Browse by author
Lookup NU author(s): Dr Owen JeffriesORCiD
This is the authors' accepted manuscript of an article that has been published in its final definitive form by Taylor and Francis , 2021.
For re-use rights please refer to the publisher's terms and conditions.
The aim of this study was to determine the effect of five days dietary nitrate (NO3-) consumption on exercise tolerance and thermoregulation during cycling in hot, dry conditions. In a double-blind, randomised crossover design, 11 healthy males participated in an exercise tolerance test (Tlim) in the heat (35°C, 28% relative humidity), cycling above the thermoneutral gas exchange threshold, after five days of dietary supplementation, with either NO3--rich beetroot juice (BR; ~ 9.2 mmol NO3-) or placebo (PLA). Changes in plasma [NO3-] and nitrite [NO2-], core and mean skin temperatures, mean local and whole-body sweat rates, heart rate, perceptual ratings and pulmonary gas exchange were measured during exercise, alongside calorimetric estimations of thermal balance. Mean arterial pressures (MAP) were recorded pre-Tlim. There were no differences in Tlim between conditions (BR = 22.8 ± 8.1 min; Placebo = 20.7 ± 7.9 min) (P = 0.184), despite increases in plasma [NO3-] and [NO2-] (P < 0.001) and a 3.8% reduction in resting MAP (P = 0.004) in the BR condition. There were no other differences in thermoregulatory, cardio-metabolic, perceptual or calorimetric responses to the Tlim between conditions (P > 0.05). Dietary NO3- supplementation had no effect on exercise tolerance or thermoregulation in hot, dry conditions, despite reductions in resting MAP and increases in plasma [NO3-] and [NO2-]. Healthy, yet physically inactive individuals with no known impairments in vasodilatory and sudomotor function do not appear to require BR for ergogenic or thermolytic effects during exercise in the heat.
Author(s): Fowler R, Jeffries O, Tallent J, Theis N, Heffernan SM, McNarry MA, Kilduff L, Waldron M
Publication type: Article
Publication status: Published
Journal: European Journal of Sports Science
Online publication date: 04/03/2020
Acceptance date: 02/03/2020
Date deposited: 03/03/2020
ISSN (print): 1746-1391
ISSN (electronic): 1536-7290
Publisher: Taylor and Francis
Altmetrics provided by Altmetric