Physical Activity As A Protective Factor Against Sleep Disorders And Depression In Different Smoking Status

In 2020, approximately 47.1 million US adults were current smokers, with smoke exposure negatively affecting lung function and cardiovascular capacity, thereby making physical activity (PA) more challenging and less enjoyable and contributing to negative mental health effects. PURPOSE: This study explored the role of PA in protecting against sleep disorders and depressive symptoms among U.S. adults, focusing on variations across smoking statuses (active smokers, secondhand smokers, and non-smokers) using serum cotinine levels as nicotine exposure markers. METHODS: Data were analyzed from the 2017-2020 National Health and Nutrition Examination Survey. Sleep disorders and depressive symptoms were assessed across six groups combined with PA guideline adherence and smoking status. The PA guidelines adherence was classified into two groups (meet PA guidelines and did not meet guidelines), and smoke exposure was categorized into three groups (non-smokers: <0.05 ng/mL, secondhand smokers: 0.05-15 ng/mL, and active smokers: >15 ng/mL). Socioeconomic status, anthropometric information, chronic conditions, and alcohol consumption related to smoking were included as covariates. Survey logistic regression was used to explore the relationships for sleep disorders and depressive symptoms, using non-smokers who met PA guidelines as the reference group. Analyses were also stratified by age groups (21-39 years, 40-59 years, 60+ years). RESULTS: Active smokers not meeting PA guidelines had significantly higher odds of depressive symptoms (OR = 4.48, p < 0.01) compared to non-smokers meeting PA guidelines. Among young adults, active smokers adhering to PA guidelines had increased odds of sleep disorders (OR = 2.86, p < 0.01). Middle-aged adults showed higher odds for sleep disorders (OR = 2.18, p < 0.01) and depressive symptoms (OR = 13.74, p < 0.05) when not meeting PA guidelines. For older adults, the odds of depressive symptoms were also elevated compared to non-smokers with met PA guidelines (OR = 3.46, p < 0.05). CONCLUSIONS: Public health strategies should prioritize increasing PA levels, especially among smokers, to mitigate mental health risks. Meeting PA guidelines continues to show positive health benefits even among individuals who smoke.