Forced expiratory volume in 1 second (FEV(1)) is a strong risk factor for cardiovascular disease, stroke, lung cancer, and all-cause mortality. One possible explanation for this association is that FEV(1) is a marker of other determinants of mortality risk, such as obesity and physical inactivity. In a population-based cohort study of 12,283 men and women aged 45-74 years from the European Prospective Investigation into Cancer-Norfolk Study recruited in 1993-1997, the cross-sectional association between physical activity and FEV(1) and that between physical activity and change in FEV(1) were analyzed. Indices of physical activity, including participation in vigorous recreational activity, stair climbing, and television viewing, were assessed with a validated questionnaire designed to assess activity in the previous year. Television viewing was negatively associated with FEV(1) in men and women (p < 0.001), whereas stair climbing and participation in vigorous leisure time activities were positively associated with FEV(1) in men and women (p < 0.001). The associations remained after adjustment for known confounders, including age, height, vitamin C, and smoking. Climbing more stairs and participating in vigorous leisure-time activity predicted a slower rate in annual percent decline in FEV(1) (p < 0.004 and p < 0.002, respectively). In conclusion, physical activity is associated with higher levels of FEV(1), whereas television viewing is associated with lower levels.