This cross-sectional study aims to evaluate the respiratory muscle strength and physical capacity of symptomatic adult smokers in Muğla. The study population will be the patients who were admitted to the pulmonary outpatient clinic of Muğla Training and Research Hospital between July 2024 and December 2024. The primary outcome is the proportion of individuals with Maximum Inspiratory Pressure (MIP) below 80%. Secondary outcomes include the 6-Minute Walk Test (6MWT) distance, Maximum Expiratory Pressure (MEP), and COPD Assessment Test (CAT) scores. Smokers will be categorized into COPD, PRISm, and Pre-COPD groups. The study will adjust for BMI as a key confounder and assess the modifying effects of gender, smoking habits, and age. Ethical approval and informed consent will be obtained, with data analysis focusing on descriptive statistics, comparative analysis, and regression models to understand the impact of smoking on respiratory health.

Inclusion Criteria:

• At least 5 packages of cigarette smokers who have an appropriate PFT done at our lab. (pulmonary function test must be performed at evaluable standards according to ERS/ATS guidelines)

Exclusion Criteria:

• Respiratory infection at the time of measurement (upper or lower resp. tract, viral or bacterial infections)
• Presence of chronic respiratory diseases (Asthma, IPF, Bronchiectasis, [except COPD])
• Exacerbation due to chronic respiratory diseases (except mild COPD exacerbation)
• Neuromuscular disease (ALS, Guillain-Bare syndrome, Muscular dystrophies, Myasthenia gravis)
• Restrictive pulmonary disease (IPF, Sarcoidozis, Progresif Pulmonary Fibrosis)

The study population will consist of symptomatic smokers admitted to the pulmonary outpatient clinic of Muğla Training and Research Hospital between July 2024 and December 2024.