HAMILTON, Ontario, June 20 (UPI) -- Exercise may be a more important part of medical therapy for older adults than thought, based on experiments with mice showing the rodents recovered faster if they'd been active.
Older mice that exercised rebuilt muscle and gained more muscle mass than those that were inactive, suggesting older adults who need to gain muscle strength include physical activity in their therapy, say researchers at McMaster University.
Exercise and strength training have already been shown in previous studies to cut risk of death by as much as half and help prevent brain aging.
Physical activity has been found to delay disability and reduce risk for loss of mobility, so it makes sense that exercise would help muscle regenerate faster after an injury, as it did with mice in the new study.
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"This is a clean demonstration that the physiological and metabolic benefits of exercise radiate to skeletal muscle satellite cells, the adult stem cells responsible for repair after injury, even in senescent animals," Dr. Thoru Pederson, editor-in-chief of The FASEB Journal, which published the study, said in a press release. "Strikingly, even as the contractile elements of muscle tissue wane with age, the capacity of the satellite cells to respond to exercise cues is maintained."
For the study, published in The FASEB Journal, researchers injected three groups of mice, two old and one young, with snake venom to induce muscle injury.
When compared at 10 days and 28 days after their injuries, older mice that exercised recovered at about the same rate as younger, sedentary mice, while the old, sedentary group did not regain as much muscle strength and mass.
The researchers say the study suggests adult stem cells in the body, even when old, respond to the body for growth, and that older patients should be prescribed some time of physical activity to aid with recovery from injury.
"Exercise pre-conditioning may improve the muscle repair response in older adults to stimuli such as acute periods of atrophy, inactivity or damage," said Dr. Gianni Parise, a researcher and associate professor at McMaster University. "Exercise-conditioning rescues delayed skeletal muscle regeneration observed in advanced age."
