Reduction of physical activity in daily life and its determinants in smokers without airflow obstruction

Background and objective: In smokers without airflow obstruction, detailed, objective and controlled quantification of the level of physical inactivity in daily life has never been performed. This study aimed to objectively assess the level of physical activity in daily life in adult smokers without airflow obstruction in comparison with matched non-smokers, and to investigate the determinants for daily physical activity in smokers.

Methods: Sixty smokers (aged 50 (39-54) years) and 50 non-smokers (aged 48 (40-53) years) matched for gender, age, anthropometric characteristics, educational level, employment status and seasons of the year assessment period were cross-sectionally assessed regarding their daily physical activity with a step counter, besides assessment of lung function, functional exercise capacity, quality of life, anxiety, depression, self-reported comorbidities carbon monoxide level, nicotine dependence and smoking habits.

Results: When compared with non-smokers, smokers walked less in daily life (7923 ± 3558 vs 9553 ± 3637 steps/day, respectively), presented worse lung function, functional exercise capacity, quality of life, anxiety and depression. Multiple regression analyses identified functional exercise capacity, Borg fatigue, self-reported motivation/physical activity behaviour and cardiac disease as significant determinants of number of steps/day in smokers (partial r(2) = 0.10, 0.12, 0.16 and 0.05; b = 15, -997, 1207 and -2330 steps/day, respectively; overall fit of the model R(2) = 0.38; P < 0.001).

Conclusions: Adult smokers without airflow obstruction presented reduced level of daily physical activity. Functional exercise capacity, extended fatigue sensation, aspects of motivation/physical activity behaviour and self-reported cardiac disease are significant determinants of physical activity in daily life in smokers.