Can a simple, nonexercise estimate of fitness help identify early dysglycemia risk in otherwise healthy adults? A prospective cohort analysis published in Diabetes & Metabolic Syndrome: Clinical Research & Reviews evaluated whether nonexercise estimated cardiorespiratory fitness (eCRF) offers predictive value for incident prediabetes and type 2 diabetes mellitus (T2DM) in normoglycemic individuals.

The analysis included 10,715 adults aged 20 to 81 years from the Aerobics Center Longitudinal Study. Estimated CRF was derived using sex-specific equations incorporating age, body mass index (BMI), resting heart rate, blood pressure, and smoking status. Incident prediabetes and T2DM were identified using fasting glucose criteria or clinical diagnosis. Cox proportional hazards models estimated associations after adjustment for established risk factors.

Over a median follow-up of 5.1 years for prediabetes and 6.7 years for T2DM, 3,912 and 320 cases occurred, respectively. Higher eCRF was associated with lower risk of prediabetes (hazard ratio [HR] 0.83; 95% confidence interval [CI] 0.77-0.90) and T2DM (HR 0.72; 95% CI 0.55-0.95) compared with unfit individuals. These associations remained significant in men for both outcomes, while in women significance was observed for prediabetes only. In contrast, the American Diabetes Association Risk Test (ADART) and BMI were associated with prediabetes risk but not T2DM after multivariable adjustment.

These findings suggest that eCRF may serve as a practical, noninvasive tool for early risk stratification, particularly in lower-risk populations.