The effect of training status on exercise performance and oxygen uptake responses to beetroot juice supplementation in cyclists

Authors

Haley McVannel, James Madison UniversityFollow

Preferred Name

Haley McVannel

Creative Commons License

This work is licensed under a Creative Commons Attribution-NonCommercial-No Derivative Works 4.0 International License.

Date of Graduation

5-11-2023

Semester of Graduation

Spring

Degree Name

Master of Science (MS)

Department

Department of Kinesiology

Second Advisor

Michael Saunders

Third Advisor

Stephanie Kurti-Luden

Abstract

Purpose: To determine if cardiovascular fitness, assessed by peak oxygen consumption (VO_2peak),influences the physiological and performance effects of beetroot juice (BRJ) supplementation and to explore if recent training habits independently influence this response. Methods: Thirteen male and female cyclists completed two graded exercise tests to assess cardiovascular fitness and four, seven-day experimental phases. Five subjects were classified as high fitness (VO_2peak: 65.9 ± 4.5 mL∙kg^-1∙min^-1) and eight as lower fitness (VO_2peak: 44.2 ± 7.0 mL∙kg^-1∙min^-1). Subjects consumed 140 ml of concentrated BRJ or placebo the last three days of each experimental phase. On day seven of each phase, subjects completed 10 min of constant load cycling at 45% and 10 min at 65% W_max at 80-100 rpm followed by a 4-km time trial. VO_2, blood lactate/glucose, heart rate, and RPE were measured during each submaximal workload. Resting blood pressure and expired nitric oxide were collected after a five-min rest pre-supplementation, and 150 min post-supplementation. Results: BRJ supplementation did not improve performance or alter the physiological responses to exercise. Likewise, VO_2max did not influence the effects of BRJ. To explore the potential impact of training volume, subjects were separated into two groups of six based on weekly training duration. Interestingly, there was a treatment x training volume group interaction (pConclusion: In contrast to our hypothesis, VO_2peak did not influence the effects of BRJ on physiology or performance. Paradoxically, our data suggests BRJ will confer more of a benefit among individuals performing higher volumes of cycle training. Due to the limited sample size, these data need to be replicated before widespread recommendations are established.