A Single Dose of Beetroot Juice Enhances Cycling Performance in Simulated Altitude

Abstract

A single dose of BR lowered V˙O2 during submaximal exercise and enhanced TT performance of trained cyclists in normobaric hypoxia. Consequently, ingestion of BR may be a practical and effective ergogenic aid for endurance exercise at altitude.

Dietary nitrate supplementation enhances high-intensity running performance in moderate normobaric hypoxia, independent of aerobic fitness

“…These findings are in line with most previous investigations [4,5,22,37], and similar to the results of a recent meta-analysis [6]. The physiological mechanisms underlying the decreased V O2 subsequent to nitrate supplementation have not been fully elucidated, but may be accounted for by: a) an improvement in the efficiency of mitochondrial respiration [35] and/or b) enhanced efficiency of muscle force production [7].…”

“…Consistent with previous investigations, plasma nitrate and nitrite, and exhaled NO concentrations were significantly elevated following dietary nitrate supplementation [1,2,5,8,55,22,39,38], signifying an increase in the 'substrates' available for NO generation via the nitrate-nitrite-NO pathway [11]. Peak plasma nitrite concentration was 602 % higher in BRJ versus PLA, similar to Arnold et al [38] (775 %) (~ 7 mmol nitrate), but considerably greater than reported by Muggeridge et al [22] (134 %) (~ 5 mmol nitrate) and Vanhatalo et al [8] (150 %) (~ 9.3 mmol).…”

“…Peak plasma nitrite concentration was 602 % higher in BRJ versus PLA, similar to Arnold et al [38] (775 %) (~ 7 mmol nitrate), but considerably greater than reported by Muggeridge et al [22] (134 %) (~ 5 mmol nitrate) and Vanhatalo et al [8] (150 %) (~ 9.3 mmol). Importantly, all participants increased plasma nitrite concentration by substantially greater than 30 % -a cut off proposed by Wilkerson [20] for identifying 'non-responders'.…”

“…This is supported by the findings of a recent study, in which nitrate supplementation improved tolerance to severe intensity cycling in hypoxia (FIO2 13.1 %) but not normoxia [36]. However, in other studies, nitrate supplementation has been shown both to improve [8,22,37] and have no effect [38][39][40] on hypoxic exercise performance. These equivocal findings may be attributed to differences in the training status of participants, exercise protocol, supplementation protocol, and hypoxic stimuli applied, and warrant further exploration.…”

“…A number of previous investigations have confirmed the beneficial effect of nitrate supplementation on TTE [8,24,37] and TT performance [22] in hypoxia. Conversely, studies in well-trained individuals exercising in hypoxia have typically found no effect of nitrate supplementation [38][39][40].…”