Um estudo de bacias crivadas e um estudo de séries de batimentos cardíacos através de ferramentas não lineares são apresentados. Bacias crivadas ocorrem em sistemas não lineares onde a simetria do espaço de fase permite a existência de um subespaço invariante capaz de atrair e repelir órbitas. Como conseqüência para todo ponto pertencente a bacia de atração do atirador existirá um ponto não pertencente numa distância arbitrariamente próxima. Pode-se verificar a presença de bacias crivadas pela análise do espaço de fase e dos expoentes máximos transversais de Lyapunov de tempo finito. A caracterização do fenômeno pode ainda ser complementada pelas leis de escala provenientes de um modelo para as flutuações dos expoentes máximos transversais de Lyapunov de tempo finito. O crivamento é analisado para um sistema mecânico e para um modelo ecológico. Comparamos para os dois sistemas as previsões teóricas, dadas por um modelo stocástico, com os resultados numéricos. No estudo de séries de batimentos cardíacos diversos grupos de dados são submetidos a diferentes análises a fim de determinar ´ndices que permitam, dado um paciente, decidir a qual grupo ele pertence. Expoentes de Lyapunov, análise depurada de flutuações e segmentação das séries foram empregados na análise das séries de intervalos RR e pressão arterial. Desses métodos empregados, nenhum foi conclusivo no sentido de caracterizar os grupos. Porém, uma nova formulação do método de segmentação das séries mostrou ser possível a caracterização através de um parâmetro, que todavia, exige séries longas de observação. / A study of riddled basins of attraction and a study of heart rate variability through nonlinear dynamics tools are presented. Riddled basins occur in nonlinear systems whose phase space symmetry allows an invariant subspace with an chaotic attractor. This invariant subspace can either attract or repel orbits. As a consequence, for every point belonging to the basin of attraction there is another point, arbitrarily close, that does not belong to the basin of attraction. The presence of riddled basins is verified by analyzing the maximal transversal Lyapunov exponent and the maximal transversal finite time Lyapunov exponent. The characterization of riddling is complemented by the calculation of scaling laws provided by a stochastic model of the transversal finite time Lyapunov exponents. Riddling is analyzed for a mechanical system and for an ecological model. The results are compared with the theoretical prediction given by the stochastic model. In the study of heart rate variability, time series of different groups were analyzed in order to determine quantifiers of healthiness and sickness, in the sense that given a patient one can say if the patient belongs to a healthy group or not. Lyapunov exponents, detrended fluctuation analysis and time series segmentation were applied to RR-intervals and blood pressure time series. These methods were not able to characterize the groups. However, a new formulation of the segmentation method indicates that it is possible to find a quantifier, although this quantifier requires long time series of observation.

Cardiovascular drift can occur during prolonged exercise and is characterized by a gradual decrease in stroke volume (SV) and a corresponding increase in heart rate (HR) over time, despite the maintenance of a constant level of work; cardiac output (CO) usually is unchanged. A number of factors may cause cardiovascular drift to occur, including increases in peripheral blood flow, decreases in plasma volume, increases in circulating catecholamines, and metabolic acidosis. These physiological events may be influenced by the relationship of the exercise intensity to ventilatory threshold (VT). Therefore, the purpose of this study was to examine the cardiovascular responses during prolonged exercise in boys and men at an intensity set relative to VT. Eight boys (10-13 yrs.) and 10 men (18-25 yrs.) completed an orientation trial, a graded maximal exercise test, and a 40 minute submaximal exercise bout at an intensity equal to the V02 at VT. During the 40 minute exercise bout, V02 increased significantly over time (P_<0.05),although the magnitude of change was similar in boys and men (P>0.05). Heart rate was higher and SV was lower in the boys compared to the men (P<_0.05), and the changes in HR and SV were significant over time. Although there was a trend for the HR increase and SV decrease to be greater in the men, the group-by-time interaction was not significant. Cardiac output and arteriovenous oxygen difference were higher in the men compared to the boys (P<0.05), but remained constant over time. Mean arterial blood pressure (MABP) was higher in the men than the boys (P<_0.05). In the men, MABP decreased significantly from 10 to 40 minutes, while in the boys, MABP decreased (P<_0.05) from 10 to 30 minutes and then increased to a value similar to that at 10 minutes. This differential response in MABP over time resulted in a significant groupby-time interaction. Total peripheral resistance was significantly higher in the boys than the men, but remained constant over time (P>0.05). Men exhibited a greater decrease in plasma volume from 0 to 40 minutes. There was no group difference in perceived exertion (RPE) between the boys and the men, although the boys exhibited a greater increase in RPE over time than the men (P<0.05). In conclusion, the cardiovascular responses during prolonged exercise are similar in boys and men, although there is a tendency for the magnitude of cardiovascular drift to be greater in the men. In addition, due to the fact that these results are similar to previous studies not accounting for individual differences in VT, it would seem that these differences in VT should not be of concern when studying the cardiovascular responses during prolonged exercise. / School of Physical Education

Thesis (MSc. (Physiology)--Faculty of Health Sciences) - University of Pretoria, 2005. / Includes bibliographical references.

