Abstract
Objectives
Dietary nitrate (NO3-) supplementation and ischaemic preconditioning (IPC) can independently improve exercise performance. The purpose of this study was to explore whether NO3- supplementation, ingested prior to an IPC protocol, could synergistically enhance parameters of exercise.
Design
Double-blind randomized crossover trial.
Methods
Ten competitive male cyclists (age 34 ± 6 years, body mass 78.9 ± 4.9 kg, V̇O2peak 55 ± 4 mL·kg·min-1) completed an incremental exercise test followed by three cycling trials comprising a square-wave submaximal component and a 16.1 km time-trial. Oxygen uptake (V̇O2) and muscle oxygenation kinetics were measured throughout. The baseline (BASE) trial was conducted without any dietary intervention or IPC. In the remaining two trials, participants received 3 × 5 min bouts of lower limb bilateral IPC prior to exercise. Participants ingested NO3--rich gel (NIT+IPC) 90 min prior to testing in one trial and a low NO3- placebo in the other (PLA+IPC). Plasma NO3- and nitrite (NO2-) were measured immediately before and after application of IPC.
Results
Plasma [NO3-] and [NO2-] were higher before and after IPC in NIT+IPC compared to BASE (P<0.001) but did not differ between BASE and PLA+IPC. There were no differences in V̇O2 kinetics or muscle oxygenation parameters between trials (all P>0.4). Performance in the time-trial was similar between trials (BASE 1343 ± 72 s, PLA+IPC 1350 ± 75 s, NIT+IPC 1346 ± 83 s, P=0.98).
Conclusions
Pre-exercise IPC did not improve sub-maximal exercise or performance measures, either alone or in combination with dietary NO3- supplementation.
Dietary nitrate (NO3-) supplementation and ischaemic preconditioning (IPC) can independently improve exercise performance. The purpose of this study was to explore whether NO3- supplementation, ingested prior to an IPC protocol, could synergistically enhance parameters of exercise.
Design
Double-blind randomized crossover trial.
Methods
Ten competitive male cyclists (age 34 ± 6 years, body mass 78.9 ± 4.9 kg, V̇O2peak 55 ± 4 mL·kg·min-1) completed an incremental exercise test followed by three cycling trials comprising a square-wave submaximal component and a 16.1 km time-trial. Oxygen uptake (V̇O2) and muscle oxygenation kinetics were measured throughout. The baseline (BASE) trial was conducted without any dietary intervention or IPC. In the remaining two trials, participants received 3 × 5 min bouts of lower limb bilateral IPC prior to exercise. Participants ingested NO3--rich gel (NIT+IPC) 90 min prior to testing in one trial and a low NO3- placebo in the other (PLA+IPC). Plasma NO3- and nitrite (NO2-) were measured immediately before and after application of IPC.
Results
Plasma [NO3-] and [NO2-] were higher before and after IPC in NIT+IPC compared to BASE (P<0.001) but did not differ between BASE and PLA+IPC. There were no differences in V̇O2 kinetics or muscle oxygenation parameters between trials (all P>0.4). Performance in the time-trial was similar between trials (BASE 1343 ± 72 s, PLA+IPC 1350 ± 75 s, NIT+IPC 1346 ± 83 s, P=0.98).
Conclusions
Pre-exercise IPC did not improve sub-maximal exercise or performance measures, either alone or in combination with dietary NO3- supplementation.
| Original language | English |
|---|---|
| Pages (from-to) | 852-857 |
| Number of pages | 6 |
| Journal | Journal of Science and Medicine in Sport |
| Volume | 22 |
| Issue number | 7 |
| Early online date | 26 Jan 2019 |
| DOIs | |
| Publication status | Published - 31 Jul 2019 |
Keywords
- nitric oxide
- blood flow
- hyperaemia
- nitrite
- exercise
