Karvonen Method (Heart Rate Reserve)
The Karvonen formula uses heart rate reserve (HRmax − HRrest) to set training intensities. More personalised than percentage of HRmax because it accounts for your resting heart rate.
The Karvonen Formula, Worked Through
The Karvonen formula uses heart rate reserve (HRR), the difference between your maximum and resting heart rate. Two athletes with the same HRmax but different resting rates end up with very different training targets — which is why %HRR is generally preferred over %HRmax for anyone who has measured their resting HR.
Target HR = HRrest + (Intensity% × (HRmax − HRrest))
Worked example: two 40-year-olds, same HRmax, different Zone 2
| Athlete |
HRmax |
HRrest |
HRR |
Zone 2 (60–70% HRR) |
Zone 2 (60–70% HRmax) |
| Trained runner | 180 | 45 | 135 | 126–140 bpm | 108–126 bpm |
| Untrained office worker | 180 | 75 | 105 | 138–149 bpm | 108–126 bpm |
Notice that %HRmax gives both athletes the same target (108–126 bpm) — clearly too low for the untrained athlete, whose easy pace already puts them at 130+ bpm. Karvonen fixes this by anchoring the range to each athlete's actual HR reserve.
Where the formula came from
Martti Karvonen and colleagues at the University of Helsinki published the method in 1957 after studying young men on a stationary bike. They observed that the linear relationship between HR and oxygen uptake held far better when expressed as a fraction of HRR than as a fraction of HRmax alone.
Reference: Karvonen MJ, Kentala E, Mustala O. The effects of training on heart rate: a longitudinal study. Annales Medicinae Experimentalis et Biologiae Fenniae. 1957;35(3):307–15.
When Karvonen breaks down
- Inaccurate resting HR — measure on 3+ mornings before you stand up, then average. A single reading after coffee or a poor night's sleep is worthless.
- Beta-blockers compress the reserve; formula-derived targets no longer correspond to metabolic zones.
- Detrained state — after a long layoff HRrest rises and HRmax may drop; recalculate after 4–6 weeks of consistent training.
Heart Rate Zones (reference: age 30, HRmax ≈ 187 bpm, Tanaka)
| Zone |
Name |
% HRmax |
BPM (age 30) |
Primary use |
| 1 | Recovery | 50–60% | 94–112 | Warm-up, recovery, active rest |
| 2 | Endurance | 60–70% | 112–131 | Aerobic base, fat oxidation |
| 3 | Aerobic | 70–80% | 131–150 | Tempo, aerobic capacity |
| 4 | Threshold | 80–90% | 150–168 | Lactate threshold intervals |
| 5 | Maximum | 90–100% | 168–187 | VO₂ max, neuromuscular power |
Maximum Heart Rate Formulas
- Tanaka (2001) — our default for men: HRmax = 208 − 0.7 × age. Meta-analysis of 18,712 participants.
- Gulati (2010) — our default for women: HRmax = 206 − 0.88 × age. Developed on 5,437 women.
- Gellish (2007): HRmax = 207 − 0.7 × age. Developed on regularly active adults.
- Nes / HUNT (2013): HRmax = 211 − 0.64 × age. Norwegian HUNT Fitness Study on 3,320 healthy adults.
- Fox (1971) — historical reference: HRmax = 220 − age. Simple and widely quoted, but a 1970s approximation with ±10–12 bpm variability that overestimates for active adults.
No formula is universally “correct.” The only way to know your true HRmax is a supervised maximum-effort test.
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