Impact of Physical Activity on Smoking, Sleep Disorders, and Depression Among U.S. Adults.

Smoking negatively impacts lung function and cardiovascular capacity, making physical activity (PA) more challenging and contributing to mental health issues. This study investigates the role of PA in mitigating the links between smoking, sleep disorders, and depressive symptoms in adults in the United States. Data from the 2017 to 2020 National Health and Nutrition Examination Survey (NHANES) were examined. Participants were categorized by PA adherence (≥ 900 metabolic equivalent tasks [METs]/week or not) and smoking status based on serum cotinine levels (< 0.05 for non-smokers, 0.05-15 for secondhand smokers, and > 15 ng/mL for active smokers). Relationships between sleep disorders, depressive symptoms, and PA/smoking were evaluated using survey logistic regression, with non-smokers meeting PA guidelines as the reference group. Stratified analyses were conducted by age group (21 - 39, 40 - 59, 60+ years). Active smokers not meeting PA guidelines had a significantly higher likelihood of moderate to severe depressive symptoms (odds ratio [OR] 2.21, 95% confidence interval [CI] = [1.34, 3.65]). Young active smokers meeting PA guidelines had greater odds of sleep disorders (OR = 2.86, 95% CI = [1.38, 5.93]). Among middle-aged adults, those not meeting PA guidelines exhibited elevated odds of sleep disorders (OR = 2.18, 95% CI = [1.33, 3.59]) and severe depressive symptoms (OR = 3.01, 95% CI = [1.11, 8.18]). For older adults, increased odds of depressive symptoms were observed (OR = 3.37, 95% CI = [1.22, 9.29]). These findings underscore the potential of PA to mitigate mental health risks among individuals exposed to smoking. Longitudinal research is required to confirm these associations and inform targeted interventions.