasympathetic and baroreceptor control of heart rate.

    PubMed

    Ferrari, A U

    1993-03-01

    The heart rate is modulated from beat to beat by efferent vagal and sympathetic fibers, the former being the predominant mediators of the chronotropic influence of arterial baroreceptors and respiration and the latter being important in the cardiac responses to physical and mental stress. Cardiac vagal influences are modulated by a number of factors. These can be grouped as: 1) neural factors, such as the wakefulness-sleep cycle, the alerting reaction, and exercise; 2) humoral-pharmacological factors, such as angiotensin II, atrial natriuretic factor, cardiac glycosides; 3) normal aging; 4) a number of cardiovascular and other diseases, such as arterial hypertension, coronary artery disease, congestive heart failure and diabetes mellitus. The mechanisms underlying modulation of cardiac vagal control are not completely understood, the range of the possibilities including structural or functional alterations in baroreceptor afferents, in central and efferent vagal pathways and in cardiac responsiveness to neural stimuli. Irrespective of the mechanisms involved, the modulation of cardiac vagal control may have important implications for normal cardiovascular homeostasis, as well as for the pathophysiology, diagnosis and prognosis of various diseases.

  1. CAFFEINE IMPROVES HEART RATE WITHOUT IMPROVING SEPSIS SURVIVAL

    PubMed Central

    Bauzá, Gustavo; Remick, Daniel

    2015-01-01

    Introduction Caffeine is consumed on a daily basis for its nervous system stimulant properties and is a global adenosine receptor antagonist. Since adenosine receptors have been found to play a major role in regulating the immune response to a septic insult, we investigated if caffeine consumption prior to a septic insult would alter immunological and physiological responses, as well as survival. Methods Two separate experimental designs were employed, both using outbred female ICR mice. In the first experiment mice were administered 20mg/kg of caffeine (equal to 2–3 cups of coffee for a human) or normal saline intraperitoneally at the time of cecal ligation and puncture (CLP). Immunological parameters including cytokines and local cell recruitment measured. In the second experiment caffeine (10mg/kg/hr) was delivered continuously for 24 hours via a subcutaneous infusion pump placed the day prior to CLP and hemodynamic parameters were examined. In both experiments survival was followed for five days. Results A single dose of caffeine at the initiation of sepsis did not alter survival. This single dose of caffeine did significantly increase in plasma levels of the chemokine KC six hours after the onset of sepsis compared to septic mice given normal saline. There were no changes in IL-6 or IL-10 levels in the caffeine groups. Peritoneal lavages performed 24 hours post-CLP showed no difference in the levels of IL-6, TNF, KC, MIP-1, IL-10 or the IL-1 receptor antagonist between caffeine and normal saline treated mice. Additionally, the lavages yielded similar numbers of cells (4.1×106 vehicle vs. 6.9×106 caffeine) and bacterial colony forming units (CFU, 4.1 million CFU vehicle vs. 2.8 million CFU caffeine). In the infusion group, caffeine also did not alter survival. However, caffeine infusion did increase heart rate prior to CLP, and prevented the decline in heart rate after CLP. Conclusion Caffeine increased heart rate in mice but does not impact cytokine

  2. Exercise Training Improves Heart Rate Variability after Methamphetamine Dependency

    PubMed Central

    Dolezal, Brett A.; Chudzynski, Joy; Dickerson, Daniel; Mooney, Larissa; Rawson, Richard A.; Garfinkel, Alan; Cooper, Christopher B.

    2014-01-01

    Purpose Heart rate variability (HRV) reflects a healthy autonomic nervous system and is increased with physical training. Methamphetamine dependence (MD) causes autonomic dysfunction and diminished HRV. We compared recently abstinent MD participants with age-matched, drug free controls (DF) and also investigated whether HRV can be improved with exercise training in the MD participants. Methods In 50 participants (MD=28; DF=22) resting heart rate (R-R intervals) was recorded over 5 min while seated using a monitor affixed to a chest strap. Previously reported time-domain (SDNN, RMSSD, pNN50) and frequency-domain (LFnu, HFnu, LF/HF) parameters of HRV were calculated with customized software. MD were randomized to thrice weekly exercise training (ME=14) or equal attention without training (MC=14) over 8 weeks. Groups were compared using paired and unpaired t-tests. Statistical significance was set at P≤0.05. Results Participant characteristics were matched between groups: age 33±6 years; body mass 82.7±12 kg, BMI 26.8±4.1 kg•min−2, mean±SD. Compared with DF, the MD group had significantly higher resting heart rate (P<0.05), LFnu, and LF/HF (P<0.001) as well as lower SDNN, RMSSD, pNN50 and HFnu (all P<0.001). At randomization, HRV indices were similar between ME and MC groups. However, after training, the ME group significantly (all P<0.001) increased SDNN (+14.7±2.0 ms, +34%), RMSSD (+19.6±4.2 ms, +63%), pNN50 (+22.6±2.7%, +173%), HFnu (+14.2±1.9, +60%) and decreased HR (−5.2±1.1 beats·min−1, −7%), LFnu (−9.6±1.5, −16%) and LF/HF (−0.7±0.3, −19%). These measures did not change from baseline in the MC group. Conclusion HRV, based on several conventional indices, was diminished in recently abstinent, methamphetamine dependent individuals. Moreover, physical training yielded a marked increase of HRV representing increased vagal modulation or improved autonomic balance. PMID:24162556

  3. Validation of Biofeedback Wearables for Photoplethysmographic Heart Rate Tracking

    PubMed Central

    Jo, Edward; Lewis, Kiana; Directo, Dean; Kim, Michael J.; Dolezal, Brett A.

    2016-01-01

    The purpose of this study was to examine the validity of HR measurements by two commercial-use activity trackers in comparison to ECG. Twenty-four healthy participants underwent the same 77-minute protocol during a single visit. Each participant completed an initial rest period of 15 minutes followed by 5 minute periods of each of the following activities: 60W and 120W cycling, walking, jogging, running, resisted arm raises, resisted lunges, and isometric plank. In between each exercise task was a 5-minute rest period. Each subject wore a Basis Peak (BPk) on one wrist and a Fitbit Charge HR (FB) on the opposite wrist. Criterion measurement of HR was administered by 12-lead ECG. Time synced data from each device and ECG were concurrently and electronically acquired throughout the entire 77-minute protocol. When examining data in aggregate, there was a strong correlation between BPk and ECG for HR (r = 0.92, p < 0.001) with a mean bias of -2.5 bpm (95% LoA 19.3, -24.4). The FB demonstrated a moderately strong correlation with ECG for HR (r = 0.83, p < 0.001) with an average mean bias of -8.8 bpm (95% LoA 24.2, -41.8). During physical efforts eliciting ECG HR > 116 bpm, the BPk demonstrated an r = 0.77 and mean bias = -4.9 bpm (95% LoA 21.3, -31.0) while the FB demonstrated an r = 0.58 and mean bias = -12.7 bpm (95% LoA 28.6, -54.0). The BPk satisfied validity criteria for HR monitors, however showed a marginal decline in accuracy with increasing physical effort (ECG HR > 116 bpm). The FB failed to satisfy validity criteria and demonstrated a substantial decrease in accuracy during higher exercise intensities. Key points Modern day wearable multi-sensor activity trackers incorporate reflective photoplethymography (PPG) for heart rate detection and monitoring at the dorsal wrist. This study examined the validity of two PPG-based activity trackers, the Basis Peak and Fitbit Charge HR. The Basis Peak performed with accuracy compared with ECG and results substantiate

  4. Sampling period determination for heart rate logging under an exercise regimen.

    PubMed

    McCarthy, M; Ringwood, J V

    2006-10-01

    Using a mathematical procedure, we determine appropriate sampling rates for logging heart rate, at a variety of exercise intensities. The mathematical procedure involves correlating exercise and heart rate data to determine a dynamical mathematical model, from which the frequency response of the relationship between exercise intensity and heart rate can be determined. The sampling rate is then straightforwardly deduced by making appropriate measurements on the frequency response curve. We show how careful consideration needs to be given to the choice of dynamical model structure and the work regimen, so that consistent and convincing conclusions can be drawn. We demonstrate that the dynamics of the work-rate/heart-rate system are dependent on the nominal work/heart rate, but a 5-s sampling period, as used in many commercial heart rate monitors, appears to be adequate, especially when some averaging is performed before logging.

  5. Determining the relationship of heart rate and blood pressure using voluntary cardio-respiratory synchronization (VCRS).

    PubMed

    Mason, Lynne I; Patterson, Robert P

    2003-11-01

    Voluntary cardio-respiratory synchronization (VCRS) was used to investigate heart rate and blood pressure changes in the supine position in 21 subjects. VCRS involves a breathing pattern that is synchronized with the cardiac cycle. The signals to inhale and exhale are derived from the ECG. In this study, the subjects inspired for four heart beats and expired for four heart beats for 35 cycles. This technique is designed to have the heart beat occur at exactly the same phase in the respiratory cycle and lends itself to the study of the influence of the respiration cycle on heart rate and blood pressure changes. The heart rate and blood pressure changed simultaneously in the same direction, with the largest significant positive change occurring on the second heart beat during inspiration. The authors discuss the potential of VCRS for research, and clinical applications as a respiration modulator for hypertension therapy or increased heart rate variability.

  6. Heart Rate and Initial Presentation of Cardiovascular Diseases (Caliber)

    ClinicalTrials.gov

    2013-09-17

    Abdominal Aortic Aneurysm; Coronary Heart Disease NOS; Unheralded Coronary Death; Intracerebral Haemorrhage; Heart Failure; Ischemic Stroke; Myocardial Infarction; Stroke; Peripheral Arterial Disease; Stable Angina Pectoris; Subarachnoid Haemorrhage; Transient Ischemic Attack; Unstable Angina; Cardiac Arrest, Sudden Cardiac Death

  7. Alterations in the heart rate and activity rhythms of three orbital astronauts on a space mission.

    PubMed

    Liu, Zhizhen; Wan, Yufeng; Zhang, Lin; Tian, Yu; Lv, Ke; Li, Yinghui; Wang, Chunhui; Chen, Xiaoping; Chen, Shanguang; Guo, Jinhu

    2015-01-01

    Environmental factors in space are dramatically different from those on Earth. The spaceflight environment has been known to influence human physiology and behavior on orbital missions. In this study, we investigated alterations in the diurnal rhythms of activity and heart rate of three Chinese astronauts on a space mission. An analysis of the heart rate data showed a significant decrease in heart rate amplitudes during flight in all three subjects. The heart rate amplitudes of all the three astronauts were significantly dampened during flight, and the minimum as well as the maximum value of heart rate increased after flight. A phase shift in heart rate was observed in one of the three astronauts after flight. These results demonstrate the influence of spaceflight on heart physiology and function. In addition, a significant decrease in body trunk activity and rhythmicity occurred during flight, demonstrating that the spaceflight environment disturbs motion adaptation and diurnal activity rhythms.

  8. Alterations in the heart rate and activity rhythms of three orbital astronauts on a space mission.

    PubMed

    Liu, Zhizhen; Wan, Yufeng; Zhang, Lin; Tian, Yu; Lv, Ke; Li, Yinghui; Wang, Chunhui; Chen, Xiaoping; Chen, Shanguang; Guo, Jinhu

    2015-01-01

    Environmental factors in space are dramatically different from those on Earth. The spaceflight environment has been known to influence human physiology and behavior on orbital missions. In this study, we investigated alterations in the diurnal rhythms of activity and heart rate of three Chinese astronauts on a space mission. An analysis of the heart rate data showed a significant decrease in heart rate amplitudes during flight in all three subjects. The heart rate amplitudes of all the three astronauts were significantly dampened during flight, and the minimum as well as the maximum value of heart rate increased after flight. A phase shift in heart rate was observed in one of the three astronauts after flight. These results demonstrate the influence of spaceflight on heart physiology and function. In addition, a significant decrease in body trunk activity and rhythmicity occurred during flight, demonstrating that the spaceflight environment disturbs motion adaptation and diurnal activity rhythms. PMID:26177621

  9. Environmental factors affecting rates of nitrogen cycling

    SciTech Connect

    Lipschultz, F.

    1984-01-01

    The nitrogen cycle in the eutrophic Delaware river was studied in late summer, 1983 using /sup 15/N tracer additions of NHG/sub 4//sup +/, NO/sub 2//sup -/, and NO/sub 3//sup -/. Rates for nine different transformations were calculated simultaneously with a least-squares minimization analysis. Light was found to stimulate ammonium uptake and to inhibit ammonium oxidation. Rates for nitrification, ammonium uptake by phytoplankton, and photosynthesis were integrated over 24 hours and river depth. High turbidity lifted the effect of light inhibition on nitrification and restricted phytoplankton uptake. Uptake of ammonium contributed over 95% of the inorganic nitrogen ration for phytoplankton, with dark uptake accounting for more than 50%. A mass-conservation, box model of river was used to calculate rate constants required to reproduce observed nutrient concentration changes. The calculated constants correlated well with the measured /sup 15/N and oxygen integrated rates. Water-column nitrification was the major loss term for NH/sub 4//sup +/, while water column regeneration was the primary source. Loss of oxidized nitrogen was insignificant. Oxygen consumption and air-water exchange far exceeded net photosynthetic oxygen production. Nitrification contributed less than 1% to the oxygen demand near Philadelphia but up to 25% further downstream. Production of NO and N/sub 2/O was measured under varying oxygen concentrations in batch cultures of the nitrifying bacteria Nitrosomonas europaea and Nitrosococcus oceanus. Production of both gases increased relative to nitrite production as oxygen levels decreased.

  10. Design of an FECG scalp electrode fetal heart rate monitor.

    PubMed

    Reguig, F B; Kirk, D L

    1996-03-01

    The design of a fetal heart rate (FHR) monitor using fetal electrocardiogram (FECG) scalp electrodes is described. It is shown that the design approach followed two stages: generation of FHR pulses at R-R intervals and FHR computation. The former uses a simple hardware approach for QRS detection and R-wave enhancement, while the latter requires a software implementation in order to produce FHR traces on a beat to beat basis. The QRS detection is based on bandpass filtering using switched mode capacitor technique; the R-wave enhancement and amplitude information are achieved by differentiation followed by fullwave rectification and peak detection. An adaptive threshold together with a comparator circuit are used to generate FHR pulses at R-R intervals. Beat to beat variations of FHR traces are produced by hardware and software implementation on a Z80 microprocessor board. Results obtained by the FHR monitor are evaluated and contrasted to other commercial FHR monitors. PMID:8673321

  11. Automated Fetal Heart Rate Analysis in Labor: Decelerations and Overshoots

    SciTech Connect

    Georgieva, A. E.; Payne, S. J.; Moulden, M.; Redman, C. W. G.

    2010-10-25

    Electronic fetal heart rate (FHR) recording is a standard way of monitoring fetal health in labor. Decelerations and accelerations usually indicate fetal distress and normality respectively. But one type of acceleration may differ, namely an overshoot that may atypically reflect fetal stress. Here we describe a new method for detecting decelerations, accelerations and overshoots as part of a novel system for computerized FHR analysis (OxSyS). There was poor agreement between clinicians when identifying these FHR features visually, which precluded setting a gold standard of interpretation. We therefore introduced 'modified' Sensitivity (SE deg.) and 'modified' Positive Predictive Value (PPV deg.) as appropriate performance measures with which the algorithm was optimized. The relation between overshoots and fetal compromise in labor was studied in 15 cases and 15 controls. Overshoots showed promise as an indicator of fetal compromise. Unlike ordinary accelerations, overshoots cannot be considered to be reassuring features of fetal health.

  12. Nonlinear modelling and control for heart rate response to exercise.

    PubMed

    Zhang, Y; Chen, W; Su, S W; Celler, B

    2012-01-01

    In order to accurately regulate cardiovascular response to exercise for individual exerciser, this study proposes a modelling and control integrated approach based on ε-insensitive Support Vector Regression (SVR) and switching control strategy. Firstly, a control oriented modelling approach is proposed to depict nonlinear behaviours of cardiovascular response at both onset and offset of treadmill exercises by using support vector machine regression. Then, based on the established nonlinear time-variant model, a novel switching Model Predictive Control (MPC) algorithm has been proposed for the optimisation of exercise efforts. The designed controller can take into account both coefficient drifting and parameter jump by embedding the identified model coefficient into the optimiser and adopting switching strategy during the transfer between onset and offset of exercises. The effectiveness of the proposed modelling and control approach was shown from the regulation of dynamical heart rate response to exercise through simulation using MATLAB.

  13. Plasma bevantolol concentration and heart rate in rabbits.

    PubMed

    Liu, X Q; Ye, X L; Zhu, H Q; Huang, S K

    1993-05-01

    Bevantolol (Bev, 5, 10 mg.kg-1) was injected i.v. to rabbits. A measure the lag time of heart rate (HR) response behind the changes in plasma Bev concentration (K(eo)), and the sensitivity of the site of action of Bev (EC50) were determined. The K(eo) were 0.03 +/- 0.02 and 0.029 +/- 0.009 min-1 and the EC50 were 0.2 +/- 0.1 and 0.27 +/- 0.14 microgram.ml-1 respectively for the 2 dosages. The peak changes in HR lagged behind the changes in plasma Bev concentration. There were no significant changes in both pharmacokinetic and pharmacodynamic parameters between the dosages.

  14. Alcohol-dependence syndrome: Postural challenge on heart rate variability

    PubMed Central

    Sucharita, S.; Pradeep, Johnson; Vincent, Anoop; Vaz, M.; Srinivasan, K.

    2012-01-01

    Background: Cardiac autonomic involvement in Alcohol-Dependence Syndrome (ADS) patients has been demonstrated using conventional autonomic tests. Resting heart rate variability (HRV) without normalization has also been reported. Aims: To evaluate cardiac autonomic changes with postural challenge using HRV in ADS and controls while controlling for confounding factors. Settings and Design: Cross-sectional study involving 27 male subjects with ADS and age-matched healthy controls. Materials and Methods: Clinical assessments included Schedules for Clinical Assessment in Neuropsychiatry and Severity of Alcohol Dependence Questionnaire. Spectral measures of HRV while lying and with active standing were assessed. Results: There was an attenuated response in delta high-frequency (P=0.06) and delta low-frequency (P=0.04) power to standing in ADS subjects compared with controls. Conclusion: Patients with ADS appear to have attenuated cardiac vagal and sympathetic responses to standing. HRV with postural challenge may help earlier recognition of autonomic dysfunction in ADS. PMID:23226850

  15. Heart Rate Variability Dynamics for the Prognosis of Cardiovascular Risk

    PubMed Central

    Ramirez-Villegas, Juan F.; Lam-Espinosa, Eric; Ramirez-Moreno, David F.; Calvo-Echeverry, Paulo C.; Agredo-Rodriguez, Wilfredo

    2011-01-01

    Statistical, spectral, multi-resolution and non-linear methods were applied to heart rate variability (HRV) series linked with classification schemes for the prognosis of cardiovascular risk. A total of 90 HRV records were analyzed: 45 from healthy subjects and 45 from cardiovascular risk patients. A total of 52 features from all the analysis methods were evaluated using standard two-sample Kolmogorov-Smirnov test (KS-test). The results of the statistical procedure provided input to multi-layer perceptron (MLP) neural networks, radial basis function (RBF) neural networks and support vector machines (SVM) for data classification. These schemes showed high performances with both training and test sets and many combinations of features (with a maximum accuracy of 96.67%). Additionally, there was a strong consideration for breathing frequency as a relevant feature in the HRV analysis. PMID:21386966

  16. Emergence of dynamical complexity related to human heart rate variability

    NASA Astrophysics Data System (ADS)

    Chang, Mei-Chu; Peng, C.-K.; Stanley, H. Eugene

    2014-12-01

    We apply the refined composite multiscale entropy (MSE) method to a one-dimensional directed small-world network composed of nodes whose states are binary and whose dynamics obey the majority rule. We find that the resulting fluctuating signal becomes dynamically complex. This dynamical complexity is caused (i) by the presence of both short-range connections and long-range shortcuts and (ii) by how well the system can adapt to the noisy environment. By tuning the adaptability of the environment and the long-range shortcuts we can increase or decrease the dynamical complexity, thereby modeling trends found in the MSE of a healthy human heart rate in different physiological states. When the shortcut and adaptability values increase, the complexity in the system dynamics becomes uncorrelated.

  17. Automated Fetal Heart Rate Analysis in Labor: Decelerations and Overshoots

    NASA Astrophysics Data System (ADS)

    Georgieva, A. E.; Payne, S. J.; Moulden, M.; Redman, C. W. G.

    2010-10-01

    Electronic fetal heart rate (FHR) recording is a standard way of monitoring fetal health in labor. Decelerations and accelerations usually indicate fetal distress and normality respectively. But one type of acceleration may differ, namely an overshoot that may atypically reflect fetal stress. Here we describe a new method for detecting decelerations, accelerations and overshoots as part of a novel system for computerized FHR analysis (OxSyS). There was poor agreement between clinicians when identifying these FHR features visually, which precluded setting a gold standard of interpretation. We therefore introduced `modified' Sensitivity (SE°) and `modified' Positive Predictive Value (PPV°) as appropriate performance measures with which the algorithm was optimized. The relation between overshoots and fetal compromise in labor was studied in 15 cases and 15 controls. Overshoots showed promise as an indicator of fetal compromise. Unlike ordinary accelerations, overshoots cannot be considered to be reassuring features of fetal health.

  18. Phasic heart rate changes during word translation of different difficulties.

    PubMed

    Pfurtscheller, Gert; Grabner, Roland H; Brunner, Clemens; Neuper, Christa

    2007-09-01

    The heart rate (HR) can be modulated by diverse mental activities ranging from stimulus anticipation to higher order cognitive information processing. In the present study we report on HR changes during word translation and examine how the HR is influenced by the difficulty of the translation task. Twelve students of translation and interpreting were presented English high- and low-frequency words as well as familiar and unfamiliar technical terms that had to be translated into German. Analyses revealed that words of higher translation difficulty were accompanied by a more pronounced HR deceleration than words that were easier to translate. We additionally show that anticipatory HR deceleration and HR changes induced by motor preparation and activity due to typing the translation do not depend on task difficulty. These results provide first evidence of a link between task difficulty in language translation and event-related HR changes. PMID:17608800

  19. Correlated and uncorrelated heart rate fluctuations during relaxing visualization

    NASA Astrophysics Data System (ADS)

    Papasimakis, N.; Pallikari, F.

    2010-05-01

    The heart rate variability (HRV) of healthy subjects practicing relaxing visualization is studied by use of three multiscale analysis techniques: the detrended fluctuation analysis (DFA), the entropy in natural time (ENT) and the average wavelet (AWC) coefficient. The scaling exponent of normal interbeat interval increments exhibits characteristics of the presence of long-range correlations. During relaxing visualization the HRV dynamics change in the sense that two new features emerge independent of each other: a respiration-induced periodicity that often dominates the HRV at short scales (<40 interbeat intervals) and the decrease of the scaling exponent at longer scales (40-512 interbeat intervals). In certain cases, the scaling exponent during relaxing visualization indicates the breakdown of long-range correlations. These characteristics have been previously seen in the HRV dynamics during non-REM sleep.

  20. Heart Rate Variability in Porcine Progressive Peritonitis-Induced Sepsis

    PubMed Central

    Jarkovska, Dagmar; Valesova, Lenka; Chvojka, Jiri; Benes, Jan; Sviglerova, Jitka; Florova, Blanka; Nalos, Lukas; Matejovic, Martin; Stengl, Milan

    2016-01-01

    Accumulating evidence suggests that heart rate variability (HRV) alterations could serve as an indicator of sepsis progression and outcome, however, the relationships of HRV and major pathophysiological processes of sepsis remain unclear. Therefore, in this experimental study HRV was investigated in a clinically relevant long-term porcine model of severe sepsis/septic shock. HRV was analyzed by several methods and the parameters were correlated with pathophysiological processes of sepsis. In 16 anesthetized, mechanically ventilated, and instrumented domestic pigs of either gender, sepsis was induced by fecal peritonitis. Experimental subjects were screened up to the refractory shock development or death. ECG was continuously recorded throughout the experiment, afterwards RR intervals were detected and HRV parameters computed automatically using custom made measurement and analysis MATLAB routines. In all septic animals, progressive hyperdynamic septic shock developed. The statistical measures of HRV, geometrical measures of HRV and Poincaré plot analysis revealed a pronounced reduction of HRV that developed quickly upon the onset of sepsis and was maintained throughout the experiment. The frequency domain analysis demonstrated a decrease in the high frequency component and increase in the low frequency component together with an increase of the low/high frequency component ratio. The reduction of HRV parameters preceded sepsis-associated hemodynamic changes including heart rate increase or shock progression. In a clinically relevant porcine model of peritonitis-induced progressive septic shock, reduction of HRV parameters heralded sepsis development. HRV reduction was associated with a pronounced parasympathetic inhibition and a shift of sympathovagal balance. Early reduction of HRV may serve as a non-invasive and sensitive marker of systemic inflammatory syndrome, thereby widening the therapeutic window for early interventions. PMID:26779039

  1. Relationship between Arousal Intensity and Heart Rate Response to Arousal

    PubMed Central

    Azarbarzin, Ali; Ostrowski, Michele; Hanly, Patrick; Younes, Magdy

    2014-01-01

    Study Objectives: The visual appearance of cortical arousals varies considerably, from barely meeting scoring criteria to very intense arousals. Arousal from sleep is associated with an increase in heart rate (HR). Our objective was to quantify the intensity of arousals in an objective manner using the time and frequency characteristics of the electroencephalogram (EEG) and to determine whether HR response to arousal correlates with arousal intensity so determined. Design: Post hoc analysis of 20 preexisting polysomnography (PSG) files. Setting: Research and Development Laboratory (YRT Limited). Participants: N/A. Interventions: None. Measurements and Results: Arousals were scored using the American Academy of Sleep Medicine criteria. The EEG signals' time and frequency characteristics were determined using wavelet analysis. An automatic algorithm was developed to scale arousal intensity based on the change in wavelet features and data from a training set obtained from 271 arousals visually scaled between zero and nine (most intense). There were 2,695 arousals in 20 PSGs that were scaled. HR response (ΔHR) was defined as the difference between the highest HR in the interval [arousal-onset to (arousal-end +8 sec)] and the highest HR between 2 and 12 sec preceding arousal onset. There was a strong correlation between arousal scale and ΔHR within each subject (average r: 0.95 ± 0.04). The slope of the relationship varied among subjects (0.7-2.4 min-1/unit scale). Conclusions: Arousal intensity, quantified by wavelet transform, is strongly associated with arousal-related tachycardia, and the gain of the relationship varies among subjects. Quantifying arousal intensity in PSGs provides additional information that may be clinically relevant. Citation: Azarbarzin A; Ostrowski M; Hanly P; Younes M. Relationship between arousal intensity and heart rate response to arousal. SLEEP 2014;37(4):645-653. PMID:24899756

  2. Running demands and heart rate response in rugby sevens referees.

    PubMed

    Suarez-Arrones, Luis; Calvo-Lluch, África; Portillo, Javier; Sánchez, Francisco; Mendez-Villanueva, Alberto

    2013-06-01

    The purpose of this study was to examine for the first time the match running demands and heart rate (HR) responses associated with elite rugby sevens referees. Twelve referees were analyzed over 38 games, using Global Positioning System. Referees covered an average distance of 1665.2 ± 203.5 m per game (15.1 ± 0.5 minutes). Over this distance, 22.3% (371.8 ± 48.9 m) was spent standing and walking, 25.9% (431.2 ± 92.6 m) jogging, 12.4% (206.5 ± 53.2 m) cruising, 23.8% (395.6 ± 94.3 m) striding, 8% (133.3 ± 61.6 m) high-intensity running, and 7.6% (126.7 ± 87.3 m) sprinting. The average maximal distance of sprints, the number of sprints, and the mean sprint distance over the game were 31.3 ± 13.4 m, 5.76 ± 3.6 sprints, and 19.9 ± 7.8 m, respectively. The referee's work-to-rest ratio was 3.5:1. There were no statistical differences between the first and second half in any of the running variables analyzed. The average HR in the second half (160 ± 9 b·min(-1); 86 ± 5% maximal heart rate (HRmax) of the estimated) was higher (p < 0.05) than the HR recorded in the first half (154 ± 11 b·min(-1); 83 ± 6% of the estimated HRmax). This study also suggests that the physical demands of referring in rugby sevens are quite different from those encountered in other rugby codes, and the training regimes need to meet the increased overall running demands and high-intensity running activity.

  3. Heart Rate and Motion Analysis by GPS in Beach Soccer

    PubMed Central

    Castellano, Julen; Casamichana, David

    2010-01-01

    Although beach soccer has become increasingly popular in recent years very little scientific research has been conducted into the sport. A pilot study was carried out with the aim of examining the physiological (heart rate) and physical (motion analysis) responses of beach soccer players during competitive matches. Ten players (age 25.5 ± 0.5 years; height 1.80 ± 0.08 m; weight 78.2 ± 5.6 kg.) were studied over five beach soccer matches. The physiological demands were analysed by measuring heart rate (HR) using telemetric devices, while the physical profile was evaluated by recording motion and speed by means of GPS devices. During competitive matches, players obtained a HRmean of 165.2 bpm (86.5% HRmax), with 59.3% of the time participating (TP) corresponding to values above 90% of the HRmax. The distance covered per minute of participation was 97.7 m, with 9.5% of this distance corresponding to high-intensity running and 2.5% to sprint; the work:rest ratio was 1.4:1 and the maximum speed 21.7 km·h-1. These results showed that beach soccer is an intermittent physical activity of greater intensity than other team games. It requires a major contribution from the anaerobic system as emphasis is placed on players making quick bursts of high-intensity activity separated by brief rest periods. Key points The distance covered per minute of play is around 100 m. Beach soccer is an intermittent sport with a work:rest ratio of 1.4:1. The playing surface in beach soccer is an important handicap to obtain maximum speeds. Beach soccer has a high physiological intensity, with more than half of the game is spent at intensities above 90 % of the HRmax. PMID:24149392

  4. Does cosmic weather affect infant mortality rate?

    PubMed

    Shamir, Lior

    2010-01-01

    In this article, the author proposes to consider a link between infant mortality rate (IMR) and galactic cosmic radiation (CR) density. The periodical increase in solar activity increases the effect of the magnetic field of the sun, and therefore weakens galactic cosmic rays hitting the Earth's surface. As a result, embryos in their early stages of development may be less exposed to high-energy ionizing cosmic rays when the solar activity peaks. In the study discussed here, cosmic ray density data were correlated with the U.S. infant mortality rate in the following year. Statistical analysis shows that in the past 30 years, Pearson correlation between the change in galactic CR flux and IMR decrease in the following year was -0.36 (p < .05). PMID:20687328

  5. Major genes affecting ovulation rate in sheep

    PubMed Central

    2005-01-01

    Research conducted since 1980 in relation to inheritance patterns and DNA testing of major genes for prolificacy has shown that major genes have the potential to significantly increase the reproductive performance of sheep flocks throughout the world. Mutations that increase ovulation rate have been discovered in the BMPR-1B, BMP15 and GDF9 genes, and others are known to exist from the expressed inheritance patterns although the mutations have not yet been located. In the case of BMP15, four different mutations have been discovered but each produces the same phenotype. The modes of inheritance of the different prolificacy genes include autosomal dominant genes with additive effects on ovulation rate (BMPR-1B; Lacaune), autosomal over-dominant genes with infertility in homozygous females (GDF9), X-linked over-dominant genes with infertility in homozygous females (BMP15), and X-linked maternally imprinted genes (FecX2). The size of the effect of one copy of a mutation on ovulation rate ranges from an extra 0.4 ovulations per oestrus for the FecX2 mutation to an extra 1.5 ovulations per oestrus for the BMPR-1B mutation. A commercial DNA testing service enables some of these mutations to be used in genetic improvement programmes based on marker assisted selection. PMID:15601592

  6. Early ventilation-heart rate breakpoint during incremental cycling exercise.

    PubMed

    Gravier, G; Delliaux, S; Ba, A; Delpierre, S; Guieu, R; Jammes, Y

    2014-03-01

    Previous observations having reported a transient hypoxia at the onset of incremental exercise, we investigated the existence of concomitant ventilatory and heart rate (HR) breakpoints.33 subjects executed a maximal cycling exercise with averaging for successive 5-s periods of HR, ventilation, tidal volume (VT), mean inspiratory flow rate (VT/Ti), and end-tidal partial pressures of O2 (PETO2) and CO2. In 10 subjects, the transcutaneous partial pressure of O2 (PtcO2) was recorded and the venous blood lactic acid (LA) concentration measured.At the beginning of exercise, PETO2 decreased, reaching a nadir, then progressively increased until the exercise ended. PtcO2 varied in parallel. Whether or not a 0-W cycling period preceded the incremental exercise, the rate of changes in VE, VT, VT/Ti and HR significantly increased when the nadir PO2 was reached. The ventilatory/ HR breakpoint was measured at 33±4% of VO2max, whereas the ventilatory threshold (VTh) was detected at 67±4% of VO2max and LA began to increase at 45 to 50% of VO2max.During incremental cycling exercise, we identified the existence of HR and ventilatory breakpoints in advance of both lactate and ventilatory thresholds which coincided with modest hypoxia and hypercapnia.

