Can exercise reverse muscle aging? Yes, and here’s how

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A new study explores how exercise can help rejuvenate aging muscles. Image credit: A Bello/Getty Images.
  • Doctors call exercise “multibites” because it can prevent and treat many of the chronic diseases that are associated with aging.
  • A new study of muscle fibers from mice and humans shows how exercise affects gene expression.
  • Exercise-induced changes “reprogram” the epigenetic expression of fibers to a more youthful state.
  • The findings could provide guidance for developing drugs to mimic these benefits in people who cannot exercise.

Research shows that people who exercise regularly not only strengthen their muscles, but also improve their overall health, no matter how late in life they started.

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

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

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

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

He believes exercise should be considered a treatment that improves health and potentially extends life, along with medication and a healthy diet.

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

Exercise can turn back the clock in muscle fibers by promoting “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 recruit the expression of certain genes when they bind to specific DNA sequences.

In 2012 Dr. Shinya Yamanaka shared Nobel Prize for Medicine for his discovery that four transcription factors can turn 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, the results of which appear in Journal of PhysiologyDr. Murach and colleagues compared the effects of OKSM factors on gene expression in muscle fibers of mice that had access to an exercise wheel and mice that did not.

In addition, 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 examined how exercise itself affected gene expression in muscle fibers from both mice and humans. The mice were 22 months old, which is equivalent to a human age of about 73 years.

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

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

Dr. Murach suggests that the findings may one day lead to the development of drugs that enhance the muscle response to exercise in people who are bedridden or the muscles of astronauts in zero gravity.

But he rejects the idea of ​​a pill that enhances the expression of Myc always replacing the need for exercise. On the one hand, exercise has a beneficial effect on the whole body, not just on the muscles.

Additional, Myc is associated with cancer, so there are inherent risks in artificially enhancing its expression.

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

Dr Murach said Medical News Today:

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

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

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

“For people over 70, I would highly recommend low-impact, full-body workouts with a focus on the lower body and core,” advised John S. Logis, an exercise physiologist at eVOLV Strong.

“Resistance training is not only appropriate but highly recommended for people 70 and older,” he said.

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

“[W]Alking is an activity I recommend along with resistance and mobility training,” advised Melissa Hendricks Vaughan, an exercise physiologist at Joy of Active Living, which offers fitness and health coaching for seniors.

“In terms of frequency, an older adult can walk every day, assuming there are no contraindications,” she added.

She recommends 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 influence exercise-related changes in gene expression.

In addition, they highlight the importance of investigating the functional consequences of epigenetic reprogramming in skeletal muscle.

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