Sodium bicarbonate ingestion improves repeated high-intensity cycling performance in the heat

The purpose of this study was to investigate the effect of sodium bicarbonate ingestion on performance and recovery of the Wingate test during exercise in the heat. At 30 °C (∼50% relative humidity), ten male team sport athletes (mean values ± SD; age = 22 ± 4 y; body mass = 76 ± 9 kg) completed two 30s Wingate tests using a resistive load of 7.5% of body mass separated by 5 min of active recovery. They consumed either sodium bicarbonate (0.5g·kg^-1 body mass) or sodium chloride as a taste-matched placebo (0.2g·kg^-1 body mass) divided into 3 doses at 4h intervals on the day of each test. Performance measures included peak power, rate of fatigue and anaerobic capacity whilst physiological measures of capillary pH, bicarbonate, base excess/deficit and lactate were taken at rest and 3 min following each Wingate test. At all time-points (baseline and following both Wingate tests) capillary pH, bicarbonate and base excess/deficit were higher with sodium bicarbonate, whilst lactate was higher following both Wingate tests with sodium bicarbonate (all p < 0.05). Anaerobic capacity was similar during Wingate 1 but was higher with sodium bicarbonate during Wingate 2 (p < 0.05), with peak power (p < 0.05) but not rate of fatigue (p > 0.05) different between the trials during Wingate 2. When performing high-intensity anaerobic exercise in the heat, sodium bicarbonate ingestion improves recovery and repeated exercise performance likely through its known effects for reducing metabolic acidosis.