Survival of the fittest? Peak oxygen uptake and all-cause mortality among older adults in Norway.

Objective: To determine the cardiorespiratory fitness (CRF) levels needed to avoid the Grim Reaper (Death) among older adults. We hypothesized that an above average peak oxygen uptake (VO) is needed for 70-77-year-old men and women to delay the encounter with Death.

Design: Prospective cohort study.

Setting: General population of older adults in Norway.

Participants: 788 women and 777 men aged 70-77 years.

Intervention: Clinical assessments, including a test of VO. Participants were categorised based on their baseline VO and changes after 1 year. This study explored associations between VO and 5-year all-cause mortality using Cox proportional hazard models.

Main Outcome Measure: All-cause mortality.

Results: Death caught up with 5.3 % of men and 3.7 % of women. Compared to unfit men and women, fewer men (Hazard Ratio [HR]: 0.34, 95 % Confidence Interval [CI] 0.15-0.78) and women (HR: 0.41, 95 % CI 0.17-0.98) classified as moderately fit encountered Death with no additional risk reduction among those classified as being more fit. It appears to be easier for the Grim Reaper to claim those in poorer physical condition, specifically VO levels <26.5 mL/kg/min for men and 22.2 mL/kg/min for women (corresponding to ≥85 % of the observed age- and sex-specific average).

Conclusion: The Grim Reaper typically targets individuals with VO levels <26.5 mL/kg/min/ and <22.2 mL/kg/min when chasing male and female souls aged 70-77 years, respectively, reflecting his penchant for limited CRF. These data underscore the importance of maintaining or enhancing CRF throughout life, providing clear targets for clinicians in assessing patient CRF levels.

Trial Registration: ClinicalTrials.govNCT01666340.