Human Forearm Muscle Metabolism during Exercise I Circulatory adaptation to prolonged forearm exercise

Abstract

Forearm muscle blood flow, oxygen uptake and net production of lactate and pyruvate were determined during 60-min forearm exercise periods in 17 healthy young men.

Brachial artery blood flow rose at the onset of exercise and at 10 min had risen slightly more than fivefold. At the same time the forearm muscle oxygen uptake had increased 12-fold. During the rest of the exercise period there occurred a further small rise in blood flow and an increase in deep venous oxygen saturation, so that the oxygen uptake was unchanged. At the same time the forearm muscle lactate production and the lactate/pyruvate production ratio declined. These changes are taken to indicate that an adaptive reaction occurred in the forearm muscle vascular bed resulting in an improved muscle cell oxygenation.

Key Words:

• Blood flow
• exercise
• forearm
• lactate
• muscle metabolism
• oxygen consumption
• pyruvate