Use It or Lose It—Literally
There’s a reason the world’s best athletes are often among its youngest adults. As we age, we lose lean muscle mass. That’s part of the reason it’s so important to remain active as we age; to forestall these inevitable losses. New research shows that after just two weeks of inactivity, young people experienced muscle strength losses similar to those experienced by people more than a half-century older.
Some loss of lean muscle is expected with advancing age, but according to Danish researchers, even young people can lose muscle strength with surprising rapidity if they fail to work their muscles regularly. In the study, healthy young subjects whose activity levels were normal, but not exceptional, lost up to one-third of the strength in their leg muscles after just two weeks of inactivity. That’s equivalent to the leg strength of a typical person 50 years older.
"Our experiments reveal that inactivity affects the muscular strength in young and older men equally. Having had one leg immobilized for two weeks, young people lose up to a third of their muscular strength, while older people lose approximately one fourth. A young man who is immobilized for two weeks loses muscular strength in his leg equivalent to aging by 40 or 50 years," said Andreas Vigelsoe, PhD, in a press release. Vigelsoe is an investigator at the Center for Healthy Aging and the Department of Biomedical Sciences at the University of Copenhagen.
Afterwards, training on a bicycle was insufficient to return subjects’ muscles to their original size and strength. Weight training was also required. The takeaway message would appear to be that it’s far easier to hold on to what you’ve got through regular activity than to regain lost ground. "Unfortunately, bicycle-training is not enough for the participants to regain their original muscular strength,” Vigelsoe said. “Cycling is, however, sufficient to help people regain lost muscle mass and reach their former fitness level. If you want to regain your muscular strength following a period of inactivity; you need to include weight training.”
“It’s interesting that inactivity causes such rapid loss of muscle mass, in fact it'll take you three times the amount of time you were inactive to regain the muscle mass that you've lost. This may be caused by the fact that when we're inactive, it's 24 hours a day," said fellow researcher, Martin Gram.
Andreas Vigelsoe, PhD et al. Six weeks’ aerobic retraining after two weeks’ immobilization restores leg lean mass and aerobic capacity but does not fully rehabilitate leg strength in young and older men. Journal of Rehabilitation Medicine, June 2015 DOI: 10.2340/16501977-1961