  7. Cognitive function, stress hormones, heart rate and nutritional status during simulated captivity in military survival training.

    PubMed

    Lieberman, Harris R; Farina, Emily K; Caldwell, John; Williams, Kelly W; Thompson, Lauren A; Niro, Philip J; Grohmann, Kyle A; McClung, James P

    2016-10-15

    Stress influences numerous psychological and physiological processes, and its effects have practical implications in a variety of professions and real-world activities. However, few studies have concurrently assessed multiple behavioral, hormonal, nutritional and heart-rate responses of humans to acute, severe stress. This investigation simultaneously assessed cognitive, affective, hormonal, and heart-rate responses induced by an intensely stressful real-world environment designed to simulate wartime captivity. Sixty males were evaluated during and immediately following participation in U.S. Army Survival, Evasion, Resistance, and Escape (SERE) school, three weeks of intense but standardized training for Soldiers at risk of capture. Simulated captivity and intense mock interrogations degraded grammatical reasoning (p<0.005), sustained-attention (p<0.001), working memory (p<0.05) and all aspects of mood assessed by the Profile of Mood States (POMS) questionnaire: Tension/Anxiety, Depression/Dejection, Anger/Hostility, Vigor/Activity, Fatigue/Inertia; Confusion/Bewilderment, and Total Mood Disturbance (p<0.001) It also elevated heart rate (p<0.001); increased serum and salivary cortisol and dehydroepiandrosterone-sulfate (DHEA-s) (p<0.01); elevated serum epinephrine, norepinephrine, and soluble transferrin receptors (sTfR) (p<0.01); increased salivary neuropeptide-Y (NPY) (p<0.001); and decreased serum prolactin and serum and salivary testosterone (p<0.001). Partial recovery was observed immediately after training, but stress-induced changes, particularly in body weight and several of the biomarkers, persisted. This study demonstrates that when individuals were exposed to realistic and controlled simulated captivity, cognition, mood, stress hormones, nutritional status and heart rate are simultaneously altered, and each of these subsequently recovers at different rates. PMID:27374427

  8. Resonance of about-weekly human heart rate rhythm with solar activity change.

    PubMed

    Cornelissen, G; Halberg, F; Wendt, H W; Bingham, C; Sothern, R B; Haus, E; Kleitman, E; Kleitman, N; Revilla, M A; Revilla, M; Breus, T K; Pimenov, K; Grigoriev, A E; Mitish, M D; Yatsyk, G V; Syutkina, E V

    1996-12-01

    In several human adults, certain solar activity rhythms may influence an about 7-day rhythm in heart rate. When no about-weekly feature was found in the rate of change in sunspot area, a measure of solar activity, the double amplitude of a circadian heart rate rhythm, approximated by the fit of a 7-day cosine curve, was lower, as was heart rate corresponds to about-weekly features in solar activity and/or relates to a sunspot cycle.

  9. Comparison of heart rate variability and pulse rate variability detected with photoplethysmography

    NASA Astrophysics Data System (ADS)

    Rauh, Robert; Limley, Robert; Bauer, Rainer-Dieter; Radespiel-Troger, Martin; Mueck-Weymann, Michael

    2004-08-01

    This study compares ear photoplethysmography (PPG) and electrocardiogram (ECG) in providing accurate heart beat intervals for use in calculations of heart rate variability (HRV, from ECG) or of pulse rate variability (PRV, from PPG) respectively. Simultaneous measurements were taken from 44 healthy subjects at rest during spontaneous breathing and during forced metronomic breathing (6/min). Under both conditions, highly significant (p > 0.001) correlations (1.0 > r > 0.97) were found between all evaluated common HRV and PRV parameters. However, under both conditions the PRV parameters were higher than HRV. In addition, we calculated the limits of agreement according to Bland and Altman between both techniques and found good agreement (< 10% difference) for heart rate and standard deviation of normal-to-normal intervals (SDNN), but only moderate (10-20%) or even insufficient (> 20%) agreement for other standard HRV and PRV parameters. Thus, PRV data seem to be acceptable for screening purposes but, at least at this state of knowledge, not for medical decision making. However, further studies are needed before more certain determination can be made.

  10. Behavioral correlates of heart rates of free-living Greater White-fronted Geese

    USGS Publications Warehouse

    Ely, C.R.; Ward, D.H.; Bollinger, K.S.

    1999-01-01

    We simultaneously monitored the heart rate and behavior of nine free-living Greater White-fronted Geese (Anser albifrons) on their wintering grounds in northern California. Heart rates of wild geese were monitored via abdominally-implanted radio transmitters with electrodes that received electrical impulses of the heart and emitted a radio signal with each ventricular contraction. Post-operative birds appeared to behave normally, readily rejoining flocks and flying up to 15 km daily from night-time roost sites to feed in surrounding agricultural fields. Heart rates varied significantly among individuals and among behaviors, and ranged from less than 100 beats per minute (BPM) during resting, to over 400 BPM during flight. Heart rates varied from 80 to 140 BPM during non-strenuous activities such as walking, feeding, and maintenance activities, to about 180 BPM when birds became alert, and over 400 BPM when birds were startled, even if they did not take flight. Postflight heart rate recovery time averaged < 10 sec. During agonistic encounters, heart rate exceeded 400 BPM; heart rates during social interactions were not predictable solely from postures, as heart rates were context-dependent, and were highest in initial encounters among individuals. Instantaneous measures of physiological parameters, such as heart rate, are often better indicators of the degree of response to external stimuli than visual observations and can be used to improve estimates of energy expenditure based solely on activity data.

  11. Chronic effects of workplace noise on blood pressure and heart rate.

    PubMed

    Lusk, Sally L; Hagerty, Bonnie M; Gillespie, Brenda; Caruso, Claire C

    2002-01-01

    Environmental noise levels in the United States are increasing, yet there are few studies in which the nonauditory effects of workplace noise are assessed. In the current study, the authors examined chronic effects of noise on blood pressure and heart rate in 374 workers at an automobile plant. Data were collected from subjects prior to the start of their workshift. Participants completed questionnaires about diet, alcohol use, lifestyle, noise annoyance, use of hearing protection, noise exposure outside of the work environment, personal and family health histories, and demographic information. Resting blood pressure, heart rate, and body mass index were obtained. Noise exposure levels were extracted retrospectively from company records for each participant for the past 5 yr. Summary statistics were generated for each variable, and the authors performed bivariate correlations to identify any unadjusted associations. The authors then completed statistical modeling to investigate the effects of noise on blood pressure and heart rate, after they controlled for other variables (e.g., gender, race, age). The authors controlled for confounding variables, after which use of hearing protection in high-noise areas was a significant predictor of a decrease in both systolic and diastolic blood pressures. The results suggested that the reduction of noise exposure by means of engineering controls or by consistent use of hearing protection by workers may positively affect health outcomes.

  12. Helping from the heart: Voluntary upregulation of heart rate variability predicts altruistic behavior.

    PubMed

    Bornemann, Boris; Kok, Bethany E; Böckler, Anne; Singer, Tania

    2016-09-01

    Our various daily activities continually require regulation of our internal state. These regulatory processes covary with changes in High Frequency Heart Rate Variability (HF-HRV), a marker of parasympathetic activity. Specifically, incidental increases in HF-HRV accompany positive social engagement behavior and prosocial action. Little is known about deliberate regulation of HF-HRV and the role of voluntary parasympathetic regulation in prosocial behavior. Here, we present a novel biofeedback task that measures the ability to deliberately increase HF-HRV. In two large samples, we find that a) participants are able to voluntarily upregulate HF-HRV, and b) variation in this ability predicts individual differences in altruistic prosocial behavior, but not non-altruistic forms of prosociality, assessed through 14 different measures. Our findings suggest that self-induction of parasympathetic states is involved in altruistic action. The biofeedback task may provide a measure of deliberate parasympathetic regulation, with implications for the study of attention, emotion, and social behavior.

  13. Cortisol release, heart rate and heart rate variability in the horse and its rider: different responses to training and performance.

    PubMed

    von Lewinski, Mareike; Biau, Sophie; Erber, Regina; Ille, Natascha; Aurich, Jörg; Faure, Jean-Michel; Möstl, Erich; Aurich, Christine

    2013-08-01

    Although some information exists on the stress response of horses in equestrian sports, the horse-rider team is much less well understood. In this study, salivary cortisol concentrations, heart rate (HR) and heart rate variability (HRV), SDRR (standard deviation of beat-to-beat interval) and RMSSD (root mean square of successive beat-to-beat intervals) were analysed in horses and their riders (n=6 each) at a public performance and an identical rehearsal that was not open to the public. Cortisol concentrations increased in both horses and riders (P<0.001) but did not differ between performance and rehearsal. HR in horses and riders increased during the rehearsal and the public performance (P<0.001) but the increase in HR was more pronounced (P<0.01) in riders than in their horses during the public performance (from 91 ± 10 to 150 ± 15 beats/min) compared to the rehearsal (from 94 ± 10 to 118 ± 12 beats/min). The SDRR decreased significantly during the equestrian tasks in riders (P<0.001), but not in their horses. The RMSSD decreased in horses and riders (P<0.001) during rehearsal and performance, indicating a decrease in parasympathetic tone. The decrease in RMSSD in the riders was more pronounced (P<0.05) during the performance (from 32.6 ± 6.6 to 3.8 ± 0.3 ms) than during the rehearsal (from 27.5 ± 4.2 to 6.6 ± 0.6 ms). The study has shown that the presence of spectators caused more pronounced changes in cardiac activity in the riders than it did in their horses.

  14. Floral symmetry affects speciation rates in angiosperms.

    PubMed Central

    Sargent, Risa D.

    2004-01-01

    Despite much recent activity in the field of pollination biology, the extent to which animal pollinators drive the formation of new angiosperm species remains unresolved. One problem has been identifying floral adaptations that promote reproductive isolation. The evolution of a bilaterally symmetrical corolla restricts the direction of approach and movement of pollinators on and between flowers. Restricting pollinators to approaching a flower from a single direction facilitates specific placement of pollen on the pollinator. When coupled with pollinator constancy, precise pollen placement can increase the probability that pollen grains reach a compatible stigma. This has the potential to generate reproductive isolation between species, because mutations that cause changes in the placement of pollen on the pollinator may decrease gene flow between incipient species. I predict that animal-pollinated lineages that possess bilaterally symmetrical flowers should have higher speciation rates than lineages possessing radially symmetrical flowers. Using sister-group comparisons I demonstrate that bilaterally symmetric lineages tend to be more species rich than their radially symmetrical sister lineages. This study supports an important role for pollinator-mediated speciation and demonstrates that floral morphology plays a key role in angiosperm speciation. PMID:15156918

  15. Heart Rate Variability for Quantification of Autonomic Dysfunction in Fibromyalgia

    PubMed Central

    Kang, Jin Ho; Hong, Seok Hyun; Lee, Chang Hyun; Choi, Byoong Yong

    2016-01-01

    Objective To quantify autonomic dysfunction in fibromyalgia patients compared to healthy controls using heart rate variability (HRV). Methods Sixteen patients with fibromyalgia and 16 healthy controls were recruited in this case control study. HRV was measured using the time-domain method incorporating the following parameters: total heartbeats, the mean of intervals between consecutive heartbeats (R-R intervals), the standard deviation of normal to normal R-R intervals (SDNN), the square root of the mean squared differences of successive R-R intervals (RMSSD), ratio of SDNN to RMSSD (SDNN/RMSSD), and difference between the longest and shortest R-R interval under different three conditions including normal quiet breathing, rate controlled breathing, and Valsalva maneuver. The severity of autonomic symptoms in the group of patients with fibromyalgia was measured by Composite Autonomic Symptom Scale 31 (COMPASS 31). Then we analyzed the difference between the fibromyalgia and control groups and the correlation between the COMPASS 31 and aforementioned HRV parameters in the study groups. Results Patients with fibromyalgia had significantly higher SDNN/RMSSD values under both normal quiet breathing and rate controlled breathing compared to controls. Differences between the longest and shortest R-R interval under Valsalva maneuver were also significantly lower in patients with fibromyalgia than in controls. COMPASS 31 score was negatively correlated with SDNN/RMSSD values under rate controlled breathing. Conclusion SDNN/RMSSD is a valuable parameter for autonomic nervous system function and can be used to quantify subjective autonomic symptoms in patients with fibromyalgia. PMID:27152281

  16. A comparison between computer-controlled and set work rate exercise based on target heart rate

    NASA Technical Reports Server (NTRS)

    Pratt, Wanda M.; Siconolfi, Steven F.; Webster, Laurie; Hayes, Judith C.; Mazzocca, Augustus D.; Harris, Bernard A., Jr.

    1991-01-01

    Two methods are compared for observing the heart rate (HR), metabolic equivalents, and time in target HR zone (defined as the target HR + or - 5 bpm) during 20 min of exercise at a prescribed intensity of the maximum working capacity. In one method, called set-work rate exercise, the information from a graded exercise test is used to select a target HR and to calculate a corresponding constant work rate that should induce the desired HR. In the other method, the work rate is controlled by a computer algorithm to achieve and maintain a prescribed target HR. It is shown that computer-controlled exercise is an effective alternative to the traditional set work rate exercise, particularly when tight control of cardiovascular responses is necessary.

  17. The effect of textile-based inductive coil sensor positions for heart rate monitoring.

    PubMed

    Koo, Hye Ran; Lee, Young-Jae; Gi, Sunok; Khang, Seonah; Lee, Joo Hyeon; Lee, Jae-Ho; Lim, Min-Gyu; Park, Hee-Jung; Lee, Jeong-Whan

    2014-02-01

    In the research related to heart rate measurement, few studies have been done using magnetic-induced conductivity sensing methods to measure the heart rate. The aim of this study was to analyze the effect of the position of a textile-based inductive coil sensor on the measurement of the heart rate. In order to assess the capability of the textile-based inductive coil sensor and the repeatability of measured cardiac muscle contractions, we proposed a new quality index based on the morphology of measured signals using a textile-based inductive coil sensor. We initially explored eight potential positions of the inductive sensor in a pilot experiment, followed by three sensor positions in the main experiment. A simultaneously measured electrocardiography (ECG) signal (Lead II) which was used as a reference signal for a comparison of the R-peak location with signals obtained from selected positions of the textile-based inductive coil sensor. The result of the main experiment indicated that the total quality index obtained from the sensor position 'P3', which was located 3 cm away from the left side from the center front line on the chest circumference line, was the highest (QI value = 1.30) among the three positions across all the subjects. This finding led us to conclude that (1) the position of the textile-based inductive coil sensor significantly affected the quality of the measurement results, and that (2) P3 would be the most appropriate position for the textile-based inductive coil sensor for heart rate measurements based on the magnetic-induced conductivity sensing principle.

  18. Heart rate variability across the menstrual cycle in young women taking oral contraceptives.

    PubMed

    Teixeira, André L; Ramos, Plínio S; Vianna, Lauro C; Ricardo, Djalma R

    2015-11-01

    Previous studies have shown that resting heart rate variability (HRV) is modified by different phases of the menstrual cycle in nonusers of oral contraceptive pills (OCP); however, the effect of OCP on autonomic control of the heart remains unclear. The purpose of this study was to investigate HRV during the low hormone (LH-not taking OCP) and during the high hormone (HH-active OCP use) phases of the menstrual cycle in young women. Seventeen healthy women (19-31 years) taking OCP for at least 6 consecutive months were enrolled in this study. Plasma estradiol and progesterone were verified at each visit. HRV was assessed by using one-lead electrocardiography in time and frequency domains, in which participants rested in the supine position for a 20-min period with a breathing rate of 15 cycles/min. In addition, resting heart rate, and systolic and diastolic blood pressure were obtained. Both plasma estradiol (LH: 19.8 ± 4.2 pg/mL vs. HH: 12.4 ± 1.5 pg/mL; p > .05) and progesterone (LH: 0.247 ± 0.58 ng/mL vs. HH: 0.371 ± 0.08 ng/mL; p > .05) (mean ± SE) levels were similar in both phases. No significant difference was obtained for any component of HRV, heart rate, or blood pressure between the LH and HH phases (p > .05). These results provide preliminary evidence that use of OCP does not affect HRV during the menstrual cycle in healthy women.

  19. Rhythmic variation in heart rate and respiration rate during space flight - Apollo 15

    NASA Technical Reports Server (NTRS)

    Rummel, J. A.

    1974-01-01

    As part of the operational biomedical monitoring for Apollo manned missions, ECG and respiration rate are telemetered at selected intervals to mission control. The data were collected as part of this monitoring program. These data were evaluated for circadian and ultradian rhythmicity because of their uniqueness. The ability to detect and quantitate biorhythms in living systems during space flight is an important aspect of evaluating hypotheses concerning the underlying mechanisms of these phenomena. Circadian variation in heart rate during space flight is demonstrated here. In analyzing generated time series data it has been found that period discrimination is much better than the theoretical limit.

  20. The autonomic nervous control of heart rate in ducks during voluntary diving.

    PubMed

    McPhail, L T; Jones, D R

    1999-01-01

    Autonomic nervous control of heart rate was studied in voluntarily diving ducks (Aythya affinis). Ducks were injected with the muscarinic blocker atropine, the beta-adrenergic blocker nadolol, the beta-adrenergic agonist isoproterenol, and a combination of both atropine and nadolol. Saline injection was used as a control treatment. The reduction in heart rate (from the predive level) normally seen during a dive was abolished by atropine. Nadolol reduced heart rate during all phases of diving activity-predive, dive, and postdive-indicating that sympathetic output to the heart was not withdrawn during diving. Isoproterenol increased heart rate before, during, and after the dive, although the proportional increase in heart rate was not as high during the dive as compared with the increase in routine heart rate or heart rate during the predive or postdive phase. The parasympathetic system predominates in the control of heart rate during diving despite the maintenance of efferent sympathetic influences to the heart, perhaps due to accentuated antagonism between the two branches of the autonomic nervous system. PMID:10068619

  1. Changes in heart rate of pitchers during semi-hard baseball practices and matches.

    PubMed

    Hashimoto, Yasuhiro; Inomata, Kimihiro

    2014-12-01

    High heart rate during competition is a response to both psychological and physiological stress, making it difficult to examine psychological stress in sport. The validity of a new method to extract psychological stress by subtracting heart rate during practice from that of competition was evaluated. The method was used in actual competition for eight pitchers. Most participants showed a "coasting phase," "increment phase," and "descent phase" for heart rate time-series data under both conditions. Heart rate in competitions was higher than during practice, and heart rate in both conditions showed a high correlation. Heart rate changes were significantly higher in situations in which two or three balls had already been thrown compared to zero balls thrown. Thus, psychological stress can be examined in various competition conditions using this method.

  2. Heart rates of elementary physical education students during the dancing classrooms program.

    PubMed

    Nelson, Larry; Evans, Melissa; Guess, Wendy; Morris, Mary; Olson, Terry; Buckwalter, John

    2011-06-01

    We examined how different types of dance activities, along with their duration, influenced heart rate responses among fifth-grade physical education students (N = 96) who participated in the Dancing Classrooms program. Results indicated that the overall Dancing Classrooms program elicits a moderate cardiovascular heart rate response (M = 124.4 bpm), in which 47% of class time was spent above a 60% maximal heart rate threshold. The swing dance in particular (M = 143.4 bpm) stimulated a much higher heart rate level than all other dances in the program, with a mean heart rate change of 52.6 bpm. Girls (127.3 bpm) achieved marginally higher heart rates (p = .059) than boys (121.1 bpm).

  3. Effects of breathing patterns and light exercise on linear and nonlinear heart rate variability.

    PubMed

    Weippert, Matthias; Behrens, Kristin; Rieger, Annika; Kumar, Mohit; Behrens, Martin

    2015-08-01

    Despite their use in cardiac risk stratification, the physiological meaning of nonlinear heart rate variability (HRV) measures is not well understood. The aim of this study was to elucidate effects of breathing frequency, tidal volume, and light exercise on nonlinear HRV and to determine associations with traditional HRV indices. R-R intervals, blood pressure, minute ventilation, breathing frequency, and respiratory gas concentrations were measured in 24 healthy male volunteers during 7 conditions: voluntary breathing at rest, and metronome guided breathing (0.1, 0.2 and 0.4 Hz) during rest, and cycling, respectively. The effect of physical load was significant for heart rate (HR; p < 0.001) and traditional HRV indices SDNN, RMSSD, lnLFP, and lnHFP (p < 0.01 for all). It approached significance for sample entropy (SampEn) and correlation dimension (D2) (p < 0.1 for both), while HRV detrended fluctuation analysis (DFA) measures DFAα1 and DFAα2 were not affected by load condition. Breathing did not affect HR but affected all traditional HRV measures. D2 was not affected by breathing; DFAα1 was moderately affected by breathing; and DFAα2, approximate entropy (ApEn), and SampEn were strongly affected by breathing. DFAα1 was strongly increased, whereas DFAα2, ApEn, and SampEn were decreased by slow breathing. No interaction effect of load and breathing pattern was evident. Correlations to traditional HRV indices were modest (r from -0.14 to -0.67, p < 0.05 to <0.01). In conclusion, while light exercise does not significantly affect short-time HRV nonlinear indices, respiratory activity has to be considered as a potential contributor at rest and during light dynamic exercise.

  4. Effects of breathing patterns and light exercise on linear and nonlinear heart rate variability.

    PubMed

    Weippert, Matthias; Behrens, Kristin; Rieger, Annika; Kumar, Mohit; Behrens, Martin

    2015-08-01

    Despite their use in cardiac risk stratification, the physiological meaning of nonlinear heart rate variability (HRV) measures is not well understood. The aim of this study was to elucidate effects of breathing frequency, tidal volume, and light exercise on nonlinear HRV and to determine associations with traditional HRV indices. R-R intervals, blood pressure, minute ventilation, breathing frequency, and respiratory gas concentrations were measured in 24 healthy male volunteers during 7 conditions: voluntary breathing at rest, and metronome guided breathing (0.1, 0.2 and 0.4 Hz) during rest, and cycling, respectively. The effect of physical load was significant for heart rate (HR; p < 0.001) and traditional HRV indices SDNN, RMSSD, lnLFP, and lnHFP (p < 0.01 for all). It approached significance for sample entropy (SampEn) and correlation dimension (D2) (p < 0.1 for both), while HRV detrended fluctuation analysis (DFA) measures DFAα1 and DFAα2 were not affected by load condition. Breathing did not affect HR but affected all traditional HRV measures. D2 was not affected by breathing; DFAα1 was moderately affected by breathing; and DFAα2, approximate entropy (ApEn), and SampEn were strongly affected by breathing. DFAα1 was strongly increased, whereas DFAα2, ApEn, and SampEn were decreased by slow breathing. No interaction effect of load and breathing pattern was evident. Correlations to traditional HRV indices were modest (r from -0.14 to -0.67, p < 0.05 to <0.01). In conclusion, while light exercise does not significantly affect short-time HRV nonlinear indices, respiratory activity has to be considered as a potential contributor at rest and during light dynamic exercise. PMID:26187271

  5. Fish heart rate telemetry in the open sea using sector scanning sonar.

    PubMed

    Storeton West, T J; Mitson, R B; Greer Walker, M G

    1978-01-01

    Real time monitoring of heart rate from free-swimming fish in the open sea has been used in conjunction with high resolution sonar to track plaice and observed the variation in heart rate in relation to environmental parameters. The heart rate can be observed at the same time as the acoustic picture of the sea bed or the midwater volume of sea surrounding the fish.

  6. Fish Consumption, Sleep, Daily Functioning, and Heart Rate Variability

    PubMed Central

    Hansen, Anita L.; Dahl, Lisbeth; Olson, Gina; Thornton, David; Graff, Ingvild E.; Frøyland, Livar; Thayer, Julian F.; Pallesen, Staale

    2014-01-01

    Study Objectives: This study investigated the effects of fatty fish on sleep, daily functioning and biomarkers such as heart rate variability (HRV), vitamin D status (serum 25-hydroxyvitamin D (25OHD), and eicosapentaenoic acid (EPA, 20:5n-3) + docosahexaenoic acid (DHA, 22:6n-3) in red blood cells. Moreover the relationship among sleep, daily functioning, HRV, vitamin D status, and levels of EPA+DHA was investigated. Methods: Ninety-five male forensic patients from a secure forensic inpatient facility in the USA were randomly assigned into a Fish or a Control group. The Fish group received Atlantic salmon three times per week from September to February, and the Control group was provided an alternative meal (e.g., chicken, pork, beef), but with the same nutritional value as their habitual diet, three times per week during the same period. Sleep (sleep latency, sleep efficiency, actual sleep time, and actual wake time), self-perceived sleep quality and daily functioning, as well as vitamin D status, EPA+DHA, and HRV, were assessed pre- and post-intervention period. Results: There was a significant increase in sleep latency from pre- to post-test in the Control group. The Fish group reported better daily functioning than the Control group during post-test. Fish consumption throughout the wintertime had also an effect on resting HRV and EPA+DHA, but not on vitamin D status. However, at post-test, the vitamin D status in the Fish group was still closer to the level regarded as optimal compared to the Control group. Vitamin D status correlated negatively with actual wake time and positively with sleep efficiency during pre-test, as well as positively with daily functioning and sleep quality during post-test. Finally, HRV correlated negatively with sleep latency and positively with daily functioning. Conclusions: Fish consumption seemed to have a positive impact on sleep in general and also on daily functioning, which may be related to vitamin D status and HRV. Citation

  7. Monty Roberts’ Public Demonstrations: Preliminary Report on the Heart Rate and Heart Rate Variability of Horses Undergoing Training during Live Audience Events

    PubMed Central

    Loftus, Loni; Marks, Kelly; Jones-McVey, Rosie; Gonzales, Jose L.; Fowler, Veronica L.

    2016-01-01

    Simple Summary Monty Roberts is a famous horse trainer, commonly referred to as a ‘horse whisperer’, who shares his training methods all over the world, including through large public audience events. These events have the potential to compromise the horse’s welfare since the horses have usually been transported to the event on the day and stabled in an unfamiliar environment before being used in demonstrations watched by hundreds of people. This paper describes the opportunistic collection and analysis of heart rate (HR; beat-to-beat intervals) and heart rate variability (HRV) of horses being trained during Monty Roberts’ public demonstrations within the United Kingdom. HR and HRV measured during the demonstrations were lower (indicative of an increase in heart rate as measured in beats-per-minute) than recordings within the stable and consistent with low-moderate exercise intensities used during training. The HR and HRV during a specific training method known as “Join-up®” were comparable to other methods of training used by Monty Roberts during public demonstrations. In conclusion, training of horses during public demonstrations is a low-moderate physiological, rather than psychological stressor for horses, with the stress response comparable or less than those previously reported in the literature for horses being trained outside of public audience events. Furthermore, we found no evidence that Join-up® alters HR and HRV in a way to suggest that this training method negatively affects the psychological welfare of horses. Abstract Effective training of horses relies on the trainer’s awareness of learning theory and equine ethology, and should be undertaken with skill and time. Some trainers, such as Monty Roberts, share their methods through the medium of public demonstrations. This paper describes the opportunistic analysis of beat-to-beat (RR) intervals and heart rate variability (HRV) of ten horses being used in Monty Roberts’ public

  8. [Design of Oxygen Saturation, Heart Rate, Respiration Rate Detection System Based on Smartphone of Android Operating System].

    PubMed

    Zhu, Mingshan; Zeng, Bixin

    2015-03-01

    In this paper, we designed an oxygen saturation, heart rate, respiration rate monitoring system based on smartphone of android operating system, physiological signal acquired by MSP430 microcontroller and transmitted by Bluetooth module. PMID:26524782

  9. [Design of Oxygen Saturation, Heart Rate, Respiration Rate Detection System Based on Smartphone of Android Operating System].

    PubMed

    Zhu, Mingshan; Zeng, Bixin

    2015-03-01

    In this paper, we designed an oxygen saturation, heart rate, respiration rate monitoring system based on smartphone of android operating system, physiological signal acquired by MSP430 microcontroller and transmitted by Bluetooth module.

  10. [Influence of different combination of mental activity and respiratory cycle on heart rate variability].

    PubMed

    Sun, F L; Li, D M; Li, G Y

    1996-03-01

    By means of spectral analysis of P-R interval, different characteristics of heart rate variability in different form of respiratory exercise was observed. The results of observation on 32 volunteers showed that mental activity that affected respiration can influence the function of autonomic nerve system in a different way. When the mind was concentrated at the inspiration, the function of autonomic nerve system was kept in balance, and both the sympathetic and the vagal activities enhanced significantly and while mind concentrated at the expiration could induce a reduction of vagal activity so as to produce marked change in the sympathovagal balance.

  11. Are novel objects perceived as stressful? The effect of novelty on heart rate.

    PubMed

    Fischer, Clare Parker; Franco, Leor A; Romero, L Michael

    2016-07-01

    Neophobia, or the fear of novel objects, is a behavior that is often found in wild animals. Neophobia appears to be related to the physiological stress response because individuals with higher glucocorticoid responses to stress often are more neophobic. The relationship between the heart rate response and novelty, however, has not been tested in a wild species. We implanted heart rate transmitters in captive European starlings (Sturnus vulgaris) to measure increases in heart rate as an index of the adrenomedullary stress response. Specifically, we measured heart rate in animals encountering novel objects on or near their food dishes using a system to display the novel objects while the experimenters remained outside the room, thereby minimizing the confounding effects of experimenter presence on heart rate. We analyzed three conditions: the period of adjustment to the experimental setup before any exposure to novelty, novel object trials, and no object controls (presented in a random order after 0-5 novel objects). Birds approached their food dishes faster during the adjustment period than during novel object trials. Although they demonstrated a behavioral aversion to novelty, the effect on heart rate was unexpected. Heart rate increased sharply when the food dishes were displayed. The duration of the startle response was longer during no object controls than during novel object exposure, the opposite of the anticipated result. There were no correlations between behavior and metrics of the heart rate response. Novel object exposure does not cause an increase in heart rate.

