Exercise Metabolites Signal Fitness Levels

Exercise altered the levels of 10% of the blood plasma metabolites evaluated in a recent study, reports a team led by Gregory D. Lewis and Robert E. Gerszten of the Massachusetts General Hospital Heart Center, in Boston (Sci. Transl. Med. 2010, 2, 33ra37). Furthermore, the study revealed “new metabolic signatures that clearly distinguish more-fit from less-fit individuals during exercise,” Lewis says. “These results have implications for the development of optimal training programs and improved assessment of cardiovascular fitness, as well as for the development of nutritional supplements to enhance exercise performance.” The researchers used mass spectrometry to analyze 210 metabolites in blood samples of study participants taken before and after exercise. The levels of 21 of the metabolites changed significantly during exercise, reflecting the processing of sugars, fats, and amino acids, as well as the body’s utilization of ATP, the primary source of cellular energy. Several of the changes involved metabolic pathways not previously associated with exercise, including increases in niacinamide, a vitamin derivative known to enhance insulin release.