Effects of Breathing Training and Nitrate on Exercise at Simulated Altitude

NCT07216755 | Recruiting

• 2 other identifiers: 25-0771R15HL173855-01A1
• Study Type: interventional
• Target: 80
• Locations: 1 country
• Sites: 1

Brief 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.

Conditions

Healthy Adults; Mechanical Ventilation Dependence; Hypoxia; Exercise Training; Exercise Intolerance; Dietary Supplement; Nitrate Supplementation; Inspiratory Muscle Training

Outcome Measures

Primary Outcomes (1)

• Change in Exercise Tolerance at Simulated Altitude

  Exercise tolerance will be measured as the time to exhaustion during a graded cycling exercise test performed under simulated moderate altitude conditions (\~2,500-3,000 meters). Tests will be conducted before and after the 4-6 week intervention period. The measure reflects overall improvements in aerobic performance and fatigue resistance following respiratory muscle training, nitrate supplementation, or their combination.

  Baseline to Post-Intervention (approximately 4-6 weeks)

Study Arms (4)

RMT + Nitrate Supplementation

EXPERIMENTAL

Participants complete a multi-week respiratory muscle training (RMT) program using a handheld breathing device that provides progressive inspiratory and expiratory resistance. Participants also consume a daily standardized dose of beetroot juice concentrate containing dietary nitrate. This combination is expected to enhance breathing muscle strength, vascular function, and exercise tolerance under simulated altitude.

Device: Respiratory Muscle Training (RMT); Dietary Supplement: Dietary Supplement: Beetroot Juice Concentrate

Respiratory Muscle Training + Placebo

PLACEBO COMPARATOR

Participants perform the same RMT program as in Arm 1 but consume a placebo beverage that is visually and taste-matched to the nitrate drink but contains no active nitrate. This group allows assessment of the independent effects of respiratory muscle training.

Device: Respiratory Muscle Training (RMT); Dietary Supplement: placebo beverage

Sham Respiratory Muscle Training + Nitrate Supplementation

SHAM COMPARATOR

Participants perform sham RMT with a very low resistance load that does not provide a training stimulus, while consuming the active nitrate beverage daily. This group isolates the independent effect of nitrate supplementation on exercise tolerance under hypoxic conditions.

Device: Sham Respiratory Muscle Training; Dietary Supplement: Dietary Supplement: Beetroot Juice Concentrate

Sham Respiratory Muscle Training + Placebo

PLACEBO COMPARATOR

Participants complete sham RMT with minimal breathing resistance and consume a placebo beverage identical in appearance and flavor to the nitrate supplement but containing no active ingredients. This serves as the control condition for comparison with all other intervention groups.

Device: Sham Respiratory Muscle Training; Dietary Supplement: placebo beverage

Interventions

Respiratory Muscle Training (RMT) DEVICE

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.

Also known as: Inspiratory Muscle Training

RMT + Nitrate Supplementation; Respiratory Muscle Training + Placebo

Sham Respiratory Muscle Training DEVICE

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.

Sham Respiratory Muscle Training + Nitrate Supplementation; Sham Respiratory Muscle Training + Placebo

Dietary Supplement: Beetroot Juice Concentrate DIETARY_SUPPLEMENT

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.

RMT + Nitrate Supplementation; Sham Respiratory Muscle Training + Nitrate Supplementation

placebo beverage DIETARY_SUPPLEMENT

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.

Respiratory Muscle Training + Placebo; Sham Respiratory Muscle Training + Placebo

Eligibility Criteria

• Age: 18 Years - 40 Years
• Sex: all
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64)

You may qualify if:

• 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 consent and comply with all study procedures.

You may not qualify if:

• Diagnosis of or history of heart disease, hypertension, diabetes, or chronic respiratory disorders (e.g., asthma, COPD).
• Current use of medications or supplements known to affect cardiovascular, metabolic, or respiratory function (e.g., beta-blockers, nitrates, stimulants).
• Smoking, vaping, or tobacco use within the past 6 months.
• Known allergy or intolerance to beetroot products or nitrates.
• Participation in another interventional research study within the past 30 days.
• Pregnant or breastfeeding women.
• Any orthopedic or musculoskeletal limitation preventing safe exercise testing.

Sponsors & Collaborators

• Embry-Riddle Aeronautical University: lead

Study Sites (1)

Embry-Riddle Aeronautical University

Daytona Beach, Florida, 32114, United States

RECRUITING

MeSH Terms

Conditions

Hypoxia

Interventions

Breathing Exercises

Condition Hierarchy (Ancestors)

Signs and Symptoms, Respiratory; Signs and Symptoms; Pathological Conditions, Signs and Symptoms

Intervention Hierarchy (Ancestors)

Mind-Body Therapies; Complementary Therapies; Therapeutics; Exercise Movement Techniques; Physical Therapy Modalities

Study Officials

• Scott K Ferguson, Ph.D.

  Embry-Riddle Aeronautical University

  PRINCIPAL INVESTIGATOR

Central Study Contacts

Scott Ferguson K Ferguson, Ph.D.

CONTACT

386-226-7381; ferguss8@erau.edu

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: QUADRUPLE
• Who Masked: PARTICIPANT, CARE PROVIDER, INVESTIGATOR, OUTCOMES ASSESSOR
• Purpose: BASIC SCIENCE
• Intervention Model: FACTORIAL
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Assistant Professor

Study Record Dates

• First Submitted: October 13, 2025
• First Posted: October 15, 2025
• Study Start: September 1, 2025
• Primary Completion (Estimated): August 31, 2028
• Study Completion (Estimated): August 31, 2028
• Last Updated: October 15, 2025

Record last verified: 2025-10

Locations

US (1)