Anxiety is an area of documented challenge for people with Autism Spectrum Disorder (ASD). Despite this, some studies state that those with ASD and language deficits have lower reported anxiety than those without language deficits. This effect may be due to the complicated task of appropriately evaluating anxiety in those with compromised language. Using biomarkers of anxiety, such as reduced Heart Rate Variability (HRV) and increased Heart Rate (HR), may improve anxiety assessment but more research is necessary. Specifically, it would be helpful to understand if the relationship between HRV/HR and anxiety is moderated by language abilities in children with ASD, and whether HRV/HR can discriminate between anxiety and other emotions, like anger, in children with ASD. This study examined the relationship between baseline HRV/HR, language ability, and different emotional states (i.e., anxiety and anger) in a sample of 23 children with ASD. It was hypothesized that receptive language would moderate the relationship between decreased HRV/increased HR and increased anxiety but not the relationship between decreased HRV/increased HR and increased anger. Multiple regression analyses indicated that HRV and HR were not significant predictors of anxiety or anger, and language was not a significant moderator. Future studies may wish to take new approaches to determining the role of language in the relationship between HRV/HR and anxiety. / Master of Science / Anxiety is an area of documented challenge for people with Autism Spectrum Disorder (ASD). Despite this, some studies state that those with ASD and language deficits have lower reported anxiety than those without language deficits. This effect may be due to the complicated task of appropriately evaluating anxiety in those with compromised language. Using biomarkers of anxiety, such as reduced Heart Rate Variability (HRV) and increased Heart Rate (HR), may improve anxiety assessment but more research is necessary. Specifically, it would be helpful to understand if the relationship between HRV/HR and anxiety is moderated by language abilities in children with ASD, and whether HRV/HR can discriminate between anxiety and other emotions, like anger, in children with ASD. This study examined the relationship between baseline HRV/HR, language ability, and different emotional states (i.e., anxiety and anger) in a sample of 23 children with ASD. It was hypothesized that receptive language would moderate the relationship between decreased HRV/increased HR and increased anxiety but not the relationship between decreased HRV/increased HR and increased anger. Multiple regression analyses indicated that HRV and HR were not significant predictors of anxiety or anger, and language was not a significant moderator. Future studies may wish to take new approaches to determining the role of language in the relationship between HRV/HR and anxiety.

Heart rate variability (HRV) and personality are related to both physical and mental health outcomes. Previous research has found a relationship between neuroticism and distress while the findings on the relationship between neuroticism and HRV are mixed. Studying the facets of neuroticism may provide a more nuanced view of the effects of personality on HRV and distress. Previous research has suggested that the vulnerability facet of neuroticism appears to be uniquely related to the cardiovascular response to stress. This study's first hypothesis is that individuals with higher scores on the vulnerability facet will have lower heart rate variability. The second hypothesis is that individuals with higher vulnerability facet scores will report higher levels of distress. Using SEM, this study evaluated the measurement model of the facets of neuroticism as well as the structural relationships between these facets and HRV as well as psychological distress. Our study's sample consisted of 374 college students, the majority of whom were young adults. The SEM results indicated that there was no significant relationship between vulnerability and HRV or psychological distress. The lack of a significant association among any of the facets of neuroticism with HRV in this study further supports the notion that the non-significant relationship between neuroticism and HRV extends even when examining neuroticism at the facet level.

Mindfulness – a receptive attentiveness to present experience – has been shown to promote more adaptive emotion regulation (Brown et al. 2008). Additionally, dispositional mindfulness has been shown to predict reduced cortisol response to social stressors (Brown et al, in press) and mindfulness training has been shown to promote more adaptive cardiac functioning at rest (Ditto et al., 2006; Tang et al., 2009; Telles et al., 2005; Zeidan et al., 2010) and in response to social stressors (Kemeny et al., 2012). To better understand the regulatory potential of a mindful disposition on cardiovascular functioning in healthy adult participants (N = 63), the study examined the role of dispositional mindfulness in predicting cardiovascular responses to a laboratory social evaluative threat called the Trier Social Stress Task (TSST; Kirschbaum, et al., 1993). Repeated measures multilevel linear modeling tested main effects of a mindful disposition on a variety of cardiovascular outcomes as well as interactive effects between mindfulness and time on these outcomes. Results showed that mindfulness predicted increased heart rate variability (HRV) across the time span, from baseline to recovery. There were also interactions between mindfulness and time on several dependent variables. Specifically, higher mindfulness predicted decreased heart rate reactivity during the TSST, faster recovery in total HRV, as well as reduced rebound effects during the initial recovery phase for high frequency HRV, low frequency HRV, and the LF/HF ratio. These results, however, were not significant above and beyond the significant relations between rumination, depressive symptoms, and trait anxiety and cardiovascular function. The results lend support to the stress-related regulatory potential of mindfulness, and suggest that this quality of attention may enhance cardiovascular functioning under stress. Further research is needed to examine how mindfulness may buffer the role of such vulnerability factors as rumination, depressive symptoms, and anxiety in predicting stress-related cardiovascular responses to social stress.