  12. Changes in Heart Rate Variability after Coronary Artery Bypass Grafting and Clinical Importance of These Findings

    PubMed Central

    Lakusic, Nenad; Mahovic, Darija; Cerkez Habek, Jasna; Novak, Miroslav; Cerovec, Dusko

    2015-01-01

    Heart rate variability is a physiological feature indicating the influence of the autonomic nervous system on the heart rate. Association of the reduced heart rate variability due to myocardial infarction and the increased postinfarction mortality was first described more than thirty years ago. Many studies have unequivocally demonstrated that coronary artery bypass grafting surgery generally leads to significant reduction in heart rate variability, which is even more pronounced than after myocardial infarction. Pathophysiologically, however, the mechanisms of heart rate variability reduction associated with acute myocardial infarction and coronary artery bypass grafting are different. Generally, heart rate variability gradually recovers to the preoperative values within six months of the procedure. Unlike the reduced heart rate variability in patients having sustained myocardial infarction, a finding of reduced heart rate variability after coronary artery bypass surgery is not considered relevant in predicting mortality. Current knowledge about changes in heart rate variability in coronary patients and clinical relevance of such a finding in patients undergoing coronary artery bypass grafting are presented. PMID:26078960

  13. Lightweight wrist photoplethysmography for heavy exercise: motion robust heart rate monitoring algorithm

    PubMed Central

    Kim, Insoo

    2015-01-01

    The challenge of heart rate monitoring based on wrist photoplethysmography (PPG) during heavy exercise is addressed. PPG is susceptible to motion artefacts, which have to be mitigated for accurate heart rate estimation. Motion artefacts are particularly apparent for wrist devices, for example, a smart watch, because of the high mobility of the arms. Proposed is a low complexity highly accurate heart rate estimation method for continuous heart rate monitoring using wrist PPG. The proposed method achieved 2.57% mean absolute error in a test data set where subjects ran for a maximum speed of 17 km/h. PMID:26609397

  14. Are novel objects perceived as stressful? The effect of novelty on heart rate.

    PubMed

    Fischer, Clare Parker; Franco, Leor A; Romero, L Michael

    2016-07-01

    Neophobia, or the fear of novel objects, is a behavior that is often found in wild animals. Neophobia appears to be related to the physiological stress response because individuals with higher glucocorticoid responses to stress often are more neophobic. The relationship between the heart rate response and novelty, however, has not been tested in a wild species. We implanted heart rate transmitters in captive European starlings (Sturnus vulgaris) to measure increases in heart rate as an index of the adrenomedullary stress response. Specifically, we measured heart rate in animals encountering novel objects on or near their food dishes using a system to display the novel objects while the experimenters remained outside the room, thereby minimizing the confounding effects of experimenter presence on heart rate. We analyzed three conditions: the period of adjustment to the experimental setup before any exposure to novelty, novel object trials, and no object controls (presented in a random order after 0-5 novel objects). Birds approached their food dishes faster during the adjustment period than during novel object trials. Although they demonstrated a behavioral aversion to novelty, the effect on heart rate was unexpected. Heart rate increased sharply when the food dishes were displayed. The duration of the startle response was longer during no object controls than during novel object exposure, the opposite of the anticipated result. There were no correlations between behavior and metrics of the heart rate response. Novel object exposure does not cause an increase in heart rate. PMID:27072510

  15. Heart rate estimation from facial photoplethysmography during dynamic illuminance changes.

    PubMed

    Dongseok Lee; Jeehoon Kim; Sungjun Kwon; Kwangsuk Park

    2015-08-01

    Camera-based remote photoplethysmography (rPPG) enables low-cost, non-contact cardiovascular activity monitoring. However, applying rPPG to practical use has some limitations caused from the artifacts by illuminance changes. During watching a video in a dark room, for example, watching a TV at night without illuminance, there is a high correlation between the brightness changes of a video and the illuminance variation on the skin of the viewer's face. In this study, we propose an artifact reduction method in rPPG, which is caused by the variation of the illuminance. The method subtracts the artifacts from the raw facial rPPG signal by applying multi-order curve fitting between the illuminance information from the facial rPPG signal and the brightness information from a video. On average, the results showed that signal-to-noise ratio (SNR) increased from -11.74 to -4.19 dB and from -15.27 to 7.99 dB for low-dynamic-brightness and high-dynamic-brightness video, respectively. In addition, the root-mean-square-error (RMSE) of estimated heart rate decreased from 11.00 to 1.82 bpm and from 9.88 to 4.65 bpm for the videos, respectively. PMID:26736863

  16. Clinical Application of Heart Rate Variability after Acute Myocardial Infarction

    PubMed Central

    Huikuri, Heikki V.; Stein, Phyllis K.

    2012-01-01

    Heart rate (HR) variability has been extensively studied in patients surviving an acute myocardial infarction (AMI). The majority of studies have shown that patients with reduced or abnormal HR variability/turbulence have an increased risk of mortality within few years after an AMI. Various measures of HR dynamics, such as time-domain, spectral, and non-linear measures of HR variability, as well as HR turbulence, have been used in risk stratification of post-AMI patients. The prognostic power of various measures, except of those reflecting rapid R–R interval oscillations, has been almost identical, albeit some non-linear HR variability measures, such as short-term fractal scaling exponent, and HR turbulence, have provided somewhat better prognostic information than the others. Abnormal HR variability predicts both sudden and non-sudden cardiac death after AMI. Because of remodeling of the arrhythmia substrate after AMI, early measurement of HR variability to identify those at high risk should likely be repeated later in order to assess the risk of fatal arrhythmia events. Future randomized trials using HR variability/turbulence as one of the pre-defined inclusion criteria will show whether routine measurement of HR variability/turbulence will become a routine clinical tool for risk stratification of post-AMI patients. PMID:22375128

  17. Effect of Acupuncture on Heart Rate Variability: A Systematic Review

    PubMed Central

    Chung, Joanne W. Y.; Yan, Vincent C. M.

    2014-01-01

    Aim. To summarize all relevant trials and critically evaluate the effect of acupuncture on heart rate variability (HRV). Method. This was a systematic review with meta-analysis. Keyword search was conducted in 7 databases for randomized controlled trials (RCTs). Data extraction and risk of bias were done. Results. Fourteen included studies showed a decreasing effect of acupuncture on low frequency (LF) and low frequency to high frequency ratio (LF/HF ratio) of HRV for nonhealthy subjects and on normalized low frequency (LF norm) for healthy subjects. The overall effect was in favour of the sham/control group for high frequency (HF) in nonhealthy subjects and for normalized high frequency (HF norm) in healthy subjects. Significant decreasing effect on HF and LF/HF ratio of HRV when acupuncture was performed on ST36 among healthy subjects and PC6 among both healthy and nonhealthy subjects, respectively. Discussion. This study partially supports the possible effect of acupuncture in modulating the LF of HRV in both healthy and nonhealthy subjects, while previous review reported that acupuncture did not have any convincing effect on HRV in healthy subjects. More published work is needed in this area to determine if HRV can be an indicator of the therapeutic effect of acupuncture. PMID:24693326

  18. Heart rate and salivary cortisol concentrations in foals at birth.

    PubMed

    Nagel, C; Erber, R; Ille, N; Wulf, M; Aurich, J; Möstl, E; Aurich, C

    2015-02-01

    Heart rate (HR), HR variability (HRV) and salivary cortisol concentrations were determined in foals (n = 13) during the perinatal phase and until 5 months of age. In the fetus, HR decreased from 77 ± 3 beats/min at 120 min before birth to 60 ± 1 beats/min at 5 min before birth (P <0.01). Within 30 min of birth, HR increased to 160 ± 9 beats/min (P <0.01). Salivary cortisol concentrations immediately after birth were 11.9 ± 3.6 ng/mL and within 2 h increased to a maximum of 52.5 ± 12.3 ng/mL (P <0.01). In conclusion, increases in HR and salivary cortisol concentrations in foals are not induced during parturition, but occur immediately after birth.

  19. Kubios HRV--heart rate variability analysis software.

    PubMed

    Tarvainen, Mika P; Niskanen, Juha-Pekka; Lipponen, Jukka A; Ranta-Aho, Perttu O; Karjalainen, Pasi A

    2014-01-01

    Kubios HRV is an advanced and easy to use software for heart rate variability (HRV) analysis. The software supports several input data formats for electrocardiogram (ECG) data and beat-to-beat RR interval data. It includes an adaptive QRS detection algorithm and tools for artifact correction, trend removal and analysis sample selection. The software computes all the commonly used time-domain and frequency-domain HRV parameters and several nonlinear parameters. There are several adjustable analysis settings through which the analysis methods can be optimized for different data. The ECG derived respiratory frequency is also computed, which is important for reliable interpretation of the analysis results. The analysis results can be saved as an ASCII text file (easy to import into MS Excel or SPSS), Matlab MAT-file, or as a PDF report. The software is easy to use through its compact graphical user interface. The software is available free of charge for Windows and Linux operating systems at http://kubios.uef.fi. PMID:24054542

  20. Kubios HRV--heart rate variability analysis software.

    PubMed

    Tarvainen, Mika P; Niskanen, Juha-Pekka; Lipponen, Jukka A; Ranta-Aho, Perttu O; Karjalainen, Pasi A

    2014-01-01

    Kubios HRV is an advanced and easy to use software for heart rate variability (HRV) analysis. The software supports several input data formats for electrocardiogram (ECG) data and beat-to-beat RR interval data. It includes an adaptive QRS detection algorithm and tools for artifact correction, trend removal and analysis sample selection. The software computes all the commonly used time-domain and frequency-domain HRV parameters and several nonlinear parameters. There are several adjustable analysis settings through which the analysis methods can be optimized for different data. The ECG derived respiratory frequency is also computed, which is important for reliable interpretation of the analysis results. The analysis results can be saved as an ASCII text file (easy to import into MS Excel or SPSS), Matlab MAT-file, or as a PDF report. The software is easy to use through its compact graphical user interface. The software is available free of charge for Windows and Linux operating systems at http://kubios.uef.fi.

  1. Sleep apnea detection using time-delayed heart rate variability.

    PubMed

    Nano, Marina-Marinela; Xi Long; Werth, Jan; Aarts, Ronald M; Heusdens, Richard

    2015-01-01

    Sleep apnea is a sleep disorder distinguished by repetitive absence of breathing. Compared with the traditional expensive and cumbersome methods, sleep apnea diagnosis or screening with physiological information that can be easily acquired is needed. This paper describes algorithms using heart rate variability (HRV) to automatically detect sleep apneas as long as it can be easily acquired with unobtrusive sensors. Because the changes in cardiac activity are usually hysteretic than the presence of apneas with a few minutes, we propose to use the delayed HRV features to identify the episodes with sleep apneic events. This is expected to help improve the apnea detection performance. Experiments were conducted with a data set of 23 sleep apnea patients using support vector machine (SVM) classifiers and cross validations. Results show that using eleven HRV features with a time delay of 1.5 minutes rather than the features without time delay for SA detection, the overall accuracy increased from 74.9% to 76.2% and the Cohen's Kappa coefficient increased from 0.49 to 0.52. Further, an accuracy of 94.5% and a Kappa of 0.89 were achieved when applying subject-specific classifiers.

  2. Heart rate estimation from facial photoplethysmography during dynamic illuminance changes.

    PubMed

    Dongseok Lee; Jeehoon Kim; Sungjun Kwon; Kwangsuk Park

    2015-08-01

    Camera-based remote photoplethysmography (rPPG) enables low-cost, non-contact cardiovascular activity monitoring. However, applying rPPG to practical use has some limitations caused from the artifacts by illuminance changes. During watching a video in a dark room, for example, watching a TV at night without illuminance, there is a high correlation between the brightness changes of a video and the illuminance variation on the skin of the viewer's face. In this study, we propose an artifact reduction method in rPPG, which is caused by the variation of the illuminance. The method subtracts the artifacts from the raw facial rPPG signal by applying multi-order curve fitting between the illuminance information from the facial rPPG signal and the brightness information from a video. On average, the results showed that signal-to-noise ratio (SNR) increased from -11.74 to -4.19 dB and from -15.27 to 7.99 dB for low-dynamic-brightness and high-dynamic-brightness video, respectively. In addition, the root-mean-square-error (RMSE) of estimated heart rate decreased from 11.00 to 1.82 bpm and from 9.88 to 4.65 bpm for the videos, respectively.

  3. Heart rate variability: a tool to explore the sleeping brain?

    PubMed Central

    Chouchou, Florian; Desseilles, Martin

    2014-01-01

    Sleep is divided into two main sleep stages: (1) non-rapid eye movement sleep (non-REMS), characterized among others by reduced global brain activity; and (2) rapid eye movement sleep (REMS), characterized by global brain activity similar to that of wakefulness. Results of heart rate variability (HRV) analysis, which is widely used to explore autonomic modulation, have revealed higher parasympathetic tone during normal non-REMS and a shift toward sympathetic predominance during normal REMS. Moreover, HRV analysis combined with brain imaging has identified close connectivity between autonomic cardiac modulation and activity in brain areas such as the amygdala and insular cortex during REMS, but no connectivity between brain and cardiac activity during non-REMS. There is also some evidence for an association between HRV and dream intensity and emotionality. Following some technical considerations, this review addresses how brain activity during sleep contributes to changes in autonomic cardiac activity, organized into three parts: (1) the knowledge on autonomic cardiac control, (2) differences in brain and autonomic activity between non-REMS and REMS, and (3) the potential of HRV analysis to explore the sleeping brain, and the implications for psychiatric disorders. PMID:25565936

  4. The role of heart rate variability in sports physiology

    PubMed Central

    DONG, JIN-GUO

    2016-01-01

    Heart rate variability (HRV) is a relevant marker reflecting cardiac modulation by sympathetic and vagal components of the autonomic nervous system (ANS). Although the clinical application of HRV is mainly associated with the prediction of sudden cardiac death and assessing cardiovascular and metabolic illness progression, recent observations have suggested its applicability to physical exercise training. HRV is becoming one of the most useful tools for tracking the time course of training adaptation/maladaptation of athletes and in setting the optimal training loads leading to improved performances. However, little is known regarding the role of HRV and the internal effects of physical exercise on an athlete, which may be useful in designing fitness programs ensuring sufficient training load that may correspond with the specific ability of the athlete. In this review, we offer a comprehensive assessment of investigations concerning the interrelation between HRV and ANS, and examine how the application of HRV to physical exercise may play a role in sports physiology. PMID:27168768

  5. Microwave radiation and heart-beat rate of rabbits.

    PubMed

    Chou, C K; Han, L F; Guy, A W

    1980-06-01

    Each of three adult New Zealand rabbits, 2 male and 1 female albinos, was exposed dorsally or ventrally, to 2450-MHz plane waves for 20 min under each of several field conditions: 1) to continuous waves (CW) at 5 mW/cm2; 2) to pulsed waves (PW) of 1-microsecond width that recurred 700 pps at an average of 5 mW/cm2 and at a peak of 7.1 W/cm2; 3) to PW of 10-microseconds width at a peak of 13.7 W/cm2 that were synchronized with and triggered by the R wave of the electrocardiogram (EKG) at various delay times (0, 100, and 200 ms; and 4) to CW at 80 mW/cm2. Carbon-loaded Teflon electrodes were used to record the EKG from forelimbs of an animal before, during, and after irradiation whilst it was maintained in a constant exposure geometry in a wooden squeeze box. Field induced changes in the heart-beat rate were observed at 80 mW/cm2 but not a lower average power densities, although a peak positive chronotropic effect might have been occasioned by PM introduced at 100 and 200 ms after the R wave peak. No cumulative effect was observed over a period of four months. Thermographic analysis revealed relatively little absorption of microwave energy by the myocardium irrespective of anatomical aspect of exposure.

  6. Extraction of Heart Rate Variability from Smartphone Photoplethysmograms

    PubMed Central

    Peng, Rong-Chao; Zhou, Xiao-Lin; Lin, Wan-Hua; Zhang, Yuan-Ting

    2015-01-01

    Heart rate variability (HRV) is a useful clinical tool for autonomic function assessment and cardiovascular diseases diagnosis. It is traditionally calculated from a dedicated medical electrocardiograph (ECG). In this paper, we demonstrate that HRV can also be extracted from photoplethysmograms (PPG) obtained by the camera of a smartphone. Sixteen HRV parameters, including time-domain, frequency-domain, and nonlinear parameters, were calculated from PPG captured by a smartphone for 30 healthy subjects and were compared with those derived from ECG. The statistical results showed that 14 parameters (AVNN, SDNN, CV, RMSSD, SDSD, TP, VLF, LF, HF, LF/HF, nLF, nHF, SD1, and SD2) from PPG were highly correlated (r > 0.7, P < 0.001) with those from ECG, and 7 parameters (AVNN, TP, VLF, LF, HF, nLF, and nHF) from PPG were in good agreement with those from ECG within the acceptable limits. In addition, five different algorithms to detect the characteristic points of PPG wave were also investigated: peak point (PP), valley point (VP), maximum first derivative (M1D), maximum second derivative (M2D), and tangent intersection (TI). The results showed that M2D and TI algorithms had the best performance. These results suggest that the smartphone might be used for HRV measurement. PMID:25685174

  7. Autonomic neural control of heart rate during dynamic exercise: revisited

    PubMed Central

    White, Daniel W; Raven, Peter B

    2014-01-01

    The accepted model of autonomic control of heart rate (HR) during dynamic exercise indicates that the initial increase is entirely attributable to the withdrawal of parasympathetic nervous system (PSNS) activity and that subsequent increases in HR are entirely attributable to increases in cardiac sympathetic activity. In the present review, we sought to re-evaluate the model of autonomic neural control of HR in humans during progressive increases in dynamic exercise workload. We analysed data from both new and previously published studies involving baroreflex stimulation and pharmacological blockade of the autonomic nervous system. Results indicate that the PSNS remains functionally active throughout exercise and that increases in HR from rest to maximal exercise result from an increasing workload-related transition from a 4 : 1 vagal–sympathetic balance to a 4 : 1 sympatho–vagal balance. Furthermore, the beat-to-beat autonomic reflex control of HR was found to be dependent on the ability of the PSNS to modulate the HR as it was progressively restrained by increasing workload-related sympathetic nerve activity. In conclusion: (i) increases in exercise workload-related HR are not caused by a total withdrawal of the PSNS followed by an increase in sympathetic tone; (ii) reciprocal antagonism is key to the transition from vagal to sympathetic dominance, and (iii) resetting of the arterial baroreflex causes immediate exercise-onset reflexive increases in HR, which are parasympathetically mediated, followed by slower increases in sympathetic tone as workloads are increased. PMID:24756637

  8. On heart rate regulation in cycle-ergometer exercise.

    PubMed

    Argha, Ahmadreza; Su, Steven W; Lee, Sangwon; Nguyen, Hung; Celler, Branko G

    2014-01-01

    In this paper, we have focused on the issue of regulating the human heart rate (HR) to a predefined reference trajectory, especially for cycle-ergometer exercise used for training or rehabilitation. As measuring HR is relatively easy compared to exercise intensity, it has been used in the wide range of training programs. The aim of this paper is to develop a non-model-based control strategy using proportional, integral and derivative (PID) controller/relay controller to regulate the HR to track a desired trajectory. In the case of using PID controller, the controller output signal is interpreted as a voice or auditory command, referred to as biofeedback, which can be heard by the exercising subject as a part of the control-loop. Alternatively, the relay controller output signals can be converted to some special words which can be recognised by the exerciser. However, in both cases, to effectively communicate to the user a change in exercise intensity, the timing of this feedback signal relative to the positions of the pedals becomes quite critical. A feedback signal delivered when the pedals are not in a suitable position to efficiently exert force may be ineffective and may lead to a cognitive disengagement of the user form the feedback controller. In this paper we examine the need and the consequence of synchronising the delivery of the feedback signal with an optimal and user specific placement of the pedal.

  9. Prone position craniotomy in pregnancy without fetal heart rate monitoring.

    PubMed

    Jacob, Jean; Alexander, Ashish; Philip, Shoba; Thomas, Anoop

    2016-09-01

    A pregnant patient in second trimester scheduled for posterior fossa craniotomy in prone position is a challenge for the anesthesiologist. Things to consider are physiological changes during pregnancy, non-obstetric surgery in pregnant patients, neuroanesthetic principles, effects of prone positioning, and need for fetal heart rate (FHR) monitoring. We have described the anesthetic management of this case and discussed intra-operative FHR monitoring including controversies about its role, indications, and various options available as per fetal gestational age. In our case we attempted intermittent intra-operative FHR monitoring to optimize maternal positioning and fetal oxygenation even though the fetus was pre-viable. However the attempt was abandoned due to practical difficulties with prone positioning. Patient made good neurological recovery following the procedure and delivered a healthy term baby 4 months later. Decisions regarding fetal monitoring should be individualized based on viability of the fetus and feasibility of emergency cesarean delivery. Good communication between a multidisciplinary team involving neurosurgeon, anesthesiologist, obstetrician, and neonatologist is important for a successful outcome for mother and fetus. We conclude that prone position neurosurgery can safely be carried out in a pregnant patient with pre-viable fetus without FHR monitoring. PMID:27555144

  10. Estimation of human core temperature from sequential heart rate observations.

    PubMed

    Buller, Mark J; Tharion, William J; Cheuvront, Samuel N; Montain, Scott J; Kenefick, Robert W; Castellani, John; Latzka, William A; Roberts, Warren S; Richter, Mark; Jenkins, Odest Chadwicke; Hoyt, Reed W

    2013-07-01

    Core temperature (CT) in combination with heart rate (HR) can be a good indicator of impending heat exhaustion for occupations involving exposure to heat, heavy workloads, and wearing protective clothing. However, continuously measuring CT in an ambulatory environment is difficult. To address this problem we developed a model to estimate the time course of CT using a series of HR measurements as a leading indicator using a Kalman filter. The model was trained using data from 17 volunteers engaged in a 24 h military field exercise (air temperatures 24-36 °C, and 42%-97% relative humidity and CTs ranging from 36.0-40.0 °C). Validation data from laboratory and field studies (N = 83) encompassing various combinations of temperature, hydration, clothing, and acclimation state were examined using the Bland-Altman limits of agreement (LoA) method. We found our model had an overall bias of -0.03 ± 0.32 °C and that 95% of all CT estimates fall within ±0.63 °C (>52 000 total observations). While the model for estimating CT is not a replacement for direct measurement of CT (literature comparisons of esophageal and rectal methods average LoAs of ±0.58 °C) our results suggest it is accurate enough to provide practical indication of thermal work strain for use in the work place.

  11. Non-Contact Heart Rate Monitoring Using Lab Color Space.

    PubMed

    Rahman, Hamidur; Ahmed, Mobyen Uddin; Begum, Shahina

    2016-01-01

    Research progressing during the last decade focuses more on non-contact based systems to monitor Heart Rate (HR) which are simple, low-cost and comfortable to use. Most of the non-contact based systems are using RGB videos which is suitable for lab environment. However, it needs to progress considerably before they can be applied in real life applications. As luminance (light) has significance contribution on RGB videos HR monitoring using RGB videos are not efficient enough in real life applications in outdoor environment. This paper presents a HR monitoring method using Lab color facial video captured by a webcam of a laptop computer. Lab color space is device independent and HR can be extracted through facial skin color variation caused by blood circulation considering variable environmental light. Here, three different signal processing methods i.e., Fast Fourier Transform (FFT), Independent Component Analysis (ICA) and Principal Component Analysis (PCA) have been applied on the color channels in video recordings and blood volume pulse (BVP) has been extracted from the facial regions. In this study, HR is subsequently quantified and compare with a reference measurement. The result shows that high degrees of accuracy have been achieved compared to the reference measurements. Thus, this technology has significant potential for advancing personal health care, telemedicine and many real life applications such as driver monitoring. PMID:27225552

  12. Different heart rate patterns in obstructive apneas during NREM sleep.

    PubMed

    Bonsignore, M R; Romano, S; Marrone, O; Chiodi, M; Bonsignore, G

    1997-12-01

    Both bradycardia and a trend to tachycardia have been reported in obstructive sleep apneas (OSA). Because heart rate (HR) behavior may yield information on parasympathetic activity during OSA, we analyzed HR in samples of consecutive apneic cycles in non-rapid eye movement (NREM) sleep, recorded in normotensive patients breathing room air (n = 7) and supplemental O2 (n = 4). In air, the patients showed different HR trends during apnea, as HR decreased (HR decreased), remained constant (HR=), or increased (HR increased). By multiple regression analysis, development of HR trends correlated with the HR fall in the late interapneic period, HR at first effort, the decrease in esophageal pressure, and the lengthening of inspiration during apnea (R2 = 0.42). O2 abolished HR decreased-OSA, whereas HR= and HR increased-OSA still occurred but at higher HR than in air. In both the air and O2 series, the HR fall preceding apnea correlated significantly with the degree of hypoxia reached in the previous apneic cycle. These data indicate a complex modulation of HR during OSA, with the HR fall in the late interapneic period possibly reflecting the effectiveness of parasympathetic cardiac control in OSA patients during sleep. PMID:9493928

  13. Heart-rate monitoring by air pressure and causal analysis

    NASA Astrophysics Data System (ADS)

    Tsuchiya, Naoki; Nakajima, Hiroshi; Hata, Yutaka

    2011-06-01

    Among lots of vital signals, heart-rate (HR) is an important index for diagnose human's health condition. For instance, HR provides an early stage of cardiac disease, autonomic nerve behavior, and so forth. However, currently, HR is measured only in medical checkups and clinical diagnosis during the rested state by using electrocardiograph (ECG). Thus, some serious cardiac events in daily life could be lost. Therefore, a continuous HR monitoring during 24 hours is desired. Considering the use in daily life, the monitoring should be noninvasive and low intrusive. Thus, in this paper, an HR monitoring in sleep by using air pressure sensors is proposed. The HR monitoring is realized by employing the causal analysis among air pressure and HR. The causality is described by employing fuzzy logic. According to the experiment on 7 males at age 22-25 (23 on average), the correlation coefficient against ECG is 0.73-0.97 (0.85 on average). In addition, the cause-effect structure for HR monitoring is arranged by employing causal decomposition, and the arranged causality is applied to HR monitoring in a setting posture. According to the additional experiment on 6 males, the correlation coefficient is 0.66-0.86 (0.76 on average). Therefore, the proposed method is suggested to have enough accuracy and robustness for some daily use cases.

  14. Heart rate never lies: interventional cardiologist and Braude's quote revised

    PubMed Central

    Cook, Stéphane; Stauffer, Jean-Christophe; Goy, Jean-Jacques; Graf, Denis; Puricel, Serban; Frobert, Aurélien; Muller, Olivier; Togni, Mario; Arroyo, Diego

    2016-01-01

    Background Interventional cardiologists may be immune to stress, allowing them to perform complex percutaneous interventions under pressure. Objectives To assess heart rate (HR) variations as a surrogate marker of stress of interventional cardiologists during percutaneous cardiac procedures and in every-day life. Design This is a single-centre observational study including a total of six male interventional cardiologists performing coronary interventions and pacemaker implantations. Participants were asked to record their HR with the Apple Watch Device during procedures, every-day life and control activities such as outpatient consultations, sport, marital conflicts and sexual intercourse. Results Average daily HR was 88±17 bpm. During work days, HR increased significantly during procedures (90±17 bpm) compared with days outside the cathlab (87±17 bpm, p=0.02). The average HR was higher during a regular week working (88±16 bpm) compared with weekends off (84±18 bpm, p=0.002). Complex cardiac procedures were associated with higher HR up to 122 bpm. Peak HR were higher during physical exertion. Of note, participants complained of hypersexuality and mania after night shifts. Conclusions Work and especially percutaneous cardiac procedures increase HR independently of physical exertion suggesting that interventional cardiologists experience mental stress and emotions. PMID:26835145

  15. Voluntary heart rate lowering following a cardiovascular arousing task.

    PubMed

    Malcuit, G; Beaudry, J

    1980-05-01

    The purpose of the research was to evaluate the effect of feedback-assisted voluntary control to lower heart rate (HR), following a non-somatic mediated task designed to induce cardiovascular activation. Twenty-seven male subjects participated in this study and were randomly divided into three groups. All subjects were submitted to an arousing mental arithmetic task for a 1 min period, followed either by a feedback-assisted HR lowering task (FG), by an unassisted HR lowering task (ICG), or by a relaxation period (RCG). During this period (2 min duration), ICG and RCG subjects were required, as a help for HR deceleration or relaxation, to track visually a sweeping line similar in form to the continuous analogue feedback of the FG subjects. This sequence, interspaced by a 1 min rest period, was repeated 10 times. Results showed that the mental arithmetic task was effective in producing consistent and repetitive HR acceleration. All three groups showed significative HR lowering during the following voluntary HR control or relaxation period. However, there was no difference in the speed or depth of HR lowering. It appeared that continuous-analogue feedback was not more effective than instructions to relax to assist HR return to lower levels.

  16. Infant diet sets the tone for parasympathetic regulation of resting heart rate: Development of vagal tone from 3 months to 2 years

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The parasympathetic nervous system (PS) influences are critical in the autonomic control of the heart. To examine how early postnatal diet affects PS development, we used a measure of tonic PS control of cardiac activity, vagal tone, derived from resting heart rate recordings in 158 breastfed (BF), ...

  17. Large-scale dimension densities for heart rate variability analysis

    NASA Astrophysics Data System (ADS)

    Raab, Corinna; Wessel, Niels; Schirdewan, Alexander; Kurths, Jürgen

    2006-04-01

    In this work, we reanalyze the heart rate variability (HRV) data from the 2002 Computers in Cardiology (CiC) Challenge using the concept of large-scale dimension densities and additionally apply this technique to data of healthy persons and of patients with cardiac diseases. The large-scale dimension density (LASDID) is estimated from the time series using a normalized Grassberger-Procaccia algorithm, which leads to a suitable correction of systematic errors produced by boundary effects in the rather large scales of a system. This way, it is possible to analyze rather short, nonstationary, and unfiltered data, such as HRV. Moreover, this method allows us to analyze short parts of the data and to look for differences between day and night. The circadian changes in the dimension density enable us to distinguish almost completely between real data and computer-generated data from the CiC 2002 challenge using only one parameter. In the second part we analyzed the data of 15 patients with atrial fibrillation (AF), 15 patients with congestive heart failure (CHF), 15 elderly healthy subjects (EH), as well as 18 young and healthy persons (YH). With our method we are able to separate completely the AF (ρlsμ=0.97±0.02) group from the others and, especially during daytime, the CHF patients show significant differences from the young and elderly healthy volunteers (CHF, 0.65±0.13 ; EH, 0.54±0.05 ; YH, 0.57±0.05 ; p<0.05 for both comparisons). Moreover, for the CHF patients we find no circadian changes in ρlsμ (day, 0.65±0.13 ; night, 0.66±0.12 ; n.s.) in contrast to healthy controls (day, 0.54±0.05 ; night, 0.61±0.05 ; p=0.002 ). Correlation analysis showed no statistical significant relation between standard HRV and circadian LASDID, demonstrating a possibly independent application of our method for clinical risk stratification.

