The Effect of a Dietary Nitrate Supplementation in the Form of a Single Shot of Beetroot Juice on Static and Dynamic Apnea Performance.

INTRODUCTION The purpose of the present study was to assess the effects of acute nitrate ([Formula: see text])-rich beetroot juice (BRJ) supplementation on peripheral oxygen saturation (SpO2), heart rate (HR), and pulmonary gas exchange during submaximal static and dynamic apnea. METHODS Nine (six males and three females) trained apneists (age: 39.6 ± 8.2 years, stature: 170.4 ± 11.5 cm, and body mass: 72.0 ± 11.5 kg) performed three submaximal static apneas at 60%, 70%, and 80% of the participant's current reported personal best time, followed by three submaximal (∼75% or personal best distance) dynamic apneas following the consumption of either a 70-ml concentrated BRJ (7.7 mmol [Formula: see text]) or a [Formula: see text]-depleted placebo (PLA; 0.1 mmol [Formula: see text]) in double-blind randomized manner. HR and SpO2 were measured via fingertip pulse oximetry at the nadir, and online gas analysis was used to assess pulmonary oxygen uptake ([Formula: see text]) during recovery following breath-holds. RESULTS There were no differences (p < .05) among conditions for HR (PLA = 59 ± 11 bpm and BRJ = 61 ± 12 bpm), SpO2 (PLA = 83% ± 14% and BRJ = 84% ±9%), or [Formula: see text] (PLA = 1.00 ± 0.22 L/min and BRJ = 0.97 ± 0.27 L/min). CONCLUSION The consumption of 7.7 mmol of beetroot juice supplementation prior to a series of submaximal static and dynamic apneas did not induce a significant change in SpO2, HR, and [Formula: see text] when compared with placebo. Therefore, there is no apparent physiological response that may benefit free divers as a result of the supplementation.