The online version of this article (doi:10.1186/s12890-015-0057-4) contains supplementary material, which is available to authorized users.
The authors declare that they have no competing interests, financial or non-financial.
DC, PB, PF and AC conceived the study. PL, JB, SB and TY recruited subjects, performed all tests and collected primary data. PL and DC performed statistical analysis. PL and DC drafted the initial manuscript. All authors read and approved the final manuscript.
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.
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.
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).
Our study does not support a role for routine dietary nitrate supplementation for enhancement of exercise endurance in COPD.
Australia and New Zealand Clinical Trial Register: ACTRN12611001088932
Additional file 1: Table S1. Safety phase data for diastolic blood pressure (DBP) on standing (mmHg) (n=23 unless otherwise stated).12890_2015_57_MOESM1_ESM.docx
Global Initiative for Chronic Obstructive Lung Disease (GOLD). Global Strategy for the Diagnosis, Management and Prevention of COPD. 2014.
World Health Organization. The Global Burden of Disease: 2004 Update. Geneva, Switzerland: World Health Organization; 2008.
Zafeiridis A. The effects of dietary nitrate (beetroot juice) supplementation on exercise performance: A review. Am J Sports Sci. 2014;2:97–110. CrossRef
Cella G, Saetta M, Baraldo S, Turato G, Papi A, Casoni G, et al. Endothelial Cell Activity in Chronic Obstructive Pulmonary Disease Without Severe Pulmonary Hypertension. Clin Appl Thromb. 2005;11:435–40. CrossRef
Malerba M, Radaeli A, Olivini A, Damiani G, Ragnoli B, Montuschi P, Ricciardolo FLM: Exhaled nitric oxide as a biomarker in COPD and related comorbidities. BioMed Res Int 2014. doi:10.1155/2014/271918
Berry MJ, Justus NW, Hauser JI, Case AH, Helms CC, Basu S, Rogers Z, Lewis MT, Miller GD: Dietary nitrate supplementation improves exercise performance and decreases blood pressure in COPD patients. Nitric Oxide. 2014. doi:10.1016/j.niox.2014.10.007
Shepherd AI, Wilkerson DP, Dobson L, Kelly J, Winyard PG, Jones AM, Benjamin N, Shore AC, Gilchrist M: The effect of dietary nitrate supplementation on the oxygen cost of cycling, walking performance and resting blood pressure in individuals with chronic obstructive pulmonary disease: A double blind placebo controlled, randomised control trial. Nitric Oxide. 2015. doi:10.1016/j.niox.2015.01.002.
Singh SJ, Morgan MD, Hardman AE, Rowe C, Bardsley PA. Comparison of oxygen uptake during a conventional treadmill test and the shuttle walking test in chronic airflow limitation. Eur Respir J. 1994;7:2016–20. PubMed
McKeough ZJ, Leung RWM, Alison JA. Shuttle walk tests as outcome measures: Are two incremental shuttle walk tests and two endurance shuttle walk tests necessary? Am J Phys Med Rehabil Assoc Acad Physiatr. 2011;90:35–9. CrossRef
Burdon JG, Juniper EF, Killian KJ, Hargreave FE, Campbell EJ. The perception of breathlessness in asthma. Am Rev Respir Dis. 1982;126:825–8. PubMed
Larsen FJ, Weitzberg E, Lundberg JO, Ekblom B. Effects of dietary nitrate on oxygen cost during exercise. Acta Physiol. 2007;191:59–66. CrossRef
Bland M. An Introduction to Medical Statistics. 3rd ed. Oxford: Oxford University Press; 2000 [Oxford Medical Publications].
Vogiatzis I, Zakynthinos S: Factors Limiting Exercise Tolerance in Chronic Lung Diseases. In Comprehensive Physiology. John Wiley & Sons, Inc.; 2012
Pepin V, Laviolette L, Brouillard C, Sewell L, Singh SJ, Revill SM, et al. Significance of changes in endurance shuttle walking performance. Thorax. 2010;66:thx.2010.146159.
- 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
Jane E Basham
Phillip G Bardin
- BioMed Central
Neu im Fachgebiet Innere Medizin
Meistgelesene Bücher aus der Inneren Medizin
Mail Icon II