What percent heart rate reserve (HRR) corresponds to Moderate Intensity?

• A. 60-89% HRR
• B. 30-39% HRR
• C. 40-59% HRR
• D. ≥90% HRR

Answer: (C)

Heart rate reserve (HRR) uses the difference between your maximum heart rate and resting heart rate to set exercise intensity. Moderate intensity falls in the 40–59% HRR range, meaning you work at a level where effort is noticeable but sustainable. To apply it, compute HRR = HRmax − HRrest, then multiply that by 0.40–0.59 and add the resting heart rate to get your target heart rate range.

For example, if resting heart rate is 60 bpm and max heart rate is 180 bpm, HRR = 120 bpm. 40% of HRR is 48; add resting 60 to get a target around 108 bpm. 59% of HRR is about 70.8; add 60 to get about 131 bpm. So the moderate zone would be roughly 108–131 bpm.

Ranges outside this reflect other effort levels: 60–89% HRR is vigorous intensity, 30–39% HRR is light intensity, and ≥90% HRR is near-maximal effort. Using HRR personalizes the target because it accounts for your resting heart rate, not just your max.