Key Takeaway
Higher cardiorespiratory fitness is associated with significantly reduced all-cause mortality, with no upper limit of benefit observed.
Summary
This large retrospective study of over 122,000 patients who underwent exercise treadmill testing found a powerful inverse relationship between cardiorespiratory fitness and all-cause mortality.
Critically, the study found no upper limit to the benefit - even "elite" fitness levels showed mortality benefits compared to "high" fitness. The lowest-fit individuals had 5x higher mortality risk than the most fit.
This research supports Zone 2 training as a longevity intervention, as it is the primary method for building cardiorespiratory fitness safely and sustainably.
Methods
- Retrospective cohort study
- 122,007 patients undergoing exercise treadmill testing (1991-2014)
- Median follow-up of 8.4 years
- Fitness categorized by age and sex-specific percentiles
Key Results
- Strong inverse association between fitness and mortality
- Low fitness associated with 500% higher mortality vs elite fitness
- No upper limit of benefit observed
- Benefit persisted across all age groups and comorbidities
Limitations
- Observational study (cannot prove causation)
- Self-selected population seeking medical testing
- Fitness measured at single time point
- Predominantly white population