Quantifying the Reduction in Mortality Risk that Accompanies Physical Fitness
It is well established that physical fitness (and the level of activity and other lifestyle choices required to sustain it) correlate with a lower risk of mortality and longer life expectancy. Human data largely cannot provide evidence for causation, but that greater activity and fitness slow aging and extend life is robustly demonstrated in animal studies. Many large epidemiological studies have quantified the reduction in mortality risk provided by exercise or physical fitness, usually with a specific focus on some narrow aspect of the relationship, and here find yet another example of the type. The data in this study shows that old people at the low end of the range of fitness experience something like twice the late life mortality risk of those at the high end of fitness.
Regular physical activity promotes healthy aging, yet clinical risk stratification in older adults relies largely on comorbidity burden, often overlooking functional capacity. Objective fitness assessment may serve as a clinically relevant indicator of physiological reserve, but evidence from large cohorts evaluating multiple fitness domains remains limited. This nationwide cohort study included community-dwelling adults aged 65 years or older who completed standardized fitness assessments in Taiwan between January 11, 2015, and November 25, 2016. Participant data were linked to National Health Insurance records, with follow-up through December 31, 2022. The main outcome was all-cause mortality.
Of 13,423 participants (mean age, 72.9 ± 6.1] years;), 1,631 (12.2%) died during a median follow-up of 7.0 years. Compared with the lowest performance quintile, participants in the highest performance quintile had lower all-cause mortality across 4 physical fitness assessments: 8-foot up-and-go (adjusted hazard ratio, AHR, 0.41), 1-leg stance (AHR 0.50), 30-second chair stand (AHR 0.55), and 2-minute step test (AHR 0.58). The composite fitness index showed the lowest risk of all-cause mortality (AHR 0.39).
To conclude, in this cohort study of older adults, objectively measured physical fitness - particularly balance and agility, lower-body strength, and cardiorespiratory fitness - was associated with lower all-cause mortality in a graded manner.