Effects of NaHCO3 loading on acid-base balance, lactate concentration, and performance in racing greyhounds

This investigation examined the effects ofNaHCO₃ loading on lactateconcentration (La]), acid-base balance, and performance for a 603.5-m sprint task. Ten greyhounds completed aNaHCO₃ (300 mg/kg body weight) andcontrol trial in a crossover design. Results are expressed as means ± SE. Presprint differences (P < 0.05) were found for NaHCO₃ vs.control, respectively, for blood pH (7.47 ± 0.01 vs. 7.42 ± 0.01), HCO₃ (28.4 ± 0.4 vs. 23.5 ± 0.3 meq/l), and base excess (5.0 ± 0.3 vs. 0.2 ± 0.3 meq/l). Peak blood La] increased(P < 0.05) inNaHCO₃ vs. control (20.4 ± 1.6 vs. 16.9 ± 1.3 mM, respectively). Relative to control,NaHCO₃ produced a greater(P < 0.05) reduction in blood baseexcess (18.5 ± 1.4 vs. 14.1 ± 0.8 meq/l) andHCO₃ (17.4 ± 1.2 vs.12.8 ± 0.7 meq/l) from presprint to postexercise. Postexercise peak muscle H⁺concentration (H⁺])was higher (P < 0.05) inNaHCO₃ vs. control (158.8 ± 8.8 vs. 137.0 ± 5.3 nM, respectively). MuscleH⁺] recoveryhalf-time (7.2 ± 1.6 vs. 11.3 ± 1.6 min) and time to predosevalues (22.2 ± 2.4 vs. 32.9 ± 4.0 min) were reduced(P < 0.05) inNaHCO₃ vs. control, respectively.No differences were found in bloodH⁺] or bloodLa] recovery curves or performance times.NaHCO₃ increased postexerciseblood La] but did not reduce the muscle or blood acid-basedisturbance associated with a 603.5-m sprint or significantly affectperformance.