- New research analyzed how exercise affects signs of aging in the muscles.
- Scientists found that older adults who exercised had younger-looking muscles.
- The findings make the case for working out regularly as you age.
It’s no secret that exercise benefits your health in myriad ways, but new research suggests there’s yet another perk to consider: It may keep you young.
That’s the major takeaway from a new study, published in the journal Nature Aging.
For the study, researchers analyzed data from 47 adults: 11 participants under the age of 30, and 36 participants over 65. The older group was divided into three sub-groups based on their physical activity levels: Those who exercised regularly, those who were “normally active,” and those who were physically impaired.
All of the participants took part in a one-hour, moderate-intensity exercise session on a stationary bike, designed to require 50% of their maximum effort. Researchers took muscle biopsies before and after the exercise session, which were analyzed through a series of tests.
One test looked at age-related changes in gene expression. The researchers found that the group that exercised regularly didn’t have about 50% of these age-related changes—meaning, their muscles appeared younger than they actually were. (The changes were present in the normally active and physically impaired groups.)
Meet the experts: Georges E. Janssens, Ph.D., lead study author and assistant professor at Amsterdam University Medical Center’s Laboratory Genetic Metabolic Diseases; Richard Dupee, M.D., chief of geriatrics at Tufts Medical Center
The researchers also looked at participants’ levels of metabolites related to NAD+, a molecule that’s crucial for DNA repair and overall cell health. Levels of NAD+ naturally decline with age, but interestingly, the exercise group had less pronounced changes in NAD+-related metabolites than the normally active and impaired groups.
“These findings highlight the potential of exercise training to substantially mitigate age-related molecular changes in muscle, offering insights into how physical activity can preserve muscle health during aging,” the researchers wrote in the conclusion.
“Rather than simply asking whether exercise is ‘good for you,’ we wanted to understand which molecular pathways in muscle remain youthful with exercise and which continue to change with age despite being physically active,” says Georges E. Janssens, Ph.D., lead study author and assistant professor at Amsterdam University Medical Center’s Laboratory Genetic Metabolic Diseases.
What’s behind these correlations, and what does it mean for you? Below, doctors break it down.
What’s behind this link?
It’s important to note that the study didn’t prove that having an exercise routine reduced age-related changes in the study participants—it simply found a link between regular exercise and improved biomarkers. The study was also relatively small. Still, doctors say there’s likely something to this association.
One of the “most striking” findings was that older adults who exercised regularly did not have a decline in mitochondrial transcripts, Janssens says. (The mitochondria is the “powerhouse” of the cell. As cells age, they have trouble balancing mitochondria’s RNA, which leads to less energy and metabolism.) Those who were less active did see this decrease. “This suggests that the difference wasn’t simply due to chronological age, but was strongly associated with maintaining a highly active lifestyle over time,” Janssens says.
Exercise seems to preserve several aspects of mitochondria and muscle function that
would otherwise decline with age, Janssens says. “At the same time, we also found pathways that were not fully restored by exercise, highlighting that while exercise is incredibly beneficial, it doesn’t completely prevent all aspects of the aging process,” Janssens says.
The findings “strengthen the biologic rationale for exercise in aging, while stopping short of claiming that it changes outcome-based geriatric practice on its own,” says Richard Dupee, M.D., chief of geriatrics at Tufts Medical Center. Meaning, while the older adults who engaged in high levels of exercise had “younger” muscles, the study didn’t explore whether that translated to outcomes like a lower risk of falls, less disability, or a longer life.
Still, Dr. Dupee says that the findings support what geriatricians see in their offices. “Regular exercise appears to preserve skeletal muscle health in older adults by
maintaining pathways involved in mitochondrial respiration, cellular energy
metabolism, NAD+ biology, and lipid handling,” he says.
How much exercise do you need?
This particular study found that people in the exercise group took an average of 14,000 steps each day. By comparison, those who were “normally” active had daily step counts of about 7,000.
Dr. Dupee points out that the participants in the exercise group were “exceptionally active.” Janssens agrees, saying the findings suggest that “preservation of muscle health may require staying exceptionally active as we age, perhaps even more active than when we’re younger.”
What’s the takeaway?
“The simplest takeaway is exercise really does matter,” Janssens says.
However, he acknowledges that higher levels of physical activity aren’t feasible for all older adults, especially those who have frailty or mobility limitations. “Our findings therefore not only reinforce the value of exercise but also identify how exercise benefits aging,” Janssens says. This could eventually lead to the development of treatments that target the same pathways in the body to benefit people who aren’t able to be physically active, he says.
Dr. Dupee says that the findings underscore that age-related muscle decline isn’t guaranteed. “That supports treating exercise as a core intervention for [loss of muscle mass], frailty, slowed gait, reduced endurance, and post-hospital deconditioning rather than as generic wellness advice,” he says. “It reinforces the importance of structured aerobic activity, resistance training, balance work, and reduction of sedentary time as part of routine care plans for older adults whenever feasible.”
Current exercise guidelines recommend getting at least 150 minutes per week of moderate-intensity exercise, along with two days of strength training.
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