The effects of smoking and exercise intensity on inflammatory markers in healthy adults

This cross-sectional study aimed to investigate the independent and interactive effects of cigarette smoking and regular physical activity on inflammatory, metabolic, respiratory, and muscular biomarkers in healthy adults. A total of 80 participants were classified into four equal groups based on smoking status (smoker/non-smoker) and physical activity level (active/inactive), using a 2×2 factorial design. All participants underwent laboratory testing including hemogram, lipid profile, fasting glucose, insulin, IL-1β, IL-6, CRP, fibrinogen, and albumin measurements. Objective assessments such as spirometry (FEV₁, FVC, FEV₁/FVC), handgrip strength via dynamometer, exhaled carbon monoxide (eCO) and carboxyhemoglobin (COHb) levels were performed. Physical activity and nicotine dependence were evaluated using the International Physical Activity Questionnaire-Short Form (IPAQ-SF) and the Fagerström Test for Nicotine Dependence, respectively. The findings revealed statistically significant differences among the groups in monocyte count, triglycerides, insulin, FEV₁/FVC ratio, eCO and COHb levels, and physical activity scores (p<0.05). The most unfavorable profiles were observed in participants who smoked and did not engage in regular exercise, whereas the most favorable values were seen in non-smokers with regular physical activity. Although IL-6 and CRP levels did not differ significantly between groups, their median values were lower in active non-smokers, indicating a potential anti-inflammatory effect of exercise. These results support the hypothesis that regular physical activity can partially mitigate the inflammatory and metabolic burden associated with smoking. The study underscores the necessity of integrating exercise counseling into smoking cessation programs and highlights the importance of addressing lifestyle factors jointly in both clinical and public health settings. Keywords: Smoking, Exercise, Inflammation, Biomarkers