Adults who begin lifting weights early in life may benefit from decreased age-related muscle loss and live independently longer, according to a report published this month by the American College of Sports Medicine.

The report, titled “Influence of Resistance Exercise on Lean Body Mass in Aging Adults: A Meta-Analysis,” was published in Medicine & Science in Sports & Exercise®, the official scientific journal of the American College of Sports Medicine. A research team with the University of Michigan compiled data from 49 studies to assemble this report. They found that older adults gain an average of 2.42 pounds of lean body mass, primarily muscle, after strength training for approximately 20 weeks.

This 2.42-pound increase counteracts the 0.4 pounds of muscle lost each year by sedentary adults over age 50. The findings suggest that aging individuals should consider beginning a strength training regimen as early as possible to maximize results and delay sarcopenia, an age-related muscle deterioration that can lead to mobility disability and loss of independence for seniors.

“The findings of this analysis are significant, given the millions of U.S. adults affected by sarcopenia,” said Mark Peterson, Ph.D., lead author of the study. “Because we have identified a robust link between resistance exercise and lean body mass, future generations of seniors who incorporate this modality may be less affected by age-related muscle loss and better able to preserve independence and quality of life.”

In addition to beginning a strength training program early in life, researchers also recommend adults consider the volume, or number of sets, of their program. The analysis suggests progression models, with gradual changes in volume and load, are appropriate to accommodate long-term growth in muscle mass.

“Our report is the first comprehensive meta-analysis to confirm a significant association between strength training volume and lean body mass increases in aging men and women,” said Dr. Peterson. “These findings suggest that, while effective for getting started, a single set of resistance exercises and/or fixed-volume programs may no longer be sufficient for individuals looking to achieve long-term changes in lean body mass.”

Researchers screened more than 5,000 references for this analysis, and 49 studies with 81 cohorts were selected for inclusion based on several criteria. The selected studies had an average participant age of at least 50 years, incorporated supervised, whole-body resistance training programs, and lasted at least eight weeks in duration.

ACSM and the Physical Activity Guidelines for Americans recommend that adults get at least 150 minutes of moderately intense physical activity each week. For more information on exercise for older adults, see the ACSM Position Stand on “Exercise and Physical Activity for Older Adults.”