  18. Differential rate responses to nicotine in rat heart: evidence for two classes of nicotinic receptors.

    PubMed

    Ji, Susan; Tosaka, Toshimasa; Whitfield, Bernard H; Katchman, Alexander N; Kandil, Abdurrahman; Knollmann, Bjoern C; Ebert, Steven N

    2002-06-01

    Nicotinic acetylcholine receptors are pentameric, typically being composed of two or more different subunits. To investigate which receptor subtypes are active in the heart, we initiated a series of experiments using an isolated perfused rat heart (Langendorff) preparation. Nicotine administration (100 microM) caused a brief decrease (-7 +/- 2%) followed by a much larger increase (17 +/- 5%) in heart rate that slowly returned to baseline within 10 to 15 min. The nicotine-induced decrease in heart rate could be abolished by an alpha7-specific antagonist, alpha-bungarotoxin (100 nM). In contrast, the nicotine-induced increase in heart rate persisted in the presence of alpha-bungarotoxin. These results suggest that the nicotinic acetylcholine receptors (nAChRs) that mediate the initial decrease in heart rate probably contain alpha7 subunits, whereas those that mediate the increase in heart rate probably do not contain alpha7 subunits. To investigate which subunits may contribute to the nicotine-induced increase in heart rate, we repeated our experiments with cytisine, an agonist at nAChRs that contain beta4 subunits. The cytisine results were similar to those obtained with nicotine, thereby suggesting that the nAChRs on sympathetic nerve terminals in the heart probably contain beta4 subunits. Thus, the results of this study show that pharmacologically distinct nAChRs are responsible for the differential effects of nicotine on heart rate. More specifically, our results suggest that alpha7 subunits participate in the initial nicotine-induced heart rate decrease, whereas beta4 subunits help to mediate the subsequent nicotine-induced rise in heart rate.

  19. Bombesin-like receptor 3 regulates blood pressure and heart rate via a central sympathetic mechanism.

    PubMed

    Lateef, Dalya M; Xiao, Cuiying; Brychta, Robert J; Diedrich, André; Schnermann, Jurgen; Reitman, Marc L

    2016-04-01

    Bombesin-like receptor 3 (BRS-3) is an orphan G protein-coupled receptor that regulates energy expenditure, food intake, and body weight. We examined the effects of BRS-3 deletion and activation on blood pressure and heart rate. In free-living, telemetered Brs3 null mice the resting heart rate was 10% lower than wild-type controls, while the resting mean arterial pressure was unchanged. During physical activity, the heart rate and blood pressure increased more in Brs3 null mice, reaching a similar heart rate and higher mean arterial pressure than control mice. When sympathetic input was blocked with propranolol, the heart rate of Brs3 null mice was unchanged, while the heart rate in control mice was reduced to the level of the null mice. The intrinsic heart rate, measured after both sympathetic and parasympathetic blockade, was similar in Brs3 null and control mice. Intravenous infusion of the BRS-3 agonist MK-5046 increased mean arterial pressure and heart rate in wild-type but not in Brs3 null mice, and this increase was blocked by pretreatment with clonidine, a sympatholytic, centrally acting α2-adrenergic agonist. In anesthetized mice, hypothalamic infusion of MK-5046 also increased both mean arterial pressure and heart rate. Taken together, these data demonstrate that BRS-3 contributes to resting cardiac sympathetic tone, but is not required for activity-induced increases in heart rate and blood pressure. The data suggest that BRS-3 activation increases heart rate and blood pressure via a central sympathetic mechanism.

  20. Clinical impact of evaluation of cardiovascular control by novel methods of heart rate dynamics.

    PubMed

    Huikuri, Heikki V; Perkiömäki, Juha S; Maestri, Roberto; Pinna, Gian Domenico

    2009-04-13

    Heart rate variability (HRV) has been conventionally analysed with time- and frequency-domain methods, which measure the overall magnitude of RR interval fluctuations around its mean value or the magnitude of fluctuations in some predetermined frequencies. Analysis of heart rate dynamics by novel methods, such as heart rate turbulence after ventricular premature beats, deceleration capacity of heart rate and methods based on chaos theory and nonlinear system theory, have gained recent interest. Recent observational studies have suggested that some indices describing nonlinear heart rate dynamics, such as fractal scaling exponents, heart rate turbulence and deceleration capacity, may provide useful prognostic information in various clinical settings and their reproducibility may be better than that of traditional indices. For example, the short-term fractal scaling exponent measured by the detrended fluctuation analysis method has been shown to predict fatal cardiovascular events in various populations. Similarly, heart rate turbulence and deceleration capacity have performed better than traditional HRV measures in predicting mortality in post-infarction patients. Approximate entropy, a nonlinear index of heart rate dynamics, which describes the complexity of RR interval behaviour, has provided information on the vulnerability to atrial fibrillation. There are many other nonlinear indices which also give information on the characteristics of heart rate dynamics, but their clinical usefulness is not as well established. Although the concepts of nonlinear dynamics, fractal mathematics and complexity measures of heart rate behaviour, heart rate turbulence, deceleration capacity in relation to cardiovascular physiology or various cardiovascular events are still far away from clinical medicine, they are a fruitful area for research to expand our knowledge concerning the behaviour of cardiovascular oscillations in normal healthy conditions as well as in disease states.

  1. Relationships between QT interval and heart rate variability at rest and the covariates in healthy young adults.

    PubMed

    Arai, Kaori; Nakagawa, Yui; Iwata, Toyoto; Horiguchi, Hyogo; Murata, Katsuyuki

    2013-01-01

    To clarify the links between ECG QT-related parameters and heart rate variability (HRV) and the covariates possibly distorting them, the averaged RR and QT intervals in a single lead ECG were measured for 64 male and 86 female subjects aged 18-26. The QT index, defined by Rautaharju et al., in the young adults was not significantly related to any HRV parameters nor heart rate, but the Bazett's corrected QT (QTc) interval was associated negatively with the parasympathetic activity and positively with heart rate. No significant differences in the QTc interval, QT index or heart rate were seen between the men and women, but they significantly differed between both sexes after adjustment for possible covariates such as age and body mass index (BMI). Significant sex differences in parasympathetic parameters of the HRV were unchanged before and after the adjustment, but significant differences observed in the unadjusted sympathetic parameters disappeared after adjusting for covariates. Age, BMI and body fat percentage also were significant covariates affecting these ECG parameters. Consequently, QT index, unaffected by heart rate and HRV parameters, appears to be a more useful indicator than the QTc interval. Instead, the QT index and HRV parameters are recommended to be simultaneously measured in epidemiological research because they are probably complementary in assessing autonomic nervous function. Also, these parameters should be analyzed in men and women separately.

  2. A particle filter framework for the estimation of heart rate from ECG signals corrupted by motion artifacts.

    PubMed

    Nathan, Viswam; Akkaya, Ilge; Jafari, Roozbeh

    2015-01-01

    In this work, we describe a methodology to probabilistically estimate the R-peak locations of an electrocardiogram (ECG) signal using a particle filter. This is useful for heart rate estimation, which is an important metric for medical diagnostics. Some scenarios require constant in-home monitoring using a wearable device. This poses a particularly challenging environment for heart rate detection, due to the susceptibility of ECG signals to motion artifacts. In this work, we show how the particle filter can effectively track the true R-peak locations amidst the motion artifacts, given appropriate heart rate and R-peak observation models. A particle filter based framework has several advantages due to its freedom from strict assumptions on signal and noise models, as well as its ability to simultaneously track multiple possible heart rate hypotheses. Moreover, the proposed framework is not exclusive to ECG signals and could easily be leveraged for tracking other physiological parameters. We describe the implementation of the particle filter and validate our approach on real ECG data affected by motion artifacts from the MIT-BIH noise stress test database. The average heart rate estimation error is about 5 beats per minute for signal streams contaminated with noisy segments with SNR as low as -6 dB. PMID:26737796

  3. Smartphone-based heart-rate measurement using facial images and a spatiotemporal alpha-trimmed mean filter.

    PubMed

    Lee, J-S; Lin, K-W; Syue, J-L

    2016-04-29

    Currently, cardiovascular disease affects a relatively high proportion of the world's population. Thus, developing simple and effective methods for monitoring patients with cardiovascular disease is critical for research. Monitoring the heart rate of patients is a relatively simple and effective method for managing patients with this condition. For patients, the desired heart rate monitoring equipment should be portable, instantaneous, and accurate. Because smartphones have become the most prevalent mobile device, we utilized this technology as a platform for developing a novel heart-rate measurement system. Catering to the phenomenon of people using the front camera of their smartphones as a mirror, the proposed system was designed to analyze facial-image sequences captured using the front camera. A spatiotemporal alpha-trimmed mean filter was developed to estimate a user's heart rate quickly and accurately. The experimental results show that in addition to achieving these objectives, the developed system outperforms a similar personal computer-based system. In addition, the system performs effectively even when users are wearing glasses. Hence, the proposed system demonstrates practical value for people who must monitor their heart rate daily. PMID:27177107

  4. The influence of mean heart rate on measures of heart rate variability as markers of autonomic function: a model study.

    PubMed

    Chiu, Hung-Wen; Wang, Ti-Ho; Huang, Lu-Chou; Tso, Han-Wen; Kao, Tsair

    2003-07-01

    Some studies have demonstrated that the assessments of autonomic activities from the alterations of heart rate variations (HRVs) after autonomic blockade and during exercise of high intensity by the spectral analysis of HRV seemed inconsistent with actual situation. The inconsistency is probably caused by the contributions of fluctuating magnitudes and mean levels of autonomic activities on HRV having not been clarified. The alterations of HRV after autonomic blockade and during exercise of high intensity using a mathematical model were simulated. The autonomic activity in normal condition was assumed first according to some experimental evidence. Then autonomic activities after sympathetic blockade, vagal blockade and during exercise of high intensity were appropriately adjusted accordingly. The HRVs in response to these given autonomic activities were simulated. We found that the effect on HRV influenced by the mean level of autonomic activity is helpful to explain alterations of HRV in these conditions. After vagal blockade, a largely reduced low frequency (LF) power could be caused by the reduced mean heartbeat interval induced by a decreased mean level of vagal activity. Increased low and high frequency powers after sympathetic blockade could be caused by the increased mean heartbeat interval induced by a decreased mean level of sympathetic activity. A decreased LF power during exercise of high intensity, in addition to the withdrawal of vagal activity, could also be caused by the decreased mean heartbeat interval induced by an increased mean level of sympathetic activity.

  5. Transcontinental and translational high-tech acupuncture research using computer-based heart rate and "Fire of Life" heart rate variability analysis.

    PubMed

    Litscher, Gerhard

    2010-09-01

    A variable heartbeat was considered a sign of good health by ancient Asian physicians. Today, new computer-based methods (e.g., "Fire of Life" analysis) allow quantification of heart rate and heart rate variability during acupuncture. The objective of this article is to compare different acupuncture methods to evaluate the influence of acupuncture on heart rhythm in short-term and long-term measurements. There were four main sections in this study: (A) a randomized controlled study using needle acupuncture and acupressure at Yintang (Ex1); (B) an innovative blue (violet) laser acupuncture randomized controlled study in Asian volunteers; (C) a comparative study using moxibustion methods; and (D) teleacupuncture. A total of 72 patients (mean age ± SD: 27.9 ± 8.6 years) were monitored over periods of 20 minutes to 24 hours in Asia and Austria. Acupuncture was performed with metal needles (in sections A, C and D) or blue laser (in section B) on Yintang, Neiguan, Guanyuan or a special acupuncture regimen for stress disorders (in sections A, B, C and D, respectively). Significant decreases in heart rate after verum intervention at Yintang, Neiguan and Guanyuan were found. Improvements in state of health following teleacupuncture were also noted. Computer-based heart rate and heart rate variability analysis was demonstrated to be effective in evaluating the status of health during acupuncture.

  6. Effects of electromagnetic radiation (bright light, extremely low-frequency magnetic fields, infrared radiation) on the circadian rhythm of melatonin synthesis, rectal temperature, and heart rate.

    PubMed

    Griefahn, Barbara; Künemund, Christa; Blaszkewicz, Meinolf; Lerchl, Alexander; Degen, Gisela H

    2002-10-01

    Electromagnetic spectra reduce melatonin production and delay the nadirs of rectal temperature and heart rate. Seven healthy men (16-22 yrs) completed 4 permuted sessions. The control session consisted of a 24-hours bedrest at < 30 lux, 18 degrees C, and < 50 dBA. In the experimental sessions, either light (1500 lux), magnetic field (16.7 Hz, 0.2 mT), or infrared radiation (65 degrees C) was applied from 5 pm to 1 am. Salivary melatonin level was determined hourly, rectal temperature and heart rate were continuously recorded. Melatonin synthesis was completely suppressed by light but resumed thereafter. The nadirs of rectal temperature and heart rate were delayed. The magnetic field had no effect. Infrared radiation elevated rectal temperature and heart rate. Only bright light affected the circadian rhythms of melatonin synthesis, rectal temperature, and heart rate, however, differently thus causing a dissociation, which might enhance the adverse effects of shiftwork in the long run.

  7. Helping from the heart: Voluntary upregulation of heart rate variability predicts altruistic behavior.

    PubMed

    Bornemann, Boris; Kok, Bethany E; Böckler, Anne; Singer, Tania

    2016-09-01

    Our various daily activities continually require regulation of our internal state. These regulatory processes covary with changes in High Frequency Heart Rate Variability (HF-HRV), a marker of parasympathetic activity. Specifically, incidental increases in HF-HRV accompany positive social engagement behavior and prosocial action. Little is known about deliberate regulation of HF-HRV and the role of voluntary parasympathetic regulation in prosocial behavior. Here, we present a novel biofeedback task that measures the ability to deliberately increase HF-HRV. In two large samples, we find that a) participants are able to voluntarily upregulate HF-HRV, and b) variation in this ability predicts individual differences in altruistic prosocial behavior, but not non-altruistic forms of prosociality, assessed through 14 different measures. Our findings suggest that self-induction of parasympathetic states is involved in altruistic action. The biofeedback task may provide a measure of deliberate parasympathetic regulation, with implications for the study of attention, emotion, and social behavior. PMID:27381930

  8. Heart rate regulation and extreme bradycardia in diving emperor penguins.

    PubMed

    Meir, Jessica U; Stockard, Torre K; Williams, Cassondra L; Ponganis, Katherine V; Ponganis, Paul J

    2008-04-01

    To investigate the diving heart rate (f(H)) response of the emperor penguin (Aptenodytes forsteri), the consummate avian diver, birds diving at an isolated dive hole in McMurdo Sound, Antarctica were outfitted with digital electrocardiogram recorders, two-axis accelerometers and time depth recorders (TDRs). In contrast to any other freely diving bird, a true bradycardia (f(H) significantly

  9. Estimating mental fatigue based on electroencephalogram and heart rate variability

    NASA Astrophysics Data System (ADS)

    Zhang, Chong; Yu, Xiaolin

    2010-01-01

    The effects of long term mental arithmetic task on psychology are investigated by subjective self-reporting measures and action performance test. Based on electroencephalogram (EEG) and heart rate variability (HRV), the impacts of prolonged cognitive activity on central nervous system and autonomic nervous system are observed and analyzed. Wavelet packet parameters of EEG and power spectral indices of HRV are combined to estimate the change of mental fatigue. Then wavelet packet parameters of EEG which change significantly are extracted as the features of brain activity in different mental fatigue state, support vector machine (SVM) algorithm is applied to differentiate two mental fatigue states. The experimental results show that long term mental arithmetic task induces the mental fatigue. The wavelet packet parameters of EEG and power spectral indices of HRV are strongly correlated with mental fatigue. The predominant activity of autonomic nervous system of subjects turns to the sympathetic activity from parasympathetic activity after the task. Moreover, the slow waves of EEG increase, the fast waves of EEG and the degree of disorder of brain decrease compared with the pre-task. The SVM algorithm can effectively differentiate two mental fatigue states, which achieves the maximum classification accuracy (91%). The SVM algorithm could be a promising tool for the evaluation of mental fatigue. Fatigue, especially mental fatigue, is a common phenomenon in modern life, is a persistent occupational hazard for professional. Mental fatigue is usually accompanied with a sense of weariness, reduced alertness, and reduced mental performance, which would lead the accidents in life, decrease productivity in workplace and harm the health. Therefore, the evaluation of mental fatigue is important for the occupational risk protection, productivity, and occupational health.

  10. Heart rate responses to Taekwondo training in experienced practitioners.

    PubMed

    Bridge, Craig A; Jones, Michelle A; Hitchen, Peter; Sanchez, Xavier

    2007-08-01

    The purpose of this study was to evaluate the heart rate (HR) responses of specific Taekwondo training activities, practiced by experienced practitioners in a natural training environment. Eight male experienced Taekwondo practitioners, with 3- 13 years (5.4 +/- 3.2 years) experience took part in a 5-day Taekwondo training camp. Continuous HR measures were recorded at 5-second intervals during 6 training sessions; each session was observed and notated, and a diary of training activities was recorded. The HR responses were assimilated into 8 fundamental training activities for analysis: elastics, technical combinations, step sparring, pad work, forms, basic techniques and forms, sparring drills, and free sparring. Taekwondo training elicited HR into 64.7-81.4% of HR maximum (%HRmax). Moderate relative exercise intensities (64.7-69.4%HRmax) were elicited by elastics, technical combinations, and step sparring. The remaining 5 training activities elicited hard relative exercise intensities (74.7-81.4%HRmax). One-way repeated-measures analysis of variance with post hoc analysis revealed that elastics, technical combinations, and step sparring elicited significantly lower relative intensities than the remaining training activities (p < 0.05). Furthermore, forms, basic techniques and forms, sparring drills, and free sparring elicited significantly higher relative intensities than the remaining training activities (p < 0.05). In conclusion, all Taekwondo training activities in this study seemed suitable for cardiovascular conditioning, although different training activities stressed the cardiovascular system to different degrees. Practically, this suggests coaches need to structure Taekwondo training sessions based not only on the technical and tactical needs of practitioners but also in a manner that enables sufficient cardiovascular conditioning for competition.

  11. Heart rate variability in childhood obstructive sleep apnea.

    PubMed

    Kwok, Ka-Li; Yung, Tak-Cheung; Ng, Daniel K; Chan, Chung-Hong; Lau, Wing-Fai; Fu, Yu-Ming

    2011-03-01

    The identification of patients with obstructive sleep apnea (OSA) is important because of morbidities associated with OSA. A previous adult study demonstrated the use of heart rate variability (HRV) as a tool to identify patients with moderate to severe OSA. Either a reduction in time parameters or an increase in LF/HF ratio was seen at overnight or 24-hr studies suggestive of increased sympathetic modulation. To study the feasibility of daytime HRV as a screening tool, a short-term recording of HRV is studied. Since it was shown in adult study that increased normalized LF, decreased normalized HF and increased LF/HF ratio could be detectable during supine rest at daytime awake period, the authors hypothesize that the differences are also detectable in children. Children who underwent sleep polysomnography for suspected OSA were recruited. Subjects were classified OSA if apnea-hypopnea index (AHI) > 1.5/hr and non-OSA if AHI ≤ 1.5/hr. Continuous 1-hr electrocardiographic monitoring was recorded in awake children during the day. Parameters from time domain and frequency domain were analyzed. Seventy-four male and 17 female snoring subjects were included in this study. Fifty-one (56%) and 40 (44%) of them were classified as "non-OSA" and "OSA," respectively. pNN50, a parameter for parasympathetic modulation, was significantly reduced in the OSA group when compared with the non-OSA group. Using multiple regression, all time domain variables were shown to be decreased in OSA group. Our results suggest that 1-hr study of HRV may be a feasible tool in identifying children with OSA.

  12. Does the Aging Process Significantly Modify the Mean Heart Rate?

    PubMed Central

    Santos, Marcos Antonio Almeida; Sousa, Antonio Carlos Sobral; Reis, Francisco Prado; Santos, Thayná Ramos; Lima, Sonia Oliveira; Barreto-Filho, José Augusto

    2013-01-01

    Background The Mean Heart Rate (MHR) tends to decrease with age. When adjusted for gender and diseases, the magnitude of this effect is unclear. Objective To analyze the MHR in a stratified sample of active and functionally independent individuals. Methods A total of 1,172 patients aged ≥ 40 years underwent Holter monitoring and were stratified by age group: 1 = 40-49, 2 = 50-59, 3 = 60-69, 4 = 70-79, 5 = ≥ 80 years. The MHR was evaluated according to age and gender, adjusted for Hypertension (SAH), dyslipidemia and non-insulin dependent diabetes mellitus (NIDDM). Several models of ANOVA, correlation and linear regression were employed. A two-tailed p value <0.05 was considered significant (95% CI). Results The MHR tended to decrease with the age range: 1 = 77.20 ± 7.10; 2 = 76.66 ± 7.07; 3 = 74.02 ± 7.46; 4 = 72.93 ± 7.35; 5 = 73.41 ± 7.98 (p < 0.001). Women showed a correlation with higher MHR (p <0.001). In the ANOVA and regression models, age and gender were predictors (p < 0.001). However, R2 and ETA2 < 0.10, as well as discrete standardized beta coefficients indicated reduced effect. Dyslipidemia, hypertension and DM did not influence the findings. Conclusion The MHR decreased with age. Women had higher values of MHR, regardless of the age group. Correlations between MHR and age or gender, albeit significant, showed the effect magnitude had little statistical relevance. The prevalence of SAH, dyslipidemia and diabetes mellitus did not influence the results. PMID:24029962

  13. Evaluation of heart rate changes: electrocardiographic versus photoplethysmographic methods

    NASA Technical Reports Server (NTRS)

    Low, P. A.; Opfer-Gehrking, T. L.; Zimmerman, I. R.; O'Brien, P. C.

    1997-01-01

    The heart rate (HR) variation to forced deep breathing (HRDB) and to the Valsalva maneuver (Valsalva ratio; VR) are the two most widely used tests of cardiovagal function in human subjects. The HR is derived from a continuously running electrocardiographic (ECG) recording. Recently, HR derived from the arterial waveform became available on the Finapres device (FinapHR), but its ability to detect rapid changes in HR remains uncertain. We therefore evaluated HRDB and VR derived from FinapHR using ECG-derived HR (ECGHR) recordings as the standard. We also compared the averaged HR on Finapres (Finapav) with beat-to-beat Finapres (FinapBB) values. Studies were undertaken in 12 subjects with large HR variations: age, 34.5 +/- 9.3 (SD) years; six males and six females. FinapBB values were superimposable upon ECGHR for both HRDB and VR. In contrast, Finapav failed to follow ECGHR for HRDB and followed HRECG with a lag for the VR. To evaluate statistically how closely FinapHR approximated ECGHR, we undertook regression analysis, using mean values for each subject. To compare the two methods, we evaluated the significance of the difference between test and standard values. For HRDB, FinapBB reproducibly recorded HR (R2 = 0.998), and was significantly (p = 0.001) better than Finapav (R2 = 0.616; p < 0.001). For VR, HRBB generated a VR that was not significantly different from the correct values, while HRav generated a value that was slightly but consistently lower than the correct values (p < 0.001). We conclude that FinapHR reliably records HR variations in the beat-to-beat mode for cardiovascular HR tests.

  14. Heart rate variability in familial Mediterranean fever patients

    PubMed Central

    Kaya, Hakan; Süner, Arif; Köroğlu, Sedat; Akçay, Ahmet; Türkbeyler, İbrahim Halil; Köleoğlu, Murat

    2014-01-01

    Objective Familial Mediterranean fever (FMF) is an autosomal recessive autoimmune disease, presenting with the attacks of fever and inflammation of serous membranes. One of the leading causes of death in autoimmune rheumatologic diseases is cardiovascular events. The purpose of this study is to evaluate the effects of FMF on the autonomic nerve and cardiovascular systems by measuring the indices of heart rate variability (HRV). Material and Methods Thirty FMF patients and the same number of healthy volunteers were enrolled to the study. Standard deviation of all R-R intervals (SDNN), the square root of the sum of the square of the differences between successive R-R intervals (RMSSD), standard deviation of 5-minute mean values of R-R interval (SDANN), low frequency (LF), and high frequency (HF) were measured. Results Time domain indices (SDNN, SDANN, and RMSSD) were: 124.67±40.79, 129.87±36.43 (p=0.605); 11.43±38.41, 11.23±38.98 (p=0.984); and 33.43±17.39, 38.17±12.8 (p=0.235) for FMF patients and controls, respectively, and similar in both groups. Frequency domain indices (HF, LF, and LF/HF) were: 290.41±290.25, 322.20±222.54 (p=0.639); 596.16±334.07, 805.80±471.00 (p=0.051); and 3.57±2.57, 3.05±1.40 (p=0.338) for FMF patients and controls, respectively, and similar in both groups. Conclusion The HRV parameters were similar in both groups. However, studies including larger populations and using different methods are required to clarify if autonomic dysfunction exists in patients with FMF.

  15. Heart rate variability in normal and pathological sleep

    PubMed Central

    Tobaldini, Eleonora; Nobili, Lino; Strada, Silvia; Casali, Karina R.; Braghiroli, Alberto; Montano, Nicola

    2013-01-01

    Sleep is a physiological process involving different biological systems, from molecular to organ level; its integrity is essential for maintaining health and homeostasis in human beings. Although in the past sleep has been considered a state of quiet, experimental and clinical evidences suggest a noteworthy activation of different biological systems during sleep. A key role is played by the autonomic nervous system (ANS), whose modulation regulates cardiovascular functions during sleep onset and different sleep stages. Therefore, an interest on the evaluation of autonomic cardiovascular control in health and disease is growing by means of linear and non-linear heart rate variability (HRV) analyses. The application of classical tools for ANS analysis, such as HRV during physiological sleep, showed that the rapid eye movement (REM) stage is characterized by a likely sympathetic predominance associated with a vagal withdrawal, while the opposite trend is observed during non-REM sleep. More recently, the use of non-linear tools, such as entropy-derived indices, have provided new insight on the cardiac autonomic regulation, revealing for instance changes in the cardiovascular complexity during REM sleep, supporting the hypothesis of a reduced capability of the cardiovascular system to deal with stress challenges. Interestingly, different HRV tools have been applied to characterize autonomic cardiac control in different pathological conditions, from neurological sleep disorders to sleep disordered breathing (SDB). In summary, linear and non-linear analysis of HRV are reliable approaches to assess changes of autonomic cardiac modulation during sleep both in health and diseases. The use of these tools could provide important information of clinical and prognostic relevance. PMID:24137133

  16. Heart Rate Variability: A Risk Factor for Female Sexual Dysfunction.

    PubMed

    Stanton, Amelia M; Lorenz, Tierney A; Pulverman, Carey S; Meston, Cindy M

    2015-09-01

    Heart rate variability (HRV) is a measure of autonomic nervous system activity, which reflects an individual's ability to adapt to physiological and environmental changes. Low resting HRV has been linked to several mental health conditions, including depression, anxiety, and alcohol dependence (Kemp et al. in Biological Psychiatry 67(11):1067-1074, 2010. doi:10.1016/j.biopsych.2009.12.012; Kemp et al. in PloS One, 7(2):e30777, 2012; Quintana et al. in Drug and Alcohol Dependence, 132(1-2):395-398, 2013. doi:10.1016/j.drugalcdep.2013.02.025). HRV has also been used as a method for indexing the relative balance of sympathetic nervous system (SNS) activity to parasympathetic nervous system activity. This balance--in particular, moderately dominant SNS activity--has been shown to play a significant role in women's genital sexual arousal in the laboratory; however, the role of SNS activity in clinically relevant sexual arousal function is unknown. The present study assessed the feasibility of using HRV as an index of women's self-reported sexual arousal function outside the laboratory. Sexual arousal function, overall sexual function, and resting HRV were assessed in 72 women, aged 18-39. Women with below average HRV were significantly more likely to report sexual arousal dysfunction (p < .001) and overall sexual dysfunction (p < .001) than both women with average HRV and women with above average HRV. In conclusion, low HRV may be a risk factor for female sexual arousal dysfunction and overall sexual dysfunction. PMID:26081002

  17. Cross-country skiing and postexercise heart-rate recovery.

    PubMed

    Mourot, Laurent; Fabre, Nicolas; Andersson, Erik; Willis, Sarah; Buchheit, Martin; Holmberg, Hans-Christer

    2015-01-01

    Postexercise heart-rate (HR) recovery (HRR) indices have been associated with running and cycling endurance-exercise performance. The current study was designed (1) to test whether such a relationship also exists in the case of cross-country skiing (XCS) and (2) to determine whether the magnitude of any such relationship is related to the intensity of exercise before obtaining HRR indices. Ten elite male cross-country skiers (mean ± SD; 28.2 ± 5.4 y, 181 ± 8 cm, 77.9 ± 9.4 kg, 69.5 ± 4.3 mL · min-1 · kg-1 maximal oxygen uptake [VO2max]) performed 2 sessions of roller-skiing on a treadmill: a 2 × 3-km time trial and the same 6-km at an imposed submaximal speed followed by a final 800-m time trial. VO2 and HR were monitored continuously, while HRR and blood lactate (BLa) were assessed during 2 min immediately after each 6-km and the 800-m time trial. The 6-km time-trial time was largely negatively correlated with VO2max and BLa. On the contrary, there was no clear correlation between the 800-m time-trial time and VO2, HR, or BLa. In addition, in no case was any clear correlation between any of the HRR indices and performance time or VO2max observed. These findings confirm that XCS performance is largely correlated with VO2max and the ability to tolerate high levels of BLa; however, postexercise HRR showed no clear association with performance. The homogeneity of the group of athletes involved and the contribution of the arms and upper body to the exercise preceding determination of HRR may explain this absence of a relationship.

  18. Categorizing Fetal Heart Rate Variability with and without Visual Aids

    PubMed Central

    Ashdown, Amanda J.; Scerbo, Mark W.; Belfore, Lee A.; Davis, Stephen S.; Abuhamad, Alfred Z.

    2016-01-01

    Objective This study examined the ability of clinicians to correctly categorize images of fetal heart rate (FHR) variability with and without the use of exemplars. Study Design A sample of 33 labor and delivery clinicians inspected static FHR images and categorized them into one of four categories defined by the National Institute of Child Health and Human Development (NICHD) based on the amount of variability within absent, minimal, moderate, or marked ranges. Participants took part in three conditions: two in which they used exemplars representing FHR variability near the center or near the boundaries of each range, and a third control condition with no exemplars. The data gathered from clinicians were compared with those from a previous study using novices. Results Clinicians correctly categorized more images when the FHR variability fell near the center rather than the boundaries of each range, F (1,32) = 71.69, p < 0.001, partial η2 = 0.69. They also correctly categorized more images when exemplars were available, F (2,64) = 5.44, p = 0.007, partial η2 = 0.15. Compared with the novices, the clinicians were more accurate and quicker in their category judgments, but this difference was limited to the condition without exemplars. Conclusion The results suggest that categorizing FHR variability is more difficult when the examples fall near the boundaries of each NICHD-defined range. Thus, clinicians could benefit from training with visual aids to improve judgments about FHR variability and potentially enhance safety in labor and delivery. PMID:27722031

  19. Cardiorespiratory fitness and heart rate recovery in obese premenopausal women.

    PubMed

    Carroll, S; Marshall, P; Ingle, L; Borkoles, E

    2012-12-01

    Post-exercise heart rate recovery (HRR) has been proposed as a measure of cardiac autonomic dysfunction in apparently healthy adults. We aimed to determine the effects of a lifestyle intervention on HRR among clinically obese premenopausal women. A randomized controlled trial was conducted to investigate the effects of a 3-month non-dieting lifestyle intervention program on cardiorespiratory fitness (CRF) and HRR among healthy clinically obese premenopausal women. Thirty-one were randomly assigned to 3-month intensive lifestyle intervention and 31 served as controls. Sixty-one participants performed a maximal treadmill walking test with metabolic gas exchange. Baseline anthropometric measures were closely related to HRR at 1 min, which may indicate reduced parasympathetic reactivation. Post-exercise HRR at 60 s (HRR60) increased from 21.3 ± 6.2 to 27.8 ± 10.2 bpm in the intervention group compared with a smaller reduction (26.8 ± 12.3 to 24.5 ± 9.9 bpm) in controls (test for interaction P = 0.0001). HRR120 showed a significant effect of time (P = 0.0002) with no significant interaction with lifestyle intervention. A significant increase in VO2 peak was evident in the lifestyle group (21.6 to 23.6 mL/kg/min) compared with a modest reduction in the controls (22.6 to 21.6 mL/kg/min; test for interaction, P = 0.001). Clinically obese healthy premenopausal women achieved significant improvements in HRR60 and VO peak following a 3-month intensive lifestyle intervention.

