Warm-up intensity does not affect the ergogenic effect of sodium bicarbonate in adult men

Abstract

This study determined the influence of a high (HI) vs. low-intensity (LI) cycling warm-up on blood acid-base responses and exercise capacity following ingestion of sodium bicarbonate (SB; 0.3 g·kg-1 body-mass (BM)) or a placebo (PLA; maltodextrin) 3-hours prior to warm-up. Twelve men (21±2 years, 79.2±3.6 kg BM, maximum power output (Wmax) 318±36 W) completed a familiarisation and four double-blind trials completed in a counterbalanced order: HI warm-up with SB (HISB); HI warm-up with PLA (HIPLA); LI warm-up with SB (LISB); and LI warm-up with PLA (LIPLA). LI warm-up was 15-minutes at 60%Wmax, while the HI warm-up (typical of elites) featured LI followed by 2 x 30-sec (3-minute break) at Wmax, finishing 30-minute prior to a cycling capacity test at 110%Wmax (CCT110%). Blood bicarbonate and lactate were measured throughout. SB supplementation increased blood bicarbonate (+6.4 [95%CI: 5.7 to 7.1 mmol·L-1]) prior to greater reductions with high intensity warm-up (-3.8 [95%CI: -5.8 to -1.8 mmol·L-1]). However, during the 30-minute recovery, blood bicarbonate rebounded and increased in all conditions, with concentrations ~5.3mmol·L-1 greater with SB supplementation (P<0.001). Blood bicarbonate significantly declined during the CCT110% with greater reductions following SB supplementation (-2.4 [95%CI: -3.8 to -0.90 mmol·L-1]). Aligned with these results, SB supplementation increased total work done during the CCT110% (+8.5 [95%CI: 3.6 to 13.4 kJ], ~19% increase) with no significant main effect of warm-up intensity (+0.0 [95%CI: -5.0 to 5.0 kJ). Collectively, the results demonstrate that SB supplementation can improve HI cycling capacity irrespective of prior warm-up intensity, likely due to blood alkalosis.