Percent of Maximal Heart Rate (%HRmax)

The %HRmax method prescribes intensity directly as a fraction of maximal heart rate:

Target HR = %intensity × HRmax

HRmax is most commonly estimated as 220 − age (see Maximum Heart Rate (220 − Age)); other prediction equations exist and all carry error of roughly ±10–12 bpm, so a measured or tested HRmax is more accurate when available.

Using the ACSM intensity classification (see Aerobic Intensity Classification (Light / Moderate / Vigorous)):

• Moderate intensity = 64–76% of HRmax.
• Vigorous intensity = ≥77% of HRmax (light intensity ≈ 50–63% HRmax).

The %HRmax method is quick and needs no resting-HR measurement, which makes it convenient for group settings. Its limitation is that it ignores resting heart rate, so two people of the same age get the same target band regardless of fitness — unlike the Karvonen / HRR method, which individualizes by subtracting resting HR (see Heart-Rate Reserve (Karvonen Method)). For the same nominal percentage, %HRmax gives a lower target heart rate than %HRR.

Worked example: a 40-year-old. HRmax ≈ 220 − 40 = 180. A 70% target = 0.70 × 180 = 126 bpm.

• Target HR = %intensity × HRmax; HRmax ≈ 220 − age (±~10–12 bpm error).
• ACSM: moderate 64–76% HRmax, vigorous ≥77% HRmax, light ~50–63% HRmax.
• Simple and convenient; no resting-HR needed.
• Less individualized than %HRR; gives a lower target than %HRR at the same percentage.