Abstract 16539: The Influence of Short-Term Changes in Cardiorespiratory Fitness Post-Exercise Training on Mortality Risk.

Introduction: Over the past 30 years, cross-sectional studies have established an inverse relationship between cardiorespiratory fitness (CRF) and mortality. Exercise training typically leads to improvements in CRF. Given the strong association between CRF and mortality, the change in CRF post-exercise training could alter one's mortality risk. However, longitudinal analyses assessing the influence of short-term changes in CRF on mortality have not been assessed in apparently healthy adults. The primary purpose of this study was to assess the influence of post-exercise training (≤8 months) changes in directly measured CRF on all-cause mortality risk in a cohort of self-referred, apparently healthy men and women. Methods: Participants included 689 adults (410 men, 279 women; mean age: 42.7± 11.0 years) who underwent two maximal cardiopulmonary exercise tests (CPX) between 1970 and 2012 to determine CRF at baseline and post-exercise training. Participants were followed for 29.8 ± 10.7 years after their post-exercise CPX for mortality outcomes. Cox-proportional hazard models were performed to determine the relationship of CRF change with all-cause mortality outcomes. Results: During follow-up, 186 participants died (27%). Overall, the change in CPX-derived CRF was inversely related to all-cause mortality, with a 7% lower risk reduction per 1 ml·kg-1·min-1 improvement. Remaining unfit was associated with approximately 2-fold higher risk for all-cause mortality (hazard ratio 1.99, 95% CI 1.18-3.35), compared with those that stayed fit. The relationship remained significant when men and women were examined independently. Following multivariable adjustment an approximately 6 and 13% lower mortality risk was found per 1 ml·kg-1·min-1 improvement in men and women respectively (p<0.01). Conclusions: Improving CRF through exercise training can lower the risk for premature mortality. Therefore, clinicians should encourage individuals, especially those identified as unfit, to participate in an exercise training program to improve CRF, as it may provide survival benefit. [ABSTRACT FROM AUTHOR]