Title Comparison of heart rate in the aquatic environment and on land. Purposes The aim is to determine whether the body immersed just below the surface of the water has a significant effect on the change in heart rate compared to heart rate measured on land. Methods This is a quantitative research carried out by comparing of heart rate frequency in 30 probands, which were evaluated using statistical methods. The main output of the values was Student's paired t-test. Location of probands during the measurement was lying on his back. The height of the water column was 26 cm. Results Compare the effect of 26 cm high water column compared to normal atmospheric conditions, operating while lying on the body. Indicator is measured heart rate. We found no significant change in heart rate during measurement in resting heart rate in water, compared to measurement on land, p <0.05. Key words swimming, heart rate, water, diving, heart rate in water

O estudo dos aspectos fisiológicos da corrida é importante não somente pela popularidade dessa atividade como também pelo seu papel na manutenção da saúde. Dessa maneira, é interessante identificar marcadores sensíveis aos efeitos agudos e crônicos desse exercício e capazes de, potencialmente, trazer informações sobre o estado fisiológico dos corredores. Nesse contexto, estimadores do controle cardíaco, como a variabilidade cardíaca (VC) e a complexidade cardíaca (CC) (cujos valores, quando baixos, estão associados à problemas de saúde), parecem ser particularmente importantes. No entanto, existem diversas controvérsias e lacunas no estudo da associação desses estimadores com a corrida. Para abordar esse problema, o presente estudo foi dividido em diversas etapas. Em um primeiro momento, foi necessário elaborar uma análise de complexidade cardíaca capaz de consistentemente caracterizar séries temporais. Dessa maneira, foi desenvolvida a a1ApEn, a qual é capaz de corrigir problemas identificados em outras análises não lineares; sendo robusta, consistente e com um tempo computacional adequado. Em seguida, investigou&minus;se o efeito agudo da corrida na VC e na CC em 3 protocolos experimentais (velocidades constantes, crescentes e decrescentes). Foi possível observar que a VC e a CC se correlacionam positivamente com a frequência cardíaca (FC) e que essa relação é melhor observada no protocolo de velocidades crescentes. Nesse protocolo, foi observado, ainda, que uma correlação negativa entre a1ApEn&minus;CC e FC está associada com sedentarismo. Essa correlação foi aprofundada sob a óptica do histórico de treinamento em maratonistas. Nesse contexto, foi possível concluir que a complexidade cardíaca obtida via a1ApEn é capaz de discernir maratonistas em função do tempo treinando para provas de longa duração. Finalmente, em experimentos realizados em velocidade constante, foi observado um componente oscilatório nos resultados tanto de VC quanto de CC. Esse componente é mais proeminente em resultados de CC e está, potencialmente, associado com fatores termorregulatórios. Dessa maneira, as abordagens propostas foram capazes de não apenas trazer diversas informações novas sobre as alterações associadas com a corrida no controle cardíaco mas, também, introduzir metodologias com grande potencial em outros contextos. / A better understanding of the physiological aspects of running is important due to the increasing popularity of this activity and, also, for its role in maintaining health. Therefore, it is interesting to identify markers capable of detecting the acute and chronic effects of this exercise and, potentially, bring additional information about the physiological status of runners. In this context, heart rate control estimators, such as heart rate variability (HRV) and heart rate complexity (HRC) (both indexes, when low, are associated with health disorders), appears to be particularly important. Nevertheless, there are several controversies and missing information regarding the association between these estimators and running. To approach these issues, the present study was divided in four parts. First of all, it was necessary to create a HRC analysis capable of consistently characterizing time series. Thereunto, the a1ApEn was developed; a robust, consistent analytical tool with an adequate computational time that is capable of correcting problems that arose in other nonlinear analyses. Next, the acute effect of running in HRV and HRC was investigated utilizing three experimental protocols (constant, increasing and decreasing speeds). HRV and HRC are positively correlated with heart rate (HR), a relationship better observed in the protocol with increasing speeds. In this protocol, it was observed that a negative correlation between a1ApEn&minus;HRC and HR is associated with sedentary. This correlation was further studied under the scope of the training background of marathoners. In this context, it was possible to conclude that the heart rate complexity, obtained through a1ApEn, is capable of discriminating marathoners in regard to the number of years training for long distance running. Finally, in experiments performed at constant speed, it was detected an oscillatory component in the HRV and HRC results. This component is more prominent in the HRC results and is, potentially, associated with termorregulatory factors. To conclude, the proposed approaches are capable of bringing several new information to the study of the effects of running in heart rate control and, moreover, to introduce new methodologies of great potential in other contexts.

