A double blind randomized placebo control crossover trial on the effect of dietary nitrate supplementation on exercise tolerance in stable moderate chronic obstructive pulmonary disease
Leong P, Basham JE, Yong T, Chazan A, Finlay P, Barnes S, Bardin PG, Campbell D
BMC pulmonary medicine · 37 citations
Review labels
Neutral facts our review recorded about how this study was done. They describe method, never whether we like the result.
How it was studied
- Design
- Randomized controlled trial (indexed by PubMed)
- Studied in
- People
- Main outcome
- Health markers and function
- Intake measured by
- Not stated
Who paid for it
- Funding
- Funding not disclosed
Publication
- Published
- 2015-05-01 · BMC Pulm Med · vol. 15 · issue 1 · p. 52
- Publisher
- BioMed Central
- Cited
- 51 citations · more than 96% of similar papers · 4.8× the field average
- Impact
- Top 10% most cited in its field
- References
- 41 works
- Access
- Open access (journal) · CC-BY
- Research areas
- Chronic Obstructive Pulmonary Disease (COPD) Research · Exercise and Physiological Responses · Nitric Oxide and Endothelin Effects
- Keywords
- Medicine, Placebo, Crossover study, COPD, VO2 max, Randomization, Physical therapy, Population, Blood pressure, Randomized controlled trial, Morning, Internal medicine, Heart rate
- MeSH
- humans, beta vulgaris, pulmonary disease, chronic obstructive, nitrates, exercise test, severity of illness index, cross-over studies, double-blind method, oxygen consumption, exercise tolerance, dietary supplements, aged, middle aged, female, male, fruit and vegetable juices
8 authors
From AU
- Paul Leong · correspondingMonash Medical Centre; Monash Health
- Jane E BashamMonash Medical Centre; Monash Institute of Medical Research
- Theresa YongMonash Medical Centre; Monash Health
- Adrian ChazanMonash Medical Centre
- Paul N. FinlayMonash Medical Centre; Monash Health; Monash University
- Sara Laura BarnesMonash Medical Centre; Monash Health; Monash University; Monash Institute of Medical Research
Abstract
Background
Dietary nitrate supplementation has been shown to decrease the oxygen cost of exercise and prolong exercise tolerance, as measured by sub-maximal exercise endurance distance and time at 85% V̇O2max, in both elite athletes and normal healthy subjects. Patients with chronic obstructive pulmonary disease (COPD) have reduced quality of life and ability to perform activities of daily living attributable to diminished exercise tolerance, and dietary nitrate may be able to ameliorate this.
Methods
We performed a double-blind, computer-randomized placebo control crossover trial at a tertiary Australian hospital to investigate whether dietary nitrate supplementation as beetroot juice (BR) would augment submaximal exercise endurance in individuals with spirometrically confirmed stable moderate COPD. Volunteers underwent an incremental shuttle walk test to determine V̇O2max followed by a test dose of BR to establish safety in the study population. Participants performed an endurance shuttle walk test (ESWT) at 85% V̇O2max after randomization to either a 3 day wash-in of BR (4.8 mmol twice a day) or placebo (nitrate deplete BR), with a final dose on the morning of testing. They then crossed over after 4 day washout. Repeated measures two sided paired t-tests were employed.
Results
35 participants were recruited with 19 completing the trial. In the initial safety phase, we measured systolic blood pressure over four hours post first dose of BR, and found a mean 10 mmHg decrement maximal at 1 hour. One individual developed symptomatic postural hypotension and was excluded. The primary outcomes of ESWT distance and time to fatigue improved by 11% and 6% respectively; however these differences did not achieve statistical significance (p = 0.494 and 0.693 respectively).
Conclusions
Our study does not support a role for routine dietary nitrate supplementation for enhancement of exercise endurance in COPD.
Trial registration
Australia and New Zealand Clinical Trial Register: ACTRN12611001088932.
Abstract via Europe PMC. Copyright remains with the authors or publisher (CC BY).
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