Comparison of Chest Expansion Values Among Smokers and Non-Smokers: An Observational Study

Abstract

Background: Chest expansion is an indirect but clinically relevant indicator of thoracic
mobility and pulmonary function. Cigarette smoking adversely affects lung compliance,
airway resistance, and respiratory muscle performance, which may reduce chest expansion
even in young adults.
Objective: To compare chest expansion values at different thoracic levels between
adult smokers and non-smokers.
Methods: A cross-sectional observational study was conducted on 120 adults aged 20–
40 years, recruited through convenience sampling at Parul University, Vadodara.
Participants were categorized as smokers (n = 58) and non-smokers (n = 62). Chest
expansion was measured using a cloth tape measure at three anatomical levels—
axillary, nipple, and xiphisternal—during maximal inspiration and expiration. Mean
values were compared between groups using appropriate descriptive and inferential
statistics.
Results: Non-smokers demonstrated greater chest expansion at all measured levels
compared with smokers. The difference was statistically significant at the nipple and
xiphisternal levels (p < 0.001), while axillary-level differences showed a smaller but
meaningful reduction in smokers. These findings indicate reduced thoracic mobility among
smokers even in early adulthood.
Conclusion: Smoking is associated with a significant reduction in chest expansion,
reflecting impaired thoracic mobility and respiratory mechanics. Early identification of
reduced chest expansion in smokers may help guide preventive and rehabilitative
physiotherapy interventions.