1 Title: Mining Physiological Data for Automated Educational Feedback Author: Bc. Kateřina Bašátková Department: Department of Physics Education Supervisor: doc. RNDr. Zdena Lustigová, CSc., Department of Physics Education Abstract: This thesis deals with mining physiological data for automated educational feedback. The first part summarizes former researches of physiological data and its assertation into human behaviour. Special attention is devoted especially to eye tracking and measuring heart rate during behavioral processes. The second part is dedicated to author's own research how blink rate and heart rate are influenced by the degree of cognitive load. The research was executed on six subjects. The obtained data confirm correlation of blink rate and heart rate with the difficulty of the task. Keywords: heart rate, heart rate variability, blink rate, cognitive load

Wu, Kin Fai. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2008. / Includes bibliographical references (leaves 88-91). / Abstracts in English and Chinese. / Abstract --- p.i / 槪要 --- p.ii / Acknowledgements --- p.iii / Table of Contents --- p.iv / List of Figures --- p.vi / List of Tables --- p.x / Chapter Chapter 1 --- Introduction --- p.1 / Chapter 1.1 --- Motivation --- p.1 / Chapter 1.2 --- Outline of the Proposed Design --- p.2 / Chapter 1.3 --- Purposes of the Present Study --- p.2 / Chapter Chapter 2 --- Background and Literature Review --- p.4 / Chapter 2.1 --- Electrocardiogram --- p.4 / Chapter 2.2 --- Conventional ECG Measurement --- p.7 / Chapter 2.3 --- Heart Rate --- p.8 / Chapter 2.4 --- Heart Rate Variability --- p.9 / Chapter 2.5 --- Capacitive Sensing --- p.11 / Chapter 2.6 --- Review of ECG Monitoring System by Capacitive Sensing On a Sleeping Bed --- p.14 / Chapter Chapter 3 --- System Design and Implementation --- p.17 / Chapter 3.1 --- Hardware --- p.17 / Chapter 3.1.1 --- Bedsheet Sensor --- p.17 / Chapter 3.1.2 --- Pre-amplifier --- p.21 / Chapter 3.1.3 --- Measuring Device --- p.30 / Chapter 3.1.4 --- Power Supply & PCB Layout --- p.49 / Chapter 3.2 --- Software --- p.52 / Chapter 3.2.1 --- Detection of R Waves --- p.52 / Chapter 3.2.2 --- Tracking of HR & Mean RR Intervals --- p.55 / Chapter 3.2.3 --- Estimation of Signal-to-Noise Ratios --- p.56 / Chapter Chapter 4 --- Preliminary Tests on the Functionality of the Proposed System --- p.57 / Chapter 4.1 --- Test I - Test on the Arrangement of Electrodes --- p.57 / Chapter 4.1.1 --- Methods --- p.57 / Chapter 4.1.2 --- Results --- p.60 / Chapter 4.2 --- Test II - Test on the ECG Measurement of Subjects in Different Sleeping Postures --- p.64 / Chapter 4.2.1 --- Methods --- p.64 / Chapter 4.2.2 --- Results --- p.65 / Chapter Chapter 5 --- Experiments on the Performance of Continuous Monitoring of ECG and HR --- p.69 / Chapter 5.1 --- Experiment I - Experiment on the Reliability of the Proposed System for Continuous Monitoring of ECG and HR on Thirty Subjects --- p.69 / Chapter 5.1.1 --- Methods --- p.70 / Chapter 5.1.2 --- Results --- p.70 / Chapter 5.2 --- Experiment II - Experiment on the Feasibility of the Proposed System for Continuous Monitoring of ECG and HR on a Subject During an Eight-hour Sleep --- p.75 / Chapter 5.2.1 --- Materials --- p.76 / Chapter 5.2.2 --- Methods --- p.76 / Chapter 5.2.3 --- Results --- p.77 / Chapter Chapter 6 --- Discussions --- p.81 / Chapter 6.1 --- Selection of the Passband of the Proposed Circuit --- p.81 / Chapter 6.2 --- Arrangement of Electrodes on the Bedsheet --- p.82 / Chapter 6.3 --- Practical Design of Electrodes --- p.83 / Chapter 6.4 --- Performance of Continuous Monitoring of HR by Using the Proposed System --- p.84 / Chapter Chapter 7 --- Conclusion --- p.86 / References --- p.88