O presente estudo, teve como objetivo desenvolver um equipamento para medir os intervalos R-R, que tivesse alta correlação com os valores do aparelho padrão ouro de eletrocardiógrafo (ECG), pelos índices de domínio do tempo e domínio da frequência. Para tanto, foi realizado um estudo com 18 alunos de Jiu-Jitsu, do sexo masculino com 35,5±8,6 anos, no mínimo uma frequência semanal de 3 vezes e 1 ano de treinamento. O local foi na academia Barra Gracie de Curitiba PR. Foram submetidos a uma análise em repouso por um período de 7 minutos e posteriormente seus resultados foram convertidos em variabilidade da frequência cardíaca (VFC) e analisados pelos índices no domínio do tempo e domínio da frequência. Os resultados foram comparados estatisticamente por meio do teste de Pearson e a correlação intraclasse (ICC) e de acordo com eles mostra-se viável o desenvolvimento deste equipamento, que apresenta alta correlação e excelente replicabilidade para medir os intervalos R-R. / This study aimed to develop a device to measure RR intervals, which have high correlation with the values of the gold standard device of electrocardiograph (ECG), by the time domain and frequency domain indices. To this end, a study was conducted with 18 students of Jiu-Jitsu, males with 35.5 ± 8.6 years, at least a weekly frequency of 3 times and one year training. The location was at the academy Gracie Barra de Curitiba PR. They underwent an examination at rest for a period of 7 minutes and then the results were converted into heart rate variability (HRV) and analyzed by the indexes in the time domain and the frequency domain. The results were compared statistically using the Pearson test and intraclass correlation (ICC) and according to them proves to be viable the development of this equipment, which is highly correlated and excellent reproducibility for measuring the RR intervals.

O presente estudo, teve como objetivo desenvolver um equipamento para medir os intervalos R-R, que tivesse alta correlação com os valores do aparelho padrão ouro de eletrocardiógrafo (ECG), pelos índices de domínio do tempo e domínio da frequência. Para tanto, foi realizado um estudo com 18 alunos de Jiu-Jitsu, do sexo masculino com 35,5±8,6 anos, no mínimo uma frequência semanal de 3 vezes e 1 ano de treinamento. O local foi na academia Barra Gracie de Curitiba PR. Foram submetidos a uma análise em repouso por um período de 7 minutos e posteriormente seus resultados foram convertidos em variabilidade da frequência cardíaca (VFC) e analisados pelos índices no domínio do tempo e domínio da frequência. Os resultados foram comparados estatisticamente por meio do teste de Pearson e a correlação intraclasse (ICC) e de acordo com eles mostra-se viável o desenvolvimento deste equipamento, que apresenta alta correlação e excelente replicabilidade para medir os intervalos R-R. / This study aimed to develop a device to measure RR intervals, which have high correlation with the values of the gold standard device of electrocardiograph (ECG), by the time domain and frequency domain indices. To this end, a study was conducted with 18 students of Jiu-Jitsu, males with 35.5 ± 8.6 years, at least a weekly frequency of 3 times and one year training. The location was at the academy Gracie Barra de Curitiba PR. They underwent an examination at rest for a period of 7 minutes and then the results were converted into heart rate variability (HRV) and analyzed by the indexes in the time domain and the frequency domain. The results were compared statistically using the Pearson test and intraclass correlation (ICC) and according to them proves to be viable the development of this equipment, which is highly correlated and excellent reproducibility for measuring the RR intervals.

Um estudo de bacias crivadas e um estudo de séries de batimentos cardíacos através de ferramentas não lineares são apresentados. Bacias crivadas ocorrem em sistemas não lineares onde a simetria do espaço de fase permite a existência de um subespaço invariante capaz de atrair e repelir órbitas. Como conseqüência para todo ponto pertencente a bacia de atração do atirador existirá um ponto não pertencente numa distância arbitrariamente próxima. Pode-se verificar a presença de bacias crivadas pela análise do espaço de fase e dos expoentes máximos transversais de Lyapunov de tempo finito. A caracterização do fenômeno pode ainda ser complementada pelas leis de escala provenientes de um modelo para as flutuações dos expoentes máximos transversais de Lyapunov de tempo finito. O crivamento é analisado para um sistema mecânico e para um modelo ecológico. Comparamos para os dois sistemas as previsões teóricas, dadas por um modelo stocástico, com os resultados numéricos. No estudo de séries de batimentos cardíacos diversos grupos de dados são submetidos a diferentes análises a fim de determinar ´ndices que permitam, dado um paciente, decidir a qual grupo ele pertence. Expoentes de Lyapunov, análise depurada de flutuações e segmentação das séries foram empregados na análise das séries de intervalos RR e pressão arterial. Desses métodos empregados, nenhum foi conclusivo no sentido de caracterizar os grupos. Porém, uma nova formulação do método de segmentação das séries mostrou ser possível a caracterização através de um parâmetro, que todavia, exige séries longas de observação. / A study of riddled basins of attraction and a study of heart rate variability through nonlinear dynamics tools are presented. Riddled basins occur in nonlinear systems whose phase space symmetry allows an invariant subspace with an chaotic attractor. This invariant subspace can either attract or repel orbits. As a consequence, for every point belonging to the basin of attraction there is another point, arbitrarily close, that does not belong to the basin of attraction. The presence of riddled basins is verified by analyzing the maximal transversal Lyapunov exponent and the maximal transversal finite time Lyapunov exponent. The characterization of riddling is complemented by the calculation of scaling laws provided by a stochastic model of the transversal finite time Lyapunov exponents. Riddling is analyzed for a mechanical system and for an ecological model. The results are compared with the theoretical prediction given by the stochastic model. In the study of heart rate variability, time series of different groups were analyzed in order to determine quantifiers of healthiness and sickness, in the sense that given a patient one can say if the patient belongs to a healthy group or not. Lyapunov exponents, detrended fluctuation analysis and time series segmentation were applied to RR-intervals and blood pressure time series. These methods were not able to characterize the groups. However, a new formulation of the segmentation method indicates that it is possible to find a quantifier, although this quantifier requires long time series of observation.

