An acute dose of inorganic dietary nitrate does not improve high-intensity, intermittent exercise performance in temperate or hot and humid conditions

Kieran Smith, David J. Muggeridge, Chris Easton, Mark D. Ross

Research output: Contribution to journalArticle

Abstract

PURPOSE: Dietary nitrate (NO 3 -) has repeatedly been shown to improve endurance and intermittent, high-intensity events in temperate conditions. However, the ergogenic effects of dietary NO 3 - on intermittent exercise performance in hot conditions have yet to be investigated.

METHODS: In a randomised, counterbalanced, double-blind crossover study, 12 recreationally trained males ingested a nitrate-rich beetroot juice shot (BRJ) (6.2 mmol NO 3 -) or a nitrate-depleted placebo (PLA) (< 0.004 mmol NO 3 -) 3 h prior to an intermittent sprint test (IST) in temperate (22 °C, 35% RH) and hot conditions (30 °C, 70% RH). The cycle ergometer IST consisted of twenty maximal 6 s sprints interspersed by 114 s of active recovery. Work done, power output, heart rate and RPE were measured throughout; tympanic temperature was measured prior to and upon completion.

RESULTS: There were no significant effects of supplement on sprint performance in either temperate or hot, humid conditions (p > 0.05). There was a reduced peak (BRJ: 659 ± 100W vs. PLA: 693 ± 139W; p = 0.056) and mean power (BRJ: 543 ± 29W vs. PLA: 575 ± 38W; p = 0.081) following BRJ compared to PLA in the hot and humid condition, but this was not statistically significant. There was no effect of supplement on total work done irrespective of environmental condition. However, ~ 75% of participants experienced performance decreases following BRJ in the hot and humid environment. No differences were observed between trials for tympanic temperature measured at the conclusion of the exercise trial.

CONCLUSION: In conclusion, an acute dose of inorganic dietary NO 3 - does not improve repeated-sprint performance in either temperate, or hot and humid conditions.

Original languageEnglish
Pages (from-to)723-733
Number of pages11
JournalEuropean Journal of Applied Physiology
Volume119
Issue number3
Early online date8 Jan 2019
DOIs
Publication statusPublished - 31 Mar 2019

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Nitrates
Placebos
Performance-Enhancing Substances
Temperature
Double-Blind Method
Cross-Over Studies
Heart Rate
High-Intensity Interval Training

Keywords

  • Nitrate
  • Exercise
  • Heat
  • High-intensity
  • Beetroot juice
  • Humidity

Cite this

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title = "An acute dose of inorganic dietary nitrate does not improve high-intensity, intermittent exercise performance in temperate or hot and humid conditions",
abstract = "PURPOSE: Dietary nitrate (NO 3 -) has repeatedly been shown to improve endurance and intermittent, high-intensity events in temperate conditions. However, the ergogenic effects of dietary NO 3 - on intermittent exercise performance in hot conditions have yet to be investigated. METHODS: In a randomised, counterbalanced, double-blind crossover study, 12 recreationally trained males ingested a nitrate-rich beetroot juice shot (BRJ) (6.2 mmol NO 3 -) or a nitrate-depleted placebo (PLA) (< 0.004 mmol NO 3 -) 3 h prior to an intermittent sprint test (IST) in temperate (22 °C, 35{\%} RH) and hot conditions (30 °C, 70{\%} RH). The cycle ergometer IST consisted of twenty maximal 6 s sprints interspersed by 114 s of active recovery. Work done, power output, heart rate and RPE were measured throughout; tympanic temperature was measured prior to and upon completion. RESULTS: There were no significant effects of supplement on sprint performance in either temperate or hot, humid conditions (p > 0.05). There was a reduced peak (BRJ: 659 ± 100W vs. PLA: 693 ± 139W; p = 0.056) and mean power (BRJ: 543 ± 29W vs. PLA: 575 ± 38W; p = 0.081) following BRJ compared to PLA in the hot and humid condition, but this was not statistically significant. There was no effect of supplement on total work done irrespective of environmental condition. However, ~ 75{\%} of participants experienced performance decreases following BRJ in the hot and humid environment. No differences were observed between trials for tympanic temperature measured at the conclusion of the exercise trial.CONCLUSION: In conclusion, an acute dose of inorganic dietary NO 3 - does not improve repeated-sprint performance in either temperate, or hot and humid conditions.",
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An acute dose of inorganic dietary nitrate does not improve high-intensity, intermittent exercise performance in temperate or hot and humid conditions. / Smith, Kieran; Muggeridge, David J.; Easton, Chris; Ross, Mark D.

