Likely additive ergogenic effects of combined pre-exercise dietary nitrate and caffeine ingestion in trained cyclists.

Aims. To evaluate the possible additive effects of beetroot juice plus caffeine on exercise performance. Methods. In a randomized, double-blinded study design, fourteen healthy well-trained men aged 22 ± 3 years performed four trials on different occasions following preexercise ingestion of placebo (PLA), PLA plus 5mg/kg caffeine (PLA+C), beetroot juice providing 8mmol of nitrate (BR), and beetroot juice plus caffeine (BR+C). Participants cycled at 60% maximal oxygen uptake (VO2max) for 30min followed by a time to exhaustion (TTE) trial at 80% VO2max. Saliva was collected before supplement ingestion, before exercise, and after the TTE trial for salivary nitrate, nitrite, and cortisol analysis. Results. In beetroot trials, saliva nitrate and nitrite increased >10-fold before exercise compared with preingestion (𝑃 ≤ 0.002). TTE in BR+C was 46% higher than in PLA (𝑃 = 0.096) and 18% and 27% nonsignificant TTE improvements were observed on BR+C compared with BR and PLA+C alone, respectively. Lower ratings of perceived exertion during TTE were found during 80% VO2max on BR+C compared with PLA and PLA+C (𝑃 < 0.05 for both). Conclusions. Acute preexercise beetroot juice coingestion with caffeine likely has additive effects on exercise performance compared with either beetroot or caffeine alone.