Sex-dependent responses to acute sodium bicarbonate different dose treatment: A randomized double-blind crossover study

Objectives

This study quantified blood bicarbonate (HCO₃⁻) kinetics and gastrointestinal upset to determine the gender-related ergogenic potential of sodium bicarbonate (0.15-, 0.25- and 0.35 g_SB·kg_{Fat-free mass (FFM)}^–1) in high intensity functional training.

Design

Double-blind randomized placebo-controlled crossover.

Methods

Thirty female and male athletes performed two bouts of the Wingate Anaerobic Test (WAnT_PRE-HIFT and WAnT_POST-HIFT) interspaced with two 3-min bouts of Wall Balls and Burpees 120 min after ingestion of three sodium bicarbonate doses. Blood HCO₃⁻ was determined pre-ingestion, after supplementation and before/post exercise. Gastrointestinal upset was evaluated 120 min post-ingestion. Control (CTRL) measurements were performed.

Results

There were significant gender × treatment interactions for: changes in blood HCO₃⁻ at 60 min post-ingestion (p = 0.014; η²_p = 0.104; at 0.15 g_SB·kg_FFM⁻¹ males experienced higher increase than females); peak power (p = 0.015; η²_p = 0.103) and average power (p = 0.005; η²_p = 0.124) during WAnT_POST-HIFT, and changes in peak power between the Wingate Anaerobic Test bouts (p = 0.049; η²_p = 0.081). Sodium bicarbonate compared to PLA had no significant impact on Wall Balls and Burpees performance. The dose of 0.35 g_SB·kg_FFM⁻¹ resulted in higher less severe gastrointestinal symptoms compared to CTRL and 0.15 g_SB·kg_FFM⁻¹ (p = 0.001; W = 0.178); and higher total gastrointestinal upset compared to CTRL, PLA and 0.15 g_SB·kg_FFM⁻¹ (p < 0.001; W = 0.323).

Conclusions

There were dose- and gender-related differences in extracellular buffering capacity and ergogenic potential of sodium bicarbonate. The study suggested a detrimental impact of gastrointestinal upset on performance.