Metabolic and hormonal responses of elite swimmers during a regular training session.

Metabolic and hormonal measures of eight elite swimmers were taken at rest and during a regular training session after a prolonged bout of swimming (4560 +/- 68 m) at moderate intensity (MI) and after medium duration-high intensity (HI) swimming exercise (1471 +/- 157 m). MI and HI swims were respectively associated with significant increases in free fatty acids (0.4 at rest to 0.8 and 0.67 microeq . ml-1) glycerol (0.1 to 0.26 and 0.25 mmol . l-1), growth hormone (14 to 65 and 51 ng . ml-1) and norepinephrine (0.5 to 3.9 and 4.1 ng . ml-1). HI contrary to MI swimming was also associated with a significant (p less than 0.01) increase in blood lactate (1.5 to 8.8 mmol . l-1) and epinephrine (0.13 to 0.71 ng . ml-1) concentrations. Glucose, insulin, glucagon, and cortisol concentrations were not changed during the training session. It is concluded that a regular training session in elite swimmers is associated with an increase in lipid utilization, and a modest change in some of the hormones directly involved in the regulation of blood glucose level.