As people age they lose muscle mass, about 1% a year starting in middle age. That muscle loss, called sarcopenia, is a major argument for continuing strength-training throughout life.
Researchers from the University of Nottingham, School of Graduate Entry Medicine and Health in Derby, England, studied two groups: eight younger people, average age 25, and eight older people, average age 65. They were tested before breakfast; then they were given a small amount of insulin to replicate their body's reaction after eating breakfast.
By following a specific amino acid that revealed how much protein was being broken down in leg muscles, the researchers found that in the younger subjects, muscles were able to use insulin to halt the muscle breakdown, while the muscles in the older participants could not.
They also discovered that the younger people had greater blood flow in their legs than the older people, causing speculation that the older people might be getting lower amounts of nutrients and hormones. Weight training, they believe, could help maintain those crucial muscles.
The study appears online in the American Journal of Clinical Nutrition.
Photo credit: Robert Lachman / Los Angeles Times