The effects of dietary nitrate supplementation on the adaptations to sprint interval training in previously untrained males

Abstract

5Objectives: Dietary nitrate can improve repeated high-intensity and supramaximal exercise 6 performance, although the effect on adaptations to training has received limited attention. The 7 purpose of this study was to investigate the effects of dietary nitrate on the response to 3-weeks 8 of sprint interval training (SIT). Design: Randomized control trial. Methods: Twenty-seven 9 untrained males (Age: 28 ± 7 y, V̇O 2Max : 42 ± 7 ml·kg -1 ·min -1 ) completed an incremental 10 exercise test at the beginning and end of the study. Participants were matched for V̇O 2Max and 11 randomly assigned to a control group (CON; n=8), SIT + placebo group (PLA; n=10), or SIT consumption (V̇O 2 ) data were filtered and smoothed data were analyzed to determine V̇O 2max . 69A plateau in V̇O 2 (determined by a rise in V̇O 2 of <50% of the expected increase for the given 70 WR) was used to confirm achievement of V̇O 2max . Based on these criteria, valid determinations 71 of V̇O 2max were obtained from all participants at each time point. The coefficient of variation 72 for our lab utilizing this protocol and method of assessment is 1.9%. VT was determined by 73 the 'V-slope' method as the break point in the association between carbon dioxide 74 production and V̇O 2 14 .

“Beet-ing” the Mountain: A Review of the Physiological and Performance Effects of Dietary Nitrate Supplementation at Simulated and Terrestrial Altitude

“…Two studies have also recently explored the effects of NO 3 − supplementation on the adaptations to SIT in normoxia [140, 141]. Muggeridge et al [140] reported greater improvements in maximal work rate during incremental exercise and indices of repeated high-intensity performance in participants who ingested NO 3 − versus placebo prior to SIT sessions (3 × 4–6 maximal 15 s cycle ergometry sprints per week, for 3 weeks).…”

“…Muggeridge et al [140] reported greater improvements in maximal work rate during incremental exercise and indices of repeated high-intensity performance in participants who ingested NO 3 − versus placebo prior to SIT sessions (3 × 4–6 maximal 15 s cycle ergometry sprints per week, for 3 weeks). Thompson et al [141] also demonstrated greater improvements in peak work rate during incremental exercise in individuals who performed SIT (3–4 × 4–5 maximal 30 s cycle ergometry sprints per week for 4 weeks) with NO 3 − compared with both training individuals given a placebo and NO 3 − -supplemented individuals who did not train.…”

“…However, this requires direct investigation given the multifarious methodological differences between studies. In particular, Puype et al [138] and De Smet et al [139] in hypoxia recruited moderately trained participants (: ~51–60 ml·kg −1 ·min −1 ), whereas Muggeridge et al [140] and Thompson et al [141] in normoxia recruited individuals with lower aerobic fitness (: ~42–50 ml·kg −1 ·min −1 ), who may exhibit a greater response to training with NO 3 − .…”

Supplements and Nutritional Interventions to Augment High-Intensity Interval Training Physiological and Performance Adaptations—A Narrative Review

“…However, more research needs to be conducted and it should be noted that the majority of works to date (five of the eight studies report no effect or a decrease in performance) do not support the ergogenic effect of dietary inorganic nitrate for repeated bouts of high-intensity exercise. Currently, there are several chronic HIIT studies (3-6 weeks) that have examined the potential for nitrate to augment training adaptations [134,141,[144][145][146][147]. Two studies found an increase in whole-body oxygen uptake (VO 2 max) following HIIT training (three-four times per week; four-five Wingates per session) in recreationally active participants with nitrate supplementation (12.8 mmol NO 3 divided into two servings) compared to HIIT and placebo [141,146], while others found no enhancement of aerobic power [134,144,147,148].…”

“…Currently, there are several chronic HIIT studies (3-6 weeks) that have examined the potential for nitrate to augment training adaptations [134,141,[144][145][146][147]. Two studies found an increase in whole-body oxygen uptake (VO 2 max) following HIIT training (three-four times per week; four-five Wingates per session) in recreationally active participants with nitrate supplementation (12.8 mmol NO 3 divided into two servings) compared to HIIT and placebo [141,146], while others found no enhancement of aerobic power [134,144,147,148]. Similarly, some studies have shown an enhancement in performance following HIIT with nitrate compared to placebo [141,[144][145][146], while others found no benefit [134,148].…”