Dietary nitrate supplementation improves rowing performance in well-trained rowers.
Increased plasma nitrate concentrations from dietary sources of nitrate have proven to benefit exercise performance. Beetroot (BR) contains relatively high levels of nitrate (NO₃⁻), which increases nitric oxide stores. This study investigated whether dietary nitrate supplementation, in the form of a BR beverage, would improve rowing performance during ergometer repetitions. In a randomized crossover design, 14 well-trained junior male rowers consumed 500 ml of either BR or placebo (PL) daily for 6 d. After supplementation, rowers completed 6 maximal 500-m ergometer repetitions and times were recorded. A 7-d washout period separated the 2 trials. Blood pressure, oxygen saturation, maximum heart rate, urine (specific gravity, pH, and nitrites), and lactates were collected for analysis at baseline and pre- and postperformance. Changes in the mean with 95% confidence limits were calculated. There was a likely benefit to average repetition time in the BR condition, compared with PL (0.4%, 95% confidence limits, ± 1.0%). In particular, Repetitions 4-6 showed an almost certain benefit in rowing time on BR (1.7%, 95% CL, ± 1.0%). The underlying mechanism for the observed results remains unknown, as differences observed in rowers' physiological measures between the 2 conditions were unclear. Conclusively, nitrate supplementation in the form of BR juice resulted in improved maximal rowing-ergometer repetitions, particularly in the later stages of exercise.
School of Sport and Exercise Science, Waikato Institute of Technology, Hamilton, New Zealand.
Hannah
H
Bond
Lillian
L
Morton
Andrea J
AJ
Braakhuis
D000293:Adolescent; D056352:Athletes; D027461:Beta vulgaris / Q000737:chemistry; D001794:Blood Pressure; D001835:Body Weight; D018592:Cross-Over Studies; D015930:Diet Records; D019587:Dietary Supplements; D004311:Double-Blind Method; D016552:Ergometry; D015444:Exercise; D017079:Exercise Tolerance / Q000502:physiology; D000067030:Fruit and Vegetable Juices; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007773:Lactates / Q000652:urine; D008297:Male; D009566:Nitrates / Q000008:administration & dosage*; D009573:Nitrites / Q000652:urine; D064133:Sports Nutritional Physiological Phenomena; D016896:Treatment Outcome
D007773:Lactates; D009566:Nitrates; D009573:Nitrites