Running volume and long-term mortality The Copenhagen City Heart Study follow-up found that people who like to exercise have at least a 30% lower risk of death than those who are not active. However, the optimal intensity of exercise for longevity is unclear, and the Copenhagen City Heart Study aims to examine the relationship between running and long-term mortality, with a particular focus on the speed, volume and frequency of running. The study followed 1098 healthy runners and 3950 healthy non-runners from 2001. Mortality was lowest among those who ran 1 to 2.4 hours per week compared to those who did not exercise (multifactorial risk ratio: 0.29). The optimal frequency of running was 2 to 3 times per week (risk ratio: 0.32) or no more than 1 time per week (risk ratio: 0.29). The optimal speed was slow (risk ratio: 0.51) or moderate (risk ratio: 0.38). Runners were also divided into low, moderate and high intensity. The lowest mortality risk ratio was for low-intensity runners (risk ratio: 0.22), followed by moderate-intensity runners (risk ratio: 0.66), and the highest was for high-intensity runners (risk ratio: 1.97). The study suggested a U-shaped curve for the association between all-cause mortality and the speed, volume and frequency of running. Mortality was lower in low- and moderate-intensity runners than in inactive runners, while there was no statistical difference between mortality in high-intensity runners and inactive groups.