Comparisons of leisure-time physical activity and cardiorespiratory fitness as predictors of all-cause mortality in men and women

Abstract

Objective: To examine the combined associations and relative contributions of leisure-time physical activity (PA) and cardiorespiratory fitness (CRF) with all-cause mortality. Design: Prospective cohort study. Setting: Aerobics centre longitudinal study. Participants: 31 818 men and 10 555 women who received a medical examination during 1978–2002. Assessment of risk factors: Leisure-time PA assessed by self-reported questionnaire; CRF assessed by maximal treadmill test. Main outcome measures: All-cause mortality until 31 December 2003. Results: There were 1492 (469 per 10 000) and 230 (218 per 10 000) deaths in men and women, respectively. PA and CRF were positively correlated in men (r=0.49) and women (r=0.47) controlling for age (p<0.001 for both). PA was inversely associated with mortality in multivariable Cox regression analysis among men, but the association was eliminated after further adjustment for CRF. No significant association of PA with mortality was observed in women. CRF was inversely associated with mortality in men and women, and the associations remained significant after further adjustment for PA. In the PA and CRF combined analysis, compared with the reference group “not meeting the recommended PA (<500 metabolic equivalent-minute/week) and unfit”, the relative risks (95% CIs) of mortality were 0.62 (0.54 to 0.72) and 0.61 (0.44 to 0.86) in men and women “not meeting the recommended PA and fit”, 0.96 (0.61 to 1.53) and 0.93 (0.33 to 2.58) in men and women “meeting the recommended PA and unfit” and 0.60 (0.51 to 0.70) and 0.56 (0.37 to 0.85) in men and women “meeting the recommended PA and fit”, respectively. Conclusions: CRF was more strongly associated with all-cause mortality than PA; therefore, improving CRF should be encouraged in unfit individuals to reduce risk of mortality and considered in the development of future PA guidelines.