– Higher cardiorespiratory fitness linked to later onset of chronic disease and more disease-free years –
How fit you are in midlife may help determine not just how long you live, but how many of those years are spent in good health, according to a new study published today in the Journal of the American College of Cardiology (JACC), the flagship journal of the American College of Cardiology.
The study found that adults with higher levels of cardiorespiratory fitness in midlife lived longer, developed fewer chronic diseases, and spent more years free from serious illness compared with those who were less fit. These benefits were observed in both men and women.
Cardiorespiratory fitness, how well the heart and lungs supply oxygen during physical activity, is already known to reduce the risk of heart disease and early death. This research extends prior findings by demonstrating that fitness also plays a meaningful role in healthy aging, defined as years lived without major chronic disease.
Key Findings: Later Disease Onset, Longer Life
Researchers followed more than 24,500 healthy men and women through age 65 and tracked their health outcomes later in life using Medicare data. Fitness was measured earlier in adulthood using a treadmill test. Researchers examined the development of 11 major chronic conditions, including heart disease, diabetes, kidney disease, and cancer.
Compared with people who had low fitness levels, those with high fitness in midlife experienced clear benefits later in life:
- Developed chronic diseases at least 1.5 years later on average
- Had fewer total chronic conditions
- Lived longer overall
These patterns held across different ages, body weights, and smoking histories.
Health Span vs. Lifespan
Importantly, the study emphasizes health span—not just lifespan—highlighting that fitness helps people live more of their lives in good health, rather than simply living longer with disease. The findings indicate that higher fitness in midlife is strongly associated with a lower overall disease burden and longer life expectancy.
“These results suggest that improving cardiorespiratory fitness during midlife may be a key strategy for promoting healthy aging and preserving quality of life later on,” the researchers concluded.
Public Health Implications
The findings underscore the public health value of physical activity, as cardiorespiratory fitness can be improved through regular movement such as brisk walking, cycling, or other aerobic exercise. Even modest increases in physical activity may yield meaningful benefits.
“The study extends prior research by showing that fitness also plays a meaningful role in healthy aging, defined as years lived without major chronic disease,” the American College of Cardiology noted in a release accompanying the study.
Study Limitations
The researchers noted several limitations. The study’s observational design does not allow researchers to establish causality. Additionally, participants were generally health-conscious, which may limit broader generalizability to the wider population.
Source:
American College of Cardiology
Journal Reference:
Meernik, C., et al. (2026). Midlife Cardiorespiratory Fitness and Healthy Aging: An Observational Cohort Study. JACC. https://www.jacc.org/doi/10.1016/j.jacc.2026.02.5122