Change in post-exercise vagal reactivation with exercise training and detraining in young men.
We studied the effects of aerobic exercise training and detraining in humans on post-exercise vagal reactivation. Ten healthy untrained men trained for 8 weeks using a cycle ergometer [70% of initial maximal oxygen uptake (VO2max) for 1 h, 3-4 days.week-1] and then did not exercise for the next 4 weeks. Post-exercise vagal reactivation was evaluated as the time constant of the beat-by-beat decrease in heart rate during the 30 s (t30) immediately following 4 min exercise at 80% of ventilatory threshold (VT). The VO2max and the oxygen uptake at VT had significantly increased after the 8 weeks training programme (P < 0.0001, P < 0.001, respectively). The t30 had shortened after training, and values after 4 weeks and 8 weeks of training were significantly shorter than the initial t30 (P < 0.05, P < 0.01, respectively). The change in the t30 after 8 weeks of training closely and inversely correlated with the initial t30 (r = -0.965, P < 0.0001). The reduced t30 was prolonged significantly after 2 weeks of detraining, and had returned almost to the baseline level after a further 2 weeks of detraining. These results suggest that aerobic exercise training of moderate intensity accelerates post-exercise vagal reactivation, but that the accelerated function regresses within a few weeks of detraining.
Sugawara
J
J
Institute of Health and Sport Sciences, University of Tsukuba Tennodai, Tsukuba-shi, Ibaraki 305-8574, Japan.
Murakami
H
H
Maeda
S
S
Kuno
S
S
Matsuda
M
M
D000328:Adult; D015444:Exercise / Q000502:physiology*; D005080:Exercise Test; D006321:Heart / Q000294:innervation / Q000502:physiology*; D006339:Heart Rate / Q000502:physiology; D006801:Humans; D008297:Male; D010101:Oxygen Consumption / Q000502:physiology; D010275:Parasympathetic Nervous System / Q000502:physiology; D014630:Vagus Nerve / Q000502:physiology*