Nitrate Supplementation Combined with a Running Training Program Improved Time-Trial Performance in Recreationally Trained Runners

Abstract

Our purpose was to verify the effects of inorganic nitrate combined to a short training program on 10-km running time-trial (TT) performance, maximum and average power on a Wingate test, and lactate concentration ([La−]) in recreational runners. Sixteen healthy participants were divided randomly into two groups: Nitrate (n = 8) and placebo (n = 8). The experimental group ingested 750 mg/day (~12 mmol) of nitrate plus 5 g of resistant starch, and the control group ingested 6 g of resistant starch, for 30 days. All variables were assessed at baseline and weekly over 30 days. Training took place 3x/week. The time on a 10-km TT decreased significantly (p < 0.001) in all timepoints compared to baseline in both groups, but only the nitrate group was faster in week 2 compared to 1. There was a significant group × time interaction (p < 0.001) with lower [La] in the nitrate group at week 2 (p = 0.032), week 3 (p = 0.002), and week 4 (p = 0.003). There was a significant group time interaction (p = 0.028) for Wingate average power and a main effect of time for maximum power (p < 0.001) and [La−] for the 60-s Wingate test. In conclusion, nitrate ingestion during a four-week running program improved 10-km TT performance and kept blood [La−] steady when compared to placebo in recreational runners.

Effects of Dietary Supplements on Adaptations to Endurance Training

“…Plasma levels of NO2 -, used as a marker of NO availability [81], are increased in a dose-dependent manner but benefits may plateau between 8 and 16 mmol NO3 - [82]. No effects of beetroot juice were observed after six weeks of cycling HIIT when ingesting ~5 mmol NO3 -per day [83], while training studies using 8 to 12.8 mmol NO3 -per day have shown benefits [75,[84][85][86].…”

“…Seven studies have supplemented dietary nitrate while undergoing supervised endurance training for at least three weeks [75,77,[83][84][85][86][87] (Table 3). Four weeks of SIT combined with beetroot juice supplementation resulted in training-induced improvements in VO2peak of 7.7 to 10.7% [85,75], which were greater than with SIT alone (+5.6%) or after SIT with potassium NO3 -(KNO3) supplementation (+4.2%) [85].…”

Possible Effects of Beetroot Supplementation on Physical Performance Through Metabolic, Neuroendocrine, and Antioxidant Mechanisms: A Narrative Review of the Literature

“…Results of Santana et al ( 52 ) and Wylie et al ( 163 ) showed that the can transfer energy source from anaerobic to oxidative sources. They stated that the benefits of consumption on the concentration of blood lactate in endurance running or strenuous exercise depended on the period of supplementation, and the level of physical fitness of the subjects.…”

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].…”

“…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]. Mechanistically, nitrate supplementation seems to have a greater impact on fast-twitch fibers [135] and impact PCG1-alpha expression [149] and, therefore may be ideal for HIIT; however, to date, there appear to be contradictory findings.…”