Energy Metabolism and Thermoregulation in Old Age

摘要

Over their life spans, mice and men alike show a 15 to 30% decrease in their minimum, or resting, levels of energy metabolism, and a 50 to 70% decrease in the metabolism of activity. This, together with age-decrements in the capacity to regulate heat loss, makes the old person more susceptible to hypothermia that the young. Two independent relations of length of life to metabolic rate have been found in mice. First, as average metabolic rate increases, survival time decreases, and second, as the fraction of metabolic energy available for activity increases, survival time increases. The second term is the important one, for it is the first experimental support for the efforts to maintain human health and vigor, and to extend life, by means of regimes of exercise and activity. If mice are good models for men in these respects, rapid progress in understanding is possible. (ERA citation 04:031453)