In the Karvonen method, how is heart rate reserve (HRR) defined?

• A. HRrest − HRmax
• B. HRmax − HRrest
• C. HRmax × HRrest
• D. (HRmax − HRrest) × 0.5

Answer: (B)

Heart rate reserve is the range of heart rate available for exercise. It’s defined as the difference between your maximal heart rate and your resting heart rate. In the Karvonen method, this reserve is used to scale exercise intensity: target heart rate equals resting heart rate plus a chosen percentage of HRR. This means HRR must be HRmax minus HRrest, not the reverse, not a product, and not half the range. For example, if HRmax is 190 and HRrest is 60, HRR is 130 bpm; at 60% intensity, target heart rate would be 60 + 0.60 × 130 = 138 bpm.