Fitness is considered to be a reliable objective marker of habitual physical activity, and body mass index (BMI) is widely accepted as a measure of overall obesity.  Duck-chul Lee, from the University of South Carolina at Columbia (South Carolina, USA), and colleagues explored the independent and combined associations of changes in fitness as estimated from a maximal treadmill test and BMI with all-cause and cardiovascular disease mortality.  The team revealed that men who were physically fit in their 40s, and maintained that fitness level for a decade,reduced their risk of all-cause death by 30% -- as compared with men who were flabby at age 40.  Specifically, during more than 11 years of follow-up, the researchers found that those men who maintained their baseline fitness levels had a 28% lower risk of cardiovascular disease death, while those who improved their fitness had a 40% and 44% lower risk of all-cause and cardiovascular disease death, respectively, as compared with those who remained unfit.  Whereas body mass index (BMI) status had little impact on risk of death in those who remained fit, BMI had variable yet non-significant impact on those who lost fitness or were unfit at the study’s start.  For every 1-metabolic equivalent (MET) improvement in fitness, there was a 15% lowering of the risk of all-cause death, and a 19% reduction in cardiovascular disease death. Observing that: “Maintaining or improving fitness is associated with a lower risk of all-cause and [cardiovascular disease] mortality in men,” the study authors urge that: “Preventing age-associated fitness loss is important for longevity regardless of [body mass index] change.”