Effect of middle-intensity exercise on carnitine and beta-hydroxybutyrate plasmatic concentration in men and women.

The purpose of this study is to describe the dynamics of carnitine, its esters and beta-hydroxybutyrate, during a prolonged moderate-intensity physical exercise, as the literature data (Angelini 1986, Carlin 1986, Lennon 1984) up to date reported were not uniform. In our study twenty-two untrained subjects (11 males, 11 females) performed a test exercise on a motor-driven treadmill for 90 min at 50-60% of VO2 max. Blood samples were obtained at rest, at 20, 40, 60 and 90 min during the exercise and after 30 min of recovery. Men show an increase over rest values in short chain acyl carnitine after 90 min of exercise higher than women (M 157%, F 80%), while women have a more elevated relative increase in beta-hydroxybutyrate (M 201%, F 233%); Total carnitine in both sexes is not significantly modified.