Cigarette smoking weakens exercise habits in healthy men

To investigate the longitudinal impact of smoking cessation and relapse on the exercise habits of apparently healthy Japanese men, 750 subjects presenting for a checkup at a metropolitan health center were surveyed annually for 7 years. Exercise was dichotomously classified as none or any. Subjects were grouped in two categories: 98 smokers who ceased smoking during the second year of the study, matched with 196 continuing smokers and 196 men who had never smoked; and 52 relapsed smokers (including 2 new smokers) who did not smoke at baseline or at Year 1 but smoked from Year 2 to final follow-up, matched with 104 continuing smokers and 104 never-smokers. Based on self-reported responses to questionnaires, exercise was consistently less prevalent among smokers who did not quit than among never-smokers throughout the study. Habitual exercise in subjects who had quit smoking increased during the follow-up (any exercise: 42.9% at baseline increased to 51% at final follow-up, p for longitudinal trend = .115). Habitual exercise in matched never-smokers did not change during the study and decreased significantly among persistent smokers (p = .025). Habitual exercise in relapsed smokers decreased during the follow-up (any exercise: 50.0% at baseline declined to 32.7% at final follow-up, p = .007), but habitual exercise in matched persistent smokers and never-smokers did not change. We conclude that smoking and sedentary lifestyle coexist continuously, that smoking cessation is associated with increased habitual exercise among healthy men, and that relapse is associated with reduced habitual exercise, suggesting that cigarette smoking weakens exercise habits.