Heart rate and blood pressure time courses during prolonged dry apnoea in breath-hold divers.

To define the dynamics of cardiovascular adjustments to apnoea, beat-to-beat heart rate (HR) and blood pressure and arterial oxygen saturation (SaO(2)) were recorded during prolonged breath-holding in air in 20 divers. Apnoea had a mean duration of 210 +/- 70 s. In all subjects, HR attained a value 14 beats min(-1) lower than control within the initial 30 s (phase I).

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.