Heart Rate Zones: How to Calculate Them and What Each One Is For
Heart rate zones help you train at the right intensity for each session: easy when your plan calls for an easy run, hard when it calls for intervals. Without them it is easy to fall into the most common mistake, which is running every day at a middling pace that neither lets you recover nor makes you fitter. This guide explains what they are, the ways to calculate them, what you train in each one and how to split your training between them.
What heart rate zones are
They are heart rate ranges that correspond to different levels of effort. They are calculated from your maximum heart rate and, in some methods, from your resting heart rate too. The most common model has five zones, from very easy to maximal.
To calculate them you need to know your maximum heart rate. The most reliable way is to measure it with a test; otherwise you can estimate it with the Tanaka formula (208 − 0.7 × age). I explain it in the guide to max heart rate.
How to calculate your heart rate zones
Method 1: percentage of maximum heart rate
This is the simplest: you multiply your maximum heart rate by each zone’s percentage. With a maximum of 185 beats per minute, zone 2 (60-70%) would run from 111 to 130.
Method 2: heart rate reserve (Karvonen)
This also takes your resting heart rate into account, so it fits your fitness better. It is based on the 1957 work by Karvonen and colleagues:
Target HR = (max HR − resting HR) × percentage + resting HR
With a maximum of 185 and a resting heart rate of 55, the reserve is 130. At 70% you get 130 × 0.7 + 55 = 146 beats per minute. There is more on measuring your resting pulse in the guide to resting heart rate.
If you would rather skip the maths, the heart rate zone calculator does it for you with both methods.
The 5 heart rate zones and what each one is for
| Zone | % of max HR | How it feels | What it is for |
|---|---|---|---|
| Zone 1 | 50-60% | Very easy | Recovery and warm-up |
| Zone 2 | 60-70% | Easy, you can talk | Aerobic base, easy runs and long runs |
| Zone 3 | 70-80% | Moderate, short sentences | Marathon pace for many runners |
| Zone 4 | 80-90% | Hard, a few words | Threshold, 10K and half marathon pace |
| Zone 5 | 90-100% | Maximal | Short intervals and VO2 max |
The percentages vary a little depending on the source and method, so treat them as a guide. What matters is that zone 2 stays easy and hard sessions are demanding.
How to split your training between heart rate zones
The review by Stephen Seiler of elite endurance athletes found a recurring pattern: about 80% of sessions are done at low intensity and the remaining 20% include hard work, such as intervals close to VO2 max. Seiler found no convincing evidence that adding more intensity gives better long-term results in athletes who are already well trained.
For a recreational runner, that means most of your runs should be in zone 2, with one or two quality sessions a week in zones 4 and 5. There is more in the guides to training in zone 2 and threshold training.
Common mistakes with heart rate zones
- Using the 220 − age formula without checking it. It can be quite far from your real maximum.
- Trusting a wrist monitor in short intervals. Heart rate takes time to rise, and for efforts of a few minutes pace or feel is a better guide.
- Forgetting cardiac drift: on long runs or in the heat your heart rate rises even if you hold the same pace. I explain it in the guide to lowering your heart rate when running.
- Not recalculating your zones. As your fitness improves, your resting heart rate drops and your zones change.
Conclusion
Heart rate zones help you run easy when you should and hard when you should. Calculate them from your maximum heart rate or, better, with the Karvonen method, which adds your resting heart rate. Do most of your sessions in zone 2 and keep one or two a week for zones 4 and 5, following the roughly 80/20 split seen in endurance athletes.
FAQ
How do I calculate my heart rate zones?
You need your maximum heart rate. You can multiply it by each zone’s percentage or use the Karvonen method, which also takes your resting heart rate into account.
Which of the heart rate zones burns the most fat?
In zone 2, fat provides a larger share of your energy, but for weight loss total energy use and diet matter more.
How much time should you train in each zone?
One reference point is to do about 80% of sessions at low intensity, in zones 1 and 2, and 20% with hard work.
Is a wrist heart rate monitor accurate?
On easy runs it usually works well. In short intervals or with a lot of arm movement, a chest strap is more accurate.
Why does my heart rate rise even though I am running at the same pace?
Because of cardiac drift: with fatigue, heat and dehydration, your heart beats faster to sustain the same effort.
