Blood flow in the brachial artery increases after intense cycling exercise

Abstract

During cycling blood flow is redistributed from physically inactive tissues to working leg muscles. It is unknown how long this situation persists after very intense exercise or whether it differs between intense exhausting and non-exhausting exercise. It is also not known to what extent the redistribution differs between different types of non-active tissues. Therefore nine healthy young men cycled first for 2min at 328 W (non-exhausting exercise, mean). Blood velocity in thigh and arm (ultrasound-doppler), perfusion of forearm skin (non-acral skin) and finger tip (acral skin, with arterio-venous anastomoses) were measured for 30min after exercise (laser-doppler). To be able to study vascular resistance and central circulation, blood pressure (Finometer), heart rate (ECG), and stroke volume (ultrasound-doppler) were measured. Thereafter the subjects cycled at the same power to exhaustion (4min), and the measurements were repeated. After both exercises mean blood pressure was unchanged (≤ 80mm Hg) despite increased cardiac output (≥ + 30% vs. pre-exercise). Blood velocity in the brachial artery was higher during the whole recovery period than at rest (p≤0.02; no differences between exercises). Blood perfusion of non-acral skin was unchanged from pre-exercise level after 2min of non-exhausting exercise, but it was twice as high after 4min cycling to exhaustion as at rest (p=0.02). Blood perfusion of acral skin rose after both exercises and did not differ between exhausting and non-exhausting exercise. In conclusion, arm blood flow increases above the pre-exercise level in the recovery period after short-lasting, strenuous exercise.