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Effects of dietary nitrate supplementation on symptoms of acute mountain sickness and basic physiological responses in a group of male adolescents during ascent to Mount Everest Base Camp

Effects of dietary nitrate supplementation on symptoms of acute mountain sickness and basic physiological responses in a group of male adolescents during ascent to Mount Everest Base Camp
Effects of dietary nitrate supplementation on symptoms of acute mountain sickness and basic physiological responses in a group of male adolescents during ascent to Mount Everest Base Camp
The purpose of this study was to investigate the effects of dietary nitrate supplementation, in the form of beetroot juice, on acute mountain sickness (AMS) symptoms and physiological responses, in a group of young males trekking to Mount Everest Base Camp (EBC). Forty healthy male students (mean age (SD): 16 (1) yrs) trekked to EBC over 11 days. Following an overnight fast, each morning participants completed the Lake Louise AMS questionnaire and underwent a series of physiological tests: resting blood pressure as well as resting and exercising heart rate, respiratory rate, and peripheral oxygen saturation. The exercise test consisted of a standardised 2-min stepping protocol and measurements were taken in the last 10 s. Participants in the intervention arm of the study consumed 140 ml of concentrated beetroot juice daily, containing approximately 10 mmol of nitrate, while those in the control arm consumed 140 ml of concentrated blackcurrant cordial with negligible nitrate content. Drinks were taken for the first seven days at high altitude (days 2–8), in two equal doses; one with breakfast, and one with the evening meal. Mixed modelling revealed no significant between-groups difference in the incidence of AMS (Odds Ratio – nitrate vs. control: 1.16 (95% CI: 0.59; 2.29)). Physiological changes occurring during ascent to high altitude generally were not significantly different between the two groups (Model Coef (95% CI) – average difference nitrate vs. control: systolic blood pressure, 0.16 (?4.47; 4.79); peripheral oxygen saturation, 0.28 (?0.85; 1.41); heart rate, ?0.48 (?8.47; 7.50) (Model Coef (95% CI) – relative difference nitrate vs. control: ventilatory rate, 0.95 (0.82; 1.08)). Modelling revealed that diastolic blood pressure was 3.37 mmHg (0.24; 6.49) higher for participants in the beetroot juice, however this difference was no larger than that found at baseline and no interaction effect was observed. Supplementation with dietary nitrate did not significantly change symptoms of AMS or alter key physiological variables, in a group of adolescent males during a high altitude trekking expedition. There was no evidence of harm from dietary nitrate supplementation in this context. Given the wide confidence intervals in all models, a larger sample size would be required to exclude a false negative result. Our data suggest that prolonged oral nitrate supplementation is safe and feasible at altitude but has little physiological or clinical effect
1089-8603
24-31
Hennis, Philip J.
b3563308-2f8e-49fb-a73f-c5afcc177ffe
Mitchell, Kay
f57f07cd-0e3a-48b2-a871-c436eec325ae
Gilbert-Kawai, Edward
9babf11e-8fd3-4924-acda-68b62cfa3121
Bountziouka, Vassiliki
6de9d079-ba1c-4b0b-ac6a-3901a374294c
Wade, Angie
b16ea563-001c-4457-b866-75121ee8b38b
Feelisch, Martin
8c1b9965-8614-4e85-b2c6-458a2e17eafd
Grocott, Michael P.
1e87b741-513e-4a22-be13-0f7bb344e8c2
Martin, Daniel S.
3e441b48-9221-4308-8ae6-49cbde20753f
Hennis, Philip J.
b3563308-2f8e-49fb-a73f-c5afcc177ffe
Mitchell, Kay
f57f07cd-0e3a-48b2-a871-c436eec325ae
Gilbert-Kawai, Edward
9babf11e-8fd3-4924-acda-68b62cfa3121
Bountziouka, Vassiliki
6de9d079-ba1c-4b0b-ac6a-3901a374294c
Wade, Angie
b16ea563-001c-4457-b866-75121ee8b38b
Feelisch, Martin
8c1b9965-8614-4e85-b2c6-458a2e17eafd
Grocott, Michael P.
1e87b741-513e-4a22-be13-0f7bb344e8c2
Martin, Daniel S.
3e441b48-9221-4308-8ae6-49cbde20753f

