Related Experiment Videos
Venous responses to rhythmic exercise in contralateral forearm and calf
D A Duprez1, M De Buyzere, J M De Sutter
1Department of Cardiology-Angiology, University Hospital, Gent, Belgium.
Summary
Rhythmic handgrip exercise causes blood vessels in non-exercising limbs to constrict. This venoconstriction is mediated by both reflexes from working muscles and central command signals.
Area of Science:
- Exercise Physiology
- Autonomic Nervous System Regulation
- Cardiovascular Physiology
Background:
- Rhythmic exercise influences blood flow distribution.
- The role of central command versus peripheral reflexes in regulating venomotor tone during exercise is not fully understood.
Purpose of the Study:
- To investigate the contribution of central command and muscle reflexes to venomotor tone changes in non-exercising limbs during rhythmic handgrip exercise.
Main Methods:
- Ten healthy subjects performed rhythmic handgrip at 30% maximal voluntary contraction (MVC).
- Contralateral forearm and calf venous capacitance were measured using venous occlusion plethysmography.
- Experiments involved conditions with and without arterial occlusion to isolate reflex contributions.
Main Results:
- Rhythmic handgrip reduced contralateral forearm and calf venous capacitance.
- Arterial occlusion during exercise amplified these decreases in venous capacitance.
- Post-exercise arterial occlusion further reduced forearm venous volume, indicating a role for chemically sensitive metaboreceptors.
Conclusions:
- Both chemically mediated reflexes from working muscles and central command contribute to increased venomotor tone in non-exercising limbs during rhythmic handgrip.
- These findings elucidate the neural control mechanisms governing blood flow redistribution during dynamic exercise.