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ABSTRACT
Siegler, JC, Midgley, AW, Polman, RCJ, and Lever, R. Effects of various sodium bicarbonate loading protocols on the time-dependent extracellular buffering profile. J Strength Cond Res 24(9): 2551-2557, 2010-Although much research has investigated the types of exercise that are enhanced with sodium bicarbonate (NaHCO^sub 3^) ingestion, to date, there has been limited research on the dosage and timing of ingestion that optimizes the associated ergogenic effects. This study investigated the effects of various NaHCO^sub 3^ loading protocols on the time-dependent blood-buffering profile. Eight male volunteers (age, 22.4 ± 5.7 yr; height, 179.8 ± 9.6 cm, body mass, 76.3 ± 14.1 kg) completed Part A, measures of alkalosis throughout 120 minutes after ingestion of various single NaHCO^sub 3^ dosages (0.3 g*kg^sup -1^, 0.2 g*kg^sup -1^, 0.1 g*kg^sup -1^, and placebo); and Part B, similar profiles after alternative NaHCO^sub 3^ loading protocols (single morning dosage [SMD], single evening dosage [SED], and dosages ingested on 3 consecutive evenings [CED]). Results from Part A are as follows. Blood buffering in the 0.1 g*kg^sup -1^ condition was significantly lower than the 0.2 g*kg^sup -1^ and 0.3 g*kg^sup -1^ conditions (p < 0.002), but there was no significant differences between the 0.2 g*kg^sup -1^ and 0.3 g*kg^sup -1^ conditions (p = 0.34). Although the blood buffering was relatively constant in the 0.1 and 0.2 conditions, it was significantly higher at 60 minutes than at 100 minutes and 120 minutes in the 0.3 g*kg^sup -1^ condition (p < 0.05). Results from Part B are as follows. Blood buffering for SMD was significantly higher than for SED and CED (p < 0.05). Blood buffering in the SMD condition was significantly lower at 17:00 hours than at 11:00 hours (p = 0.007). The single 0.2 and 0.3 g*kg^sup -1^ NaHCO^sub 3^ dosages appeared to be the most effective for increasing blood-buffering capacity. The 0.2 g*kg^sup -1^ dosage is best ingested 40 to 50 minutes before exercise and the 0.3 g*kg^sup -1^ dosage 60 minutes before exercise.
KEY WORDS metabolic alkalosis, buffering capacity, soda loading
INTRODUCTION
Over the past 3 decades, extensive research has investigated the potential of sodium bicarbonate (NaHCO^sub 3^) ingestion for inducing metabolic alkalosis and enhancing subsequent physical performance (see McNaughton and colleagues [18] for a recent review). Early research...