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Vascular responses in forearm and calf to contralateral static exercises
D A Duprez1, L K Essandoh, P M Vanhoutte
1Department of Physiology and Biophysics, Mayo Clinic, Rochester, Minnesota 55905.
Journal of Applied Physiology (Bethesda, Md. : 1985)
|February 1, 1989
Summary
Isometric exercise impacts blood flow differently in arms and legs. Forearm blood vessels constrict during both finger and leg exercises, while calf vessels dilate more significantly during leg exercise, showing varied vascular responses.
Area of Science:
- Cardiovascular Physiology
- Exercise Physiology
Background:
- Understanding the differential regulation of vascular resistance in various limbs during isometric exercise is crucial for comprehending systemic cardiovascular responses.
- Previous research suggests localized and systemic effects of exercise on blood flow, but heterogeneity in responses across different vascular beds requires further investigation.
Purpose of the Study:
- To investigate the distinct effects of isometric handgrip and leg exercise on forearm and calf vascular resistance.
- To determine if the intensity of isometric exercise influences the observed vascular responses in contralateral limbs.
Main Methods:
- Ten healthy subjects performed 90-second isometric exercises at 20%, 30%, and 40% of maximal voluntary contraction (MVC) using either finger or quadriceps muscles.
- Contralateral forearm and calf blood flows were measured using strain gauge plethysmography, alongside arterial blood pressure via auscultation.
Main Results:
- Both finger and quadriceps isometric exercises induced a decrease in forearm vascular resistance and a progressive increase in calf vascular resistance, with effects being more pronounced at 40% MVC.
- Quadriceps exercise resulted in significantly greater increases in calf vascular resistance compared to finger exercise.
- Circulatory arrest in exercising muscles prior to exercise cessation caused an immediate increase in forearm vascular resistance and a decrease in calf resistance.
Conclusions:
- Isometric exercise elicits heterogeneous responses in forearm and calf vascular resistance vessels.
- The observed differences suggest distinct regulatory mechanisms for vascular beds in the upper and lower limbs during isometric contractions.
- These findings contribute to a better understanding of limb-specific vascular control during physical exertion.