The Venomotor Response to Static Muscular Exercise

Abstract

The venous blood pressure response to static muscular exercise was studied in seven young normal subjects by the occluded-limb technique. A slight pressure increase was obtained during the first seconds of the contraction period. Then the pressure response subsided, and the control level was reached after 1/2–1 1/2 min despite sustained contraction. The response was of the same type as that elicited by a voluntary deep breath, but usually of lesser magnitude. It seems to differ from the response to dynamic muscular exercise, suggesting that a continuous stiffening of the capacitance vessels, to maintain a high venous response, is not needed to the same extent during static muscular exercise. In previous studies a similar pressure increase has been obtained during short-lasting static muscular exercise. The present study shows that this pressure increase is confined to the initial part of the contraction period. Observations made after administration of phenoxybenza-mine and atropine indicate that the venomotor response is mediated through sympathetic adrenergic nerves.

Key Words:

• Muscular exercise
• static
• venomotor response