  20. Heart Rate Level and Antisocial Behavior in Children and Adolescents: A Meta-Analysis

    ERIC Educational Resources Information Center

    Ortiz, Jame; Raine, Adrian

    2004-01-01

    Objective: To assess whether antisocial children are characterized by low heart rate. Method: A meta-analysis was conducted on 45 independent effect sizes of the resting heart rate-antisocial behavior relationship obtained from 40 studies meeting inclusion and exclusion criteria. Studies were conducted between 1971 to 2002 using a total of 5,868…

  1. [Clinical and diagnostic value of heart rate variabilities in workers exposed to noise and vibration].

    PubMed

    Serebriakov, P V; Melent'ev, A V; Demina, I D

    2010-01-01

    Noise and vibration cause disorders of vegetative regulation of cardiovascular system. Daily ECG monitoring with heart rate variabilities analysis enables quanitative evaluation of disordered vegetative control over heart rate and diagnosis of cardioneuropathy caused by long occupational exposure to noise and vibration. PMID:20857555

  2. Cardiovascular Fitness and Maximal Heart Rate Differences Among Three Ethnic Groups.

    ERIC Educational Resources Information Center

    Farrell, S. W.

    1988-01-01

    Examination of differences in maximal heart rate and treadmill time among three ethnic groups revealed no significant age-adjusted differences among white, black, and Mexican-American males, and suggested that black females' lower maximal heart rate may be explained by their lower cardiovascular fitness level when compared to those of other…

  3. Heart Rates of Elementary Physical Education Students during the Dancing Classrooms Program

    ERIC Educational Resources Information Center

    Nelson, Larry; Evans, Melissa; Guess, Wendy; Morris, Mary; Olson, Terry; Buckwalter, John

    2011-01-01

    We examined how different types of dance activities, along with their duration, influenced heart rate responses among fifth-grade physical education students (N = 96) who participated in the Dancing Classrooms program. Results indicated that the overall Dancing Classrooms program elicits a moderate cardiovascular heart rate response (M = 124.4…

  4. The Influence of Motor Impairment on Autonomic Heart Rate Modulation among Children with Cerebral Palsy

    ERIC Educational Resources Information Center

    Zamuner, Antonio Roberto; Cunha, Andrea Baraldi; da Silva, Ester; Negri, Ana Paola; Tudella, Eloisa; Moreno, Marlene Aparecida

    2011-01-01

    The study of heart rate variability is an important tool for a noninvasive evaluation of the neurocardiac integrity. The present study aims to evaluate the autonomic heart rate modulation in supine and standing positions in 12 children diagnosed with cerebral palsy and 16 children with typical motor development (control group), as well as to…

  5. Middle School Student's Heart Rates during Different Curricular Activities in Physical Education

    ERIC Educational Resources Information Center

    Gao, Zan; Hannon, James C.; Carson, Russell L.

    2009-01-01

    The purpose of this study was to determine if students' heart rate outcomes in physical education varied as a function of activity and grade. A total of 146 sixth to eighth graders participated in different activities (i.e., walking/jogging, line dancing, soccer, and catch ball). Their average heart rate (AHR) and percentage of time in and above…

  6. Effects of exogenous changes in heart rate on facilitation of thought and resistance to persuasion.

    PubMed

    Cacioppo, J T

    1979-04-01

    Two experiments were conducted to examine the effects of an accelerated heart rate on information processing and resistance to persuasion. Experiment 1 addressed the effects on cognitive performance of manipulating heart rate exogenously for brief periods of time. Fourteen subjects wearing implanted demand-type cardiac pacemakers performed reading comprehension and sentence generation tasks while their heart rate was either accelerated or not accelerated. Results revealed that performance was better when heart rate was accelerated than when it was not accelerated. Experiment 2 addressed the effects on counterargumentation and resistance to persuasion of manipulating heart rate using the cardiac-pacing technique employed in Experiment 1. Subjects read highly involving counterattitudinal communications while their heart rate was either ostensibly or actually accelerated. Accelerated heart rate resulted in the generation of more total thoughts and counterarguments than did basal heart rate; resistance to persuasion was related significantly to the number of counterarguments generated. The methodology used provides a means by which social psychologists can study the effects on social processes of actual but unperceived changes in physiological processes. PMID:448631

  7. Effects of head-down bed rest on complex heart rate variability: Response to LBNP testing

    NASA Technical Reports Server (NTRS)

    Goldberger, Ary L.; Mietus, Joseph E.; Rigney, David R.; Wood, Margie L.; Fortney, Suzanne M.

    1994-01-01

    Head-down bed rest is used to model physiological changes during spaceflight. We postulated that bed rest would decrease the degree of complex physiological heart rate variability. We analyzed continuous heart rate data from digitized Holter recordings in eight healthy female volunteers (age 28-34 yr) who underwent a 13-day 6 deg head-down bed rest study with serial lower body negative pressure (LBNP) trials. Heart rate variability was measured on a 4-min data sets using conventional time and frequency domain measures as well as with a new measure of signal 'complexity' (approximate entropy). Data were obtained pre-bed rest (control), during bed rest (day 4 and day 9 or 11), and 2 days post-bed rest (recovery). Tolerance to LBNP was significantly reduced on both bed rest days vs. pre-bed rest. Heart rate variability was assessed at peak LBNP. Heart rate approximate entropy was significantly decreased at day 4 and day 9 or 11, returning toward normal during recovery. Heart rate standard deviation and the ratio of high- to low-power frequency did not change significantly. We conclude that short-term bed rest is associated with a decrease in the complex variability of heart rate during LBNP testing in healthy young adult women. Measurement of heart rate complexity, using a method derived from nonlinear dynamics ('chaos theory'), may provide a sensitive marker of this loss of physiological variability, complementing conventional time and frequency domain statistical measures.

  8. Developmental Change in Feedback Processing as Reflected by Phasic Heart Rate Changes

    ERIC Educational Resources Information Center

    Crone, Eveline A.; Jennings, J. Richard; Van der Molen, Maurits W.

    2004-01-01

    Heart rate was recorded from 3 age groups (8-10, 12, and 20-26 years) while they performed a probabilistic learning task. Stimuli had to be sorted by pressing a left versus right key, followed by positive or negative feedback. Adult heart rate slowed following negative feedback when stimuli were consistently mapped onto the left or right key…

  9. Catecholamine effects on blood pressure and heart rate in the American bullfrog, Rana catesbeiana.

    PubMed

    Herman, C A; Sandoval, E J

    1983-10-01

    The effects of catecholamines and adrenergic blocking agents were studied in vivo on the blood pressure and heart rate of the unanaesthetized American bullfrog, Rana catesbeiana. Bullfrogs were chronically cannulated with a T cannula in the right sciatic artery. The mean systemic arterial blood pressure prior to the infusion of catecholamines was 18.5 +/- 1.5 mm Hg. Mean preinfusion heart rate was 30.9 +/- 2.0 beats/min. Epinephrine elicited the largest increase in blood pressure, with an accompanying decrease in heart rate. Norepinephrine and phenylephrine were less effective. Isoproterenol was the only catecholamine tested which elevated heart rate in a dose-dependent manner. It had no effect on blood pressure. The beta adrenergic antagonist, propranolol, blocked the increase in heart rate elicited by isoproterenol but had no effect on the blood pressure increases elicited by the other catecholamines. The alpha adrenergic antagonist, phentolamine, partially blocked the blood pressure increase by epinephrine, norepinephrine, and phenylephrine as well as the elevation of heart rate by isoproterenol. Atropine alone elevated heart rate 19 +/- 3 beats/min, and prevented slowing of the heart due to epinephrine, norepinephrine, and phenylephrine. Stimulatory effects of epinephrine on heart rate were observed only after atropine had been administered. Beta adrenergic receptors, therefore, appear to function in heart rate regulation; however, the predominant effect of catecholamines is reflex slowing of the heart due to stimulation of the vagus nerve. In contrast, the alpha receptor, stimulated by epinephrine, appears to be the main adrenergic receptor controlling blood pressure changes.

  10. Optogenetic stimulation of Drosophila heart rate at different temperatures and Ca2+ concentrations.

    PubMed

    Zhu, Yue C; Uradu, Henry; Majeed, Zana R; Cooper, Robin L

    2016-02-01

    Optogenetics is a revolutionary technique that enables noninvasive activation of electrically excitable cells. In mammals, heart rate has traditionally been modulated with pharmacological agents or direct stimulation of cardiac tissue with electrodes. However, implanted wires have been known to cause physical damage and damage from electrical currents. Here, we describe a proof of concept to optically drive cardiac function in a model organism, Drosophila melanogaster. We expressed the light sensitive channelrhodopsin protein ChR2.XXL in larval Drosophila hearts and examined light-induced activation of cardiac tissue. After demonstrating optical stimulation of larval heart rate, the approach was tested at low temperature and low calcium levels to simulate mammalian heart transplant conditions. Optical activation of ChR2.XXL substantially increased heart rate in all conditions. We have developed a system that can be instrumental in characterizing the physiology of optogenetically controlled cardiac function with an intact heart. PMID:26834237

  11. Heart rate and blood pressure variability in cardiac diseases: pharmacological implications.

    PubMed

    Cloarec-Blanchard, L

    1997-01-01

    Even at rest, blood pressure and heart fluctuate continuously around their mean values. Considerable interest has recently focused on the assessment of spontaneous in fluctuations in heart rate and blood pressure, i.e., heart rate and blood pressure variability, using time or frequency domain indexes. Heart rate variability has been extensively studied in cardiovascular disease and has emerged as a valuable parameter for detecting abnormalities in autonomic cardiovascular control, evaluating the prognosis and assessing the impact of drug therapy on the autonomic nervous system in patients with myocardial infarction, congestive heart failure or a heart transplant. In contrast, until the recent development of noninvasive methods for continuous blood pressure recording, blood pressure variability received little attention, and this parameter remains to be evaluated in cardiovascular disease.

  12. The occurrence of individual slow waves in sleep is predicted by heart rate.

    PubMed

    Mensen, Armand; Zhang, Zhongxing; Qi, Ming; Khatami, Ramin

    2016-07-22

    The integration of near-infrared spectroscopy and electroencephalography measures presents an ideal method to study the haemodynamics of sleep. While the cortical dynamics and neuro-modulating influences affecting the transition from wakefulness to sleep is well researched, the assumption has been that individual slow waves, the hallmark of deep sleep, are spontaneously occurring cortical events. By creating event-related potentials from the NIRS recording, time-locked to the onset of thousands of individual slow waves, we show the onset of slow waves is phase-locked to an ongoing oscillation in the NIRS recording. This oscillation stems from the moment to moment fluctuations of light absorption caused by arterial pulsations driven by the heart beat. The same oscillating signal can be detected if the electrocardiogram is time-locked to the onset of the slow wave. The ongoing NIRS oscillation suggests that individual slow wave initiation is dependent on that signal, and not the other way round. However, the precise causal links remain speculative. We propose several potential mechanisms: that the heart-beat or arterial pulsation acts as a stimulus which evokes a down-state; local fluctuations in energy supply may lead to a network effect of hyperpolarization; that the arterial pulsations lead to corresponding changes in the cerebral-spinal-fluid which evokes the slow wave; or that a third neural generator, regulating heart rate and slow waves may be involved.

  13. The occurrence of individual slow waves in sleep is predicted by heart rate

    PubMed Central

    Mensen, Armand; Zhang, Zhongxing; Qi, Ming; Khatami, Ramin

    2016-01-01

    The integration of near-infrared spectroscopy and electroencephalography measures presents an ideal method to study the haemodynamics of sleep. While the cortical dynamics and neuro-modulating influences affecting the transition from wakefulness to sleep is well researched, the assumption has been that individual slow waves, the hallmark of deep sleep, are spontaneously occurring cortical events. By creating event-related potentials from the NIRS recording, time-locked to the onset of thousands of individual slow waves, we show the onset of slow waves is phase-locked to an ongoing oscillation in the NIRS recording. This oscillation stems from the moment to moment fluctuations of light absorption caused by arterial pulsations driven by the heart beat. The same oscillating signal can be detected if the electrocardiogram is time-locked to the onset of the slow wave. The ongoing NIRS oscillation suggests that individual slow wave initiation is dependent on that signal, and not the other way round. However, the precise causal links remain speculative. We propose several potential mechanisms: that the heart-beat or arterial pulsation acts as a stimulus which evokes a down-state; local fluctuations in energy supply may lead to a network effect of hyperpolarization; that the arterial pulsations lead to corresponding changes in the cerebral-spinal-fluid which evokes the slow wave; or that a third neural generator, regulating heart rate and slow waves may be involved. PMID:27445083

  14. Natriuretic Peptides as Cardiovascular Safety Biomarkers in Rats: Comparison With Blood Pressure, Heart Rate, and Heart Weight.

    PubMed

    Engle, Steven K; Watson, David E

    2016-02-01

    Cardiovascular (CV) toxicity is an important cause of failure during drug development. Blood-based biomarkers can be used to detect CV toxicity during preclinical development and prioritize compounds at lower risk of causing such toxicities. Evidence of myocardial degeneration can be detected by measuring concentrations of biomarkers such as cardiac troponin I and creatine kinase in blood; however, detection of functional changes in the CV system, such as blood pressure, generally requires studies in animals with surgically implanted pressure transducers. This is a significant limitation because sustained changes in blood pressure are often accompanied by changes in heart rate and together can lead to cardiac hypertrophy and myocardial degeneration in animals, and major adverse cardiovascular events (MACE) in humans. Increased concentrations of NPs in blood correlate with higher risk of cardiac mortality, all-cause mortality, and MACE in humans. Their utility as biomarkers of CV function and toxicity in rodents was investigated by exploring the relationships between plasma concentrations of NTproANP and NTproBNP, blood pressure, heart rate, and heart weight in Sprague Dawley rats administered compounds that caused hypotension or hypertension, including nifedipine, fluprostenol, minoxidil, L-NAME, L-thyroxine, or sunitinib for 1-2 weeks. Changes in NTproANP and/or NTproBNP concentrations were inversely correlated with changes in blood pressure. NTproANP and NTproBNP concentrations were inconsistently correlated with relative heart weights. In addition, increased heart rate was associated with increased heart weights. These studies support the use of natriuretic peptides and heart rate to detect changes in blood pressure and cardiac hypertrophy in short-duration rat studies. PMID:26609138

  15. Simultaneous measurement of breathing rate and heart rate using a microbend multimode fiber optic sensor

    NASA Astrophysics Data System (ADS)

    Chen, Zhihao; Lau, Doreen; Teo, Ju Teng; Ng, Soon Huat; Yang, Xiufeng; Kei, Pin Lin

    2014-05-01

    We propose and demonstrate the feasibility of using a highly sensitive microbend multimode fiber optic sensor for simultaneous measurement of breathing rate (BR) and heart rate (HR). The sensing system consists of a transceiver, microbend multimode fiber, and a computer. The transceiver is comprised of an optical transmitter, an optical receiver, and circuits for data communication with the computer via Bluetooth. Comparative experiments conducted between the sensor and predicate commercial physiologic devices showed an accuracy of ±2 bpm for both BR and HR measurement. Our preliminary study of simultaneous measurement of BR and HR in a clinical trial conducted on 11 healthy subjects during magnetic resonance imaging (MRI) also showed very good agreement with measurements obtained from conventional MR-compatible devices.

  16. Comparison of body composition, heart rate variability, aerobic and anaerobic performance between competitive cyclists and triathletes.

    PubMed

    Arslan, Erşan; Aras, Dicle

    2016-04-01

    [Purpose] The aim of this study was to compare the body composition, heart rate variability, and aerobic and anaerobic performance between competitive cyclists and triathletes. [Subjects] Six cyclists and eight triathletes with experience in competitions voluntarily participated in this study. [Methods] The subjects' body composition was measured with an anthropometric tape and skinfold caliper. Maximal oxygen consumption and maximum heart rate were determined using the incremental treadmill test. Heart rate variability was measured by 7 min electrocardiographic recording. The Wingate test was conducted to determine anaerobic physical performance. [Results] There were significant differences in minimum power and relative minimum power between the triathletes and cyclists. Anthropometric characteristics and heart rate variability responses were similar among the triathletes and cyclists. However, triathletes had higher maximal oxygen consumption and lower resting heart rates. This study demonstrated that athletes in both sports have similar body composition and aerobic performance characteristics. PMID:27190476

  17. Comparison of body composition, heart rate variability, aerobic and anaerobic performance between competitive cyclists and triathletes

    PubMed Central

    Arslan, Erşan; Aras, Dicle

    2016-01-01

    [Purpose] The aim of this study was to compare the body composition, heart rate variability, and aerobic and anaerobic performance between competitive cyclists and triathletes. [Subjects] Six cyclists and eight triathletes with experience in competitions voluntarily participated in this study. [Methods] The subjects’ body composition was measured with an anthropometric tape and skinfold caliper. Maximal oxygen consumption and maximum heart rate were determined using the incremental treadmill test. Heart rate variability was measured by 7 min electrocardiographic recording. The Wingate test was conducted to determine anaerobic physical performance. [Results] There were significant differences in minimum power and relative minimum power between the triathletes and cyclists. Anthropometric characteristics and heart rate variability responses were similar among the triathletes and cyclists. However, triathletes had higher maximal oxygen consumption and lower resting heart rates. This study demonstrated that athletes in both sports have similar body composition and aerobic performance characteristics. PMID:27190476

  18. Effect of suprachiasmatic lesions on diurnal heart rate rhythm in the rat

    NASA Technical Reports Server (NTRS)

    Saleh, M. A.; Winget, C. M.

    1977-01-01

    Heart rate and locomotor activity of rats kept under 12L/12D illumination regimen were recorded every six minutes for ten days using implantable radio transmitters. Some of the rats then received bilateral RF lesions into the suprachiasmatic nucleus (SCN). Control sham operations were performed on the rest of the animals. After recovery from surgery, recording of heart rate and locomotor activity was continued for ten days. SCN-lesioned rats showed no significant diurnal fluctuation in heart rate, while normal and sham-operated rats showed the normal diurnal rhythm in that function. The arrhythmic diurnal heart-rate pattern of SCN rats appeared to be correlated with their sporadic activity pattern. The integrity of the suprachiasmatic nucleus is therefore necessary for the generation and/or expression of diurnal rhythmicity in heart rate in the rat.

  19. Unobtrusive heart rate estimation during physical exercise using photoplethysmographic and acceleration data.

    PubMed

    Mullan, Patrick; Kanzler, Christoph M; Lorch, Benedikt; Schroeder, Lea; Winkler, Ludwig; Laich, Larissa; Riedel, Frederik; Richer, Robert; Luckner, Christoph; Leutheuser, Heike; Eskofier, Bjoern M; Pasluosta, Cristian

    2015-08-01

    Photoplethysmography (PPG) is a non-invasive, inexpensive and unobtrusive method to achieve heart rate monitoring during physical exercises. Motion artifacts during exercise challenge the heart rate estimation from wrist-type PPG signals. This paper presents a methodology to overcome these limitation by incorporating acceleration information. The proposed algorithm consisted of four stages: (1) A wavelet based denoising, (2) an acceleration based denoising, (3) a frequency based approach to estimate the heart rate followed by (4) a postprocessing step. Experiments with different movement types such as running and rehabilitation exercises were used for algorithm design and development. Evaluation of our heart rate estimation showed that a mean absolute error 1.96 bpm (beats per minute) with standard deviation of 2.86 bpm and a correlation of 0.98 was achieved with our method. These findings suggest that the proposed methodology is robust to motion artifacts and is therefore applicable for heart rate monitoring during sports and rehabilitation. PMID:26737687

  20. Algorithm for heart rate extraction in a novel wearable acoustic sensor.

    PubMed

    Chen, Guangwei; Imtiaz, Syed Anas; Aguilar-Pelaez, Eduardo; Rodriguez-Villegas, Esther

    2015-02-01

    Phonocardiography is a widely used method of listening to the heart sounds and indicating the presence of cardiac abnormalities. Each heart cycle consists of two major sounds - S1 and S2 - that can be used to determine the heart rate. The conventional method of acoustic signal acquisition involves placing the sound sensor at the chest where this sound is most audible. Presented is a novel algorithm for the detection of S1 and S2 heart sounds and the use of them to extract the heart rate from signals acquired by a small sensor placed at the neck. This algorithm achieves an accuracy of 90.73 and 90.69%, with respect to heart rate value provided by two commercial devices, evaluated on more than 38 h of data acquired from ten different subjects during sleep in a pilot clinical study. This is the largest dataset for acoustic heart sound classification and heart rate extraction in the literature to date. The algorithm in this study used signals from a sensor designed to monitor breathing. This shows that the same sensor and signal can be used to monitor both breathing and heart rate, making it highly useful for long-term wearable vital signs monitoring.

  1. Changes in heart rate variability associated with acute alcohol consumption: current knowledge and implications for practice and research.

    PubMed

    Romanowicz, Magdalena; Schmidt, John E; Bostwick, John M; Mrazek, David A; Karpyak, Victor M

    2011-06-01

    Alcohol consumption is associated with a broad array of physiologic and behavioral effects including changes in heart rate. However, the physiologic mechanisms of alcohol effects and the reasons for individual differences in the cardiac response remain unknown. Measuring changes in resting heart rate (measured as beats/min) has not been found to be as sensitive to alcohol's effects as changes in heart rate variability (HRV). HRV is defined as fluctuations in interbeat interval length which reflect the heart's response to extracardiac factors that affect heart rate. HRV allows simultaneous assessment of both sympathetic and parasympathetic activity and the interplay between them. Increased HRV has been associated with exercise and aerobic fitness, while decreased HRV has been associated with aging, chronic stress, and a wide variety of medical and psychiatric disorders. Decreased HRV has predictive value for mortality in general population samples and patients with myocardial infarction and used as an indicator of altered autonomic function. A significant inverse correlation was found between HRV and both the severity of depression and the duration of the depressive episode. HRV analysis provides insights into mechanisms of autonomic regulation and is extensively used to clarify relationships between depression and cardiovascular disease. This article will review the methodology of HRV measurements and contemporary knowledge about effects of acute alcohol consumption on HRV. Potential implications of this research include HRV response to alcohol that could serve as a marker for susceptibility to alcoholism. At present however there is almost no research data supporting this hypothesis. PMID:21332532

  2. [Body composition and heart rate variability in patients with chronic obstructive pulmonary disease pulmonary rehabilitation candidates].

    PubMed

    Curilem Gatica, Cristian; Almagià Flores, Atilio; Yuing Farías, Tuillang; Rodríguez Rodríguez, Fernando

    2014-07-01

    Body composition is a non-invasive method, which gives us information about the distribution of tissues in the body structure, it is also an indicator of the risk of mortality in patients with chronic obstructive pulmonary disease. The heart rate variability is a technique that gives us information of autonomic physiological condition, being recognized as an indicator which is decreased in a number of diseases. The purpose of this study was to assess body composition and heart rate variability. The methodology used is that of Debora Kerr (1988) endorsed by the International Society for advances in Cineantropometría for body composition and heart rate variability of the guidelines described by the American Heart Association (1996). Roscraff equipment, caliper Slimguide and watch Polar RS 800CX was used. , BMI 26.7 ± 3.9 kg / m²; Muscle Mass 26.1 ± 6.3 kg ; Bone Mass 1.3 kg ± 8.1 76 ± 9.9 years Age : 14 candidates for pulmonary rehabilitation patients were evaluated , Adipose mass 16.4 ± 3.6 kg ; FEV1 54 ± 14%. Increased waist circumference and waist hip ratio was associated with a lower overall heart rate variability. The bone component was positively related to the variability of heart rate and patients with higher forced expiratory volume in one second had lower high frequency component in heart rate variability. In these patients, the heart rate variability is reduced globally and is associated with cardiovascular risk parameters.

  3. Conventional heart rate variability analysis of ambulatory electrocardiographic recordings fails to predict imminent ventricular fibrillation

    NASA Technical Reports Server (NTRS)

    Vybiral, T.; Glaeser, D. H.; Goldberger, A. L.; Rigney, D. R.; Hess, K. R.; Mietus, J.; Skinner, J. E.; Francis, M.; Pratt, C. M.

    1993-01-01

    OBJECTIVES. The purpose of this report was to study heart rate variability in Holter recordings of patients who experienced ventricular fibrillation during the recording. BACKGROUND. Decreased heart rate variability is recognized as a long-term predictor of overall and arrhythmic death after myocardial infarction. It was therefore postulated that heart rate variability would be lowest when measured immediately before ventricular fibrillation. METHODS. Conventional indexes of heart rate variability were calculated from Holter recordings of 24 patients with structural heart disease who had ventricular fibrillation during monitoring. The control group consisted of 19 patients with coronary artery disease, of comparable age and left ventricular ejection fraction, who had nonsustained ventricular tachycardia but no ventricular fibrillation. RESULTS. Heart rate variability did not differ between the two groups, and no consistent trends in heart rate variability were observed before ventricular fibrillation occurred. CONCLUSIONS. Although conventional heart rate variability is an independent long-term predictor of adverse outcome after myocardial infarction, its clinical utility as a short-term predictor of life-threatening arrhythmias remains to be elucidated.

  4. Voxelwise atlas rating for computer assisted diagnosis: Application to congenital heart diseases of the great arteries.

    PubMed

    Zuluaga, Maria A; Burgos, Ninon; Mendelson, Alex F; Taylor, Andrew M; Ourselin, Sébastien

    2015-12-01

    Atlas-based analysis methods rely on the morphological similarity between the atlas and target images, and on the availability of labelled images. Problems can arise when the deformations introduced by pathologies affect the similarity between the atlas and a patient's image. The aim of this work is to exploit the morphological dissimilarities between atlas databases and pathological images to diagnose the underlying clinical condition, while avoiding the dependence on labelled images. We propose a voxelwise atlas rating approach (VoxAR) relying on multiple atlas databases, each representing a particular condition. Using a local image similarity measure to assess the morphological similarity between the atlas and target images, a rating map displaying for each voxel the condition of the atlases most similar to the target is defined. The final diagnosis is established by assigning the condition of the database the most represented in the rating map. We applied the method to diagnose three different conditions associated with dextro-transposition of the great arteries, a congenital heart disease. The proposed approach outperforms other state-of-the-art methods using annotated images, with an accuracy of 97.3% when evaluated on a set of 60 whole heart MR images containing healthy and pathological subjects using cross validation.

  5. Assessment of heart rate variability based on mobile device for planning physical activity

    NASA Astrophysics Data System (ADS)

    Svirin, I. S.; Epishina, E. V.; Voronin, V. V.; Semenishchev, E. A.; Solodova, E. N.; Nabilskaya, N. V.

    2015-05-01

    In this paper we present a method for the functional analysis of human heart based on electrocardiography (ECG) signals. The approach using the apparatus of analytical and differential geometry and correlation and regression analysis. ECG contains information on the current condition of the cardiovascular system as well as on the pathological changes in the heart. Mathematical processing of the heart rate variability allows to obtain a great set of mathematical and statistical characteristics. These characteristics of the heart rate are used when solving research problems to study physiological changes that determine functional changes of an individual. The proposed method implemented for up-to-date mobile Android and iOS based devices.

  6. Rate Control Management of Atrial Fibrillation: May a Mathematical Model Suggest an Ideal Heart Rate?

    PubMed Central

    Anselmino, Matteo; Scarsoglio, Stefania; Camporeale, Carlo; Saglietto, Andrea; Gaita, Fiorenzo; Ridolfi, Luca

    2015-01-01

    Background Despite the routine prescription of rate control therapy for atrial fibrillation (AF), clinical evidence demonstrating a heart rate target is lacking. Aim of the present study was to run a mathematical model simulating AF episodes with a different heart rate (HR) to predict hemodynamic parameters for each situation. Methods The lumped model, representing the pumping heart together with systemic and pulmonary circuits, was run to simulate AF with HR of 50, 70, 90, 110 and 130 bpm, respectively. Results Left ventricular pressure increased by 57%, from 33.92±37.56 mmHg to 53.15±47.56 mmHg, and mean systemic arterial pressure increased by 27%, from 82.66±14.04 mmHg to 105.3±7.6 mmHg, at the 50 and 130 bpm simulations, respectively. Stroke volume (from 77.45±8.50 to 39.09±8.08 mL), ejection fraction (from 61.10±4.40 to 39.32±5.42%) and stroke work (SW, from 0.88±0.04 to 0.58±0.09 J) decreased by 50, 36 and 34%, at the 50 and 130 bpm simulations, respectively. In addition, oxygen consumption indexes (rate pressure product – RPP, tension time index per minute – TTI/min, and pressure volume area per minute – PVA/min) increased from the 50 to the 130 bpm simulation, respectively, by 186% (from 5598±1939 to 15995±3219 mmHg/min), 56% (from 2094±265 to 3257±301 mmHg s/min) and 102% (from 57.99±17.90 to 117.4±26.0 J/min). In fact, left ventricular efficiency (SW/PVA) decreased from 80.91±2.91% at 50 bpm to 66.43±3.72% at the 130 bpm HR simulation. Conclusion Awaiting compulsory direct clinical evidences, the present mathematical model suggests that lower HRs during permanent AF relates to improved hemodynamic parameters, cardiac efficiency, and lower oxygen consumption. PMID:25764321

  7. Heart Rate Variability and Wavelet-based Studies on ECG Signals from Smokers and Non-smokers

    NASA Astrophysics Data System (ADS)

    Pal, K.; Goel, R.; Champaty, B.; Samantray, S.; Tibarewala, D. N.

    2013-12-01

    The current study deals with the heart rate variability (HRV) and wavelet-based ECG signal analysis of smokers and non-smokers. The results of HRV indicated dominance towards the sympathetic nervous system activity in smokers. The heart rate was found to be higher in case of smokers as compared to non-smokers ( p < 0.05). The frequency domain analysis showed an increase in the LF and LF/HF components with a subsequent decrease in the HF component. The HRV features were analyzed for classification of the smokers from the non-smokers. The results indicated that when RMSSD, SD1 and RR-mean features were used concurrently a classification efficiency of > 90 % was achieved. The wavelet decomposition of the ECG signal was done using the Daubechies (db 6) wavelet family. No difference was observed between the smokers and non-smokers which apparently suggested that smoking does not affect the conduction pathway of heart.

  8. Heart rate and respiratory rhythm dynamics on ascent to high altitude

    NASA Technical Reports Server (NTRS)

    Lipsitz, L. A.; Hashimoto, F.; Lubowsky, L. P.; Mietus, J.; Moody, G. B.; Appenzeller, O.; Goldberger, A. L.

