Quantitative analysis of autonomic nervous activity during passive leg cycle exercise

We investigated whether passive leg cycle exercise (PLE) for the elderly and patients with spinal cord injuries leads to the modulation of autonomic nervous activity in healthy female subjects. To evaluate changes in autonomic nervous activity during PLE, we used autoregressive (AR) power spectra of pulse interval variability (PIV) corresponded to R-R interval variability and systolic blood pressure variability (SPV). Our results showed that LF and HF powers and the ratio power (LF/HF) of PIV reflecting cardiac sympathetic, parasympathetic tone and sympathovagal balance were not changed during PLE, but during recovery period immediately after PLE, LF and HF powers and total power of PIV was significantly (p<0.05) increased. On the other side, LF power of SPV showing vasomotor sympathetic tone was significantly (p<0.05) decreased. We conclude that PLE causes to modulate the autonomic nervous activity in healthy subjects with normal autonomic function, and may be used as the useful exercise for the elderly who need some therapeutics without the abrupt modulation of autonomic nervous activity