Older adults with coronary artery disease (CAD) have impaired vascular and inspiratory muscle function. The overarching goal of this double-blind, randomized, crossover, placebo-controlled pilot trial was to inform the development of a fully powered trial to evaluate the effects of dietary nitrate supplementation in older adults with CAD. We aimed to address the following objectives: (a) assess the feasibility, tolerability, and safety of the study protocol; (b) gather preliminary evidence on the effects of nitrate-rich beetroot juice compared with nitrate-depleted beetroot juice (placebo), and estimate the effect sizes; and (c) determine if a full-scale definitive trial is justified.

Inclusion Criteria:

• Adults with coronary artery disease (CAD) based on an angiogram >50% stenosis in any major epicardial vessel or history of myocardial infarction or history of coronary revascularization.
• Considered to have stable CAD on optimal medical therapy
• 60 to 85 years of age
• Males and females (females must be postmenopausal either natural or surgical)
• Able to give consent

Exclusion Criteria:

• Unstable angina, recent myocardial infarction or heart failure within 6 months
• Coronary revascularization, including percutaneous coronary intervention and coronary artery bypass graft or thoracic surgery within 6 months.
• Stroke, obstructive pulmonary disease, hepatitis B, C, HIV, seizures, or other relevant ongoing or recurrent illness
• Individuals who have participated in respiratory training within the last 12 months or cardiac rehabilitation within the last 6 months
• Uncontrolled hypertension
• Use of tobacco products including smoking traditional or e-cigarettes
• Use of hormone replacement therapy in women or men (e.g., estrogen, progesterone or testosterone)
• Unwilling to stop using mouthwash at least 1 week before the start of the study and during study participation
• Unwilling to remain weight stable during study participation