Abstract
Purpose: The objective of this study is to examine the effects of acute ingestion of dietary nitrate on endurance running performance in highly trained cross-country skiers. Dietary nitrate has been shown to reduce the oxygen cost of submaximal exercise and improve tolerance of high-intensity exercise, but it is not known if this holds true for highly trained endurance athletes.
Methods: Ten male junior cross-country skiers (V·O2max [almost equal to] 70 mL·kg-1·min-1) each completed two trials in a randomized, double-blind design. Participants ingested potassium nitrate (614-mg nitrate) or a nitrate-free placebo 2.5 h before two 5-min submaximal tests on a treadmill at 10 km·h-1 ([almost equal to]55% of V·O2max) and 14 km·h-1 ([almost equal to]75% of V·O2max), followed by a 5-km running time trial on an indoor track.
Results: Plasma nitrite concentrations were higher after nitrate supplementation (325 ± 95 nmol·L-1) compared with placebo (143 ± 59 nmol·L-1, P < 0.001). There was no significant difference in 5-km time-trial performance between nitrate (1005 ± 53 s) and placebo treatments (996 ± 49 s, P = 0.12). The oxygen cost of submaximal running was not significantly different between placebo and nitrate trials at 10 km·h-1 (both 2.84 ± 0.34 L·min-1) and 14 km·h-1 (3.89 ± 0.39 vs. 3.77 ± 0.62 L·min-1).
Conclusions: Acute ingestion of dietary nitrate may not represent an effective strategy for reducing the oxygen cost of submaximal exercise or for enhancing endurance exercise performance in highly trained cross-country skiers.
Methods: Ten male junior cross-country skiers (V·O2max [almost equal to] 70 mL·kg-1·min-1) each completed two trials in a randomized, double-blind design. Participants ingested potassium nitrate (614-mg nitrate) or a nitrate-free placebo 2.5 h before two 5-min submaximal tests on a treadmill at 10 km·h-1 ([almost equal to]55% of V·O2max) and 14 km·h-1 ([almost equal to]75% of V·O2max), followed by a 5-km running time trial on an indoor track.
Results: Plasma nitrite concentrations were higher after nitrate supplementation (325 ± 95 nmol·L-1) compared with placebo (143 ± 59 nmol·L-1, P < 0.001). There was no significant difference in 5-km time-trial performance between nitrate (1005 ± 53 s) and placebo treatments (996 ± 49 s, P = 0.12). The oxygen cost of submaximal running was not significantly different between placebo and nitrate trials at 10 km·h-1 (both 2.84 ± 0.34 L·min-1) and 14 km·h-1 (3.89 ± 0.39 vs. 3.77 ± 0.62 L·min-1).
Conclusions: Acute ingestion of dietary nitrate may not represent an effective strategy for reducing the oxygen cost of submaximal exercise or for enhancing endurance exercise performance in highly trained cross-country skiers.
| Original language | English |
|---|---|
| Pages (from-to) | 2213-2219 |
| Number of pages | 6 |
| Journal | Medicine and Science in Sports and Exercise |
| Volume | 44 |
| Issue number | 11 |
| DOIs | |
| Publication status | Published - Nov 2012 |