Sodium bicarbonate supplementation minimally affects the accumulated oxygen deficit during intense cycling to exhaustion

The aim of this investigation was to test whether sodium bicarbonate (NaHCO₃) affects the anaerobic energy contribution during a high-intensity cycling task. Eight participants (mean ± SD; age 25 ± 4 years) completed 4 different testing sessions separated by at least 48 hours. During the first 2 sessions, participants performed a series of intermittent bouts of 5 minutes submaximal steady-state cycling and responses were used to calculate the VO₂ -power regression and estimate the O₂ demand of high-intensity cycling. In the final 2 sessions under either a control (PLA = 0.3 g·kg⁻¹ body mass calcium carbonate) or experimental condition (ALK = 0.3 g·kg⁻¹ body mass NaHCO₃), participants cycled at 125% VO₂ to volitional exhaustion during which VO₂ was measured and the accumulated O₂ uptake and O₂ deficit were estimated. Times to volitional exhaustion during high-intensity cycling did not differ significantly between ALK (101.3 ± 20.2 seconds) and PLA (98.7 ± 21.4 seconds), and alkalosis did not significantly affect the AOD (ALK: 44.8 ± 10.8 mL·kg⁻¹) and PLA (44.2 ± 12.8 mL·kg⁻¹; P =.82). As such, we would conclude that anaerobic capacity during short-term, high-intensity exercise is minimally affected by metabolic alkalosis induced by NaHCO₃ supplementation.