Morris, D., Arms, J., & Collier, S. (2014). Effects of beetroot supplementation on oxygen consumption, arterial oxygen saturation, and exercise performance in hypoxia. Medicine & Science in Sports & Exercise, 46(5), Supplement abstract number 1560.

“Hypoxic pulmonary vasoconstriction is a contributing factor to arterial O2 desaturation and reductions in oxygen consumption and performance during exercise in hypoxia. Previous investigations of high altitude exercise have shown that hypoxic pulmonary vasoconstriction can be reduced and blood oxygen saturation and exercise performance partially restored using pulmonary vasodilators such as PDE-5 inhibitors. Exogenous dietary nitrate found in beetroot juice has been shown to cause systemic vasodilation and improve exercise performance in normoxia but the effect on pulmonary vascular tone and exercise performance in hypoxia is unknown.”

This study determined the effects of acute beetroot juice supplementation on arterial oxygen saturation, oxygen consumption, and performance during an extended (~175 kJ) cycling time trial in hypoxia (PIO2 = 88 Torr). Male cyclists (N = 9) completed a familiarization time-trial (2.5 kJ per kg of body mass) on an electronically braked cycle ergometer. Ss returned to the laboratory on three separate occasions to perform the time-trial (TT) in hypoxia (PIO2 = 88 Torr) 2.5 hours following acute consumption of 70 mL of the following treatments: i) beetroot juice, ii) denitrated beetroot juice, or iii) water (control condition) applied in a randomized, double-blind, crossover fashion. Oxygen consumption and oxygen saturation were measured during the time-trial and time to completion of the time-trial were the dependent variables.

No significant differences were detected due to treatment in time-trial completion time, mean oxygen saturation during the time-trial, or mean oxygen consumption during the time-trial.

Implication. Acute beetroot juice consumption does not enhance performance, arterial oxygen saturation, or oxygen consumption during intense, prolonged exercise in hypoxia.

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