Heart rate training zones
Updated on June 30, 2026 · by Rafael Rossi
Training zones divide effort into heart-rate bands, each producing a different adaptation. The model is useful — but the two things that matter most about it are rarely said: how to calculate the zone correctly and how far the formula can be off for you.
The starting point: maximum heart rate
Everything rests on max HR, and that is where the trouble begins. Two formulas are in common use:
- 220 − age — the famous one, created in the 1970s from aggregated data, never validated for individual use.
- 208 − 0.7 × age (Tanaka) — derived from a meta-analysis and considered more accurate, especially above 40.
| Age | 220 − age | Tanaka | Difference |
|---|---|---|---|
| 20 | 200 | 194 | −6 |
| 40 | 180 | 180 | 0 |
| 60 | 160 | 166 | +6 |
| 70 | 150 | 159 | +9 |
The two agree exactly at age 40 and diverge in both directions from there. But the decisive fact is a different one: both carry a standard deviation of 10 to 12 bpm between individuals. Two 40-year-olds can have true max heart rates of 165 and 195 — and the formula tells both of them 180.
The practical consequence: a "zone 2" calculated from a formula may, in your physiology, be zone 1 or zone 3. Treat the number as a starting point and adjust by perceived effort.
The five zones
| Zone | % of max HR | How it feels | What it builds |
|---|---|---|---|
| 1 | 50–60% | very easy, conversation effortless | warm-up and active recovery |
| 2 | 60–70% | easy, full sentences possible | aerobic base, fat as fuel |
| 3 | 70–80% | moderate, short sentences | aerobic endurance |
| 4 | 80–90% | hard, single words | lactate threshold, race pace |
| 5 | 90–100% | maximal, no speech | power, short intervals |
Karvonen: the calculation most apps skip
Taking a zone as a plain percentage of max HR ignores that your heart never drops to zero. The Karvonen method uses heart rate reserve:
target HR = (max HR − resting HR) × % + resting HR
For someone with a max of 180 and a resting rate of 60, the difference is large:
| Intensity | Plain % of max | Karvonen |
|---|---|---|
| 60% | 108 bpm | 132 bpm |
| 70% | 126 bpm | 144 bpm |
| 80% | 144 bpm | 156 bpm |
That is up to 24 bpm of difference for the same nominal intensity. Karvonen tends to track perceived effort better, and it matters most for people with a very low resting heart rate — precisely the best-trained, who would be most misled by the plain calculation.
The 80/20 rule and the zone 3 trap
The most consistent finding in endurance training literature is counter-intuitive: around 80% of volume should be easy, in zones 1 and 2, with only 20% at high intensity. This is polarised training, and it is how elite athletes across several sports actually train.
The temptation for self-coached athletes is to spend most of their time in zone 3 — the "moderately hard" pace that feels productive. It is precisely the worst choice: too hard to recover well, too easy to drive high-intensity adaptations. It accumulates fatigue without delivering the benefit of either end.
Frequently asked questions
How do I find my real max heart rate? Only by testing, never by formula. The gold standard is a supervised graded exercise test. Maximal field tests exist but require a training base and are not appropriate for beginners or anyone with cardiovascular risk factors.
How do I measure resting heart rate? Lying down, immediately on waking, before getting up. Measure across three to five mornings and average — a single morning varies considerably with sleep and the previous day's caffeine.
Can I use perceived effort instead of a monitor? You can, and for most people it works very well. The talk test translates the zones directly: full sentences is zone 2; short sentences, zone 3; single words, zone 4.
Why does my heart rate rise at the same pace on different days? Heat, dehydration, poor sleep, caffeine, altitude and stress all raise heart rate for the same effort — a phenomenon called cardiac drift. It is why training strictly by heart rate on a hot day can have you running slower than you should.
Sources: Tanaka H, Monahan KD, Seals DR — Age-predicted maximal heart rate revisited (Journal of the American College of Cardiology, 2001); Karvonen MJ et al. (1957). Informational content — seek medical guidance before beginning intense training.