Discrete physiological effects of beetroot juice and potassium nitrate supplementation following 4 weeks sprint interval training
journal contributionposted on 26.03.2018, 08:21 by Christopher Thompson, Anni Vanhatalo, Stefan Kadach, Lee J. Wylie, Jonathan Fulford, Scott K. Ferguson, Jamie R. Blackwell, Stephen BaileyStephen Bailey, Andrew M. Jones
The physiological and exercise performance adaptations to sprint interval training (SIT) may be modified by dietary nitrate (NO3-) supplementation. However, it is possible that different types of NO3- supplementation evoke divergent physiological and performance adaptations to SIT. The purpose of this study was to compare the effects of 4 weeks SIT with and without concurrent dietary NO3- supplementation administered as either NO3--rich beetroot juice (BR) or potassium NO3- (KNO3). Thirty recreationally-active subjects completed a battery of exercise tests before and after a 4 week intervention in which they were allocated to one of three groups: 1) SIT undertaken without dietary NO3- supplementation (SIT); 2) SIT accompanied by concurrent BR supplementation (SIT+BR); or 3) SIT accompanied by concurrent KNO3 supplementation (SIT+KNO3). During severe-intensity exercise, VO2peak and time to task failure were improved to a greater extent with SIT+BR than SIT and SIT+KNO3 (P<0.05). There was also a greater reduction in the accumulation of muscle lactate at 3-min of severe-intensity exercise in SIT+BR compared to SIT+KNO3 (P<0.05). Plasma [NO2-] fell to a greater extent during severe-intensity exercise in SIT+BR compared to SIT and SIT+KNO3 (P<0.05). There were no differences between groups in the reduction in the muscle phosphocreatine recovery time constant from pre- to post-intervention (P>0.05). These findings indicate that 4 weeks SIT with concurrent BR supplementation results in greater exercise capacity adaptations compared to SIT alone and SIT with concurrent KNO3 supplementation. This may be the result of greater NO-mediated signalling in SIT+BR compared to SIT+KNO3.
- Sport, Exercise and Health Sciences