    1995-01-01

    OBJECTIVE--To investigate the alterations in autonomic control of heart rate at high altitude and to test the hypothesis that hypoxaemic stress during exposure to high altitude induces non-linear, periodic heart rate oscillations, similar to those seen in heart failure and the sleep apnoea syndrome. SUBJECTS--11 healthy subjects aged 24-64. MAIN OUTCOME MEASURES--24 hour ambulatory electrocardiogram records obtained at baseline (1524 m) and at 4700 m. Simultaneous heart rate and respiratory dynamics during 2.5 hours of sleep by fast Fourier transform analysis of beat to beat heart rate and of an electrocardiographically derived respiration signal. RESULTS--All subjects had resting hypoxaemia at high altitude, with an average oxyhaemoglobin saturation of 81% (5%). There was no significant change in mean heart rate, but low frequency (0.01-0.05 Hz) spectral power was increased (P < 0.01) at high altitude. Time series analysis showed a complex range of non-linear sinus rhythm dynamics. Striking low frequency (0.04-0.06 Hz) heart rate oscillations were observed during sleep in eight subjects at high altitude. Analysis of the electrocardiographically derived respiration signal indicated that these heart rate oscillations correlated with low frequency respiratory oscillations. CONCLUSIONS--These data suggest (a) that increased low frequency power during high altitude exposure is not simply attributable to increased sympathetic modulation of heart rate, but relates to distinctive cardiopulmonary oscillations at approximately 0.05 Hz and (b) that the emergence of periodic heart rate oscillations at high altitude is consistent with an unstable cardiopulmonary control system that may develop on acute exposure to hypoxaemic stress.

  9. Heart Rate Variability as an Indicator of Chronic Stress Caused by Lameness in Dairy Cows

    PubMed Central

    Kulcsár-Huszenicza, Margit; Tőzsér, János

    2015-01-01

    Most experimental studies on animal stress physiology have focused on acute stress, while chronic stress, which is also encountered in intensive dairy cattle farming–e.g. in case of lameness–, has received little attention. We investigated heart rate (HR) and heart rate variability (HRV) as indicators of the autonomic nervous system activity and fecal glucocorticoid concentrations as the indicator of the hypothalamic–pituitary–adrenal axis activity in lame (with locomotion scores 4 and 5; n = 51) and non-lame (with locomotion scores 1 and 2; n = 52) Holstein-Friesian cows. Data recorded during the periods of undisturbed lying–representing baseline cardiac activity–were involved in the analysis. Besides linear analysis methods of the cardiac inter-beat interval (time-domain geometric, frequency domain and Poincaré analyses) non-linear HRV parameters were also evaluated. With the exception of standard deviation 1 (SD1), all HRV indices were affected by lameness. Heart rate was lower in lame cows than in non-lame ones. Vagal tone parameters were higher in lame cows than in non-lame animals, while indices of the sympathovagal balance reflected on a decreased sympathetic activity in lame cows. All geometric and non-linear HRV measures were lower in lame cows compared to non-lame ones suggesting that chronic stress influenced linear and non-linear characteristics of cardiac function. Lameness had no effect on fecal glucocorticoid concentrations. Our results demonstrate that HRV analysis is a reliable method in the assessment of chronic stress, however, it requires further studies to fully understand the elevated parasympathetic and decreased sympathetic tone in lame animals. PMID:26270563

  10. Running demands and heart rate response in rugby union referees.

    PubMed

    Suarez-Arrones, Luis; Portillo, Luis J; García, Jose M; Calvo-Lluch, Africa; Roberts, Simon P; Mendez-Villanueva, Alberto

    2013-11-01

    The aim of this study was to examine the match physical demands and exercise intensity associated with men rugby union refereeing using global positioning system technology. Ten male rugby union referees (age, 37.1 ± 5.9 years; body mass, 83.7 ± 4.8 kg; height, 175.5 ± 6.2 cm) were analyzed 2-4 times during a total of 30 national level matches. The average total distance covered by the referees throughout the game was 6,322.2 ± 564.9 m. As a percentage of total distance, 37.3% (2,356.9 ± 291.3 m) was spent walking, 24.1% (1,524.4 ± 229.4 m) jogging, 10.4% (656.2 ± 130.7 m) running at low intensity, 17.6% (1,110.3 ± 212.2 m) at medium intensity, 5.5% (347.1 ± 27.1 m) at high intensity, and 5.2% (328.1 ± 230.3 m) at sprint. A significant decrease (p < 0.05) in running performance was observed between the first and the second halves in the last 3 speed zones. When the total distance traveled during consecutive 10-minute periods was compared, there was a significantly greater distance covered in the first 10 minutes of the game (876.3 ± 163 m) compared with 50-60 minutes (679.8 ± 117.6 m), 60-70 minutes (713.03 ± 122.3 m), and 70-80 minutes (694.2 ± 125.7 m; all p < 0.05). The average heart rate responses were similar (p > 0.05) in the first (157 ± 7 b · min; 85% HRmax) and second half (155 ± 7 b · min; 84% HRmax). This study provides evidence of reduced high-intensity running toward the end of the game. These findings offer important information to design better training strategies adapted to the requirements and demands of rugby union refereeing.

  11. Nonlinear analysis of heart rate variability in patients with eating disorders.

    PubMed

    Vigo, Daniel E; Castro, Mariana N; Dörpinghaus, Andrea; Weidema, Hylke; Cardinali, Daniel P; Siri, Leonardo Nicola; Rovira, Bernardo; Fahrer, Rodolfo D; Nogués, Martín; Leiguarda, Ramón C; Guinjoan, Salvador M

    2008-01-01

    Patients with anorexia nervosa or bulimia nervosa often have signs of autonomic dysfunction potentially deleterious to the heart. The aim of this study was to ascertain the nonlinear properties of heart rate variability in patients with eating disorders. A group of 33 women with eating disorders (14 anorexia, 19 bulimia) and 19 healthy controls were included in the study. Conventional time- and frequency-domain heart rate variability measurements, along with nonlinear heart rate variability measurements including the short-term fractal scaling exponent alpha and approximate entropy (ApEn) were calculated. Anorexia nervosa patients exhibited decreased values of alpha, while bulimia nervosa patients had decreased values of ApEn. Low-frequency heart rate variability was decreased in patients with anorexia. In conclusion, these results are compatible with the view that a more severe alteration of cardiac autonomic function is present in anorexia than in bulimia.

  12. Gender- and age-related differences in heart rate dynamics: are women more complex than men?

    NASA Technical Reports Server (NTRS)

    Ryan, S. M.; Goldberger, A. L.; Pincus, S. M.; Mietus, J.; Lipsitz, L. A.

    1994-01-01

    OBJECTIVES. This study aimed to quantify the complex dynamics of beat-to-beat sinus rhythm heart rate fluctuations and to determine their differences as a function of gender and age. BACKGROUND. Recently, measures of heart rate variability and the nonlinear "complexity" of heart rate dynamics have been used as indicators of cardiovascular health. Because women have lower cardiovascular risk and greater longevity than men, we postulated that there are important gender-related differences in beat-to-beat heart rate dynamics. METHODS. We analyzed heart rate dynamics during 8-min segments of continuous electrocardiographic recording in healthy young (20 to 39 years old), middle-aged (40 to 64 years old) and elderly (65 to 90 years old) men (n = 40) and women (n = 27) while they performed spontaneous and metronomic (15 breaths/min) breathing. Relatively high (0.15 to 0.40 Hz) and low (0.01 to 0.15 Hz) frequency components of heart rate variability were computed using spectral analysis. The overall "complexity" of each heart rate time series was quantified by its approximate entropy, a measure of regularity derived from nonlinear dynamics ("chaos" theory). RESULTS. Mean heart rate did not differ between the age groups or genders. High frequency heart rate power and the high/low frequency power ratio decreased with age in both men and women (p < 0.05). The high/low frequency power ratio during spontaneous and metronomic breathing was greater in women than men (p < 0.05). Heart rate approximate entropy decreased with age and was higher in women than men (p < 0.05). CONCLUSIONS. High frequency heart rate spectral power (associated with parasympathetic activity) and the overall complexity of heart rate dynamics are higher in women than men. These complementary findings indicate the need to account for gender-as well as age-related differences in heart rate dynamics. Whether these gender differences are related to lower cardiovascular disease risk and greater longevity in

  13. Visualization of Heart Rate Variability of Long-Term Heart Transplant Patient by Transition Networks: A Case Report.

    PubMed

    Wdowczyk, Joanna; Makowiec, Danuta; Dorniak, Karolina; Gruchała, Marcin

    2016-01-01

    We present a heart transplant patient at his 17th year of uncomplicated follow-up. Within a frame of routine check out several tests were performed. With such a long and uneventful follow-up some degree of graft reinnervation could be anticipated. However, the patient's electrocardiogram and exercise parameters seemed largely inconclusive in this regard. The exercise heart rate dynamics were suggestive of only mild, if any parasympathetic reinnervation of the graft with persisting sympathetic activation. On the other hand, traditional heart rate variability (HRV) indices were inadequately high, due to erratic rhythm resulting from interference of the persisting recipient sinus node or non-conducted atrial parasystole. New tools, originated from network representation of time series, by visualization short-term dynamical patterns, provided a method to discern HRV increase due to reinnervation from other reasons.

  14. Visualization of Heart Rate Variability of Long-Term Heart Transplant Patient by Transition Networks: A Case Report.

    PubMed

    Wdowczyk, Joanna; Makowiec, Danuta; Dorniak, Karolina; Gruchała, Marcin

    2016-01-01

    We present a heart transplant patient at his 17th year of uncomplicated follow-up. Within a frame of routine check out several tests were performed. With such a long and uneventful follow-up some degree of graft reinnervation could be anticipated. However, the patient's electrocardiogram and exercise parameters seemed largely inconclusive in this regard. The exercise heart rate dynamics were suggestive of only mild, if any parasympathetic reinnervation of the graft with persisting sympathetic activation. On the other hand, traditional heart rate variability (HRV) indices were inadequately high, due to erratic rhythm resulting from interference of the persisting recipient sinus node or non-conducted atrial parasystole. New tools, originated from network representation of time series, by visualization short-term dynamical patterns, provided a method to discern HRV increase due to reinnervation from other reasons. PMID:27014081

  15. Visualization of Heart Rate Variability of Long-Term Heart Transplant Patient by Transition Networks: A Case Report

    PubMed Central

    Wdowczyk, Joanna; Makowiec, Danuta; Dorniak, Karolina; Gruchała, Marcin

    2016-01-01

    We present a heart transplant patient at his 17th year of uncomplicated follow-up. Within a frame of routine check out several tests were performed. With such a long and uneventful follow-up some degree of graft reinnervation could be anticipated. However, the patient's electrocardiogram and exercise parameters seemed largely inconclusive in this regard. The exercise heart rate dynamics were suggestive of only mild, if any parasympathetic reinnervation of the graft with persisting sympathetic activation. On the other hand, traditional heart rate variability (HRV) indices were inadequately high, due to erratic rhythm resulting from interference of the persisting recipient sinus node or non-conducted atrial parasystole. New tools, originated from network representation of time series, by visualization short-term dynamical patterns, provided a method to discern HRV increase due to reinnervation from other reasons. PMID:27014081

  16. Influence of microwaves on the beating rate of isolated rat hearts.

    PubMed

    Yee, K C; Chou, C K; Guy, A W

    1988-01-01

    Previous reports have shown that microwave exposure can decrease the beating rate of isolated rat hearts. These experiments were conducted at room temperature and with the hearts exposed to air. We observed arrhythmia frequently at room temperature, and the variation of heart beat was so large that it makes the results difficult to reproduce. Therefore, we employed a double-circulating system to provide perfusion through the coronary artery and around the outside of the heart to maintain the rat hearts at 37.7 degrees C. No arrhythmias were observed in our experiments, and the hearts were beating for at least 1 h. The effects of 16-Hz modulated 2,450-MHz pulsed microwaves (10 microseconds, 100 pps) on the beating rate of 50 isolated rat hearts were studied. Results showed no statistically significant changes of heart rate in exposed groups at SARs of 2 and 10 W/kg compared with the control group. The effect seen at 200 W/kg was shown to be similar to that resulting from heating the heart.

  17. Influence of microwaves on the beating rate of isolated rat hearts

    SciTech Connect

    Yee, K.C.; Chou, C.K.; Guy, A.W.

    1988-01-01

    Previous reports have shown that microwave exposure can decrease the beating rate of isolated rat hearts. These experiments were conducted at room temperature and with the hearts exposed to air. We observed arrhythmia frequently at room temperature, and the variation of heart beat was so large that it makes the results difficult to reproduce. Therefore, we employed a double-circulating system to provide perfusion through the coronary artery and around the outside of the heart to maintain the rat hearts at 37.7 degrees C. No arrhythmias were observed in our experiments, and the hearts were beating for at least 1 h. The effects of 16-Hz modulated 2,450-MHz pulsed microwaves (10 microseconds, 100 pps) on the beating rate of 50 isolated rat hearts were studied. Results showed no statistically significant changes of heart rate in exposed groups at SARs of 2 and 10 W/kg compared with the control group. The effect seen at 200 W/kg was shown to be similar to that resulting from heating the heart.

  18. Validity of a heart rate monitor during work in the laboratory and on the Space Shuttle

    NASA Technical Reports Server (NTRS)

    Moore, A. D. Jr; Lee, S. M.; Greenisen, M. C.; Bishop, P.

    1997-01-01

    Accurate heart rate measurement during work is required for many industrial hygiene and ergonomics situations. The purpose of this investigation was to determine the validity of heart rate measurements obtained by a simple, lightweight, commercially available wrist-worn heart rate monitor (HRM) during work (cycle exercise) sessions conducted in the laboratory and also during the particularly challenging work environment of space flight. Three different comparisons were made. The first compared HRM data to simultaneous electrocardiogram (ECG) recordings of varying heart rates that were generated by an ECG simulator. The second compared HRM data to ECG recordings collected during work sessions of 14 subjects in the laboratory. Finally, ECG downlink and HRM data were compared in four astronauts who performed cycle exercise during space flight. The data were analyzed using regression techniques. The results were that the HRM recorded virtually identical heart rates compared with ECG recordings for the data set generated by an ECG simulator. The regression equation for the relationship between ECG versus HRM heart rate data during work in the laboratory was: ECG HR = 0.99 x (HRM) + 0.82 (r2 = 0.99). Finally, the agreement between ECG downlink data and HRM data during space flight was also very high, with the regression equation being: Downlink ECG HR = 1.05 x (HRM) -5.71 (r2 = 0.99). The results of this study indicate that the HRM provides accurate data and may be used to reliably obtain valid data regarding heart rate responses during work.

  19. Minimal changes in heart rate of incubating American Oystercatchers (Haematopus palliatus) in response to human activity

    USGS Publications Warehouse

    Borneman, Tracy E.; Rose, Eli T.; Simons, Theodore R.

    2014-01-01

    An organism's heart rate is commonly used as an indicator of physiological stress due to environmental stimuli. We used heart rate to monitor the physiological response of American Oystercatchers (Haematopus palliatus) to human activity in their nesting environment. We placed artificial eggs with embedded microphones in 42 oystercatcher nests to record the heart rate of incubating oystercatchers continuously for up to 27 days. We used continuous video and audio recordings collected simultaneously at the nests to relate physiological response of birds (heart rate) to various types of human activity. We observed military and civilian aircraft, off-road vehicles, and pedestrians around nests. With the exception of high-speed, low-altitude military overflights, we found little evidence that oystercatcher heart rates were influenced by most types of human activity. The low-altitude flights were the only human activity to significantly increase average heart rates of incubating oystercatchers (12% above baseline). Although statistically significant, we do not consider the increase in heart rate during high-speed, low-altitude military overflights to be of biological significance. This noninvasive technique may be appropriate for other studies of stress in nesting birds.

  20. Components of the cannabinoid system in the dorsal periaqueductal gray are related to resting heart rate.

    PubMed

    Dean, Caron; Hillard, Cecilia J; Seagard, Jeanne L; Hopp, Francis A; Hogan, Quinn H

    2016-08-01

    The present study was undertaken to examine whether variations in endocannabinoid signaling in the dorsal periaqueductal gray (dPAG) are associated with baseline autonomic nerve activity, heart rate, and blood pressure. Blood pressure was recorded telemetrically in rats, and heart rate and power spectral analysis of heart rate variability were determined. Natural variations from animal to animal provided a range of baseline values for analysis. Transcript levels of endocannabinoid signaling components in the dPAG were analyzed, and endocannabinoid content and catabolic enzyme activity were measured. Higher baseline heart rate was associated with increased anandamide content and with decreased activity of the anandamide-hydrolyzing enzyme, fatty acid amide hydrolase (FAAH), and it was negatively correlated with transcript levels of both FAAH and monoacylglycerol lipase (MAGL), a catabolic enzyme for 2-arachidonoylglycerol (2-AG). Autonomic tone and heart rate, but not blood pressure, were correlated to levels of FAAH mRNA. In accordance with these data, exogenous anandamide in the dPAG of anesthetized rats increased heart rate. These data indicate that in the dPAG, anandamide, a FAAH-regulated lipid, contributes to regulation of baseline heart rate through influences on autonomic outflow.

  1. Components of the cannabinoid system in the dorsal periaqueductal gray are related to resting heart rate

    PubMed Central

    Dean, Caron; Hillard, Cecilia J.; Seagard, Jeanne L.; Hopp, Francis A.; Hogan, Quinn H.

    2016-01-01

    The present study was undertaken to examine whether variations in endocannabinoid signaling in the dorsal periaqueductal gray (dPAG) are associated with baseline autonomic nerve activity, heart rate, and blood pressure. Blood pressure was recorded telemetrically in rats, and heart rate and power spectral analysis of heart rate variability were determined. Natural variations from animal to animal provided a range of baseline values for analysis. Transcript levels of endocannabinoid signaling components in the dPAG were analyzed, and endocannabinoid content and catabolic enzyme activity were measured. Higher baseline heart rate was associated with increased anandamide content and with decreased activity of the anandamide-hydrolyzing enzyme and fatty acid amide hydrolase (FAAH), and it was negatively correlated with transcript levels of both FAAH and monoacylglycerol lipase (MAGL), a catabolic enzyme for 2-arachidonoylglycerol (2-AG). Autonomic tone and heart rate, but not blood pressure, were correlated to levels of FAAH mRNA. In accordance with these data, exogenous anandamide in the dPAG of anesthetized rats increased heart rate. These data indicate that in the dPAG, anandamide, a FAAH-regulated lipid, contributes to regulation of baseline heart rate through influences on autonomic outflow. PMID:27280429

  2. Music can enhance exercise-induced sympathetic dominancy assessed by heart rate variability.

    PubMed

    Urakawa, Kayoko; Yokoyama, Kazuhito

    2005-07-01

    Many studies have been conducted on physiological responses of music, yielding controversial results. In the present study, we examined whether music affects the exercise-induced changes in the autonomic nervous system activity in twelve healthy female college students. On the first day, the subjects were asked to rest, exercise, and then rest for 15 min, respectively. On the second day, they were asked to rest with music, exercise, and then rest with music for 15 min, respectively. Heart rate variability was measured for the pre- and post-exercise periods. Music was given according to subjects' preferences using a vibroacoustic apparatus (body sonic system), i.e. a chair on which subjects laid and felt low-pitch sounds by their body in addition to listening music. With music, ratio of low frequency to high frequency component of heart rate variability (LH/HF) was significantly increased after exercise as compared with before exercise (p < 0.01). By contrast, the changes in LH/HF were not significant without music (p > 0.05). It is suggested that after exercise in which sympathetic nerve activity is dominant, preferred music synchronizes with the activated physical response, further promoting the response and increasing sympathetic nerve activity. Combining music with exercise is therefore not only enjoyable in terms of mood but also may promote physiological excitation and enhance physical activation. PMID:15942147

  3. The non-contact heart rate measurement system for monitoring HRV.

    PubMed

    Huang, Ji-Jer; Yu, Sheng-I; Syu, Hao-Yi; See, Aaron Raymond

    2013-01-01

    A noncontact ECG monitoring and analysis system was developed using capacitive-coupled device integrated to a home sofa. Electrodes were placed on the backrest of a sofa separated from the body with only the chair covering and the user's clothing. The study also incorporates measurements using different fabric materials, and a pure cotton material was chosen to cover the chair's backrest. The material was chosen to improve the signal to noise ratio. The system is initially implemented on a home sofa and is able to measure non-contact ECG through thin cotton clothing and perform heart rate analysis to calculate the heart rate variability (HRV) parameters. It was also tested under different conditions and results from reading and sleeping exhibited a stable ECG. Subsequently, results from our calculated HRV were found to be identical to those of a commercially available HRV analyzer. However, HRV parameters are easily affected by motion artifacts generated during drinking or eating with the latter producing a more severe disturbance. Lastly, parameters measured are saved on a cloud database, providing users with a long-term monitoring and recording for physiological information.

  4. Effects of caffeine on blood pressure, heart rate, and forearm blood flow during dynamic leg exercise.

    PubMed

    Daniels, J W; Molé, P A; Shaffrath, J D; Stebbins, C L

    1998-07-01

    This study examined the acute effects of caffeine on the cardiovascular system during dynamic leg exercise. Ten trained, caffeine-naive cyclists (7 women and 3 men) were studied at rest and during bicycle ergometry before and after the ingestion of 6 mg/kg caffeine or 6 mg/kg fructose (placebo) with 250 ml of water. After consumption of caffeine or placebo, subjects either rested for 100 min (rest protocol) or rested for 45 min followed by 55 min of cycle ergometry at 65% of maximal oxygen consumption (exercise protocol). Measurement of mean arterial pressure (MAP), forearm blood flow (FBF), heart rate, skin temperature, and rectal temperature and calculation of forearm vascular conductance (FVC) were made at baseline and at 20-min intervals. Plasma ANG II was measured at baseline and at 60 min postingestion in the two exercise protocols. Before exercise, caffeine increased both systolic blood pressure (17%) and MAP (11%) without affecting FBF or FVC. During dynamic exercise, caffeine attenuated the increase in FBF (53%) and FVC (50%) and accentuated exercise-induced increases in ANG II (44%). Systolic blood pressure and MAP were also higher during exercise plus caffeine; however, these increases were secondary to the effects of caffeine on resting blood pressure. No significant differences were observed in heart rate, skin temperature, or rectal temperature. These findings indicate that caffeine can alter the cardiovascular response to dynamic exercise in a manner that may modify regional blood flow and conductance. PMID:9655769

  5. Cannabis coadministration potentiates the effects of "ecstasy" on heart rate and temperature in humans.

    PubMed

    Dumont, G J; Kramers, C; Sweep, F C; Touw, D J; van Hasselt, J G; de Kam, M; van Gerven, J M; Buitelaar, J K; Verkes, R J

    2009-08-01

    This study assessed the acute physiologic effects over time of (co)administration of Delta9-tetrahydrocannabinol (Delta9-THC) (the main psychoactive compound of cannabis) and 3,4-methylenedioxymethamphetamine (MDMA or "ecstasy") in 16 healthy volunteers. Pharmacokinetics and cardiovascular, temperature, and catecholamine responses were assessed over time. Both single-drug conditions robustly increased heart rate, and coadministration showed additive effects. MDMA increased epinephrine and norepinephrine concentrations, whereas THC did not affect the catecholamine response. Coadministration of MDMA and THC attenuated the increase of norepinephrine concentrations relative to administration of MDMA alone. These results show that THC mediates heart rate increase independent of sympathetic (catecholaminergic) activity, probably through direct cannabinoid receptor type 1 (CB(1)) agonism in cardiac tissue. Furthermore, THC coadministration did not prevent MDMA-induced temperature increase, but it delayed the onset and prolonged the duration of temperature elevation. These effects may be of particular relevance for the cardiovascular safety of ecstasy users who participate in energetic dancing in nightclubs with high ambient temperature. PMID:19440186

  6. Heart Rate and Energy Expenditure in Division I Field Hockey Players During Competitive Play.

    PubMed

    Sell, Katie M; Ledesma, Allison B

    2016-08-01

    Sell, KM and Ledesma, AB. Heart rate and energy expenditure in Division I field hockey players during competitive play. J Strength Cond Res 30(8): 2122-2128, 2016-The purpose of this study was to quantify energy expenditure and heart rate data for Division I female field hockey players during competitive play. Ten female Division I collegiate field hockey athletes (19.8 ± 1.6 years; 166.4 ± 6.1 cm; 58.2 ± 5.3 kg) completed the Yo-Yo intermittent endurance test to determine maximal heart rate. One week later, all subjects wore a heart rate monitor during a series of 3 matches in an off-season competition. Average heart rate (AvHR), average percentage of maximal heart rate (AvHR%), peak exercise heart rate (PExHR), and percentage of maximal heart rate (PExHR%), time spent in each of the predetermined heart rate zones, and caloric expenditure per minute of exercise (kcalM) were determined for all players. Differences between positions (backs, midfielders, and forwards) were assessed. No significant differences in AvHR, AvHR%, PExHR, PExHR%, and %TM were observed between playing positions. The AvHR% and PExHR% for each position fell into zones 4 (77-93% HRmax) and 5 (>93% HRmax), respectively, and significantly more time was spent in zone 4 compared with zones 1, 2, 3, and 5 across all players (p ≤ 0.05). The kcalM reflected very heavy intensity exercise. The results of this study will contribute toward understanding the sport-specific physiological demands of women's field hockey and has specific implications for the duration and schedule of training regimens.

  7. Estimation of respiratory rate and heart rate during treadmill tests using acoustic sensor.

    PubMed

    Popov, B; Sierra, G; Telfort, V; Agarwal, R; Lanzo, V

    2005-01-01

    The objective was to test the robustness of an acoustic method to estimate respiratory rates (RR) during treadmill test. The accuracy was assessed by the comparison with simultaneous estimates from a capnograph, using as a common reference a pneumotachometer. Eight subjects without any pulmonary disease were enrolled. Tracheal sounds were acquired using a contact piezoelectric sensor placed on the subject's throat and analyzed using a combined investigation of the sound envelope and frequency content. The capnograph and pneumotachometer were coupled to a face mask worn by the subjects. There was a strong linear correlation between all three methods (r2ranged from 0.8 to 0.87), and the SEE ranged from 1.97 to 2.36. As a conclusion, the accuracy of the respiratory rate estimated from tracheal sounds on adult subjects during treadmill stress test was comparable to the accuracy of a commercial capnograph. The heart rate (HR) estimates can also be derived from carotid pulse using the same single sensor placed on the subject's throat. Compared to the pulse oximeter the results show an agreement of acoustic method with r2=0.76 and SEE = 3.51. PMID:17281599

  8. Heart Rate and Treatment Effect in Children with Disruptive Behavior Disorders

    ERIC Educational Resources Information Center

    Stadler, Christina; Grasmann, Dorte; Fegert, Jorg M.; Holtmann, Martin; Poustka, Fritz; Schmeck, Klaus

    2008-01-01

    Objective: To examine whether children with disruptive behavior disorders (DBDs; hyperkinetic conduct disorder, conduct disorder, hyperkinetic disorder) characterized by low heart rate profit less from an intensive cognitive behavioral intervention aimed at reducing impulsive, oppositional and aggressive behavior problems. Method: Basal heart rate…

  9. Smart pillow for heart-rate monitoring using a fiber optic sensor

    NASA Astrophysics Data System (ADS)

    Chen, Zhihao; Teo, Ju Teng; Ng, Soon Huat; Yim, Huiqing

    2011-03-01

    In this paper, we propose and demonstrate a new method to monitor heart rate using fiber optic microbending based sensor for in-bed non-intrusive monitoring. The sensing system consists of transmitter, receiver, sensor mat, National Instrument (NI) data acquisition (DAQ) card and a computer for signal processing. The sensor mat is embedded inside a commercial pillow. The heart rate measurement system shows an accuracy of +/-2 beats, which has been successfully demonstrated in a field trial. The key technological advantage of our system is its ability to measure heart rate with no preparation and minimal compliance by the patient.

  10. Voluntary control of breathing does not alter vagal modulation of heart rate

    NASA Technical Reports Server (NTRS)

    Patwardhan, A. R.; Evans, J. M.; Bruce, E. N.; Eckberg, D. L.; Knapp, C. F.

    1995-01-01

    Variations in respiratory pattern influence the heart rate spectrum. It has been suggested, hence, that metronomic respiration should be used to correctly assess vagal modulation of heart rate by using spectral analysis. On the other hand, breathing to a metronome has been reported to increase heart rate spectral power in the high- or respiratory frequency region; this finding has led to the suggestion that metronomic respiration enhances vagal tone or alters vagal modulation of heart rate. To investigate whether metronomic breathing complicates the interpretation of heart rate spectra by altering vagal modulation, we recorded the electrocardiogram and respiration from eight volunteers during three breathing trials of 10 min each: 1) spontaneous breathing (mean rate of 14.4 breaths/min); 2) breathing to a metronome at the rate of 15, 18, and 21 breaths/min for 2, 6, and 2 min, respectively; and 3) breathing to a metronome at the rate of 18 breaths/min for 10 min. Data were also collected from eight volunteers who breathed spontaneously for 20 min and breathed metronomically at each subject's mean spontaneous breathing frequency for 20 min. Results from the three 10-min breathing trials showed that heart rate power in the respiratory frequency region was smaller during metronomic breathing than during spontaneous breathing. This decrease could be explained fully by the higher breathing frequencies used during trials 2 and 3 of metronomic breathing. When the subjects breathed metronomically at each subject's mean breathing frequency, the heart rate powers during metronomic breathing were similar to those during spontaneous breathing. Our results suggest that vagal modulation of heart rate is not altered and vagal tone is not enhanced during metronomic breathing.

  11. Crank inertial load affects freely chosen pedal rate during cycling.

    PubMed

    Hansen, Ernst Albin; Jørgensen, Lars Vincents; Jensen, Kurt; Fregly, Benjamin Jon; Sjøgaard, Gisela

    2002-02-01

    Cyclists seek to maximize performance during competition, and gross efficiency is an important factor affecting performance. Gross efficiency is itself affected by pedal rate. Thus, it is important to understand factors that affect freely chosen pedal rate. Crank inertial load varies greatly during road cycling based on the selected gear ratio. Nevertheless, the possible influence of crank inertial load on freely chosen pedal rate and gross efficiency has never been investigated. This study tested the hypotheses that during cycling with sub-maximal work rates, a considerable increase in crank inertial load would cause (1) freely chosen pedal rate to increase, and as a consequence, (2) gross efficiency to decrease. Furthermore, that it would cause (3) peak crank torque to increase if a constant pedal rate was maintained. Subjects cycled on a treadmill at 150 and 250W, with low and high crank inertial load, and with preset and freely chosen pedal rate. Freely chosen pedal rate was higher at high compared with low crank inertial load. Notably, the change in crank inertial load affected the freely chosen pedal rate as much as did the 100W increase in work rate. Along with freely chosen pedal rate being higher, gross efficiency at 250W was lower during cycling with high compared with low crank inertial load. Peak crank torque was higher during cycling at 90rpm with high compared with low crank inertial load. Possibly, the subjects increased the pedal rate to compensate for the higher peak crank torque accompanying cycling with high compared with low crank inertial load. PMID:11784546

  12. Leptin decreases heart rate associated with increased ventricular repolarization via its receptor.

    PubMed

    Lin, Yen-Chang; Huang, Jianying; Hileman, Stan; Martin, Karen H; Hull, Robert; Davis, Mary; Yu, Han-Gang

    2015-11-15

    Leptin has been proposed to modulate cardiac electrical properties via β-adrenergic receptor activation. The presence of leptin receptors and adipocytes in myocardium raised a question as to whether leptin can directly modulate cardiac electrical properties such as heart rate and QT interval via its receptor. In this work, the role of local direct actions of leptin on heart rate and ventricular repolarization was investigated. We identified the protein expression of leptin receptors at cell surface of sinus node, atrial, and ventricular myocytes isolated from rat heart. Leptin at low doses (0.1-30 μg/kg) decreased resting heart rate; at high doses (150-300 μg/kg), leptin induced a biphasic effect (decrease and then increase) on heart rate. In the presence of high-dose propranolol (30 mg/kg), high-dose leptin only reduced heart rate and sometimes caused sinus pauses and ventricular tachycardia. The leptin-induced inhibition of resting heart rate was fully reversed by leptin antagonist. Leptin also increased heart rate-corrected QT interval (QTc), and leptin antagonist did not. In isolated ventricular myocytes, leptin (0.03-0.3 μg/ml) reversibly increased the action potential duration. These results supported our hypothesis that in addition to indirect pathway via sympathetic tone, leptin can directly decrease heart rate and increase QT interval via its receptor independent of β-adrenergic receptor stimulation. During inhibition of β-adrenergic receptor activity, high concentration of leptin in myocardium can cause deep bradycardia, prolonged QT interval, and ventricular arrhythmias.

