You pound out workouts in the gym, hit the pavement when the weather’s nice, and partake in physical activities in your free time, too. For you, maintaining your muscle mass, endurance, and strength is relatively simple. But 30 years down the line, a healthy, agile body is a luxury that doesn’t come with a guarantee. Or does it?
Duke Medicine researchers believe they’ve found a molecule that can optimize and improve energy in exercising muscles—effectively boosting exercise tolerance in older age.
For the study, researchers engineered mice that lacked a metabolic enzyme called carnitine acetyltransferase, or CrAT, which boosts energy economy in skeletal muscle cells. Then they evaluated their exercise performance against a control group of mice (with the CrAT gene). The mice lacking the CrAT gene tired earlier during exercise tests, proving their muscles had a harder time meeting energy demands.
Next, the researchers introduced a carnitine supplement to both groups of mice. But exercise tolerance only improved in the control group of mice with normal CrAT activity in muscle. They were able to run longer and farther, indicating that carnitine and the CrAT enzyme work favorably together to enhance muscle energy metabolism during exercise.
Researchers caution that this doesn't mean everyone should start popping canitine supplements—more research is needed first to fully understand its effects on exercise. Plus, “We need to consider underlying genetics, lifestyle factors and acquired conditions,” said senior author Deborah Muoio, Ph.D, director of basic research at the Duke Molecular Physiology Institute and Sarah W. Stedman Nutrition and Metabolism Center in a release. Long term, the researchers hope to find other genes and metabolic pathways that can help them develop exercise programs optimized for individuals.