Dietary beetroot juice - effects on physical performance in COPD patients: a randomized controlled crossover trial

Area of Science:

• Cardiovascular Physiology
• Respiratory Medicine
• Nutritional Science

Background:

• Dietary beetroot juice (BR) is known to reduce oxygen consumption and blood pressure (BP) in healthy individuals.
• The effects of BR supplementation on exercise performance in patients with chronic obstructive pulmonary disease (COPD) are not well-established.
• Previous trials in COPD patients used lower doses of BR for shorter durations.

Purpose of the Study:

• To investigate the effects of higher-dose, longer-duration BR supplementation on exercise performance in COPD patients.
• To assess changes in oxygen consumption, walking capacity, and blood pressure following BR ingestion in COPD.

Main Methods:

• A randomized, placebo-controlled crossover trial involving 15 COPD patients.
• Participants consumed concentrated BR (600 mg nitrate daily) or placebo for 6 consecutive days.
• Testing on day 7 included a 6-minute walk test (6MWT) and submaximal cycling, with BP measurements.

Main Results:

• Plasma nitrite concentrations were significantly higher after BR supplementation compared to placebo.
• No significant differences were observed in 6MWT distance, submaximal exercise oxygen consumption, or physical activity levels.
• Diastolic blood pressure (DBP) was significantly reduced after BR ingestion compared to baseline.

Conclusions:

• Seven days of BR supplementation effectively increased plasma nitrite and reduced DBP in COPD patients.
• BR supplementation did not enhance functional walking capacity or improve oxygen consumption during submaximal exercise in this cohort.
• Further research may be needed to explore optimal dosing or different patient subgroups.