What heart rate zones are for
Training "by heart rate" means using your pulse to judge how hard you are working. Easy, long sessions build endurance and are where most recreational athletes should spend most of their time. Hard intervals improve speed and the ability to sustain high effort. Zones are simply ranges of heart rate that match these purposes, based on a percentage of your maximum heart rate.
Estimating your maximum heart rate
Classic: max HR = 220 − age
Tanaka (2001): max HR = 208 − 0.7 × age
The classic formula is easy to remember. A large analysis by Tanaka and colleagues found that 208 − 0.7 × age fits measured maximum heart rates better, especially in people over 40. Both are averages: individuals often differ by 10 beats per minute or more from either formula. If you know your real maximum from a supervised test or a recent all-out effort, enter it instead.
Two ways to calculate zones
Percentage of maximum heart rate
Target = max HR × intensity %
Karvonen (heart rate reserve)
Heart rate reserve = max HR − resting HR
Target = resting HR + reserve × intensity %
The Karvonen method uses your resting pulse, so it reflects your fitness: a fit person with a low resting heart rate gets higher targets for the same percentage. If you enter a resting heart rate, the calculator uses this method.
The five zones
| Zone | Intensity | How it feels | Main purpose |
|---|---|---|---|
| 1 · Recovery | 50–60% | Very easy, can chat freely | Warm-up, cool-down, recovery days |
| 2 · Endurance | 60–70% | Easy, can hold a conversation | Aerobic base, fat use, long sessions |
| 3 · Tempo | 70–80% | Moderate to hard, short sentences | Aerobic fitness |
| 4 · Threshold | 80–90% | Hard, a few words only | Sustaining faster paces |
| 5 · Maximum | 90–100% | All-out, cannot talk | Short intervals, top speed |
The American Heart Association describes moderate exercise as about 50–70% of maximum heart rate and vigorous exercise as about 70–85%. Adults are advised to do at least 150 minutes of moderate or 75 minutes of vigorous activity per week.
Worked example
A 30-year-old with a resting heart rate of 60 bpm, using 220 − age:
- Max HR = 220 − 30 = 190 bpm (Tanaka gives 208 − 21 = 187 bpm).
- Heart rate reserve = 190 − 60 = 130 beats.
- Moderate (50–70%): 60 + 130 × 0.5 = 125 to 60 + 130 × 0.7 = 151 bpm.
- Vigorous (70–85%): 151 to 60 + 130 × 0.85 = 171 bpm.
Without a resting heart rate, the simple percentages give 95–133 bpm for 50–70%. The difference shows why the Karvonen method is more useful for fitter people.
Practical tips
- Measure resting heart rate on several mornings, before getting up, and use the average.
- Wrist sensors can lag or jump during intervals. A chest strap is more accurate for hard sessions.
- Heat, dehydration, caffeine, stress and poor sleep all raise heart rate at the same effort. On such days, go by feel as well.
- The talk test is a good cross-check: if you can talk in full sentences, you are in the easy zones.
Safety
Some medicines, especially beta blockers, lower heart rate, so formula-based zones do not apply. If you have a heart condition, high blood pressure or are starting exercise after a long break, ask your doctor which intensity is safe. Stop exercising and seek help if you have chest pain, severe breathlessness, dizziness or an irregular heartbeat.
Frequently asked questions
What is my maximum heart rate?
A common estimate is 220 minus your age, or 208 − 0.7 × age (Tanaka). For a 30-year-old that is about 187–190 bpm, but individuals can differ by 10 bpm or more.
What heart rate burns the most fat?
Easy zone 2 (about 60–70%) uses the highest share of fat for fuel, but harder sessions burn more total calories. Overall energy balance matters most for weight loss.
What is a good resting heart rate?
For most adults 60–100 bpm is considered normal; fit people often have 50–60 or lower. A resting rate that is unusually high or low with symptoms should be checked by a doctor.
Should I use 220 − age or Tanaka?
Tanaka is slightly more accurate on average, especially after 40, but both are estimates. A field test or a real measured maximum is better.
What is the Karvonen formula?
Target = resting HR + (max HR − resting HR) × intensity. It uses your resting pulse, so the zones reflect your fitness level.
Sources
- Tanaka H, Monahan KD, Seals DR. Age-predicted maximal heart rate revisited. Journal of the American College of Cardiology, 2001; 37: 153–156.
- Karvonen MJ, Kentala E, Mustala O. The effects of training on heart rate; a longitudinal study. Annales Medicinae Experimentalis et Biologiae Fenniae, 1957; 35: 307–315.
- American Heart Association. Target heart rates chart and recommendations for physical activity in adults.
Last reviewed 5 October 2026. Results are estimates; see our disclaimer.