Impact of Respiratory Muscle Training and Nitrate Therapy on Exercise Tolerance in Simulated Altitude
Embry-Riddle Aeronautical University
Summary
This study investigates whether respiratory muscle training (RMT) and dietary nitrate supplementation can improve exercise tolerance under simulated moderate altitude conditions. Exposure to reduced oxygen availability at altitude places additional strain on the cardiovascular and respiratory systems, which may limit endurance performance. By combining RMT-designed to strengthen the muscles involved in breathing-with nitrate therapy, which enhances nitric oxide availability and vascular function, this study aims to determine whether these interventions independently or synergistically improve oxygen delivery, reduce physiological strain, and enhance exercise performance. The findings will help identify non-pharmacological strategies to improve physical performance and tolerance to hypoxia in both clinical and operational environments.
Description
This study is designed to test whether two non-drug interventions-respiratory muscle training (RMT) and dietary nitrate supplementation-can improve exercise performance and tolerance when oxygen levels are lower than normal, such as at moderate altitude. When people exercise in low-oxygen environments, the body must work harder to deliver enough oxygen to the muscles. This can lead to faster fatigue and reduced endurance. Strengthening the breathing muscles and improving blood vessel function may help the body adapt better to these conditions. This study will explore how RMT and nitrate suppl…
Eligibility
- Age range
- 18–40 years
- Sex
- All
- Healthy volunteers
- Yes
Inclusion Criteria: * Healthy adults between 18 and 40 years old. Recreationally active (performing ≥3 hours of structured physical activity per week). Non-smokers for at least the past 6 months. Free from any known cardiovascular, pulmonary, metabolic, or neuromuscular disease as determined by health screening questionnaire and medical history. Able to perform cycle ergometer exercise to volitional fatigue. Willing to abstain from high-nitrate foods and supplements (e.g., beets, spinach, arugula) for 48 hours prior to each testing session. Able and willing to provide written informed c…
Interventions
- DeviceRespiratory Muscle Training (RMT)
Participants perform supervised respiratory muscle training (RMT) using a handheld resistive breathing device designed to strengthen the inspiratory and expiratory muscles. Training sessions are conducted 5 days per week for approximately 4-6 weeks. Each session includes a series of resisted breathing maneuvers with progressively increased load as tolerated. The device is calibrated to maintain a constant pressure threshold to ensure consistent training intensity.
- DeviceSham Respiratory Muscle Training
Participants use an identical handheld breathing device with minimal resistance, providing no meaningful training stimulus. The training schedule and session duration match those of the active RMT group to maintain participant blinding.
- Dietary SupplementDietary Supplement: Beetroot Juice Concentrate
Participants consume a standardized dose of concentrated beetroot juice daily for the duration of the training period (approximately 4-6 weeks). The supplement provides a fixed quantity of dietary nitrate known to enhance nitric oxide availability and support vascular and metabolic function during exercise.
- Dietary Supplementplacebo beverage
Participants consume a placebo beverage identical in color, taste, and appearance to the nitrate supplement but containing no active nitrate. The beverage is consumed daily following the same schedule as the active supplement.
Location
- Embry-Riddle Aeronautical UniversityDaytona Beach, Florida