O estudo dos aspectos fisiológicos da corrida é importante não somente pela popularidade dessa atividade como também pelo seu papel na manutenção da saúde. Dessa maneira, é interessante identificar marcadores sensíveis aos efeitos agudos e crônicos desse exercício e capazes de, potencialmente, trazer informações sobre o estado fisiológico dos corredores. Nesse contexto, estimadores do controle cardíaco, como a variabilidade cardíaca (VC) e a complexidade cardíaca (CC) (cujos valores, quando baixos, estão associados à problemas de saúde), parecem ser particularmente importantes. No entanto, existem diversas controvérsias e lacunas no estudo da associação desses estimadores com a corrida. Para abordar esse problema, o presente estudo foi dividido em diversas etapas. Em um primeiro momento, foi necessário elaborar uma análise de complexidade cardíaca capaz de consistentemente caracterizar séries temporais. Dessa maneira, foi desenvolvida a a1ApEn, a qual é capaz de corrigir problemas identificados em outras análises não lineares; sendo robusta, consistente e com um tempo computacional adequado. Em seguida, investigou&minus;se o efeito agudo da corrida na VC e na CC em 3 protocolos experimentais (velocidades constantes, crescentes e decrescentes). Foi possível observar que a VC e a CC se correlacionam positivamente com a frequência cardíaca (FC) e que essa relação é melhor observada no protocolo de velocidades crescentes. Nesse protocolo, foi observado, ainda, que uma correlação negativa entre a1ApEn&minus;CC e FC está associada com sedentarismo. Essa correlação foi aprofundada sob a óptica do histórico de treinamento em maratonistas. Nesse contexto, foi possível concluir que a complexidade cardíaca obtida via a1ApEn é capaz de discernir maratonistas em função do tempo treinando para provas de longa duração. Finalmente, em experimentos realizados em velocidade constante, foi observado um componente oscilatório nos resultados tanto de VC quanto de CC. Esse componente é mais proeminente em resultados de CC e está, potencialmente, associado com fatores termorregulatórios. Dessa maneira, as abordagens propostas foram capazes de não apenas trazer diversas informações novas sobre as alterações associadas com a corrida no controle cardíaco mas, também, introduzir metodologias com grande potencial em outros contextos. / A better understanding of the physiological aspects of running is important due to the increasing popularity of this activity and, also, for its role in maintaining health. Therefore, it is interesting to identify markers capable of detecting the acute and chronic effects of this exercise and, potentially, bring additional information about the physiological status of runners. In this context, heart rate control estimators, such as heart rate variability (HRV) and heart rate complexity (HRC) (both indexes, when low, are associated with health disorders), appears to be particularly important. Nevertheless, there are several controversies and missing information regarding the association between these estimators and running. To approach these issues, the present study was divided in four parts. First of all, it was necessary to create a HRC analysis capable of consistently characterizing time series. Thereunto, the a1ApEn was developed; a robust, consistent analytical tool with an adequate computational time that is capable of correcting problems that arose in other nonlinear analyses. Next, the acute effect of running in HRV and HRC was investigated utilizing three experimental protocols (constant, increasing and decreasing speeds). HRV and HRC are positively correlated with heart rate (HR), a relationship better observed in the protocol with increasing speeds. In this protocol, it was observed that a negative correlation between a1ApEn&minus;HRC and HR is associated with sedentary. This correlation was further studied under the scope of the training background of marathoners. In this context, it was possible to conclude that the heart rate complexity, obtained through a1ApEn, is capable of discriminating marathoners in regard to the number of years training for long distance running. Finally, in experiments performed at constant speed, it was detected an oscillatory component in the HRV and HRC results. This component is more prominent in the HRC results and is, potentially, associated with termorregulatory factors. To conclude, the proposed approaches are capable of bringing several new information to the study of the effects of running in heart rate control and, moreover, to introduce new methodologies of great potential in other contexts.