  13. Music close to one's heart: heart rate variability with music, diagnostic with e-bra and smartphone

    NASA Astrophysics Data System (ADS)

    Hegde, Shantala; Kumar, Prashanth S.; Rai, Pratyush; Mathur, Gyanesh N.; Varadan, Vijay K.

    2012-04-01

    Music is a powerful elicitor of emotions. Emotions evoked by music, through autonomic correlates have been shown to cause significant modulation of parameters like heart rate and blood pressure. Consequently, Heart Rate Variability (HRV) analysis can be a powerful tool to explore evidence based therapeutic functions of music and conduct empirical studies on effect of musical emotion on heart function. However, there are limitations with current studies. HRV analysis has produced variable results to different emotions evoked via music, owing to variability in the methodology and the nature of music chosen. Therefore, a pragmatic understanding of HRV correlates of musical emotion in individuals listening to specifically chosen music whilst carrying out day to day routine activities is needed. In the present study, we aim to study HRV as a single case study, using an e-bra with nano-sensors to record heart rate in real time. The e-bra developed previously, has several salient features that make it conducive for this study- fully integrated garment, dry electrodes for easy use and unrestricted mobility. The study considers two experimental conditions:- First, HRV will be recorded when there is no music in the background and second, when music chosen by the researcher and by the subject is playing in the background.

  14. Effects of heart rate on myocardial thallium-201 uptake and clearance

    SciTech Connect

    Nordrehaug, J.E.; Danielsen, R.; Vik-Mo, H. )

    1989-12-01

    The effects of heart rate on the myocardial uptake and clearance of {sup 201}Tl were studied prospectively in seven healthy men, mean age 43 +/- 7 (s.d.) yr. Initial and delayed (3 hr) thallium images were obtained in three views after three bicycle exercise tests: to maximal, 80% and 60% of predicted maximal heart rate. The mean of three views initial myocardial {sup 201}Tl uptake was higher at maximal than at both 80% and 60% of predicted maximal heart rate, being 81% (p less than 0.01) and 60% (p less than 0.01) of maximal activity, respectively. The myocardial activity in the delayed images was identical. There was a linear relationship between heart rate and the initial myocardial activity, r = 0.86 (p less than 0.001). The mean (range) {sup 201}Tl clearance was 58% (51-65), 47% (34-56), and 34% (22-49) (all differences p less than 0.01), respectively. Concordance among the three individual views in estimating clearance was best for the highest exercise level. There was a linear relationship between heart rate and clearance, r = 0.80 (p less than 0.001). Clearance was altered by only 1.67 x 10%/heart bpm (0.024 hr/heart beat). Clearance in the liver, spleen and lungs increased at submaximal exercise levels. Thus, a linear relationship between heart rate and clearance is the result of changes in the initial exercise myocardial {sup 201}Tl activity. Submaximal exercise may reduce reproducibility of clearance estimation, and the change of myocardial clearance with heart rate seems less than previously suggested.

  15. Cardiovascular and Cerebrovascular Control on Return from International Space Station (CCISS)- Heart Rate and Activity

    NASA Astrophysics Data System (ADS)

    Hughson, R. L.; Shoemaker, J. K.; Blaber, A. P.; Arbeille, Ph.; Zuj, K. A.; Greaves, D. K.

    2008-06-01

    CCISS is a project to study the cardiovascular and cerebrovascular responses of astronauts before, during and after long-duration (>60-day) stays on the International Space Station. The CCISS experiments consist of three phases that are designed to achieve an integrated examination of components responsible for return of blood to the heart, the pumping of blood from the heart and the distribution to the vascular territories including the brain. In this report the data are obtained from the 24-h monitoring of physical activity (Actiwatch on wrist and ankle) and of heart rate (Holter monitor). The data show clear patterns of change in physical activity from predominantly leg-based on Earth to relatively little activity of the ankles with maintained or increased activity of the wrists on ISS. Both on Earth and on ISS the largest changes in heart rate occur during the periods of leg activity. Average heart rate was changed little during the periods of minimal activity or of sleep in comparisons of Earth with in-flight recording both within the first two weeks of flight and the last two weeks. These data clearly show the importance of monitoring heart rate and physical activity simultaneously and show that attempts to derive indicators of autonomic activity from spectral analysis of heart rate variability should not be performed in the absence of knowledge of both variables.

  16. Coefficient of Variation of Coarsely Sampled Heart Rate Is Associated with Early Vasopressor Independence in Severe Sepsis and Septic Shock

    PubMed Central

    Brown, Samuel M.; Tate, M. Quinn; Jones, Jason P.; Kuttler, Kathryn G.; Lanspa, Michael; Rondina, Matthew T.; Grissom, Colin K.; Mathews, V.J.

    2014-01-01

    Purpose Determine whether variability of coarsely sample heart rate and blood pressure early in the course of severe sepsis and septic shock predicts successful resuscitation, defined as vasopressor independence at 24 hours after admission. Methods In an observational study of patients admitted with severe sepsis or septic shock from 2009 to 2011 to one of two ICUs at a tertiary-care hospital, in whom blood pressure was measured via an arterial catheter, we sampled heart rate and blood pressure every 30 seconds over the first six hours of ICU admission and calculated coefficient of variability of those measurements. Primary outcome was vasopressor independence at 24 hours; secondary outcome was 28-day mortality. Results We studied 165 patients, of which 97 (59%) achieved vasopressor independence at 24 hours. Overall 28-day mortality was 15%. Significant predictors of vasopressor independence at 24 hours included the coefficient of variation of heart rate, age, APACHE II, the number of increases in vasopressor dose, mean vasopressin dose, mean blood pressure, and time-pressure integral of mean blood pressure below 60mm Hg. Lower sampling frequencies (up to once every 5 minutes) did not affect the findings. Conclusions Increased variability of coarsely sampled heart rate was associated with vasopressor independence at 24 hours after controlling for possible confounders. Sampling frequencies of once in five minutes may be similar to once in 30 seconds. PMID:24578465

  17. Communication and Stress: Effects of Hope Evocation and Rumination Messages on Heart Rate, Anxiety, and Emotions After a Stressor.

    PubMed

    Chadwick, Amy E; Zoccola, Peggy M; Figueroa, Wilson S; Rabideau, Erin M

    2016-12-01

    How we cope with the many stressors that we encounter throughout our lives has implications for our well-being. By affecting how individuals appraise stressful events, communication can prolong or ameliorate physiological and emotional responses to stress. This study investigated the short-term effects of hope-inducing and rumination-inducing messages on heart rate, state anxiety, and emotions after a standardized, social-evaluative stressor. Continuous heart rate was monitored for 127 college students (64 female, 63 male) throughout an experiment that included a performance stressor and messages designed to (a) cause feelings of hope, (b) evoke rumination, or (c) be a distraction (control). Heart rate varied by message, such that heart rate was lowest in the hope evocation condition. State anxiety was lower in the hope evocation and distraction control conditions than in the rumination condition. The rumination condition led to greater anger, greater guilt, and less happiness than did the other conditions. This study advances our knowledge about potential ways that communication messages can counter the psychological and biological effects of stressful life events. Overall, the study provides preliminary evidence that hope evocation messages may be a form of supportive communication and can ameliorate stress. PMID:27054822

  18. Increased Efferent Cardiac Sympathetic Nerve Activity and Defective Intrinsic Heart Rate Regulation in Type 2 Diabetes.

    PubMed

    Thaung, H P Aye; Baldi, J Chris; Wang, Heng-Yu; Hughes, Gillian; Cook, Rosalind F; Bussey, Carol T; Sheard, Phil W; Bahn, Andrew; Jones, Peter P; Schwenke, Daryl O; Lamberts, Regis R

    2015-08-01

    Elevated sympathetic nerve activity (SNA) coupled with dysregulated β-adrenoceptor (β-AR) signaling is postulated as a major driving force for cardiac dysfunction in patients with type 2 diabetes; however, cardiac SNA has never been assessed directly in diabetes. Our aim was to measure the sympathetic input to and the β-AR responsiveness of the heart in the type 2 diabetic heart. In vivo recording of SNA of the left efferent cardiac sympathetic branch of the stellate ganglion in Zucker diabetic fatty rats revealed an elevated resting cardiac SNA and doubled firing rate compared with nondiabetic rats. Ex vivo, in isolated denervated hearts, the intrinsic heart rate was markedly reduced. Contractile and relaxation responses to β-AR stimulation with dobutamine were compromised in externally paced diabetic hearts, but not in diabetic hearts allowed to regulate their own heart rate. Protein levels of left ventricular β1-AR and Gs (guanine nucleotide binding protein stimulatory) were reduced, whereas left ventricular and right atrial β2-AR and Gi (guanine nucleotide binding protein inhibitory regulatory) levels were increased. The elevated resting cardiac SNA in type 2 diabetes, combined with the reduced cardiac β-AR responsiveness, suggests that the maintenance of normal cardiovascular function requires elevated cardiac sympathetic input to compensate for changes in the intrinsic properties of the diabetic heart.

  19. Use of heart rate monitoring for an individualized and time-variant decompression model.

    PubMed

    Gutvik, Christian R; Wisløff, Ulrik; Brubakk, Alf O

    2010-11-01

    Individual differences, physiological pre-conditions and in-dive conditions like workload and body temperature have been known to influence bubble formation and risk of decompression sickness in diving. Despite this fact, such effects are currently omitted from the decompression algorithms and tables that are aiding the divers. There is an apparent need to expand the modeling beyond depth and time to increase safety and efficiency of diving. The present paper outlines a mathematical model for how heart rate monitoring in combination with individual parameters can be used to obtain a customized and time-variant decompression model. We suggest that this can cover some of the individual differences and dive conditions that are affecting bubble formation. The model is demonstrated in combination with the previously published Copernicus decompression model, and is suitable for implementation in dive computers and post dive simulation software for more accurate risk analysis. PMID:20577757

  20. Destruction of neurons in the VPM thalamus prevents rabbit heart rate conditioning.

    PubMed

    McCabe, P M; McEchron, M D; Green, E J; Schneiderman, N

    1995-01-01

    The present study examined the role of the ventral posterior medial nucleus of the thalamus (VPM) in classical heart rate (HR) conditioning using an acoustic conditioned stimulus (CS) and a corneal air puff unconditioned stimulus (US). Previous research suggests that VPM neurons are activated during the presentation of a corneal air puff US. Rabbits were given ibotenic acid lesions in the VPM and subjected to one Pavlovian HR conditioning session. The results of the present study demonstrate that destruction of cell bodies in the VPM reduces HR conditioning to the level of a pseudoconditioning control without affecting HR baseline, or orienting responses to the CS. Lesions of the VPM also significantly augment the tachycardiac unconditioned response, suggesting that VPM lesions alter the somatosensory processing of the US.

  1. Association between the Rating Perceived Exertion, Heart Rate and Blood Lactate in Successive Judo Fights (Randori)

    PubMed Central

    Branco, Braulio H.M.; Massuça, Luis M.; Andreato, Leonardo V.; Marinho, Bruno F.; Miarka, Bianca; Monteiro, Luis; Franchini, Emerson

    2013-01-01

    Purpose This study aims to investigate the association between the rating of perceived exertion (RPE), heart rate (HR) and the blood lactate concentration ([La]) in successive judo fight simulations (randori). Methods Ten athletes participated in the study (age: 25.6±2.1 years; stature: 1.75±0.07 m; body mass: 75.6±14.9kg; %BF: 11.5±7.8%; practice: 14.5±6.2 years) and completed 4 judo fight simulations (T1 to T4) with duration of 5 min separated by 5 min passive recovery periods. Before each randori, [La] and HR were collected, and after each randori, the same measures and the RPE (CR-10 scale) were collected. Results Significant correlations were observed between: (1) CR-10 and HR (T2: r =0.70; T3: r =0.64; both, P<0.05); (2) ΔCR-10 and Δ[La] (T1-T2: r = .71, P< 0.05; T2-T3: r =0.92, P<0.01; T3-T4: r =0.73, P<0.05). Moreover, significant differences were noted in the behavior of the HR between the 2nd (T2) and 3rd (T3) judo fight simulations (P<0.05). Conclusion The use of CR-10 in the evaluation process, as well as in deciding the load of training in judo, should be done with caution. PMID:23802054

  2. Ambulatory blood pressure and heart rate during shuttle flight, entry and landing

    NASA Technical Reports Server (NTRS)

    Thornton, W.; Moore, T. P.; Uri, J.

    1993-01-01

    Ambulatory blood pressures (BP) and heart rates (HR) were recorded on a series of early Shuttle flights during preflight and pre-entry, entry, landing and egress. There were no significant differences between flight and preflight values during routine activity. Systolic blood pressure was slightly elevated in the deorbit period and systolic and diastolic blood pressure and heart rates were all elevated with onset of gravitoinertial loads and remained so through egress. Two of seven subjects had orthostatic problems in egress but their data did not show significant differences from others except in heart rate. Comparison of this data to that from recent studies show even larger increase in HR/BP values during current deorbit and entry phases which is consistent with increased heat and weight loads imposed by added survival gear. Both value and limitations of ambulatory heart rate/blood pressure data in this situation are demonstrated.

  3. Nonlinear control techniques for the heart rate regulation in treadmill exercises.

    PubMed

    Scalzi, Stefano; Tomei, Patrizio; Verrelli, Cristiano Maria

    2012-03-01

    It has been recently shown in the literature that a robust output feedback controller for the heart rate regulation can be designed for an experimentally validated second order nonlinear model of the human heart rate response during long-duration treadmill exercises: It is based on piecewise linear approximations of the original nonlinear model and involves (local) robust linear control techniques. In this letter, we resort to recent nonlinear advanced control techniques in order to illustrate the existence of a nonlocal and nonswitching control which guarantees heart rate regulation with no exact knowledge of model parameters and nonlinearities: It simply generalizes to the nonlinear framework the classical proportional-integral control design for linear models of heart rate response during treadmill exercises. Simulation and experimental results demonstrate the effectiveness of the proposed approach in typical training exercises involving warm up/holding/cool down phases.

  4. Motion artifact cancellation and outlier rejection for clip-type ppg-based heart rate sensor.

    PubMed

    Shimazaki, Takunori; Hara, Shinsuke; Okuhata, Hiroyuki; Nakamura, Hajime; Kawabata, Takashi

    2015-01-01

    Heart rate sensing can be used to not only understand exercise intensity but also detect life-critical condition during sports activities. To reduce stress during exercise and attach heart rate sensor easily, we developed a clip-type photoplethysmography (PPG)-based heart rate sensor. The sensor can be attached just by hanging it to the waist part of undershorts, and furthermore, it employs the motion artifact (MA) cancellation technique. However, due to its low contact pressure, sudden jumps and drops, which are called "outliers," are often observed in the sensed heart rate, so we also developed a simple outlier rejection technique. By an experiment using five male subjects (4 sets per subject), we confirmed the MA cancellation and outlier rejection capabilities. PMID:26736684

  5. Development and validation of an improved smartphone heart rate acquisition system

    NASA Astrophysics Data System (ADS)

    Karapetyan, G.; Barseghyan, R.; Sarukhanyan, H.; Agaian, S.

    2015-03-01

    In this paper we propose a robust system for touchless heart rate (HR) acquisition on mobile devices. The application allows monitor heart rate signal during usual mobile device usage such as video watching, games playing, article reading etc. The system is based on algorithm of acquiring heart rate via recording of skin color variations with built-in cameras of mobile device. The signal is acquired from different ROIs of human face, which make it more clear and the amplification of the signal improve the robustness in low lightening conditions. The effectiveness and robustness of the developed system has been demonstrated under different distances from camera source and illumination conditions. The experiments have been done with different mobile devices HRs were collected from 10 subjects, ages 22 to 65, by using the 3 devices. Moreover, we compared the developed method with Food and Drug Administration (FDA) approved sensors and related commercial applications of remote heart rate measurements on mobile devices.

  6. Long-term heart rate fluctuations in postoperative and brain-dead patients.

    PubMed

    Tamura, T; Maekawa, T; Nakajima, K; Sadamitsu, D; Tateishi, A

    1998-11-01

    Long-term heart rate fluctuations in postoperative and brain-dead patients were investigated. Heart rates were monitored continuously, and the data were stored, edited, and interpolated to allow for data lost during calibration and disconnection of the sensors for various treatments. Heart rate power spectra were calculated using the fast Fourier transform method. The power spectra of the patients who recovered showed that the heart rate fluctuated and produced a 1/f relationship, termed 1/f fluctuations, whereas those of patients who died in the intensive care unit (ICU) consisted of white-noise-like signals. The power spectra in brain-dead patients showed a 1/f relationship under steady-state conditions, while the power density and variation of the frequency distribution were lower than those in a normal subject. Therefore, 1/f fluctuations appear to be universal and occur independent of the central nervous system. PMID:9844751

  7. Using complexity metrics with R-R intervals and BPM heart rate measures

    PubMed Central

    Wallot, Sebastian; Fusaroli, Riccardo; Tylén, Kristian; Jegindø, Else-Marie

    2013-01-01

    Lately, growing attention in the health sciences has been paid to the dynamics of heart rate as indicator of impending failures and for prognoses. Likewise, in social and cognitive sciences, heart rate is increasingly employed as a measure of arousal, emotional engagement and as a marker of interpersonal coordination. However, there is no consensus about which measurements and analytical tools are most appropriate in mapping the temporal dynamics of heart rate and quite different metrics are reported in the literature. As complexity metrics of heart rate variability depend critically on variability of the data, different choices regarding the kind of measures can have a substantial impact on the results. In this article we compare linear and non-linear statistics on two prominent types of heart beat data, beat-to-beat intervals (R-R interval) and beats-per-min (BPM). As a proof-of-concept, we employ a simple rest-exercise-rest task and show that non-linear statistics—fractal (DFA) and recurrence (RQA) analyses—reveal information about heart beat activity above and beyond the simple level of heart rate. Non-linear statistics unveil sustained post-exercise effects on heart rate dynamics, but their power to do so critically depends on the type data that is employed: While R-R intervals are very susceptible to non-linear analyses, the success of non-linear methods for BPM data critically depends on their construction. Generally, “oversampled” BPM time-series can be recommended as they retain most of the information about non-linear aspects of heart beat dynamics. PMID:23964244

  8. Heart Rate Variability and the Efficacy of Biofeedback in Heroin Users with Depressive Symptoms

    PubMed Central

    Lin, I-Mei; Ko, Jiun-Min; Fan, Sheng-Yu; Yen, Cheng-Fang

    2016-01-01

    Objective Low heart rate variability (HRV) has been confirmed in heroin users, but the effects of heart-rate-variability–biofeedback in heroin users remain unknown. This study examined (1) correlations between depression and HRV indices; (2) group differences in HRV indices among a heroin-user group, a group with major depressive disorder but no heroin use, and healthy controls; and (3) the effects of heart-rate-variability–biofeedback on depressive symptoms, HRV indices, and respiratory rates within the heroin group. Methods All participants completed a depression questionnaire and underwent electrocardiogram measurements, and group differences in baseline HRV indices were examined. The heroin group underwent electrocardiogram and respiration rate measurements at baseline, during a depressive condition, and during a happiness condition, before and after which they took part in the heart-rate-variability–biofeedback program. The effects of heart-rate-variability–biofeedback on depressive symptoms, HRV indices, and respiration rates were examined. Results There was a negative correlation between depression and high frequency of HRV, and a positive correlation between depression and low frequency to high frequency ratio of HRV. The heroin group had a lower overall and high frequency of HRV, and a higher low frequency/high frequency ratio than healthy controls. The heart-rate-variability–biofeedback intervention increased HRV indices and decreased respiratory rates from pre-intervention to post-intervention. Conclusion Reduced parasympathetic and increased sympathetic activations were found in heroin users. Heart-rate-variability–biofeedback was an effective non-pharmacological intervention to restore autonomic balance. PMID:27121428

  9. Diurnal variations in arousal: a naturalistic heart rate study in children with ADHD.

    PubMed

    Imeraj, Lindita; Antrop, Inge; Roeyers, Herbert; Deschepper, Ellen; Bal, Sarah; Deboutte, Dirk

    2011-08-01

    Previous studies suggest an altered circadian regulation of arousal in children with attention-deficit hyperactivity disorder (ADHD) as measured by activity, circadian preference, and sleep-wake patterns. Although heart rate is an important measure to evaluate arousal profiles, to date it is unknown whether 24-h heart rate patterns differentiate between children with and without ADHD. In this study, 24-h heart rate data were collected in 30 non-medicated children with ADHD (aged 6-11) and 30 sex-, class-, and age-matched normal controls in their naturalistic home and school setting, during 5 days. Simultaneously, 24-h activity patterns were registered. Confounding effects of demographic variables (e.g., age, sex, BMI, pubertal stage) and comorbid internalizing and externalizing problems on heart rate levels were additionally assessed. Longitudinal analysis showed that heart rate levels were overall higher in the ADHD group (p < 0.01)--with the largest effects during afternoon and night--in a model controlling for age. Other factors did not significantly contribute to variations in heart rate levels. Compared to controls, children with ADHD showed higher activity levels during daytime (especially early afternoon), but not during nighttime (p < 0.05). Post hoc analyses showed that environmental effects might influence daytime variations. Findings suggest an autonomic imbalance in children with ADHD as compared to controls, with higher heart rate levels in the ADHD group. Nighttime tachycardia in this group could not be explained by nighttime activity levels or comorbid externalizing/internalizing problems. Further research on autonomic functioning in ADHD is recommended because of the major impact of higher resting heart rate on health outcomes.

  10. Heart rate variability in 1-day-old infants born at 4330 m altitude.

    PubMed

    Mortola, J P; León-Velarde, F; Aguero, L; Frappell, P B

    1999-02-01

    In fetuses and newborn infants heart rate variability changes in conditions of acute and chronic hypoxia; we therefore asked whether heart rate variability of infants born at high altitude differed from that of low-altitude infants. Short-term recordings (4-5 min) of inter-beat intervals were obtained in 19 infants in Lima (50 m altitude) and in 15 infants in Cerro de Pasco (4330 m, barometric pressure approximately 450 mmHg, inspired oxygen pressure approximately 94 mmHg) during quiet rest in warm conditions (ambient temperature, Ta, approximately 35 degrees C). In 12 infants from each group recordings were also obtained during cooling (Ta approximately 26 degrees C). Heart rate variability was evaluated from 512 consecutive inter-beat intervals, with analysis based on time-domain and frequency-domain methods. At warm Ta, heart rate variability did not differ between the two groups. During cooling, heart rate increased only in the low-altitude group. As in the warm, during cooling most parameters of heart rate variability did not differ between the two groups. The only exception was the inter-beat interval power of the high-frequency range of the spectrum (0.15-0.4 Hz), which, at least in adults, is believed to be a reflection of vagal activity, and was greater in the high-altitude group. It is concluded that gestation at high altitude, despite its blunting effects on fetal growth, does not have a major impact on heart rate variability of the newborn. Nevertheless, the possibility that differences in response to cooling may reflect some limitation in heart rate control needs to be examined further.

  11. Nonlinear systems dynamics in cardiovascular physiology: The heart rate delay map and lower body negative pressure

    NASA Technical Reports Server (NTRS)

    Hooker, John C.

    1990-01-01

    A preliminary study of the applicability of nonlinear dynamic systems analysis techniques to low body negative pressure (LBNP) studies. In particular, the applicability of the heart rate delay map is investigated. It is suggested that the heart rate delay map has potential as a supplemental tool in the assessment of subject performance in LBNP tests and possibly in the determination of susceptibility to cardiovascular deconditioning with spaceflight.

  12. Heart rate variability during "alarm stage" of burnout syndrome in emergency doctors.

    PubMed

    Kotov, A V; Revina, N E

    2012-09-01

    The parameters of heart rate variations were examined in emergency care doctors that demonstrated the initial signs of defensive psychological burnout syndrome related to their professional activity. These parameters were compared within each of two groups with different individual typological features. The differences in the heart rate variability parameters were revealed between the examinees that were at the compensation or alarm stages of the burnout syndrome.

  13. Contact-free Measurement of Heart Rate Variability via a Microwave Sensor

    PubMed Central

    Lu, Guohua; Yang, Fang; Tian, Yue; Jing, Xijing; Wang, Jianqi

    2009-01-01

    Measures of heart rate variability (HRV) are widely used to assess autonomic nervous system (ANS) function. HRV can be recorded via electrocardiography (ECG), which is both non-invasive and widely available. However, ECG needs three electrodes touching the body of the subjects, which makes them feel nervous and uncomfortable, thus potentially affecting the recording. Contact-free detection of the heartbeat via a microwave sensor constitutes another means of determining the timing of cardiac cycles by continuous monitoring of mechanical contraction of the heart. This technique can measure the heartbeat without any electrodes touching human body and penetrate the clothes at some distances, which in some instances may prove a practical basis for HRV analysis. Comparison of 5-minute recordings demonstrated that there were no significant differences in the temporal, frequency domains and in non-linear dynamic analysis of HRV measures derived from heartbeat and ECG, which suggested this technique may prove a practical alternative to ECG for HRV analysis. PMID:22303140

  14. Monty Roberts' Public Demonstrations: Preliminary Report on the Heart Rate and Heart Rate Variability of Horses Undergoing Training during Live Audience Events.

    PubMed

    Loftus, Loni; Marks, Kelly; Jones-McVey, Rosie; Gonzales, Jose L; Fowler, Veronica L

    2016-01-01

    Effective training of horses relies on the trainer's awareness of learning theory and equine ethology, and should be undertaken with skill and time. Some trainers, such as Monty Roberts, share their methods through the medium of public demonstrations. This paper describes the opportunistic analysis of beat-to-beat (RR) intervals and heart rate variability (HRV) of ten horses being used in Monty Roberts' public demonstrations within the United Kingdom. RR and HRV was measured in the stable before training and during training. The HRV variables standard deviation of the RR interval (SDRR), root mean square of successive RR differences (RMSSD), geometric means standard deviation 1 (SD1) and 2 (SD2), along with the low and high frequency ratio (LF/HF ratio) were calculated. The minimum, average and maximum RR intervals were significantly lower in training (indicative of an increase in heart rate as measured in beats-per-minute) than in the stable ( p = 0.0006; p = 0.01; p = 0.03). SDRR, RMSSD, SD1, SD2 and the LF/HF ratio were all significantly lower in training than in the stable ( p = 0.001; p = 0.049; p = 0.049; p = 0.001; p = 0.01). When comparing the HR and HRV of horses during Join-up (®) to overall training, there were no significant differences in any variable with the exception of maximum RR which was significantly lower ( p = 0.007) during Join-up (®) , indicative of short increases in physical exertion (canter) associated with this training exercise. In conclusion, training of horses during public demonstrations is a low-moderate physiological, rather than psychological stressor for horses. The physiological stress responses observed within this study were comparable or less to those previously reported in the literature for horses being trained outside of public audience events. Furthermore, there is no evidence that the use of Join-up (®) alters HR and HRV in a way to suggest that this training method negatively affects the psychological welfare of

  15. Monty Roberts' Public Demonstrations: Preliminary Report on the Heart Rate and Heart Rate Variability of Horses Undergoing Training during Live Audience Events.

    PubMed

    Loftus, Loni; Marks, Kelly; Jones-McVey, Rosie; Gonzales, Jose L; Fowler, Veronica L

    2016-01-01

    Effective training of horses relies on the trainer's awareness of learning theory and equine ethology, and should be undertaken with skill and time. Some trainers, such as Monty Roberts, share their methods through the medium of public demonstrations. This paper describes the opportunistic analysis of beat-to-beat (RR) intervals and heart rate variability (HRV) of ten horses being used in Monty Roberts' public demonstrations within the United Kingdom. RR and HRV was measured in the stable before training and during training. The HRV variables standard deviation of the RR interval (SDRR), root mean square of successive RR differences (RMSSD), geometric means standard deviation 1 (SD1) and 2 (SD2), along with the low and high frequency ratio (LF/HF ratio) were calculated. The minimum, average and maximum RR intervals were significantly lower in training (indicative of an increase in heart rate as measured in beats-per-minute) than in the stable ( p = 0.0006; p = 0.01; p = 0.03). SDRR, RMSSD, SD1, SD2 and the LF/HF ratio were all significantly lower in training than in the stable ( p = 0.001; p = 0.049; p = 0.049; p = 0.001; p = 0.01). When comparing the HR and HRV of horses during Join-up (®) to overall training, there were no significant differences in any variable with the exception of maximum RR which was significantly lower ( p = 0.007) during Join-up (®) , indicative of short increases in physical exertion (canter) associated with this training exercise. In conclusion, training of horses during public demonstrations is a low-moderate physiological, rather than psychological stressor for horses. The physiological stress responses observed within this study were comparable or less to those previously reported in the literature for horses being trained outside of public audience events. Furthermore, there is no evidence that the use of Join-up (®) alters HR and HRV in a way to suggest that this training method negatively affects the psychological welfare of

  16. Sports-medical studies on parachute jumpers with particular reference to the behavior of heart rate.

    PubMed

    Jung, K; Schulze, J

    1982-01-01

    The aim of the experiment was to record the heart rate tracings of three groups of parachutists - with manually operated parachutes, automatically operated parachutes and formation parachutists (sky divers) - during the jump and to compare these with the findings obtained during bicycle ergometer stress tests. A total of 112 parachute jumps involving 31 subjects were evaluated. All the subjects exhibited a significant increase in heart rate during the exit, canopy opening and landing phases. Qualitatively, the heart rate curves of the formation, manual and automatic parachutists showed a similar trend. Rises in heart rate during the opening of the parachute (for the formation parachutists) and during landing (for the automatic parachutists) were, however, particularly pronounced. The increase in heart rate can be principally ascribed to emotional tension and a state of anticipation rather than to physical stress. The comparative evaluation of the ergometer tests showed that as a general rule stress factors in the submaximal region occur during parachuting, but that in extreme situations heart rates in the maximal region of physical stress may well be expected.

  17. [Changes in heart rate variability after myocardial infarction. Value of Poincareé's diagram].

