Midlife Cardiorespiratory Fitness and Healthy Aging

BACKGROUND: Higher cardiorespiratory fitness (CRF) is associated with a lower risk for chronic disease and death, but its relation to healthy aging more broadly remains understudied. OBJECTIVES: The aim of this study was to examine the associations between midlife CRF and later life health span (years without major chronic disease), disease burden, and lifespan among adults who remained apparently healthy through 65 years of age. METHODS: This cohort study included 24,576 participants (25% women) from the CCLS (Cooper Center Longitudinal Study) (1971-2017) linked to Medicare administrative claims (1999-2019). CRF was estimated using a maximal treadmill test at a preventive medicine clinic visit before age 65 years. Eleven major chronic conditions were identified from the Medicare Chronic Conditions Data Warehouse and used to define disease as: 1) any of the 11 conditions (composite); 2) any condition within a clinical group (cardiovascular, cardiovascular-kidney-metabolic, cancer); or 3) an individual condition. Multivariable illness-death models estimated the likelihood of transitioning between health, disease, and death by CRF level (low, moderate, or high). Model parameters were used to calculate adjusted Aalen-Johansen probabilities and expected times in each state of health, disease, and death; these were then used to calculate expected health span, number of diseases, disease-years, and lifespan by CRF. RESULTS: When disease was defined as any of 11 major chronic conditions, high-fit men had a 2% (95% CI: 1%-2%) longer health span, 9% (95% CI: 1%-17%) fewer diseases, and a 3% (95% CI: 2%-4%) longer lifespan compared with low-fit men, with similar patterns among women. When disease was clinically grouped, 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. On average, 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. Results were consistent across clinical subgroups defined by clinic visit year (before or after 1990), age (younger or older than 45 years), smoking status (current smoking, nonsmoking, or missing smoking), and weight status according to body mass index (healthy weight and overweight or obese). CONCLUSIONS: Higher midlife CRF was associated with longer health span, lower multimorbidity, and longer lifespan among men and women.