Are you ready to unlock the secrets of youthful muscles? Scientists at Duke-NUS Medical School have made a groundbreaking discovery, revealing how exercise helps aging muscles repair themselves. This research sheds light on why physical activity remains one of the most effective ways to maintain strength and mobility as we get older.
Working with collaborators from Singapore General Hospital and Cardiff University, the team found that exercise helps restore a crucial balance within muscle cells that is disrupted by age. These findings, published in the Proceedings of the National Academy of Sciences (PNAS), offer new insights into the biological processes behind muscle aging and may pave the way for future strategies to combat age-related muscle loss.
Think about it: strong, healthy muscles are essential for everything from walking and lifting to regulating your metabolism. But from mid-life onward, muscle function naturally declines. This increases the risk of falls and fractures, slows recovery from illness or injury, and can make it harder to manage blood sugar levels. These effects extend beyond the individual, placing a greater burden on caregivers and increasing healthcare costs. In aging societies like Singapore, maintaining muscle health is absolutely critical for preserving independence and a high quality of life.
At the heart of muscle health is a growth pathway called mTORC1, which controls protein production and the maintenance of muscle tissue. As muscles age, this pathway can become overactive. This means the muscles prioritize building new proteins while slowing down the removal of damaged ones. The accumulation of these damaged proteins stresses muscle cells, contributing to gradual weakening. But what triggers this imbalance? That was the question.
The researchers identified a gene called DEAF1 as a key driver of this protein imbalance in aging muscles. They found that rising DEAF1 levels in aging muscles push the growth regulator mTORC1 into overdrive, disrupting normal protein turnover and accelerating muscle decline.
But here's where it gets controversial... DEAF1 is usually kept in check by a group of regulatory proteins called FOXOs. However, FOXO activity declines with age, allowing DEAF1 to rise unchecked. This loss of control appears to tip the balance away from muscle repair and towards deterioration.
The good news? The study showed that exercise can reverse this imbalance—but only when this regulatory system remains responsive.
Assistant Professor Tang Hong-Wen from the Cancer and Stem Cell Biology Programme at Duke-NUS, the study’s lead author, explained, “Exercise can reverse this process, correcting the imbalance. Physical activity activates certain proteins which lower DEAF1 levels, bringing the growth pathway back into balance. This allows ageing muscles to clear out damaged proteins, rebuild themselves properly, and help them stay stronger and more resilient.”
However, the researchers also found that when DEAF1 levels remain too high or FOXO activity is severely reduced—as can happen in older muscles—exercise alone may not fully restore muscle repair. This helps explain why some older adults may not see the full benefits of exercise as compared to others, and underscores the importance of understanding muscle biology alongside lifestyle interventions.
To validate their findings, the team conducted experiments in both fruit flies and older mice. In both models, increasing DEAF1 levels led to rapid muscle weakness, while lowering DEAF1 restored protein balance and muscle strength, highlighting its conserved role across species.
The findings also have implications beyond aging. DEAF1 is also known to influence muscle stem cells, which play a crucial role in tissue repair and regeneration. These stem cells naturally decline with age, and when DEAF1 is out of balance, muscle recovery slows even further. The findings also have potential benefits for people recovering from illness, surgery, or chronic conditions such as cancer. Adjusting DEAF1 levels may allow researchers to mimic some of exercise’s effects at the molecular level, helping muscles stay strong even with limited physical activity.
Priscillia Choy Sze Mun, a research assistant with the Cancer and Stem Cell Biology Programme at Duke-NUS, and the study’s first author, put it this way: “Exercise tells muscles to ‘clean up and reset.’ Lowering DEAF1 helps older muscles regain strength and balance, almost like hitting the rewind button. With millions of older adults at risk of muscle decline, understanding DEAF1 could lead to new ways to protect muscles and improve quality of life.”
Professor Patrick Tan, Senior Vice-Dean for Research at Duke-NUS, added: “This study helps explain, at a molecular level, why ageing muscles lose their ability to repair themselves and why exercise can restore that balance in some individuals. By identifying DEAF1 as a key regulator in this process, these findings may lead to new ways in which the benefits of exercise can be brought to societies with rapidly ageing populations.”
Duke-NUS is a global leader in medical education and biomedical research, combining basic scientific research with translational know-how to bring a better understanding to common diseases and develop new treatment approaches to improve the lives of people in Singapore and beyond.
What do you think? Does this research change your perspective on exercise and aging? Do you think there are other factors that influence muscle health as we get older? Share your thoughts in the comments below!
