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Description

Dietary nitrate (NO3-) has been shown to impact oxygen consumption (VO2) as well as exercise performance in a number of prior studies. To date, previous investigations have observed NO3- effects at moderate to high-intensity (e.g. time to fatigue, time trials) exercise and often in trained athletes. However, less is known in regards to maximal and prolonged exercise and the potential impact of NO3- on post-exercise excess oxygen consumption (EPOC), particularly in untrained individuals. Here, we tested the hypothesis that acute dietary nitrate supplementation would attenuate VO2 during and following cycle ergometry at maximal efforts. Six young, moderately active, healthy males (age: 26±2 years, body mass index: 23.5±0.5 kg/m2; VO2max: 37.7±5.1 ml/kg/min) performed step-wise maximal cycle exercise (8±1 min) in control (anti-bacterial mouthwash) and acute NO3- supplemented conditions [70ml concentrated beet root juice (0.4g NO3-), 2 hrs prior to exercise] on separate occasions. Measurements of VO2 (indirect calorimetry), arterial blood pressure (MAP; sphygmomanometry), and heart rate (HR; ECG) were made for 45 min prior, during, and 60 min following exercise bouts. NO3- reduced MAP at rest ~1-3mmHg and this was accompanied by reflex-mediated HR increases (2-4 bpm). Additionally, NO3- slighty attenuated VO2 max during exercise (Ctrl: 30.9±3.4 ml/kg/min vs NO3-: 29.4±3.2/kg/min) and post exercise energy expenditure (Ctrl: 112.9±22.1 kcal/min vs NO3-: 94.1±15.7 kcal/min). While NO3- supplementation may have performance benefits, especially in elite athletes exercising at high intensities, it would not be an ideal choice of a supplement to aid in weight loss and increased energy expenditure.

Publication Date

4-9-2016

Project Designation

Honors Thesis

Primary Advisor

Anne Crecelius

Primary Advisor's Department

Health and Sport Science

Keywords

Stander Symposium poster

Effects of single-dose dietary nitrate on oxygen consumption during and after maximal exercise in healthy humans

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