Seasonal training and heart rate and blood pressure variabilities in young swimmers.

To evaluate if changes in athletes' physical fitness due to seasonal training are associated with changes in cardiovascular autonomic control, nine swimmers (three males and six females; aged 14-18 years) were evaluated before and after 5 months of training and competitions. Maximal oxygen consumption (VO2max) and ventilatory threshold were determined during a maximal test; heart rate (HR) and blood pressure (BP) variabilities' power spectra were calculated at rest (supine and sitting positions) and in the recovery of two exercises at 25 and 80% pre-training VO2max. At the end of the season: (a) VO2max and ventilatory threshold increased respectively by 12 and 34% (P<0.