The Relationship Between Physical Activity Level, Respiratory Muscle Strength, and Cough Strength in Individuals with...

Background/Objectives: Pulmonary complications and respiratory muscle weakness are common in individuals with type 2 diabetes mellitus (Type 2 DM). Physical inactivity may further contribute to impaired respiratory muscle performance and reduced cough effectiveness in this population. The aim of this study was to examine the relationship between physical activity level, respiratory muscle strength, and cough strength in individuals with Type 2 DM. This study was an observational cross-sectional study. Methods: Thirty individuals with Type 2 DM and thirty age- and sex-matched healthy controls were included. Their physical activity level was assessed using the International Physical Activity Questionnaire (IPAQ), and respiratory muscle strength was evaluated using maximal inspiratory pressure (MIP) and maximal expiratory pressure (MEP), whereas cough strength was assessed using a peak expiratory flow meter. Group comparisons were performed using the Mann-Whitney U test, and associations were analyzed using Spearman's correlation coefficients. Additional multivariable regression analyses were conducted after adjustment for body mass index (BMI) and waist circumference. Results: Physical activity level, respiratory muscle strength, and cough strength were significantly lower in individuals with Type 2 DM than in healthy controls (p < 0.05). Within the Type 2 DM group, IPAQ scores were positively correlated with MIP (r = 0.438, p = 0.016), MEP (r = 0.581, p = 0.001), and cough strength (r = 0.619, p < 0.001), and diabetes duration was negatively correlated with MIP (r = -0.412, p = 0.024). After adjustment for BMI and waist circumference, Type 2 DM status remained independently associated with lower MIP (B = -15.69, 95% CI: -26.58 to -4.80, p = 0.006) and lower cough strength (B = -90.51, 95% CI: -161.52 to -19.50, p = 0.013). Conclusions: Individuals with Type 2 DM demonstrated lower physical activity levels, respiratory muscle strength, and cough strength than healthy controls. Higher physical activity levels were associated with better respiratory muscle strength and cough strength, whereas longer diabetes duration was associated with lower inspiratory muscle strength. These findings suggest that respiratory muscle function and cough performance may be adversely affected in individuals with Type 2 DM, warranting further investigation in larger longitudinal studies.