Midlife Cardiorespiratory Fitness and the Long-Term Risk of Mortality: 46 Years of Follow-Up.
Level 3 - non-randomized controlled study
Prospective non-randomized cohort follow-up study
PubMed 30139444 · doi:10.1016/j.jacc.2018.06.045
What was done
Researchers analyzed 5,107 employed Danish men (mean age 48.8 ± 5.4 years) free of cardiovascular disease from the Copenhagen Male Study (1970–1971). Baseline cardiorespiratory fitness (Vo2 max estimated via bicycle ergometer) was grouped into 4 age-adjusted categories: below the lower limit of normal (lowest 5%), low normal (45%), high normal (45%), and above the upper limit of normal (top 5%). All-cause and cardiovascular mortality were tracked over 46 years through Danish national registers using multivariable restricted mean survival time models. Reverse causation was evaluated by excluding deaths in the first 10 years of follow-up.
What was found
Over 46 years of follow-up, 4,700 men (92%) died, including 2,149 (42.1%) from cardiovascular causes. Compared to men below the lower limit of normal fitness, life expectancy was longer by 2.1 years (95% CI: 0.7 to 3.4; p = 0.002) in the low normal group, 2.9 years (95% CI: 1.5 to 4.2; p < 0.001) in the high normal group, and 4.9 years (95% CI: 3.1 to 6.7; p < 0.001) in the above upper limit of normal group. Each unit increase in Vo2 max was associated with a 45-day increase in longevity (95% CI: 30 to 61; p < 0.001). Results were similar for cardiovascular mortality and remained essentially unchanged after excluding deaths in the first 10 years.
Why it matters
This study shows that midlife cardiorespiratory fitness has an enduring, dose-dependent relationship with survival over nearly five decades. It demonstrates that fitness-associated longevity gains are sustained into late life and are not merely artifacts of short-term reverse causation.
Limits
The study included only employed Danish men enrolled in the early 1970s, limiting applicability to women, unemployed individuals, and other ethnic populations. Vo2 max was estimated using an ergometer rather than directly measured with respiratory gas analysis, and fitness was assessed only at baseline without accounting for changes during follow-up.
Cited by
- supports Moving from low cardiorespiratory fitness to low normal is associated with a 2-year increase in life expectancy, moving to high normal is associated with nearly a 3-year increase, and moving to high fitness is associated with a 5-year increase in life expectancy.