Nonexercise Cardiorespiratory Fitness and Mortality in Older Adults

Introduction: High cardiorespiratory fitness (CRF) is strongly associated with longer life among older adults. CRF can be assessed by exercise-based methods, which are not feasible in most clinical settings. Thus, nonexercise algorithms to estimate CRF have been developed, but whether they predict mortality in older adults is uncertain. Methods: A cohort of 1470 men and 1460 women, representative of the Spanish population age >= 60 yr, was established in 2000/2001 and followed up prospectively through 2011. At baseline, nonexercise CRF was estimated with the sex-specific algorithms developed by Jackson et al. Analyses were performed with Cox regression and adjusted for the main confounders. Results: During an average follow-up of 9.4 yr, 570 (38.8%) deaths occurred in men and 295 (20.2%) in women. Among men, no association was observed between nonexercise CRF and all-cause mortality. Compared with women in the lowest quartile of CRF, the hazard ratio (95% confidence interval) for all-cause death was 0.81 (0.62-1.06) in the second quartile, 0.68 (0.48-0.95) in the third quartile, and 0.56 (0.36-0.87) in the highest quartile (P for trend = 0.004). Results held regardless of age, body mass index, waist circumference, HR, subjective health, functional limitations, and disease status. Conclusions: Higher nonexercise CRF was related to lower risk of death in older women but not in men. Because previous research does not support clear sexspecific association, further research is required to assess whether nonexercise CRF predicts mortality in older adults or new algorithms should be developed for this population, with special attention to older men.