Effects of 8 weeks of breathing resistance-based hypoxemia training on cardiovascular function and metabolic risk factors in obese individuals

INTERVENTION: Behavioral : This study is a three‐arm, parallel, randomized controlled trial comparing normoxic aerobic training (NOR), normobaric hypoxic aerobic training (HYP), and breathing resistance‐based aerobic training (BR) in adult men with obesity. A total of 36 participants are randomly allocated to the three groups in a 1:1:1 ratio. Participants perform 24 supervised treadmill aerobic exercise sessions over 8 weeks (three sessions per week). Exercise intensity is prescribed at 45–50% of heart‐rate reserve (HRR), with 50 minutes of continuous aerobic exercise per session. The NOR group exercises under normoxic conditions (FiO2 approximately 20.9%). The HYP group exercises under normobaric hypoxic conditions corresponding to approximately 3,000 m altitude (FiO2 14.9%). The BR group exercises under normoxic conditions while wearing a breathing‐resistance mask that provides an inspiratory resistance of approximately 29.9 Pa. Outcomes assessed before and after the intervention include 24‐hour ambulatory blood pressure, heart‐rate variability, pulmonary and respiratory muscle function, macrovascular and microvascular function, body composition, and metabolic‐related measures. CONDITION: Endocrine, nutritional and metabolic diseases PRIMARY OUTCOME: 24‐hour ambulatory blood pressure: systolic blood pressure, diastolic blood pressure, and mean arterial pressure SECONDARY OUTCOME: Cardiopulmonary exercise capacity and ventilatory responses: oxygen uptake (VO2), ventilation (VE), VE/VCO2, VT/Ti, and VT/RR Heart rate variability (HRV): SDNN, RMSSD, LF, HF, and LF/HF ratio Macrovascular function: brachial and common femoral artery diameter, blood flow velocity, and flow‐mediated dilation (FMD) Metabolic and hematological biomarkers: fasting blood glucose, HbA1c, insulin, total cholesterol, HDL‐C, LDL‐C, triglycerides, red blood cell count, hemoglobin, and hematocrit Microvascular function and skeletal muscle oxygenation responses: cutaneous blood flow and muscle oxygenation recovery during post‐occlusion reactive hyperemia Pulmonary and respiratory muscle function: FVC, FEV1, MVV, maximal inspiratory pressure (MIP), and maximal expiratory pressure (MEP) INCLUSION CRITERIA: Adult men aged 19–30 years. Body mass inde X(BMI) =25 kg/m² and waist circumference =90 cm according to the World Health Organization criteria for the Asia‐Pacific region. No history of diagnosed cardiovascular, metabolic, or respiratory disease. No participation in a structured exercise program within the previous 6 months. Current non‐smokers. No use of medications known to affect cardiovascular, respiratory, or metabolic responses. No contraindications to hypoxic exposure or breathing‐resistance exercise based on a health‐screening questionnaire and medical‐history assessment.