In: European Journal of Applied Physiology, Vol. 119, No. 3, 31.03.2019, p. 723-733.

Research output: Contribution to journalArticle

TY - JOUR

T1 - An acute dose of inorganic dietary nitrate does not improve high-intensity, intermittent exercise performance in temperate or hot and humid conditions

AU - Smith, Kieran

AU - Muggeridge, David J.

AU - Easton, Chris

AU - Ross, Mark D.

PY - 2019/3/31

Y1 - 2019/3/31

N2 - PURPOSE: Dietary nitrate (NO 3 -) has repeatedly been shown to improve endurance and intermittent, high-intensity events in temperate conditions. However, the ergogenic effects of dietary NO 3 - on intermittent exercise performance in hot conditions have yet to be investigated. METHODS: In a randomised, counterbalanced, double-blind crossover study, 12 recreationally trained males ingested a nitrate-rich beetroot juice shot (BRJ) (6.2 mmol NO 3 -) or a nitrate-depleted placebo (PLA) (< 0.004 mmol NO 3 -) 3 h prior to an intermittent sprint test (IST) in temperate (22 °C, 35% RH) and hot conditions (30 °C, 70% RH). The cycle ergometer IST consisted of twenty maximal 6 s sprints interspersed by 114 s of active recovery. Work done, power output, heart rate and RPE were measured throughout; tympanic temperature was measured prior to and upon completion. RESULTS: There were no significant effects of supplement on sprint performance in either temperate or hot, humid conditions (p > 0.05). There was a reduced peak (BRJ: 659 ± 100W vs. PLA: 693 ± 139W; p = 0.056) and mean power (BRJ: 543 ± 29W vs. PLA: 575 ± 38W; p = 0.081) following BRJ compared to PLA in the hot and humid condition, but this was not statistically significant. There was no effect of supplement on total work done irrespective of environmental condition. However, ~ 75% of participants experienced performance decreases following BRJ in the hot and humid environment. No differences were observed between trials for tympanic temperature measured at the conclusion of the exercise trial.CONCLUSION: In conclusion, an acute dose of inorganic dietary NO 3 - does not improve repeated-sprint performance in either temperate, or hot and humid conditions.

AB - PURPOSE: Dietary nitrate (NO 3 -) has repeatedly been shown to improve endurance and intermittent, high-intensity events in temperate conditions. However, the ergogenic effects of dietary NO 3 - on intermittent exercise performance in hot conditions have yet to be investigated. METHODS: In a randomised, counterbalanced, double-blind crossover study, 12 recreationally trained males ingested a nitrate-rich beetroot juice shot (BRJ) (6.2 mmol NO 3 -) or a nitrate-depleted placebo (PLA) (< 0.004 mmol NO 3 -) 3 h prior to an intermittent sprint test (IST) in temperate (22 °C, 35% RH) and hot conditions (30 °C, 70% RH). The cycle ergometer IST consisted of twenty maximal 6 s sprints interspersed by 114 s of active recovery. Work done, power output, heart rate and RPE were measured throughout; tympanic temperature was measured prior to and upon completion. RESULTS: There were no significant effects of supplement on sprint performance in either temperate or hot, humid conditions (p > 0.05). There was a reduced peak (BRJ: 659 ± 100W vs. PLA: 693 ± 139W; p = 0.056) and mean power (BRJ: 543 ± 29W vs. PLA: 575 ± 38W; p = 0.081) following BRJ compared to PLA in the hot and humid condition, but this was not statistically significant. There was no effect of supplement on total work done irrespective of environmental condition. However, ~ 75% of participants experienced performance decreases following BRJ in the hot and humid environment. No differences were observed between trials for tympanic temperature measured at the conclusion of the exercise trial.CONCLUSION: In conclusion, an acute dose of inorganic dietary NO 3 - does not improve repeated-sprint performance in either temperate, or hot and humid conditions.

KW - Nitrate

KW - Exercise

KW - Heat

KW - High-intensity

KW - Beetroot juice

KW - Humidity

U2 - 10.1007/s00421-018-04063-9

DO - 10.1007/s00421-018-04063-9

M3 - Article

C2 - 30617465

VL - 119

SP - 723

EP - 733

JO - European Journal of Applied Physiology

JF - European Journal of Applied Physiology

SN - 1439-6319

IS - 3

ER -