A team of the Cleveland Clinic Foundation performed a retrospective cohort study between January 1991 and December 2014 to assess the association of all-cause mortality and cardiorespiratory fitness in 122,077 patients undergoing exercise treadmill testing
Death occurred in 13,637 patients during 1.1 million person-years of observation. Risk-adjusted all-cause mortality was inversely proportional to cardiorespiratory fitness and was lowest in elite performers. The increase in all-cause mortality associated with reduced cardiorespiratory fitness was comparable to or greater than traditional clinical risk factors. In subgroup analysis, the benefit of elite over high performance was present in patients 70 years or older and patients with hypertension. Extreme cardiorespiratory fitness was associated with the lowest risk-adjusted all-cause mortality compared with all other performance groups.