The Effects of a Novel Sodium Bicarbonate Ingestion System on Repeated 4 km Cycling Time Trial Performance in Well-Trained Male Cyclists

Background

A novel sodium bicarbonate (SB) product has come to market named the “Bicarb System” (M-SB; Maurten AB, Gothenburg, Sweden). It claims to minimise gastrointestinal (GI) discomfort whilst still improving exercise performance.

Aim

To investigate the effects of M-SB ingestion on repeated 4 km cycling time trials (TT1 and TT2) in well-trained male cyclists.

Methods

The study recruited ten well-trained cyclists (maximal oxygen uptake (\(\dot{V}{\text{O}}_{2\max }\)): 67 ± 4 ml kg⁻¹ min⁻¹ BM; peak power output (PPO) at \(\dot{V}{\text{O}}_{2\max }\): 423 ± 21 W) to take part in this randomised, crossover and double-blinded study. Following one visit to determine \(\dot{V}{\text{O}}_{2\max }\), participants completed a second visit to identify individual time to peak blood bicarbonate (HCO₃⁻) (ITTP) in a rested state. Visit three was a familiarisation trial mimicking the experimental procedures. Visits four to seven consisted of completing 2 × 4 km cycling TTs separated by 45 min passive recovery, following one of either: 0.3 g kg⁻¹ BM M-SB, 0.21 g kg⁻¹ BM sodium chloride (placebo; PLA) in vegetarian capsules (size 00), or a control trial (CON). Supplements (M-SB or placebo) were ingested pre-exercise at their respective ITTP.

Results

Performance in TT1 was faster in the M-SB condition compared with TT1 in CON (− 5.1 s; p = 0.004) and PLA (− 3.5 s; p < 0.001). In TT2, performance was also significantly faster in the M-SB condition compared with CON (− 4.4 s; p = 0.018) or PLA (− 4.1 s; p = 0.002). Total aggregated GI symptoms were generally low and not significantly different between PLA and the M-SB conditions for a range of symptoms.

Conclusions

The ingestion of M-SB improves repeated 4 km cycling TT performance and the recovery of acid–base balance between bouts, whilst causing minimal GI discomfort.