The effects of serial and acute NaHCO3 loading in well-trained cyclists

Many studies have reported substantial performance gains in well-trained athletes following acute ingestion of sodium bicarbonate (NaHCO₃). However, acute NaHCO₃ ingestion is not always practical. The aim of the current study was to compare acute NaHCO₃ loading with serial NaHCO3 loading (split doses over three days) in well-trained cyclists. Eight male cyclists (mean ± SD; age = 28 ± 8 years; peak = 66.8 ± 8.4 ml.kg^-1min^-1) completed three tests in a double blind, randomized design over a three week time-frame: acute NaHCO₃ loading (AL), serial NaHCO3 loading (SL) and a placebo loading condition (P). Following each loading protocol, cyclists completed a 4-minute performance test on a cycling ergometer. was measured during each test and blood samples were taken throughout the study to measure lactate, bicarbonate ion concentration ([HCO₃^-]) and pH levels. Both the AL and SL trials produced a significantly higher average power in the 4-minute test (mean ± SD; 3.3 ± 2.0% and 2.3 ± 2.5%; p < 0.001 and p = 0.01 respectively) when compared to the P trial, with no significant difference between AL and SL trials (p = 0.29). The AL trial produced a significantly greater post-loading alkalosis as determined by blood [HCO₃^-] when compared to the SL and P trial. Both acute and serial NaHCO₃ loading significantly improve 4-minute cycling performance when compared to a placebo trial. However, serial NaHCO₃ loading may provide a convenient and practical alternative approach for athletes preparing for competition.