Introduction: Exercise is widely accepted to improve health, reducing the risk of premature mortality, cardiovascular disease (CVD) and cancer. However, several epidemiological studies suggest that the exercise-longevity relationship may be 'J' shaped; with elite athlete's likely training above these intensity and volume thresholds. Therefore, the aim of this meta-analysis was to examine this relationship in former elite athletes.
Methods: 38,047 English language articles were retrieved from Web of Science, PubMed and SportDiscus databases published after 1970, of which 44 and 24 were included in the systematic review and meta-analysis, respectively. Athletes were split into three groups depending on primary sport: Endurance (END), Mixed/Team, or power (POW). Standard mortality ratio's (SMR) and standard proportionate mortality ratio (SPMR) were obtained, or calculated, and combined for the meta-analysis.
Results: Athletes lived significantly longer than the general population (male SMR 0.69 [95% CI 0.61-0.78]; female SMR 0.51 [95% CI 0.40-0.65]; both p < 0.01). There was no survival benefit for male POW athletes compared to the general population (SMR 1.04 [95% CI 0.91-1.12]). Although male athlete's CVD (SMR 0.73 [95% CI 0.62-0.85]) and cancer mortality (SMR 0.75 [95% CI 0.63-0.89]), were significantly reduced compared to the general population, there was no risk-reduction for POW athletes CVD mortality (SMR 1.10 [0.86-1.40]) or END athletes cancer mortality (SMR 0.73 [0.50-1.07]). There was insufficient data to calculate female sport-specific SMR's.
Discussion: Overall, athletes live longer and have a reduced incidence of both CVD and cancer mortality compared to the general population, refuting the 'J' shape hypothesis. However, different health risks may be apparent according to sports classification, and between sexes, warranting further investigation. Trial registration PROSPERO (registration number: CRD42019130688).