The Impact of Aging on Metabolism

Many of us have heard the common adage that metabolism declines with age, but this doesn’t happen automatically as time passes; rather, changes to lifestyle choices and muscle loss account for it. Resistance training can slow the effects of aging on metabolic rate.

Scientists have long held that tissue-specific energy expenditure (TEE) increases steadily throughout childhood before reaching its highest point during adulthood, but new research published in Science suggests this pattern may be far more complicated than previously believed. Researchers examined TEE of 6,421 people between 8 days old and 95 years of age living across 29 different countries between 8 days old and 95 years of age in order to examine TEE along with fat-free mass (the amount of your body made up of muscle, bones, organs), fat percentage, TEE rates over time as part of this research study.

The findings were quite startling. “What we found was that both total and basal metabolic rates remained relatively steady from infancy through about age 20. At that point, they began to decrease slightly due to a reduction in lean body mass,” write the authors of this study. They used height and weight measurements of each participant to get an accurate depiction of their metabolism; however they failed to account for sex differences or variables such as hormone effects like thyroxine or leptin on TEE.