Want to delay dementia, heart disease and cancer? Your fitness in midlife may matter- The Week

Higher levels of fitness in middle age may do more than help people stay active; they could also delay chronic illness and extend life, according to a major new study published in the Journal of the American College of Cardiology.

The studytitled “Midlife Cardiorespiratory Fitness and Healthy Aging: An Observational Cohort Study,” found that adults who were more aerobically fit in their 40s and 50s not only lived longer, but also spent more of those later years free from major chronic diseases.

Researchers wrote that “higher midlife CRF was associated with longer health span, lower multimorbidity, and longer lifespan among men and women.” CRF, or cardiorespiratory fitness, refers to the body’s ability to supply oxygen during sustained physical activity.

The research followed 24,576 participants — about 25 percent of them women — from the long-running Cooper Center Longitudinal Study. Participants underwent treadmill-based fitness testing before age 65 and were later tracked through Medicare records between 1999 and 2019.

The investigators examined whether people developed any of 11 major chronic conditions, including cardiovascular disease, cancer, kidney disease and dementia. They then compared outcomes among participants classified as having low, moderate, or high fitness levels in midlife.

The results showed consistent advantages for those who were fitter in middle age. “When disease was defined as any of 11 major chronic conditions, high-fit men had a 2 per cent longer health span, 9 per cent fewer diseases, and a 3 per cent longer lifespan compared with low-fit men, with similar patterns among women,” the researchers reported.

The study also found that “the onset of each of the 11 chronic conditions occurred at least 1.5 years later among high-fit men and women compared with low-fit individuals.” In practical terms, that means fitter adults tended to remain healthier for longer before developing serious illnesses associated with ageing.

The authors noted that the benefits extended across several categories of disease. “Higher fit men and women generally had a later onset of cardiovascular, cardiovascular-kidney-metabolic, and cancer outcomes and developed fewer conditions within each group,” they wrote.

Importantly, the findings held true across a wide range of participants. According to the study, “results were consistent across clinical subgroups defined by clinic visit year, age, smoking status, and weight status according to body mass index.”

The researchers emphasized that the participants included in the study had all remained “apparently healthy through 65 years of age” at the start of Medicare tracking, allowing the team to focus specifically on how fitness influenced aging trajectories later in life.

Using advanced statistical models, the team estimated participants’ “expected health span, number of diseases, disease-years, and lifespan by CRF.” The analysis suggested that higher fitness was linked not only to living longer, but also to compressing the burden of illness into fewer years at the end of life.

The study adds to growing evidence that exercise during midlife can have long-term health consequences decades later. While the research was observational and cannot prove direct causation, the scale and duration of the data make it one of the most comprehensive examinations yet of fitness and healthy ageing.

The authors concluded that maintaining stronger aerobic fitness in midlife may be a key factor in extending both lifespan and the number of years lived in good health, an increasingly important public health goal as populations age worldwide.

This story is done in collaboration with First Checkwhich is the health journalism vertical of DataLEADS