This study examined effectiveness of heart rate variability (HRV) biofeedback-assisted stress management training in reducing anxiety and stress in pregnant women and the effect of maternal stress management skills practice on fetal heart rate measures in real time. Participants were seven working pregnant women who volunteered in response to recruitment announcements and invitations from cooperating midwives. Reported state and trait anxiety and pregnancy specific stress were measured during five 45- to 50-minute training sessions. Training included bibliotherapy, instruction in the use of emotion-focused stress management techniques, and HRV biofeedback. Subjects used portable biofeedback units for home practice and were encouraged to practice the skills for 20 minutes a day and for short periods of time during stressful life events. At the end of training, fetal heart rate was monitored and concurrent maternal HRV measures were recorded. Repeated measures ANOVA and paired samples t-test analysis of study data revealed no statistically significant reductions in state or trait anxiety measures or in pregnancy specific stress measures. Partial eta squared (n²) and Cohen's d calculations found small to medium effect sizes on the various test scales. Friedman's analysis of variance of biofeedback measures showed a statistically significant decrease in low HRV coherence scores (X2 = 10.53, p = .03) and medium HRV coherence scores (X2 = 11.58, p = .02) and a statistically significant increase in high HRV coherence scores (X2 = 18.16, p = .001). This change is an indication of improved autonomic function. Results of concurrent maternal and fetal HRV recordings were generally inconclusive. A qualitative discussion of individual subject results is included. During follow-up interviews five subjects reported that they felt they were better able to cope with stress at the end of the study than at the beginning, that they used the stress management skills during labor, and that they continue to practice the skills in their daily lives.

<p>Cilj ove teze bio je utvrđivanje polnih razlika<br />u mehanizmima vegetativne regulacije srčane<br />frekvencije, kao i utvrđivanje razlika u regulaciji srčane frekvencije kod žena po<br />fazama menstrualnog ciklusa. Kori&scaron;ćeni su<br />parametri varijabilnosti srčanog ritma (heart<br />rate variability) - HRV i oporavka srčane<br />frekvencije (heart rate recovery) - HRR.</p><p>Ispitivanje je obuhvatilo 90 ispitanika; 45<br />osoba mu&scaron;kog pola (20.4&plusmn;0.7 god., 184&plusmn;5.00<br />cm, 79.38&plusmn;9.42 kg, BMI 23.53&plusmn;2.83) i 45<br />osoba ženskog pola (20.5&plusmn;0.6 god., 168&plusmn;5.25<br />cm, 60.96&plusmn;6.93 kg, BMI 21.57&plusmn;2.23) -<br />studenata Univerziteta u Novom Sadu. Za<br />prikupljanje podataka kori&scaron;ćen je pulsmetar<br />(Polar, Finska). Ispitivanje je sprovedeno u<br />mirovanju, kao i u periodu oporavka posle<br />kratkotrajnog fizičkog opterećenja poznatog<br />intenziteta. U prvom modulu snimanje je<br />obavljano u miru, u sedećem poloţaju na<br />samom ergo-biciklu, stopala na platformi<br />ispred pedala, noge u fleksiji od 90&deg; u<br />kolenom zglobu, ruke na natkolenicama. U<br />drugom modulu snimanje je obavljeno u<br />priodu petominutnog oporavka posle<br />maksimalnog opteraćenja u trajanju od 30<br />sekundi (supramaksimalno opterećenje) -<br />Wingate protokol. U grupi mu&scaron;karaca<br />sprovedeno je jednokratno merenje, dok su za<br />grupu ţena isti moduli snimanja primenjeni u ri navrata: 1. U fazi menstrualnog krvarenja,<br />rana folikularna faza - najniži nivoi estrogena<br />i progesterona. 2. Kasna folikularna faza -<br />visok estrogen. 3. Srednja lutealna faza -<br />visok nivo progesterona i estrogena.