This interventional study aims to investigate the acute effects of different types of exercise on cerebral and peripheral muscle oxygenation in patients with chronic obstructive pulmonary disease (COPD). Functional near-infrared spectroscopy (fNIRS) and near-infrared spectroscopy (NIRS) will be used simultaneously to measure oxygenation changes in the prefrontal cortex and the vastus lateralis muscle during rest, Stroop task performance, the six-minute walk test, aerobic, strengthening, and breathing exercises.

The study will compare COPD patients and age- and sex-matched healthy controls to determine how brain and muscle oxygenation responses differ between groups and among exercise modalities. The findings are expected to guide the design of safe, individualized pulmonary rehabilitation programs that optimize oxygenation without compromising safety.

Functional near-infrared spectroscopy (fNIRS) and near-infrared spectroscopy (NIRS) allow real-time, non-invasive assessment of tissue oxygenation. Although widely used in neurology and exercise physiology, their application in pulmonary diseases such as COPD remains limited.

This study is designed as a non-randomized controlled, multidisciplinary trial conducted at Yedikule Chest Diseases and Thoracic Surgery Training and Research Hospital, Istanbul. The research team includes specialists in physiotherapy and rehabilitation, pulmonology, and neuroscience.

Participants will undergo a single standardized pulmonary rehabilitation (PR) session comprising three exercise modalities:Aerobic training, Peripheral strengthening exercises and Breathing exercises.

Before and after exercise, participants will perform the Stroop cognitive task to evaluate executive function and its relationship with cerebral oxygenation. Continuous fNIRS and NIRS monitoring will occur at rest, during each exercise, and during recovery.

Inclusion Criteria

• Age 40-70 years
• Diagnosis of moderate-to-severe COPD (GOLD stage II-III)
• Stable disease (no exacerbation in previous 4 weeks)
• BMI 18.5-24.9 kg/m²
• Manual muscle strength ≥ 4 (MRC scale)
• Ability to perform exercise tests safely
• Written informed consent

Exclusion Criteria

• Severe comorbid conditions (uncontrolled cardiac, neurological, or orthopedic disease)
• Need for high-flow oxygen therapy (>2 L/min)
• History of cerebrovascular disease or transient ischemic attack
• Musculoskeletal or dermatological conditions impairing NIRS measurement sites
• Restrictive lung disease, interstitial lung disease, or small-airway disease
• Participation in an exercise program within the last 12 months

Healthy Controls

• Age 40-70 years
• No acute or chronic disease
• Non-smoker
• BMI 18.5-24.9 kg/m²
• No musculoskeletal limitations