METABOLIC EFFECTS OF LOCAL ISCHEMIA DURING MUSCULAR EXERCISE

Abstract

Certain interrelations between oxygen consumption, lactic acid production and removal from the blood stream have been studied on normal subjects whose limbs were rendered ischemic while they were walking in a steady state. During the ischemia, O2 ventilation and O2 consumption were reduced by about 25%. After the ischemia was relieved, ventilation, consumption and blood lactate all increased far above the control value, and then returned to this level. The process of restoration was much more rapid if the subject continued to walk than if he began to rest when the ischemia was relieved. The amt. of extra O2 used per g. of lactate removed from the body was far greater at rest than during work. No simple relation was found between the rate of repaying the O2 debt and the rate of removal of lactate. The rate of removal of lactate was the same after the O2 debt was paid as it was at the beginning of the recovery period. Diffusion of lactic acid from the working muscles to the local venous blood was a rapid process.