Individual fat burning during exercise varies widely, challenging the notion of a universal "fat-burning zone." Icahn School of Medicine researchers suggest clinical exercise testing as a more effective method to personalize fat loss goals. Commercial exercise machines' fat-burning zones may not align with personal goals. A study compared measured and predicted heart rates, revealing discrepancies. Tailored exercise prescriptions could lead to improved metabolic health. Clinical exercise testing could redefine exercise intensity for optimal fat loss.