OBJECTIVE:
To evaluate the associations between heart rate variability (HRV) with cardiorespiratory fitness.
METHODS:
Sixty-two women (aged 22.1 ± 3.3) were divided into four groups: aerobic training (AER, n = 15), strength training (STR, n = 13), combined aerobic and strength training (AER+STR, n = 15) and controls (C, n = 19). Cardiopulmonary exercise testing was performed to measure cardiorespiratory fitness by assessing peak oxygen consumption (VO2peak). The HR was recorded at rest in the supine position. The HRV was analyzed by linear and nonlinear methods.
RESULTS:
The AER and AER+STR groups had higher vagal HRV (linear and nonlinear) indicators of vagal modulation and lower indices of HRV indicators of sympathetic modulation, compared to group C. The AER and AER+STR groups showed greater complexity and lower regularity of R-R intervals and higher peak compared to STR and C groups. The VO2peak was correlated with HRV indices.
CONCLUSION:
This study showed that aerobic and combined exercise significantly contributed to greater autonomic modulation of HR and cardiorespiratory fitness. The autonomic HR modulation, assessed by linear and nonlinear methods, was associated with a greater oxygen consumption.
exercise; autonomic nervous system; oxygen consumption