    PubMed

    Copie, X; Le Heuzey, J Y; Iliou, M C; Pousset, F; Lavergne, T; Guize, L

    1995-11-01

    The variability of the heart rate is reduced after myocardial infarction. It then progressively increases, to return to near normal values after several months. However, these changes in heart rate variability occur at the same time as slowing of the heart rate which makes interpretation difficult. Poincaré's diagram is constructed from a Holter recording plotting each RR interval against the preceding RR interval. The authors have developed a geometric approach to this diagram to evaluate parasympathetic tone for a given heart rate. By measuring the dispersion in height of the Poincaré's diagram, the authors evaluate the shor-term variability for a given RR interval. Two 24 hr Holter recordings were performed in 52 patients at one and two weeks after a myocardial infarction. The dispersion in the height of the Poincaré's diagrams was measured at the 10th, 25th, 50th, 75th and 90th percentiles of the total dispersion. The authors have shown an increase in the short-term variability of the shortest RR intervals (1th, 25th and 50th percentiles) which is not observed in the longer RR intervals (75th and 90th percentiles). In conclusion, theres is an increase in the heart rate variability at the shortest RR intervals. This suggests that the recovery of parasympathic tone after myocardial infarction occurs mainly at the fastest heart rates. PMID:8745997

  18. Are smoking and passive smoking related with heart rate variability in male adolescents?

    PubMed Central

    Gondim, Renata Melo; Farah, Breno Quintella; Santos, Carolina da Franca Bandeira Ferreira; Ritti-Dias, Raphael Mendes

    2015-01-01

    Objective To analyze the relation between smoking and passive smoking with heart rate variability parameters in male adolescents. Methods The sample consisted of 1,152 males, aged 14 and 19 years. Data related to smoking and passive smoking were collected using a questionnaire. RR intervals were obtained by a heart rate monitor, on supine position, for 10 minutes. After collecting the RR intervals, time (standard deviation of all RR intervals, root mean square of the squared differences between adjacent normal RR intervals and the percentage of adjacent intervals over 50ms) and frequency domains (low and high frequency and sympathovagal balance) parameters of heart rate variability were obtained. Results No significant differences between smoker and nonsmoker adolescents were observed in heart rate variability parameters (p>0.05). Similarly, heart rate variability parameters did not show significant difference between exposed and not exposed to passive smoking (p>0.05). Conclusion Cigarette smoking and passive smoking are not related to heart rate variability in adolescence. PMID:25993065

  19. Heart Rate Detection During Sleep Using a Flexible RF Resonator and Injection-Locked PLL Sensor.

    PubMed

    Kim, Sung Woo; Choi, Soo Beom; An, Yong-Jun; Kim, Byung-Hyun; Kim, Deok Won; Yook, Jong-Gwan

    2015-11-01

    Novel nonintrusive technologies for wrist pulse detection have been developed and proposed as systems for sleep monitoring using three types of radio frequency (RF) sensors. The three types of RF sensors for heart rate measurement on wrist are a flexible RF single resonator, array resonators, and an injection-locked PLL resonator sensor. To verify the performance of the new RF systems, we compared heart rates between presleep time and postsleep onset time. Heart rates of ten subjects were measured using the RF systems during sleep. All three RF devices detected heart rates at 0.2 to 1 mm distance from the skin of the wrist over clothes made of cotton fabric. The wrist pulse signals of a flexible RF single resonator were consistent with the signals obtained by a portable piezoelectric transducer as a reference. Then, we confirmed that the heart rate after sleep onset time significantly decreased compared to before sleep. In conclusion, the RF system can be utilized as a noncontact nonintrusive method for measuring heart rates during sleep.

  20. The effect of competition on heart rate during kart driving: A field study

    PubMed Central

    2011-01-01

    Background Both the act of competing, which can create a kind of mental stress, and participation in motor sports, which induces physical stress from intense g-forces, are known to increase heart rate dramatically. However, little is known about the specific effect of competition on heart rate during motor sports, particularly during four-wheel car driving. The goal of this preliminary study, therefore, was to investigate whether competition increases heart rate under such situations. Findings The participants drove an entry-level formula kart during two competitive races and during solo driving against the clock while heart rate and g-forces were measured. Analyses showed that heart rate values during the races (168.8 beats/min) were significantly higher than those during solo driving (140.9 beats/min) and rest (75.1 beats/min). Conclusions The results of this preliminary study indicate that competition heightens heart rate during four-wheel car driving. Kart drivers should be concerned about maintaining good health and developing physical strength. PMID:21906298

  1. Estimation of heart rate variability using a compact radiofrequency motion sensor.

    PubMed

    Sugita, Norihiro; Matsuoka, Narumi; Yoshizawa, Makoto; Abe, Makoto; Homma, Noriyasu; Otake, Hideharu; Kim, Junghyun; Ohtaki, Yukio

    2015-12-01

    Physiological indices that reflect autonomic nervous activity are considered useful for monitoring peoples' health on a daily basis. A number of such indices are derived from heart rate variability, which is obtained by a radiofrequency (RF) motion sensor without making physical contact with the user's body. However, the bulkiness of RF motion sensors used in previous studies makes them unsuitable for home use. In this study, a new method to measure heart rate variability using a compact RF motion sensor that is sufficiently small to fit in a user's shirt pocket is proposed. To extract a heart rate related component from the sensor signal, an algorithm that optimizes a digital filter based on the power spectral density of the signal is proposed. The signals of the RF motion sensor were measured for 29 subjects during the resting state and their heart rate variability was estimated from the measured signals using the proposed method and a conventional method. A correlation coefficient between true heart rate and heart rate estimated from the proposed method was 0.69. Further, the experimental results showed the viability of the RF sensor for monitoring autonomic nervous activity. However, some improvements such as controlling the direction of sensing were necessary for stable measurement.

  2. [Changes in heart rate variability after myocardial infarction. Value of Poincareé's diagram].

    PubMed

    Copie, X; Le Heuzey, J Y; Iliou, M C; Pousset, F; Lavergne, T; Guize, L

    1995-11-01

    The variability of the heart rate is reduced after myocardial infarction. It then progressively increases, to return to near normal values after several months. However, these changes in heart rate variability occur at the same time as slowing of the heart rate which makes interpretation difficult. Poincaré's diagram is constructed from a Holter recording plotting each RR interval against the preceding RR interval. The authors have developed a geometric approach to this diagram to evaluate parasympathetic tone for a given heart rate. By measuring the dispersion in height of the Poincaré's diagram, the authors evaluate the shor-term variability for a given RR interval. Two 24 hr Holter recordings were performed in 52 patients at one and two weeks after a myocardial infarction. The dispersion in the height of the Poincaré's diagrams was measured at the 10th, 25th, 50th, 75th and 90th percentiles of the total dispersion. The authors have shown an increase in the short-term variability of the shortest RR intervals (1th, 25th and 50th percentiles) which is not observed in the longer RR intervals (75th and 90th percentiles). In conclusion, theres is an increase in the heart rate variability at the shortest RR intervals. This suggests that the recovery of parasympathic tone after myocardial infarction occurs mainly at the fastest heart rates.

  3. Estimation of heart rate variability using a compact radiofrequency motion sensor.

    PubMed

    Sugita, Norihiro; Matsuoka, Narumi; Yoshizawa, Makoto; Abe, Makoto; Homma, Noriyasu; Otake, Hideharu; Kim, Junghyun; Ohtaki, Yukio

    2015-12-01

    Physiological indices that reflect autonomic nervous activity are considered useful for monitoring peoples' health on a daily basis. A number of such indices are derived from heart rate variability, which is obtained by a radiofrequency (RF) motion sensor without making physical contact with the user's body. However, the bulkiness of RF motion sensors used in previous studies makes them unsuitable for home use. In this study, a new method to measure heart rate variability using a compact RF motion sensor that is sufficiently small to fit in a user's shirt pocket is proposed. To extract a heart rate related component from the sensor signal, an algorithm that optimizes a digital filter based on the power spectral density of the signal is proposed. The signals of the RF motion sensor were measured for 29 subjects during the resting state and their heart rate variability was estimated from the measured signals using the proposed method and a conventional method. A correlation coefficient between true heart rate and heart rate estimated from the proposed method was 0.69. Further, the experimental results showed the viability of the RF sensor for monitoring autonomic nervous activity. However, some improvements such as controlling the direction of sensing were necessary for stable measurement. PMID:26603507

  4. Sports-medical studies on parachute jumpers with particular reference to the behavior of heart rate.

    PubMed

    Jung, K; Schulze, J

    1982-01-01

    The aim of the experiment was to record the heart rate tracings of three groups of parachutists - with manually operated parachutes, automatically operated parachutes and formation parachutists (sky divers) - during the jump and to compare these with the findings obtained during bicycle ergometer stress tests. A total of 112 parachute jumps involving 31 subjects were evaluated. All the subjects exhibited a significant increase in heart rate during the exit, canopy opening and landing phases. Qualitatively, the heart rate curves of the formation, manual and automatic parachutists showed a similar trend. Rises in heart rate during the opening of the parachute (for the formation parachutists) and during landing (for the automatic parachutists) were, however, particularly pronounced. The increase in heart rate can be principally ascribed to emotional tension and a state of anticipation rather than to physical stress. The comparative evaluation of the ergometer tests showed that as a general rule stress factors in the submaximal region occur during parachuting, but that in extreme situations heart rates in the maximal region of physical stress may well be expected. PMID:7183353

  5. Effect of predator odors on heart rate and metabolic rate of wapiti (Cervus elaphus canadensis).

    PubMed

    Chabot, D; Gagnon, P; Dixon, E A

    1996-04-01

    We measured the heart rate (HR) and oxygen consumption ([Formula: see text]) of wapiti (Cervus elaphus canadensis) before, during, and after presentation of biologically irrelevant odors (pentane, thiophene, and a perfume), artificial predator odors (an ether extract of cougar feces, and PDT, a compound found in mustelid anal gland secretion), stale predator odors (dog feces and urine and fox urine, kept at ambient temperature for a few weeks), and fresh predator odors (wolf, coyote, and cougar feces and the odor of a dead coyote, kept frozen between collection and test). Overall, responses to odors were small compared to other stressful stimuli. Individual variability was high among scents and among wapiti, but two of the fresh predator odors (cougar and wolf feces) produced larger HR and[Formula: see text] responses than the other scents and were more often successful at producing responses. As a group, fresh predator odors produced larger tachycardias and elicited a larger number of significant HR responses than biologically irrelevant novel odors. although the two classes of odors did not differ in their effect on[Formula: see text]. Although several other studies have shown that ungulates have reduced feeding levels when their food is scented with predator odors, it is not clear if this is due to reduced palatability or antipredator behavior. This study is the first demonstration that a wild ungulate species reacted more strongly to predator odors than to other odors in a nonfeeding situation.

  6. Influence of transvaginal ultrasound-guided follicular punctures in the mare on heart rate, respiratory rate, facial expression changes, and salivary cortisol as pain scoring.

    PubMed

    Diego, Rodrigo; Douet, Cécile; Reigner, Fabrice; Blard, Thierry; Cognié, Juliette; Deleuze, Stefan; Goudet, Ghylène

    2016-10-15

    Transvaginal ultrasound-guided follicular punctures are widely used in the mare for diagnosis, research, and commercial applications. The objective of our study was to determine their influence on pain, stress, and well-being in the mare, by evaluating heart rate, breath rate, facial expression changes, and salivary cortisol before, during, and after puncture. For this experiment, 21 pony mares were used. Transvaginal ultrasound-guided aspirations were performed on 11 mares. After injections for sedation, analgesia, and antispasmodia, the follicles from both ovaries were aspirated with a needle introduced through the vagina wall into the ovary. In the control group, 10 mares underwent similar treatments and injections, but no follicular aspiration. Along the session, heart rate and breath rate were evaluated by a trained veterinarian, ears position, eyelid closure, and contraction of facial muscles were evaluated, and salivary samples were taken for evaluation of cortisol concentration. A significant relaxation was observed after sedative injection in the punctured and control mares, according to ear position, eyelid closure, and contraction of facial muscles, but no difference between punctured and control animals was recorded. No significant modification of salivary cortisol concentration during puncture and no difference between punctured and control mares at any time were observed. No significant modification of the breath rate was observed along the procedure for the punctured and the control mares. Heart rate increased significantly but transiently when the needle was introduced in the ovary and was significantly higher at that time for the punctured mares than that for control mares. None of the other investigated parameters were affected at that time, suggesting discomfort is minimal and transient. Improving analgesia, e.g., through a multimodal approach, during that possibly more sensitive step could be recommended. The evaluation of facial expression

  7. Influence of transvaginal ultrasound-guided follicular punctures in the mare on heart rate, respiratory rate, facial expression changes, and salivary cortisol as pain scoring.

    PubMed

    Diego, Rodrigo; Douet, Cécile; Reigner, Fabrice; Blard, Thierry; Cognié, Juliette; Deleuze, Stefan; Goudet, Ghylène

    2016-10-15

    Transvaginal ultrasound-guided follicular punctures are widely used in the mare for diagnosis, research, and commercial applications. The objective of our study was to determine their influence on pain, stress, and well-being in the mare, by evaluating heart rate, breath rate, facial expression changes, and salivary cortisol before, during, and after puncture. For this experiment, 21 pony mares were used. Transvaginal ultrasound-guided aspirations were performed on 11 mares. After injections for sedation, analgesia, and antispasmodia, the follicles from both ovaries were aspirated with a needle introduced through the vagina wall into the ovary. In the control group, 10 mares underwent similar treatments and injections, but no follicular aspiration. Along the session, heart rate and breath rate were evaluated by a trained veterinarian, ears position, eyelid closure, and contraction of facial muscles were evaluated, and salivary samples were taken for evaluation of cortisol concentration. A significant relaxation was observed after sedative injection in the punctured and control mares, according to ear position, eyelid closure, and contraction of facial muscles, but no difference between punctured and control animals was recorded. No significant modification of salivary cortisol concentration during puncture and no difference between punctured and control mares at any time were observed. No significant modification of the breath rate was observed along the procedure for the punctured and the control mares. Heart rate increased significantly but transiently when the needle was introduced in the ovary and was significantly higher at that time for the punctured mares than that for control mares. None of the other investigated parameters were affected at that time, suggesting discomfort is minimal and transient. Improving analgesia, e.g., through a multimodal approach, during that possibly more sensitive step could be recommended. The evaluation of facial expression

  8. Effect of varying heart rate on intra-ventricular filling fluid dynamics

    NASA Astrophysics Data System (ADS)

    Santhanakrishnan, Arvind; Okafor, Ikechukwu; Angirish, Yagna; Yoganathan, Ajit

    2013-11-01

    Impaired exercise tolerance is used to delineate asymptomatic patients during the clinical diagnosis of diastolic left heart failure. Examining the effects of varying heart rate on intra-ventricular filling can provide a physical understanding of the specific flow characteristics that are impacted during exercise. In this study, diastolic filling was investigated with an anatomical left ventricle (LV) physical model under normal heart rate of 70 bpm, and varying exercise conditions of 100 bpm and 120 bpm. The LV model was incorporated into a flow loop and tuned for physiological inflow rates and outflow pressures. 2D PIV measurements were conducted along 3 parallel longitudinal planes. The systemic pressure was maintained the same across all test conditions. The E/A ratio was maintained within 1.0-1.2 across all heart rates. The strength of the mitral vortex ring formed during E-wave, as well as the peak incoming jet velocity, decreased with increasing heart rate. During peak flow of the A-wave, the vortex ring propagated farther into the LV for 120 bpm as compared to 70 bpm. The results point to the heightened role of the atrial kick for optimal LV filling during exercise conditions. This study was funded by a grant from the National Heart, Lung and Blood Institute (RO1HL70262).

  9. Heart rate changes in relation to cosmic ray intensity variability: A wide investigation in different latitudes and longitudes

    NASA Astrophysics Data System (ADS)

    Mavromichalaki, Helen; Safaraly-Oghlu Babayev, Elchin; -Christina Papailiou, Maria; Dimitrova, Svetla; Kudela, Karel; Stetiarova, Jana; Giannaropoulou, Elisavet; Loucas, Panayiotis

    The increased number of recent studies over the last years, regarding the possible effect of geomagnetic disturbances and cosmic ray intensity variations may have on human physiological parameters (such as heart rate, arterial diastolic and systolic blood pressure, etc) suggests that biological objects and, particularly, human health are potentially affected by solar activity and related geophysical changes. Different scientific groups from Azerbaijan (Baku), Bulgaria (Sofia), Greece (Athens) and Slovakia (Kosice) have conducted relevant researches, separately or in cooperation with each another, using medical data from 1994 to 2008. The results of collaborative study of human heart rate changes in relation to cosmic ray intensity variations are presented in this paper. Heart rate data were digitally registered: 1) for seven functionally healthy persons on working days (including Saturdays) during experiments at the Laboratory of Heliobiology located at the Medical Centre INAM, Baku, for the time period from July 15, 2006 to March 3, 2008; 2) for 86 healthy volunteers of the Solar -Terrestrial Laboratory of the Bulgarian Academy of Sciences, Sofia on every working day during the autumn and spring in years of maximal solar activity, from October 1, 2001 to November 9, 2001 and from April 8, 2002 to May 28, 2002; 3) for 225 persons with no cardiac symptoms or hospital admission, of the cardiological clinic of the KAT Hospital in Athens, for the time period from 2002 to 2006; and 4) for 4018 Slovak aviators during the time period from January 1, 1994 to December 31, 2002. It should be noted that considered period covers different phases of solar activity cycles and is characterized by such time intervals of strong solar and geomagnetic activity as October -November 2003, November 2004, January and July 2005 and December 2006. The statistical methods were applied to establish a statistical significance of the effect of cosmic ray intensity variations on heart rate

  10. Validation of pulse rate variability as a surrogate for heart rate variability in chronically instrumented rabbits

    PubMed Central

    Pellegrino, Peter R.; Schiller, Alicia M.

    2014-01-01

    Heart rate variability (HRV) is a function of cardiac autonomic tone that is widely used in both clinical and animal studies. In preclinical studies, HRV measures are frequently derived using the arterial pulse waveform from an implanted pressure telemetry device, termed pulse rate variability (PRV), instead of the electrocardiogram signal in accordance with clinical guidelines. The acceptability of PRV as a surrogate for HRV in instrumented animals is unknown. Using rabbits implanted with intracardiac leads and chronically implanted pressure transducers, we investigated the correlation and agreement of time-domain, frequency-domain, and nonlinear indexes of HRV and PRV at baseline. We also investigated the effects of ventricular pacing and autonomic blockade on both measures. At baseline, HRV and PRV time- and frequency-domain parameters showed robust correlations and moderate to high agreement, whereas nonlinear parameters showed slightly weaker correlations and varied agreement. Ventricular pacing almost completely eliminated HRV, and spectral analysis of the PRV signal revealed a HRV-independent rhythm. After cardiac autonomic blockade with atropine or metoprolol, the changes in time- and non-normalized frequency-domain measures of PRV continued to show strong correlations and moderate to high agreement with corresponding changes in HRV measures. Blockade-induced changes in nonlinear PRV indexes correlated poorly with HRV changes and showed weak agreement. These results suggest that time- and frequency-domain measures of PRV are acceptable surrogates for HRV even in the context of changing cardiac autonomic tone, but caution should be used when nonlinear measures are a primary end point or when HRV is very low as HRV-independent rhythms may predominate. PMID:24791786

  11. Effects of hot-iron branding on heart rate, breathing rate and behaviour of anaesthetised Steller sea lions.

    PubMed

    Walker, K A; Mellish, J E; Weary, D M

    2011-10-01

    This study assessed the heart rate, breathing rate and behavioural responses of 12 juvenile Steller sea lions during hot-iron branding under isoflurane anaesthesia. Physiological and behavioural measures were recorded in four periods: baseline (five minutes), sham branding (one minute), branding (approximately 2.7 minutes) and postbranding (five minutes). No difference in heart rate was noted from baseline to sham branding, but heart rate increased from mean (sem) 78.3 (2.4) bpm in the baseline period to 85.6 (2.5) bpm in the branding period. Heart rate remained elevated in the postbranding period, averaging 84.7 (2.5) bpm. Breathing rate averaged 2.5 (1.0) breaths/minute in the baseline and sham branding periods increased to 8.9 (1.0) breaths/minute during branding, but returned to baseline by the postbranding period. Behaviourally, half of the sea lions exhibited trembling and head and shoulder movements during branding.

  12. Ice cream structural elements that affect melting rate and hardness.

    PubMed

    Muse, M R; Hartel, R W

    2004-01-01

    Statistical models were developed to reveal which structural elements of ice cream affect melting rate and hardness. Ice creams were frozen in a batch freezer with three types of sweetener, three levels of the emulsifier polysorbate 80, and two different draw temperatures to produce ice creams with a range of microstructures. Ice cream mixes were analyzed for viscosity, and finished ice creams were analyzed for air cell and ice crystal size, overrun, and fat destabilization. The ice phase volume of each ice cream were calculated based on the freezing point of the mix. Melting rate and hardness of each hardened ice cream was measured and correlated with the structural attributes by using analysis of variance and multiple linear regression. Fat destabilization, ice crystal size, and the consistency coefficient of the mix were found to affect the melting rate of ice cream, whereas hardness was influenced by ice phase volume, ice crystal size, overrun, fat destabilization, and the rheological properties of the mix.

  13. Short term Heart Rate Variability to predict blood pressure drops due to standing: a pilot study

    PubMed Central

    2015-01-01

    Background Standing from a bed or chair may cause a significant lowering of blood pressure (ΔBP), which may have severe consequences such as, for example, falls in older subjects. The goal of this study was to develop a mathematical model to predict the ΔBP due to standing in healthy subjects, based on their Heart Rate Variability, recorded in the 5 minutes before standing. Methods Heart Rate Variability was extracted from an electrocardiogram, recorded from 10 healthy subjects during the 5 minutes before standing. The blood pressure value was measured before and after rising. A mathematical model aiming to predict ΔBP based on Heart Rate Variability measurements was developed using a robust multi-linear regression and was validated with the leave-one-subject-out cross-validation technique. Results The model predicted correctly the ΔBP in 80% of experiments, with an error below the measurement error of sphygmomanometer digital devices (±4.5 mmHg), a false negative rate of 7.5% and a false positive rate of 10%. The magnitude of the ΔBP was associated with a depressed and less chaotic Heart Rate Variability pattern. Conclusions The present study showes that blood pressure lowering due to standing can be predicted by monitoring the Heart Rate Variability in the 5 minutes before standing. PMID:26391336

  14. Does lung diffusion impairment affect exercise capacity in patients with heart failure?

    PubMed Central

    Agostoni, P G; Bussotti, M; Palermo, P; Guazzi, M

    2002-01-01

    Objective: To determine whether there is a relation between impairment of lung diffusion and reduced exercise capacity in chronic heart failure. Design: 40 patients with heart failure in stable clinical condition and 40 controls participated in the study. All subjects underwent standard pulmonary function tests plus measurements of resting lung diffusion (carbon monoxide transfer, Tlco), pulmonary capillary volume (Vc), and membrane resistance (Dm), and maximal cardiopulmonary exercise testing. In 20 patients and controls, the following investigations were also done: (1) resting and constant work rate Tlco; (2) maximal cardiopulmonary exercise testing with inspiratory O2 fractions of 0.21 and 0.16; and (3) rest and peak exercise blood gases. The other subjects underwent Tlco, Dm, and Vc measurements during constant work rate exercise. Results: In normoxia, exercise induced reductions of haemoglobin O2 saturation never occurred. With hypoxia, peak exercise uptake (peak V̇o2) decreased from (mean (SD)) 1285 (395) to 1081 (396) ml/min (p < 0.01) in patients, and from 1861 (563) to 1771 (457) ml/min (p < 0.05) in controls. Resting Tlco correlated with peak V̇o2 in heart failure (normoxia < hypoxia). In heart failure patients and normal subjects, Tlco and peak V̇o2 correlated with O2 arterial content at rest and during peak exercise in both normoxia and hypoxia. Tlco, Vc, and Dm increased during exercise. The increase in Tlco was greater in patients who had a smaller reduction of exercise capacity with hypoxia. Alveolar–arterial O2 gradient at peak correlated with exercise capacity in heart failure during normoxia and, to a greater extent, during hypoxia. Conclusions: Lung diffusion impairment is related to exercise capacity in heart failure. PMID:12381630

  15. Autonomic control of heart rate during forced activity and digestion in the snake Boa constrictor.

    PubMed

    Wang, T; Taylor, E W; Andrade, D; Abe, A S

    2001-10-01

    Reptiles, particularly snakes, exhibit large and quantitatively similar increments in metabolic rate during muscular exercise and following a meal, when they are apparently inactive. The cardiovascular responses are similar during these two states, but the underlying autonomic control of the heart remains unknown. We describe both adrenergic and cholinergic tonus on the heart during rest, during enforced activity and during digestion (24-36 h after ingestion of 30 % of their body mass) in the snake Boa constrictor. The snakes were equipped with an arterial catheter for measurements of blood pressure and heart rate, and autonomic tonus was determined following infusion of the beta-adrenergic antagonist propranolol (3 mg kg(-1)) and the muscarinic cholinoceptor antagonist atropine (3 mg kg(-1)). The mean heart rate of fasting animals at rest was 26.4+/-1.4 min(-1), and this increased to 36.1+/-1.4 min(-1) (means +/- S.E.M.; N=8) following double autonomic block (atropine and propranolol). The calculated cholinergic and adrenergic tones were 60.1+/-9.3 % and 19.8+/-2.2 %, respectively. Heart rate increased to 61.4+/-1.5 min(-1) during enforced activity, and this response was significantly reduced by propranolol (maximum values of 35.8+/-1.6 min(-1)), but unaffected by atropine. The cholinergic and adrenergic tones were 2.6+/-2.2 and 41.3+/-1.9 % during activity, respectively. Double autonomic block virtually abolished tachycardia associated with enforced activity (heart rate increased significantly from 36.1+/-1.4 to 37.6+/-1.3 min(-1)), indicating that non-adrenergic, non-cholinergic effectors are not involved in regulating heart rate during activity. Blood pressure also increased during activity. Digestion was accompanied by an increase in heart rate from 25.6+/-1.3 to 47.7+/-2.2 min(-1) (N=8). In these animals, heart rate decreased to 44.2+/-2.7 min(-1) following propranolol infusion and increased to 53.9+/-1.8 min(-1) after infusion of atropine, resulting in small

  16. Effects of Age, Exercise Duration, and Test Conditions on Heart Rate Variability in Young Endurance Horses.

    PubMed

    Younes, Mohamed; Robert, Céline; Barrey, Eric; Cottin, François

    2016-01-01

    Although cardiac recovery is an important criterion for ranking horses in endurance competitions, heart rate variability (HRV) has hardly ever been studied in the context of this equestrian discipline. In the present study, we sought to determine whether HRV is affected by parameters such as age, exercise duration and test site. Accordingly, HRV might be used to select endurance horses with the fastest cardiac recovery. The main objective of the present study was to determine the effects of age, exercise duration, and test site on HRV variables at rest and during exercise and recovery in young Arabian endurance horses. Over a 3-year period, 77 young Arabian horses aged 4-6 years performed one or more exercise tests (consisting of a warm-up, cantering at 22 km.h(-1)and a final 500 m gallop at full speed) at four different sites. Beat-to-beat RR intervals were continuously recorded and then analyzed (using a time-frequency approach) to determine the instantaneous HRV components before, during and after the test. At rest, the root-mean-square of successive differences in RR intervals (RMSSD) was higher in the 4-year-olds (54.4 ± 14.5 ms) than in the 5-or 6-year-olds (44.9 ± 15.5 and 49.1 ± 11.7 ms, respectively). During the first 15 min of exercise (period T), the heart rate (HR) and RMSSD decreased with age. In 6-year-olds, RMSSD decreased as the exercise duration increased (T: 3.0 ± 1.4 vs. 2T: 3.6 ± 2.2 vs. 3T: 2.8 ± 1.0). During recovery, RMSSD was negatively correlated with the cardiac recovery time (CRT) and the recovery heart rate (RHR; R = -0.56 and -0.53, respectively; p < 0.05). At rest and during exercise and recovery, RMSSD and several HRV variables differed significantly as a function of the test conditions. HRV in endurance horses appears to be strongly influenced by age and environmental factors (such as ambient temperature, ambient humidity, and track quality). Nevertheless, RMSSD can be used to select endurance horses with the fastest cardiac

  17. Effects of Age, Exercise Duration, and Test Conditions on Heart Rate Variability in Young Endurance Horses.

    PubMed

    Younes, Mohamed; Robert, Céline; Barrey, Eric; Cottin, François

    2016-01-01

    Although cardiac recovery is an important criterion for ranking horses in endurance competitions, heart rate variability (HRV) has hardly ever been studied in the context of this equestrian discipline. In the present study, we sought to determine whether HRV is affected by parameters such as age, exercise duration and test site. Accordingly, HRV might be used to select endurance horses with the fastest cardiac recovery. The main objective of the present study was to determine the effects of age, exercise duration, and test site on HRV variables at rest and during exercise and recovery in young Arabian endurance horses. Over a 3-year period, 77 young Arabian horses aged 4-6 years performed one or more exercise tests (consisting of a warm-up, cantering at 22 km.h(-1)and a final 500 m gallop at full speed) at four different sites. Beat-to-beat RR intervals were continuously recorded and then analyzed (using a time-frequency approach) to determine the instantaneous HRV components before, during and after the test. At rest, the root-mean-square of successive differences in RR intervals (RMSSD) was higher in the 4-year-olds (54.4 ± 14.5 ms) than in the 5-or 6-year-olds (44.9 ± 15.5 and 49.1 ± 11.7 ms, respectively). During the first 15 min of exercise (period T), the heart rate (HR) and RMSSD decreased with age. In 6-year-olds, RMSSD decreased as the exercise duration increased (T: 3.0 ± 1.4 vs. 2T: 3.6 ± 2.2 vs. 3T: 2.8 ± 1.0). During recovery, RMSSD was negatively correlated with the cardiac recovery time (CRT) and the recovery heart rate (RHR; R = -0.56 and -0.53, respectively; p < 0.05). At rest and during exercise and recovery, RMSSD and several HRV variables differed significantly as a function of the test conditions. HRV in endurance horses appears to be strongly influenced by age and environmental factors (such as ambient temperature, ambient humidity, and track quality). Nevertheless, RMSSD can be used to select endurance horses with the fastest cardiac

  18. Effects of Age, Exercise Duration, and Test Conditions on Heart Rate Variability in Young Endurance Horses

    PubMed Central

    Younes, Mohamed; Robert, Céline; Barrey, Eric; Cottin, François

    2016-01-01

    Although cardiac recovery is an important criterion for ranking horses in endurance competitions, heart rate variability (HRV) has hardly ever been studied in the context of this equestrian discipline. In the present study, we sought to determine whether HRV is affected by parameters such as age, exercise duration and test site. Accordingly, HRV might be used to select endurance horses with the fastest cardiac recovery. The main objective of the present study was to determine the effects of age, exercise duration, and test site on HRV variables at rest and during exercise and recovery in young Arabian endurance horses. Over a 3-year period, 77 young Arabian horses aged 4–6 years performed one or more exercise tests (consisting of a warm-up, cantering at 22 km.h−1and a final 500 m gallop at full speed) at four different sites. Beat-to-beat RR intervals were continuously recorded and then analyzed (using a time-frequency approach) to determine the instantaneous HRV components before, during and after the test. At rest, the root-mean-square of successive differences in RR intervals (RMSSD) was higher in the 4-year-olds (54.4 ± 14.5 ms) than in the 5-or 6-year-olds (44.9 ± 15.5 and 49.1 ± 11.7 ms, respectively). During the first 15 min of exercise (period T), the heart rate (HR) and RMSSD decreased with age. In 6-year-olds, RMSSD decreased as the exercise duration increased (T: 3.0 ± 1.4 vs. 2T: 3.6 ± 2.2 vs. 3T: 2.8 ± 1.0). During recovery, RMSSD was negatively correlated with the cardiac recovery time (CRT) and the recovery heart rate (RHR; R = −0.56 and −0.53, respectively; p < 0.05). At rest and during exercise and recovery, RMSSD and several HRV variables differed significantly as a function of the test conditions. HRV in endurance horses appears to be strongly influenced by age and environmental factors (such as ambient temperature, ambient humidity, and track quality). Nevertheless, RMSSD can be used to select endurance horses with the fastest

  19. Chronic intermittent hypoxia-hypercapn