Cardiac Autonomic Modulation Is Determined by Gender and Is Independent of Aerobic Physical Capacity in Healthy Subjects

Abstract

BackgroundAerobic physical capacity plays an important role in reducing morbidity and mortality rates in subjects with cardiovascular diseases. This action is often related to an improvement in the autonomic modulation of heart rate variability (HRV). However, controversies remain regarding the effects of physical training on cardiac autonomic control in healthy subjects. Therefore, our objective was to investigate whether aerobic capacity interferes with the autonomic modulation of HRV and whether gender differences exist.MethodsHealthy men and women (N=96) were divided into groups according to aerobic capacity: low (VO2: 22-38 ml/kg-1 min-1), moderate (VO2: 38-48 ml/kg-1 min-1) and high (VO2 >48 ml/kg-1 min-1.) We evaluated the hemodynamic parameters and body composition. The autonomic modulation of HRV was investigated using spectral analysis. This procedure decomposes the heart rate oscillatory signal into frequency bands: low frequency (LF=0.04-0.15Hz) is mainly related to sympathetic modulation, and high frequency (HF=0.15-0.5Hz) corresponds to vagal modulation.ResultsAerobic capacity, regardless of gender, determined lower values of body fat percentage, blood pressure and heart rate. In turn, the spectral analysis of HRV showed that this parameter did not differ when aerobic capacity was considered. However, when the genders were compared, women had lower LF values and higher HF values than the respective groups of men.ConclusionThe results suggest that aerobic physical capacity does not interfere with HRV modulation; however, the cardiac modulatory balance differs between genders and is characterized by a greater influence of the autonomic vagal component in women and by the sympathetic component in men.

Dysautonomias in Parkinson's disease: cardiovascular changes and autonomic modulation in conscious rats after infusion of bilateral 6-OHDA in substantia nigra

“…The relative powers of the LF and HF bands of the PI spectra were calculated by taking into account the total power of the spectra minus the power of the very low oscillations (Ͻ0.2 Hz). To assess the cardiac sympathovagal balance, we calculated the ratio between the powers of the LF and HF bands (LF/HF) of the PI spectrum (12,37).…”

Modulação Autonômica Da Frequência Cardíaca E Capacidade Funcional Aeróbica Em Hemiparéticos

“…No estudo de Dutra et al 33 , os resultados mostram que, em sujeitos saudáveis, maiores valores de VO 2 não promovem melhora adicional da modulação autonômica da frequência cardíaca, caracterizada por maior participação do componente vagal, diferente de indivíduos com doenças metabólica e cardiovascular, que respondem com melhores índices autonômicos cardíacos diante de maior capacidade aeróbica. Ou seja, quando o sistema autonômico está preservado, maiores valores de VO 2 não resultará em melhor controle autonômico cardíaco.…”

Effects of Physical Training on Cardiac Modulation in Normal Weight, Overweight, and Obese Individuals: A Comparative Study

“…Time series were divided into contiguous segments of 200 beats and then superposed over the segments of 100 beats from the earlier time series. After calculating mean and variation of each segment, these were submitted to autoregressive spectral analysis as described above [20][21][22][23]. The oscillatory components present in the stationary segments, beat-to-beat RRi, were calculated based on the LevinsonDurbin recursion according to the Akaike's criteria [20].…”

“…The power of LF and HF components in the RRi variability was also expressed in normalized units, which were obtained by calculating the percentage of LF and HF variability oscillations (HRV<0.04 Hz). The normalization procedure tends to minimize the effect of total force changes on absolute values in the variability of LH and HF components [20][21][22][23]. Finally, the LF/HF ratio was calculated to establish an index of autonomic modulation.…”