Insulative Power of Body Fat on Deep Muscle Temperatures and Isometric Endurance.

摘要

Four male subjects were examined to assess the relationship of body fat content to deep muscle temperature and the endurance of a fatiguing isometric handgrip contraction at a tension set at 40% maximum voluntary contractions. Muscle temperature was altered by immersion of the forearm in water at temperatures varying from 7.5 to 40 C. In all subjects, there was a water bath temperature above and below which isometric endurance decreased markedly; the difference among individuals was solely accounted for by the individual's body fat content. Thus, subjects with higher body fat content required lower bath temperatures to cool the forearm musculature to its optimum temperature, which was found always to be approximately 27 C measured 2 cm perpendicularly to the skin in the belly of the brachioradialis muscle. Further, in one subject it was found that a reduction in his body fat content resulted in a corresponding increase in the water bath temperature necessary to cool his muscles to their optimum isometric performance. These data demonstrate the striking insulative power of the thin layer of fat around the forearm in man in protecting shell tissues from cold exposure.