Influence of dietary nitrate supplementation on physiological and muscle metabolic adaptations to sprint interval training

Abstract

We hypothesized that 4 wk of dietary nitrate supplementation would enhance exercise performance and muscle metabolic adaptations to sprint interval training (SIT). Thirty-six recreationally active subjects, matched on key variables at baseline, completed a series of exercise tests before and following a 4-wk period in which they were allocated to one of the following groups: ) SIT and [Formula: see text]-depleted beetroot juice as a placebo (SIT+PL);) SIT and [Formula: see text]-rich beetroot juice (~13 mmol [Formula: see text]/day; SIT+BR); or ) no training and [Formula: see text]-rich beetroot juice (NT+BR). During moderate-intensity exercise, pulmonary oxygen uptake was reduced by 4% following 4 wk of SIT+BR and NT+BR ( < 0.05) but not SIT+PL. The peak work rate attained during incremental exercise increased more in SIT+BR than in SIT+PL ( < 0.05) or NT+BR ( < 0.001). The reduction in muscle and blood [lactate] and the increase in muscle pH from preintervention to postintervention were greater at 3 min of severe-intensity exercise in SIT+BR compared with SIT+PL and NT+BR ( < 0.05). However, the change in severe-intensity exercise performance was not different between SIT+BR and SIT+PL ( > 0.05). The relative proportion of type IIx muscle fibers in the vastus lateralis muscle was reduced in SIT+BR only ( < 0.05). These findings suggest that BR supplementation may enhance some aspects of the physiological adaptations to SIT. We investigated the influence of nitrate-rich and nitrate-depleted beetroot juice on the muscle metabolic and physiological adaptations to 4 wk of sprint interval training. Compared with placebo, dietary nitrate supplementation reduced the O cost of submaximal exercise, resulted in greater improvement in incremental (but not severe-intensity) exercise performance, and augmented some muscle metabolic adaptations to training. Nitrate supplementation may facilitate some of the physiological responses to sprint interval training.

The benefits and risks of beetroot juice consumption: a systematic review

“…Ferguson et al (2013) found that the fall in oxygen cost/ delivery ratio at contraction onset was slowed after BRJ administration in rats, reflecting an improved metabolic control (Ferguson et al 2013a). Decreased metabolic perturbation measured in lactate concentration was found in other studies as well, in both rats (Ferguson et al 2013b) and humans (Carriker, Mermier, et al 2016; C. Thompson et al 2017). One study specifically tested nitrate supplementations in subjects exposed to a state of hypoxia, and found that BRJ increased tolerance to exercise and oxidative function values to values normally found in normoxia, and decreased metabolic perturbation in hypoxia ).…”

“…In several studies, ingestion of BRJ was found to significantly decrease VO 2 , regardless of the duration of BRJ consumption and type of intervention Kelly et al 2014;Kuennen et al 2015;Lansley, Winyard, Fulford, et al 2011;Masschelein et al 2012;Muggeridge et al 2013Muggeridge et al , 2014Rienks et al 2015;Tan et al 2018;Thompson et al 2017;Vanhatalo et al 2010;Whitfield et al 2016;Wylie, Kelly, Fulford, et al 2013). Tan et al (2018) found that a 3day supplementation of BRJ before, and ingestion of BRJ during moderate-intensity exercise attenuated the increase in VO 2 that normally accompanies sportive performance, compared to placebo (Tan et al 2018).…”

“…It should be noted that the majority of the studies which did not establish effects on VO 2 used "well-trained" or "elite" athletes as subjects (Arnold et al 2015;Boorsma, Whitfield, and Spriet 2014;Christensen, Nyberg, and Bangsbo 2013;MacLeod et al 2015). In contrast, studies that demonstrate the positive effects were performed with healthy and recreationally active individuals (Breese et al 2013;Kelly et al 2014;Lansley, Winyard, Fulford, et al 2011;Masschelein et al 2012;Rienks et al 2015;Tan et al 2018;Vanhatalo et al 2010;Whitfield et al 2016), or "trained", but not "well-trained" subjects Muggeridge et al 2013Muggeridge et al , 2014Thompson et al 2017). This may be due to the fact that training has a modifying effect on the body, for example by increasing nitric oxide synthase levels, an enzyme that is used to form NO from L-arginine.…”

“…Also, performance was not significantly improved after short term BRJ supplementation in a 10 kmrun . Nevertheless, some studies showed that maximal sprint performance and high intensity intermittent performance was enhanced after shortterm BRJ consumption (Esen et al 2019;Thompson et al 2017;Thompson et al 2015). Wylie et al found that BRJ consumption resulted in improved performance in 24 repetitions of 6 s all-out sprints interspersed with 24 s of recovery.…”

Effects of Grape Seed Extract Supplementation on Exercise Performance in Athletes

“…One possible approach involves the study of dietary factors that may act as ergogenic aids via their actions on cardiovascular function. For example, acute supplementation with beet root juice, which is high in nitrates, has been shown to enhance cardiac output and oxygen utilization and reduce vascular resistance and blood pressure at a given sub-maximal work intensity [2,3]. These effects are indicative of increased O 2 delivery to skeletal muscle.…”