Background Few studies have prospectively evaluated the association of leisure-time physical activity (LTPA) with mortality in Asians, who are more susceptible to insulin resistance than their Caucasian counterparts.

Methods Data from two large prospective cohort studies conducted in Shanghai were evaluated. After excluding participants who had a history of cancer, coronary heart disease or stroke at baseline, or who died within the first 3 years after study enrolment, 53 839 men and 66 888 women, followed for an average of 9.2 and 14.7 years, respectively, remained for the study.

Results Compared with those who reported no exercise, a reduction in mortality with an HR of 0.86 (95% CI 0.80 to 0.93) was observed in those who regularly engage in moderate-intensity LTPA, even those who reported an LTPA level lower than the minimum amount recommended by the current physical activity guidelines (150 min or 7.5 metabolic equivalent hours per week). The association between moderate-intensity exercise and mortality followed a dose–response pattern until the amount of LTPA reached 3–5 times the recommended minimum level. A similar pattern of association was observed for cause-specific mortality due to cardiovascular disease (CVD), cancer or other causes.

Conclusion Regular participation in moderate-intensity LTPA was associated with reduced mortality, particularly CVD mortality, even when the LTPA was below the minimum level recommended by current guidelines. Increasing the amount of moderate-intensity LTPA was associated with further risk reduction up to a potential threshold of 3–5 times the recommended minimum.