SUMMARY

Large changes in skin blood flow occur after exercise. Most studies have concentrated on the systemic effects of vigorous exercise on skin blood flow. We were interested in the post-exercise response in the neighborhood of focal exercise. We used a painless neuromuscular electronic stimulator to exercise the muscles of the forearm, producing flexion of the fingers. There was no change in blood pressure and only a small increase in heart rate during this exercise. We measured blood flow during a five minute pre-exercise period and a five minute post-exercise period at the forearm, at the dorsum of the index finger, and on the pad of the index finger. We also measured values on the contralateral non-exercised extremity during exercise as well as during matched time periods in control experiments with no exercise. Exercise did elicit an increased blood flow in the post-exercise period at all three sites both as compared to the no exercise and to the contralateral extremity control periods. For example, the increase in blood flow at the finger dorsum was 2.1 + 0.1 ml/min/100 gm after exercise compared to -0.08 + 0.09 ml/min/100 gm during the control experiment and 0.1 + 0.1 ml/min/100 gm on the contralateral arm (all p<0.01). The local application of heat at the site of blood flow monitoring produced a substantial increase in the post-exercise response at the two finger locations (27.4 + 0.4 ml/min/100 gm at the finger dorsum), but not at the arm.

This is the first demonstration that highly focal exercise, unaccompanied by a systemic hemodynamic response, can elicit a post-exercise cutaneous hyperemia. Local heating produced a large synergistic increase in the post-exercise hyperemia at sites with arteriovenous microvascular perfusion but not at sites with primarily nutritive perfusion. These findings show that local vasoregulatory changes occur in response to exercise, even in the absence of whole body hemodynamic and thermal change.

For more information on this topic, click here!