886. Physical fitness is a modifiable predictor of early cardiovascular death: A 35 year follow-up study of 2014 healthy middle age men
Commentary by Steve Gilbert, AusPAnet Executive, The University of Sydney, Australia
Physical fitness is now an established predictor of cardiovascular morbidity and mortality, with those who have the highest fitness enjoying the lowest risk of poor cardiovascular health. This relationship is predominantly based upon evidence derived from studies where exercise capacity is measured at a single time-point and compared against health outcomes seen at the end of the follow-up period. These studies rely on assumption that the relationship between fitness and health outcomes do not change over the duration of a follow-up period, and cannot detect the effect of subsequent changes in fitness on health outcomes.
The recent study by Engeseth et al. has explored the sustainability of physical fitness as a predictor of cardiovascular, or all-cause mortality over the early (<12 years), intermediate (12-23 years) and late (>23 years) phases of a 35 year follow-up. Physical fitness, was measured on two occasions (first test conducted 1972-1975, second tests conducted 1979-1982), with the effects of the initial fitness level and the change in fitness both analyzed against health outcomes in an initial sample of 2014 Norwegian men aged 49-59 years at the point of their baseline assessment.
After adjustment for classic cardiovascular risk factors, it was found that low physical fitness at the first assessment was associated with increased risk of cardiovascular death during the first 23 years of the observation period, but lost its predictive power over the last 12 years of observation. However, the relationship between physical fitness and risk of all-cause mortality was maintained throughout the 35 year follow-up period. Also, it was found that change in physical fitness between the first and second assessments was predictive of cardiovascular mortality through the subsequent 28 year period to the end of the observation period.
While these findings add further weight to the evidence that measures of physical fitness are predictive of cardiovascular risk, they demonstrate that the predictive value of a single measure of physical fitness may be time-limited. From the perspective of practitioners and clinicians, these findings highlight the need for repeat assessment of physical fitness to gain the greatest estimation of cardiovascular risk. However, for the patient, these results highlight the importance of achieving higher levels of fitness, and notably, demonstrate that changes in fitness in midlife can influence health in later life.
With the population of this sample including men moving from mid-life into retirement and older age, these findings highlight the importance of increasing physical activity in this group. To reduce the risk of cardiovascular mortality men in this age group must be shown that there are benefits to be gained from making health improvements at this stage of life.