Why does exercise seem almost like medicine for aging muscles? Scientists may now have a much clearer answer.
A new study from Duke-NUS Medical School has identified a gene that appears to control whether older muscles can repair themselves properly. The discovery could eventually lead to treatments that help preserve muscle strength as people age.
Muscles do much more than help us move. They help control blood sugar, support metabolism, protect joints, and allow people to remain active and independent. Beginning around middle age, however, muscles gradually lose strength and size. This process increases the chance of falls and slows recovery after injury or illness.
Researchers wanted to understand exactly what changes inside muscle cells during aging. They focused on a natural system that constantly removes damaged proteins while replacing them with healthy ones. Young muscles perform this housekeeping job very well, but older muscles slowly lose this ability.
The team discovered that a gene called DEAF1 plays an important role in this decline. As people age, DEAF1 becomes more active. This increases activity in a growth pathway called mTORC1.
Although mTORC1 helps muscles grow, too much activity creates problems. Muscle cells keep making new proteins but become less efficient at removing damaged ones. Over time, waste builds up inside the cells, making muscles weaker.
Another important discovery involved proteins called FOXOs. These proteins normally keep DEAF1 under control. As FOXO activity naturally decreases with age, DEAF1 rises even further, creating a cycle that gradually reduces muscle quality.
Exercise interrupts this harmful cycle. Physical activity switches on signals that lower DEAF1 levels, helping muscles remove damaged proteins and restore a healthier balance. In simple terms, exercise gives muscle cells a chance to tidy up, repair themselves, and continue working efficiently.
The scientists confirmed these findings by studying both fruit flies and older mice. In both animals, raising DEAF1 weakened muscles, while lowering it improved muscle function. Seeing the same pattern in two different species gives researchers greater confidence that the mechanism is real.
The research also suggests why some people respond differently to exercise. If DEAF1 levels become extremely high or FOXO activity falls too much, exercise alone may not completely reverse the damage. Understanding these differences could eventually allow doctors to personalize treatments for older adults.
Looking ahead, the researchers hope medicines that target DEAF1 could one day work alongside exercise to protect muscle strength. Such treatments could be especially valuable for people who cannot exercise because of advanced age, disability, surgery, or chronic disease.
Although these therapies are still years away, the discovery represents an important step toward healthier aging and maintaining independence later in life.
The research was published in the Proceedings of the National Academy of Sciences (PNAS).
Study review and analysis: This study provides strong evidence because the researchers combined molecular biology with experiments in fruit flies and older mice, allowing them to test how the DEAF1 gene affects muscle aging.
However, the work has not yet shown that treatments targeting DEAF1 will produce the same benefits in humans. More clinical studies will be needed before new medicines become available.
Even so, the findings help explain why exercise is so beneficial for aging muscles and may eventually lead to therapies that help people who are unable to exercise because of illness or disability.
If you care about muscle, please read studies about factors that can cause muscle weakness in older people, and scientists find a way to reverse high blood sugar and muscle loss.
For more health information, please see recent studies about an easy, cheap way to maintain muscles, and results showing these vegetables essential for your muscle strength.
Source: Duke-NUS Medical School.
