Handgrip exercise and post-exercise ischaemia did not abolish vagal baroreflex rhythms, which oscillated at a nearly constant frequency of approximately 0.06 Hz throughout the protocol.
Do physiological, rhythmic fluctuations of vagal baroreflex gain persist during exercise, post-exercise ischaemia, and recovery in healthy individuals?
Vagal baroreflex rhythms persist during exercise and post-exercise ischaemia, indicating robust physiological autonomic regulation under physical stress.
AIM: To determine whether physiological, rhythmic fluctuations of vagal baroreflex gain persist during exercise, post-exercise ischaemia and recovery. METHODS: We studied responses of six supine healthy men and one woman to a stereotyped protocol comprising rest, handgrip exercise at 40% maximum capacity to exhaustion, post-exercise forearm ischaemia and recovery. We measured electrocardiographic R-R intervals, photoplethysmographic finger arterial pressures and peroneal nerve muscle sympathetic activity. We derived vagal baroreflex gains from a sliding (25-s window moved by 2-s steps) systolic pressure-R-R interval transfer function at 0.04-0.15 Hz. RESULTS: Vagal baroreflex gain oscillated at low, nearly constant frequencies throughout the protocol (at approx. 0.06 Hz - a period of about 18 s); however, during exercise, most oscillations were at low-gain levels, and during ischaemia and recovery, most oscillations were at high-gain levels. CONCLUSIONS: Vagal baroreflex rhythms are not abolished by exercise, and they are not overwhelmed after exercise during ischaemia and recovery.
Eckberg et al. (Fri,) conducted a other in Healthy (n=7). Handgrip exercise and post-exercise forearm ischaemia vs. Rest and recovery phases was evaluated on Vagal baroreflex gain fluctuations. Handgrip exercise and post-exercise ischaemia did not abolish vagal baroreflex rhythms, which oscillated at a nearly constant frequency of approximately 0.06 Hz throughout the protocol.
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