Study Reveals How Exercise May Promote Healthy Aging

The research results could lead to new strategies for preserving muscle function as people age.

Exercise is a significant component of healthy aging. Regular exercise improves cardiovascular function, helps prevent falls, and may improve brain function.

However, the underlying cellular mechanisms that produce these effects are poorly understood.

Recently, scientists from Joslin Diabetes Center in Boston investigated one cellular mechanism — dynamic mitochondrial remodeling — to see what relationship it has with exercise, fitness, and aging.

The study was published on January 3 in the Proceedings of the National Academy of Sciences (PNAS).

According to the research, mitochondria are the specialized structures within cells responsible for producing energy. In addition, when a person exercises, their muscles undergo a pattern of fatigue, restoration, and recovery. This pattern is a mitochondrial dynamic cycle.

To investigate the role mitochondrial dynamics play in exercise, the scientists created an exercise model using C. elegans — a microscopic worm species frequently used in metabolic and aging research.

For the first part of the experiment, the team recorded data as the worms swam or crawled throughout their 15 days of adulthood. They found that as the worms aged, their mitochondria became increasingly disorganized.

For example, young worms recovered from exercise within 24 hours. In contrast, the older worms took longer than 24 hours, and their mitochondria reorganization was reduced compared to younger worms.

“Aging dampened the extent to which this occurred and induced a parallel decline in physical fitness. That suggested that mitochondrial dynamics might be important for maintaining physical fitness and possibly for physical fitness to be enhanced by a bout of exercise,” said first author Juliane Cruz Campos in a news release.

During the second set of experiments, the researchers put the worms through an exercise training program. This program allowed the worms to swim one hour a day for 10 consecutive days. Not surprisingly, the middle-aged worms showed fitness improvements on day 10. In addition, the training also lessened age-related impaired mitochondrial dynamics.

Then the team investigated the role AMPK — a molecule that regulates energy and mitochondria remodeling — plays in improving exercise capacity during aging.

Aging worms with increased AMPK showed improved fitness levels and maintenance of exercise performance. In contrast, the aging worms engineered to lack AMPK showed reduced physical fitness, impairment of the exercise recovery cycle, and a lack of age-delaying benefits associated with exercise.

According to the study, these results suggest that the mitochondrial dynamics cycle and AMPK activation are critical for maintaining physical fitness and exercise responsiveness during aging.

“Targeting mechanisms to optimize mitochondrial fission and fusion, as well as AMPK activation, may represent promising strategies for promoting muscle function during aging,” the authors wrote.

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