Hennis, Philip J., Mitchell, Kay, Gilbert-Kawai, Edward, Bountziouka, Vassiliki, Wade, Angie, Feelisch, Martin, Grocott, Michael P. and Martin, Daniel S. (2016) Effects of dietary nitrate supplementation on symptoms of acute mountain sickness and basic physiological responses in a group of male adolescents during ascent to Mount Everest Base Camp. Nitric Oxide, 60, 24-31. (doi:10.1016/j.niox.2016.08.007). (PMID:27593617)

Record type: Article

Abstract

The purpose of this study was to investigate the effects of dietary nitrate supplementation, in the form of beetroot juice, on acute mountain sickness (AMS) symptoms and physiological responses, in a group of young males trekking to Mount Everest Base Camp (EBC). Forty healthy male students (mean age (SD): 16 (1) yrs) trekked to EBC over 11 days. Following an overnight fast, each morning participants completed the Lake Louise AMS questionnaire and underwent a series of physiological tests: resting blood pressure as well as resting and exercising heart rate, respiratory rate, and peripheral oxygen saturation. The exercise test consisted of a standardised 2-min stepping protocol and measurements were taken in the last 10 s. Participants in the intervention arm of the study consumed 140 ml of concentrated beetroot juice daily, containing approximately 10 mmol of nitrate, while those in the control arm consumed 140 ml of concentrated blackcurrant cordial with negligible nitrate content. Drinks were taken for the first seven days at high altitude (days 2–8), in two equal doses; one with breakfast, and one with the evening meal. Mixed modelling revealed no significant between-groups difference in the incidence of AMS (Odds Ratio – nitrate vs. control: 1.16 (95% CI: 0.59; 2.29)). Physiological changes occurring during ascent to high altitude generally were not significantly different between the two groups (Model Coef (95% CI) – average difference nitrate vs. control: systolic blood pressure, 0.16 (?4.47; 4.79); peripheral oxygen saturation, 0.28 (?0.85; 1.41); heart rate, ?0.48 (?8.47; 7.50) (Model Coef (95% CI) – relative difference nitrate vs. control: ventilatory rate, 0.95 (0.82; 1.08)). Modelling revealed that diastolic blood pressure was 3.37 mmHg (0.24; 6.49) higher for participants in the beetroot juice, however this difference was no larger than that found at baseline and no interaction effect was observed. Supplementation with dietary nitrate did not significantly change symptoms of AMS or alter key physiological variables, in a group of adolescent males during a high altitude trekking expedition. There was no evidence of harm from dietary nitrate supplementation in this context. Given the wide confidence intervals in all models, a larger sample size would be required to exclude a false negative result. Our data suggest that prolonged oral nitrate supplementation is safe and feasible at altitude but has little physiological or clinical effect

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Hennis et al, Dietary nitrate on AMS_unedited version_NOx journal.pdf - Accepted Manuscript
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More information

Accepted/In Press date: 31 August 2016
Published date: 2 September 2016
Organisations: Clinical & Experimental Sciences

Identifiers

Local EPrints ID: 400520
URI: https://eprints.soton.ac.uk/id/eprint/400520
ISSN: 1089-8603
PURE UUID: 67e8a7fb-b158-4954-96ca-925fd6672b5a
ORCID for Kay Mitchell: ORCID iD orcid.org/0000-0001-6393-8475
ORCID for Martin Feelisch: ORCID iD orcid.org/0000-0003-2320-1158
ORCID for Michael P. Grocott: ORCID iD orcid.org/0000-0002-9484-7581

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Date deposited: 19 Sep 2016 08:42
Last modified: 03 Dec 2019 06:33

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