Can exercise reverse muscle aging? Yes, and so it is

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A new study examines how exercise can help rejuvenate aging muscles. Image credit: A Bello/Getty Images.
  • Doctors call exercise a “polypill” because it can prevent and treat many chronic diseases associated with aging.
  • A new study of mouse and human muscle fibers shows how exercise affects gene expression.
  • The exercise-induced changes “reprogram” the epigenetic expression of the fibers to a more youthful state.
  • The results could provide avenues for the development of drugs to mimic these benefits in people unable to exercise.

Research shows that people who exercise regularly not only build muscle, but also improve their overall health, regardless of how they end up living.

For example, recent studies have shown that exercise reduces the risk of cardiovascular disease, as well as Alzheimer’s and Parkinson’s in older people.

Conversely, reductions in muscle mass and strength are associated with lower quality of life and higher all-cause mortality.

Because of its proven ability to prevent and treat several chronic diseases at low cost, doctors have called exercise a drug-free “polypill” that can benefit almost anyone.

“Exercise is the most powerful medicine we have,” says Dr. Kevin Murach, assistant professor at the Center for Exercise Science Research, University of Arkansas, Fayetteville, AR.

He believes that exercise should be seen as a health-promoting and potentially life-prolonging treatment, alongside medication and a healthy diet.

Scientists hope that a better understanding of how exercise rejuvenates aging muscles at the molecular level will provide clues for future anti-aging therapies.

Exercise can turn back the muscle fiber clock by promoting the “epigenetic reprogramming” of chromosomes in cell nuclei.

Epigenetics refers to how chemical changes affect the activity or “expression” of genes. For example, proteins called transcription factors can increase the expression of particular genes when they bind to specific DNA sequences.

In 2012, Dr. Shinya Yamanaka shared the Nobel Prize in Medicine for his discovery that four transcription factors can transform specialized mature cells into younger, flexible cells called pluripotent stem cells.

The four factors are called Oct3/4, Klf4, Sox2 and Myc, or OKSM for short.

In a new study whose results appear in The Journal of PhysiologyDr. Murach and colleagues compared the effects of OKSM factors on gene expression in muscle fibers from mice with access to an exercise wheel and mice without access.

Additionally, they compared the effects of OKSM factors on muscle with the effects of a single transcription factor, Myc. Scientists have found that exercise induces the expression of Myc to a greater extent than the other three factors.

The researchers also studied how exercise alone affected gene expression in muscle fibers of mice and humans. The mice were 22 months old, which equates to a human age of about 73 years.

The mice in the exercise group were free to run on an unweighted wheel for the first week, then over the next 8 weeks the scientists gradually made the wheel heavier by attaching magnetic weights to it.

The results suggest that exercise reprograms muscle fibers to a more youthful state through increased expression of genes that make Yamanaka factors, in particular Myc.

Dr. Murach suggests that the findings could one day lead to the development of drugs that amplify the exercise response of the muscles of people confined to beds or the muscles of astronauts in weightlessness.

But he dismisses the idea of ​​a pill that boosts the expression of Myc never replace the need to exercise. For one thing, exercise benefits the whole body, not just the muscles.

Moreover, Myc has been linked to cancer, so there are inherent risks in artificially stimulating its expression.

In their paper, the researchers also note that drugs that are gaining a popular reputation as “life extenders” may actually block some of the beneficial effects of exercise on muscles.

Dr Murach said Medical News Today:

“Evidence suggests that ‘life-extending’ drugs such as metformin and rapamycin interfere with the positive benefits of exercise specifically in skeletal muscle.”

He said it was “not out of the realm of possibility” that the drugs could disrupt the epigenetic reprogramming of muscles that occurs with exercise.

DTM asked exercise physiologists to recommend the best type of exercise for older adults.

“For people over 70, I would strongly recommend low-impact, lower-body and core-focused, full-body workouts,” advised John C. Loges, exercise physiologist at eVOLV Strong.

“Resistance training is not only suitable but highly recommended for people over 70,” he said.

“The key is to start slow and progress slowly with consistency,” he added.

“[W]aking is an activity I recommend, as well as resistance and mobility training,” advised Melissa Hendrix Wogahn, exercise physiologist at Joy of Active Living, which offers fitness and health classes to the elderly.

“In terms of frequency, an older person can walk every day, assuming they have no contraindications,” she added.

She recommended strength training at least two days a week and mobility training, including stretching, every day.

The authors of the new study acknowledge that it had some limitations. For example, exercise type, training status, biological sex, and several other factors can affect exercise-associated gene expression changes.

Furthermore, they highlight the importance of studying the functional consequences of epigenetic reprogramming in skeletal muscle.

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