<br />U miru kao i u poslednjem trominutnom<br />intervalu petominutnog oporavka određeni su<br />sledeći parametri varijabilnosti srčanog ritma:<br />srednja vrednost NN intervala - RRNN,<br />standardna devijacija NN intervala - SDNN,<br />kvadratni koren iz srednje vrednosti kvadrata<br />sukcesivnih razlika susednih NN intervala<br />(root mean square of successive differences) -<br />RMSSD, broj sucesivnih NN intervala koji<br />se razlikuju za vi&scaron;e od 50ms - NN50 i<br />procentualni udeo NN50 u ukupnom broju<br />NN intervala - pNN50. Od parametara<br />frekvencijskog domena, nakon brze Furijeove<br />transformacije analizirani su sledeći<br />parametri: snaga spektra niske frekvencije<br />(LF; 0,04-0,15Hz) i snaga spektra visoke<br />frekvencije (HF; 0,15-0,40Hz).<br />Oporavak srčane frekvencije u toku<br />petominutnog oporavka nakon<br />supramaksimalnog opterećenja na bicikl<br />ergometru procenjivan je pomoću sledećih parametara: 1. Apsolutna razlika između<br />vrednosti srčane frekvencije odmah po<br />zavr&scaron;etku opterećenja i frekvencije<br />registrovane nakon 60 sekundi oporavka -<br />HRR60. 2. Vremenska konstanta<br />kratkoročnog oporavka srčane frekvencije u<br />prvih 30 sekundi - T30. 3. Vremenska<br />konstanta opadanja srčane frekvencije u toku<br />petominutnog oporavka - T.<br />Utvrđeno je da mu&scaron;karci imaju veći pik snage<br />kao i prosečnu snagu pri supramaksimalnom<br />opterećenju u odnosu na grupu ţena bez<br />obzira na fazu menstrualnog ciklusa; dok su<br />bazalna i maksimalna srčana frekvencija bile<br />iste u obe grupe.<br />Postoje polne razlike u mehanizmima<br />vegetativne regulacije srčane frekvencije u<br />mirovanju. Najbolje su vidljive kroz<br />parametre frekvencijkog domena HRV-a (LF<br />i HF), odnosno prirodne logaritme ovih<br />vrednosti (lnLF i lnHF). Statistički značajne<br />razlike u vrednostima parametara<br />frekvencijskog domena HRV-a između grupe<br />mu&scaron;karaca i grupe ţena u sve tri faze<br />menstrualnog ciklusa potvrđene su i u fazi<br />oporavka posle supramaksimalnog opterećenja.<br />Postoje polne razlike u parasimpatičkoj<br />reaktivaciji posle supramaksimalnog<br />opterećenja koja je značajno brţa kod<br />mu&scaron;karaca. One se najbolje mogu proceniti<br />kroz matematičke modele oporavka srčane<br />frekvencije i vremensku konstantu opadanja<br />srčane frekvencije u prvih 30 sekundi<br />oporavka - T30.<br />Nisu utvrđene razlike u mehanizmima<br />vegetativne regulacije srčane frekvencije u<br />miru u grupi ţena po fazama menstrualnog<br />ciklusa; procenjeno kroz parametre<br />vremenskog i frekvencijskog domena HRVa.<br />Parametri vremenskog i frekvencijskog<br />domena HRV-a registrovani u mirovanju kao<br />i u fazi odmora posle supramaksimalnog<br />opterećenja nisu dovoljno osetljivi za<br />utvrđivanje razlika u vegetativnoj regulaciji<br />srčane frekvencije kod žena po fazama<br />menstrualnog ciklusa.<br />Nijedan od registrovanih parametara<br />oporavka srčane frekvencije (HRmax,<br />HRoporavak, HRR60, T i T30) nije se pokazao<br />dovoljno osetljivim za utvrđivanje promena u<br />parasimpetičkoj reaktivaciji kroz faze<br />menstrualnog ciklusa.</p> / <p>The aim of this study was to determine<br />gender differences in autonomic heart rate<br />control mechanisms, as well as to determine<br />heart rate control differences in women<br />during menstrual cycle. Heart rate variability<br />- HRV and heart rate recovery - HRR parameters were used.<br />The study included 90 participants; 45 males<br />(20.4&plusmn;0.7 yrs., 184&plusmn;5.00 cm, 79.38&plusmn;9.42 kg,<br />BMI 23.53&plusmn;2.83) and 45 females (20.5&plusmn;0.6<br />yrs., 168&plusmn;5.25 cm, 60.96&plusmn;6.93 kg, BMI<br />21.57&plusmn;2.23) - students of the University of<br />Novi Sad. Heart rate monitor (Polar,<br />Finland) was used for data collection.