Acid-base balance during repeated cycling sprints in boys and men

Laboratoire Interuniversitaire de Biologie des Activités Physiques et Sportives, F-63001 Clermont-Ferrand, France The aim of this study was to investigate the acid-base balance during repeated cycling sprints in children and adults. Eleven boys (9.6 ± 0.7 yr) and ten men (20.4 ± 0.8 yr) performed ten 10-s sprints on a cycle ergometer separated by 30-s passive recovery intervals. To measure the time course of lactate ([La]), hydrogen ions ([H + ]), bicarbonate ions ([HCO ]), and base excess concentrations and the arterial partial pressure of CO 2 , capillary blood samples were collected at rest and after each sprint. Ventilation and CO 2 output were continuously measured. After the 10th sprint, concentrations of boys vs. men were as follows: [La], 8.5 ± 2.1 vs. 15.4 ± 2.0 mmol/l; [H + ], 43.8 ± 1.3 vs. 66.9 ± 9.9 nmol/l ( P