To examine if a rhythm can be entrained in either heart rate or oxygen consumption in late stage embryos (days 17-19.5) with light as a zeitgeber, chicken embryos were incubated in complete darkness (D:D) and 12:12 light:dark cycle (L:D). Light had no impact on oxygen consumption (390 µL O2∙min-1∙egg-1) but increased heart rate for non-internally pipped embryos (260 to 270 beats∙min-1 during light cycle). Oxygen consumption increased independent of pipping while heart rate increased (255 to 265 beats∙min-1) in D:D embryos due to pipping. A light-induced rhythm or effect occurred in heart rate but not oxygen consumption, suggesting heart rate and oxygen consumption may be uncoupled.

The purpose of this study was to investigate the effect of hand-weights and exaggerated arm swing on heart rate, blood pressure, and ratings of perceived exertion during submaximal walking. Twenty middle-aged (40- 59 years) female volunteers were given four submaximal treadmill tests at 3.0 mph and 0 grade. The four treatment conditions were as follows: 1) walking with unexaggerated arm swing (AS); 2) walking with unexaggerated arm swing with hand-held weights (ASHW); 3) walking with exaggerated arm swing (EAS), and 4) walking with exaggerated arm swing with hand-held weights (EASHW). The testing sequence was randomized and a minimum of 48 hr was given between tests.

The present study evaluated the utility of heart rhythm coherence (HRC) feedback to reduce the reported pain intensity of patients enrolled in a multimodal pain management program. Participants were recruited and assigned to a usual treatment group (UT) or a heart rhythm coherence feedback group (UT+HRC). It was hypothesized that UT+HRC participants who achieved heart rhythm coherence would report a reduction of pain intensity, as measured by the McGill Pain Inventory. For those whose pain intensity decreased, it was also expected that their self reported levels of depression as measured by the Beck Depression Inventory-Second Edition and state anger as measured by the State Trait Anger Inventory would decrease. It is also hypothesized that with a reduction in pain levels, anger, and depression, blood pressure would also decrease among those who had high blood pressure prior to the intervention. Multivariate analyses of variance (MANOVA) were used to investigate the relationship between treatment condition, coherence status and pain levels. A series of independent t-tests were utilized to investigate the change in pain, depression, and state anger from baseline to posttest, followed by Pearson product moment correlation coefficients on difference scores to understand the relationship between the outcome variables for Hypothesis 2. Standard multiple regression analyses were computed using difference scores to determine if the outcome measures were significant predictors of systolic blood pressure and diastolic blood pressure. Results indicated a failure to reject the null with regard to hypothesis one. No relationship between treatment assignment, coherence status or pain levels were found. Hypothesis 2 was partially supported. Although there was a positive significant relationship between depression and anger when utilizing difference scores, these affective measures were not related to difference scores on either pain measure. In regard to Hypothesis 3, there was also a failure to reject the null. None of the outcome measures utilized in this study emerged as being significantly related to changes in systolic or diastolic blood pressure. Limitations of the study and implications for future research are offered.

This study examined the effects of music and metronomic beat on heart rate (HR). ratings of perceived exertion (RPE). and physical endurance in healthy females ages 18 to 30. Volunteers were screened via a health questionnaire and the Astrand Work Test on a Monark bicycle ergometer. yielding a predicted aerobic working capacity (V02) of 28 mililiters or more. The 30 subjects were then randomly assigned to one of two experimental conditions (music or metronome group) for a cycling test at 75% capacity. HR and Borg RPE were measured repeatedly, with a posttest measure of physical endurance (kilometers travelled). No significant differences were found between the groups in HR. RPE. or kilometers travelled. A music questionnaire administered to the music group following the posttest examined the subjects' preference for and familiarity with the music, perceived and preferred volume, and experience with music. Trends and suggestions for future research are discussed.