<br />Measurements were conducted while resting<br />as well as in a short recovery period after a<br />brief physical strain of known intensity. In<br />the first mode, heart rate monitoring was<br />conducted on relaxed subjects, in a sitting<br />position on an ergo-bike, feet on the<br />platform in front of the pedals, legs bent at<br />knees at 90&deg;, hands on thighs. In the second<br />mode heart rate monitoring was conducted in<br />a five-minute resting period after 30 seconds<br />of maximal exercise (supramaximal<br />exercise) - Wingate protocol. There was a<br />single monitoring in the male group, while in<br />the female group each monitoring mode was<br />conducted three times: 1. During the phase<br />of menstrual bleeding, early follicular phase<br />- the lowest levels of estrogen and<br />progesterone 2. Late follicular phase - high<br />estrogen. 3. Mid-luteal phase - high progesterone and estrogen.<br />While resting as well as in the last three<br />minutes of five-minute recovery period after<br />the exercise the following parameters of<br />heart rate variability were determined: the<br />mean value of NN intervals - RRNN, the<br />standard deviation of NN intervals - SDNN,<br />the square root of the mean of the squares of<br />the successive differences between adjacent<br />NN intervals (root mean square of<br />successive differences) - RMSSD, the<br />number of pairs of successive NN intervals<br />that differ by more than 50 ms - NN50 and<br />the proportion of NN50 divided by total<br />number of NN intervals pNN50. After the<br />fast Fourier transformation, following<br />frequency domain parameters were<br />analyzed: power spectrum of low frequency<br />(LF; 0,04-0,15Hz) and power spectrum of<br />high frequency (HF; 0,15-0,40Hz).<br />Heart rate recovery during the five-minute<br />resting period after the supramaximal<br />exercise on the ergo-bike was evaluated<br />through following parameters: 1. Absolute<br />difference between the heart rate<br />immediately after the exercise and the heart rate registered after 60 seconds of recovery -<br />HRR60. 2. Time constant of short-time heart<br />rate recovery in the first 30 seconds - T30. 3.<br />Time constant of heart rate decay<br />during the five-minute recovery period - T.<br />It was found that men had greater peak and<br />average power during supramaximal<br />exercise compared to a group of women<br />regardless of the phase of menstrual cycle;<br />while basal and maximal heart rate were the<br />same in both groups.<br />There are gender differences in autonomic<br />heart rate control mechanisms while resting.<br />These are best visible through frequency<br />domain HRV parameters (LF and HF), and<br />their natural logarithms (lnLF and lnHF).<br />Statistically significant differences in the<br />frequency domain HRV parameters between<br />the group of men and the group of women in<br />all three phases of the menstrual cycle, were<br />also found in recovery period after<br />supramaximal exercise.<br />There are gender differences in<br />parasympathetic reactivation after<br />supramaximal exercise which is significantly faster in men. These differences are best<br />assessed through mathematical models of<br />heart rate recovery and the time constant of<br />short-time heart rate recovery in the first 30<br />seconds - T30 .<br />No differences in autonomic heart rate<br />control mechanisms while resting in the<br />female group during three phases of<br />menstrual cycle were found; assessed<br />through the time and frequency domain<br />HRV parameters. The time and frequency<br />domain HRV parameters registered while<br />resting and during recovery period after<br />supramaximal еxеrcise were not sensitive<br />enough to determine differences in<br />autonomic heart rate control in women<br />through three phases of menstrual cycle.<br />None of the registered heart rate recovery<br />parameters (HRmax, HRR60, HRoporavak, T i<br />T30) were sensitive enough to determine<br />changes in parasympathetic reactivation<br />through a menstrual cycle.</p>