Hunt B E, Davy K P, Jones P P, DeSouza C A, Van Pelt R E, Tanaka H, Seals D R
Human Cardiovascular Research Laboratory, Center for Physical Activity, Disease Prevention, and Aging, Department of Kinesiology and Applied Physiology, University of Colorado, Boulder 80309, USA.
Am J Physiol. 1998 Oct;275(4):H1178-82. doi: 10.1152/ajpheart.1998.275.4.H1178.
Fat-free mass (FFM) (primarily skeletal muscle mass) is related to maximal aerobic capacity among healthy humans across the adult age range. The basis for this physiological association is assumed to be a direct relation between skeletal muscle mass and its capacity to consume oxygen. We tested the alternative hypothesis that FFM exerts its influence on maximal aerobic capacity in part via an association with central circulatory function. To do so, we analyzed data from 103 healthy sedentary adults aged 18-75 yr. FFM was strongly and positively related to maximal oxygen consumption (r = 0.80, P < 0. 001). FFM was also strongly and positively related to supine resting levels of blood volume (r = 0.79, P < 0.001) and stroke volume (r = 0.75, P < 0.001). Statistically controlling for the collective influences of blood volume and stroke volume abolished the tight relation between FFM and maximal oxygen consumption (r = 0.12, not significant). These results indicate that 1) FFM may be an important physiological determinant of blood volume and stroke volume among healthy sedentary adult humans of varying age; and 2) this relation between FFM and central circulatory function appears to represent the primary physiological basis for the strong association between FFM and maximal aerobic capacity in this population. Our findings suggest that sarcopenia (loss of skeletal muscle mass with aging) may contribute to the age-related decline in maximal aerobic capacity primarily via reductions in blood volume and stroke volume rather than a direct effect on the oxygen-consuming potential of muscle per se.
无脂肪体重（FFM）（主要是骨骼肌质量）与成年各年龄段健康人的最大有氧能力相关。这种生理关联的基础被认为是骨骼肌质量与其耗氧能力之间的直接关系。我们检验了另一种假设，即FFM部分通过与中心循环功能的关联对最大有氧能力产生影响。为此，我们分析了103名年龄在18 - 75岁的健康久坐成年人的数据。FFM与最大耗氧量呈强正相关（r = 0.80，P < 0.001）。FFM还与仰卧位静息血容量水平（r = 0.79，P < 0.001）和每搏输出量（r = 0.75，P < 0.001）呈强正相关。对血容量和每搏输出量的综合影响进行统计学控制后，FFM与最大耗氧量之间的紧密关系消失（r = 0.12，无统计学意义）。这些结果表明：1）FFM可能是不同年龄健康久坐成年人体内血容量和每搏输出量的重要生理决定因素；2）FFM与中心循环功能之间的这种关系似乎代表了该人群中FFM与最大有氧能力之间强关联的主要生理基础。我们的研究结果表明，肌肉减少症（随着年龄增长骨骼肌质量的丧失）可能主要通过血容量和每搏输出量的减少而非对肌肉本身耗氧潜力的直接影响，导致与年龄相关的最大有氧能力下降。
