High dose Nitrate ingestion does not improve 40 km cycling time trial performance in trained cyclists

ABSTRACT

This study evaluated the chronic effects of nitrate (NO₃^?) ingestion over three days, on 40 km TT performance in 11trained cyclists (VO_2max: 60.8 ± 7.4 ml.kg^?1.min^?1; age: 36 ± 9 years; height: 1.80 ± 0.06 m; body mass: 87.2 ± 12.0 kg). Utilising a double-blind randomised cross-over design, participants completed three 40 km TT on a Velotron® ergometer following the ingestion of either a 140 ml of “BEET It sport®” NO₃^? shot containing 12.8 mmol or 800 mg of NO₃^?, a placebo drink or nothing (control). Performance, oxygen consumption (VO₂), blood bicarbonate (HCO3-), pH and lactate (BLa) and ratings of perceived exertion (RPE) were measured every 10 km throughout the TT. The present findings show that NO₃^? ingestion had no effect on TT performance (NO₃^?: 4098.0 ± 209.8 vs. Placebo: 4161.9 ± 263.3 s, p = 0.296, ES = 0.11), or VO₂ (p = 0.253, ES = 0.13). Similarly, blood lactate and RPE were also unaffected by the experimental conditions (p = 0.522, ES = 0.06; p = 0.085, ES = 0.30) respectively. Therefore, these results suggest that a high dose of NO₃^? over three days has limited efficacy as an ergogenic aid for 40 km TT cycling performance in trained cyclists.