Max heart rate
193bpm
Tanaka
220 − age
199bpm
classic
Zone 2
116–135bpm
aerobic base
Vigorous from
149bpm
about 77% of max
Show the math
Max HR = 208 − 0.7 × 21 = 193 bpm
Heart rate zones at 21
| Zone | BPM | % of max | Feels like |
|---|---|---|---|
| Zone 1 · Recovery | 97–116 | 50–60% | Easy, conversational |
| Zone 2 · Aerobic base | 116–135 | 60–70% | Steady, can still talk |
| Zone 3 · Tempo | 135–155 | 70–80% | Comfortably hard |
| Zone 4 · Threshold | 155–174 | 80–90% | Hard, short phrases |
| Zone 5 · Max effort | 174–193 | 90–100% | All-out, seconds to minutes |
Karvonen zones by resting heart rate
| Resting HR | Zone 1 | Zone 2 | Zone 3 | Zone 4 |
|---|---|---|---|---|
| Resting 55 | 124–138 | 138–152 | 152–166 | 166–179 |
| Resting 65 | 129–142 | 142–155 | 155–168 | 168–180 |
| Resting 75 | 134–146 | 146–158 | 158–170 | 170–181 |
Karvonen: resting + (max − resting) × intensity. More personal if you know your resting rate.
How to use it
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These are estimates, not a diagnosis. A clinician can account for your health history and medicines.
Other ages
Common questions
What is a good heart rate zone for a 21-year-old?
Zone 2, about 116 to 135 bpm, builds aerobic base. Moderate exercise sits around 124 to 147 bpm.
What is the max heart rate at 21?
About 193 bpm by the Tanaka formula, or 199 by 220 minus age. Individual max can differ by 10 or more beats.