Effects of Breathing Training and Nitrate on Exercise at Simulated Altitude

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 consent and comply with all study procedures. Exclusion Criteria: * 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. Failure to meet inclusion criteria or inability to complete familiarization and baseline testing.