Heart rate zones for running: how to set yours
Percentage of max heart rate, or Karvonen? Both give five zones for running, but a slow resting pulse moves the easy ones up 15 to 25 beats.
Updated
Take a runner with a max of 185 and a resting heart rate of 50.
Out of the box, their watch calls 111 to 130 bpm zone 2. Add the resting number and zone 2 becomes 131 to 145. Same runner, same easy run, and the two setups disagree by 15 to 20 beats on what easy means.
What your watch does out of the box
Garmin, Polar, Coros and Apple Watch all start from the same five bands, each a slice of your max heart rate:
| Zone | Share of max heart rate | What it feels like |
|---|---|---|
| 1 | 50–60% | Very easy, recovery jog |
| 2 | 60–70% | Easy, you can talk in full sentences |
| 3 | 70–80% | Steady, talking gets harder |
| 4 | 80–90% | Hard, around threshold pace |
| 5 | 90–100% | Very hard, short intervals and race finishes |
With a 185 max, the boundaries fall at 93, 111, 130, 148, 167 and 185 bpm. The percentages are a convention. Your actual thresholds land wherever your fitness puts them: well inside zone 4 if you’re trained, already in zone 3 if you’re starting out.
Adding your resting heart rate
Karvonen’s method works from your heart rate reserve, which is max minus resting, and puts each boundary at resting + percentage × reserve, so for the same runner 185 minus 50 gives a reserve of 135 beats and these zones:
- Zone 1: 118–131 bpm
- Zone 2: 131–145 bpm
- Zone 3: 145–158 bpm
- Zone 4: 158–172 bpm
- Zone 5: 172–185 bpm
The easy zones move up 15 to 25 beats. A percentage of reserve tracks oxygen use more closely than a percentage of max, and it’s what the American College of Sports Medicine uses for its intensity guidelines. Know your resting heart rate? Use Karvonen.
If you’d rather leave your watch on percentage of max, that works too. Just run your easy days near the top of zone 2, 130 on that 185 example, not down at 111.
Both methods trust your max
Both setups start from max heart rate, and that’s where the error is. Age formulas, Tanaka (208 − 0.7 × age) included, miss by more than 10 beats for about one adult in three.
Get it 10 beats wrong and every boundary shifts with it, and the zones still look precise on the screen.
A max you’ve actually seen on a chest strap, at the end of an all-out race or a hill workout, beats any formula. The max heart rate guide walks through the test.
Resting heart rate is easier. Take it lying down before coffee on three mornings, and keep the usual low value rather than the average.
How much time to spend in each
Seiler and Kjerland followed Norwegian junior cross-country skiers training 10 to 12 hours a week, and about 75% of their sessions stayed below the first threshold, with 5 to 10% between the two thresholds and 15 to 20% above the second. You’re probably not training 12 hours a week. Copy the ratio, not the hours.
If more than half your runs end up in zone 3, your easy days are too hard.
Why it creeps up on long runs
Hold a steady pace on a long run and your heart rate climbs anyway. Your heart pumps a little less blood per beat as the run goes on, so it beats faster to keep up. Heat makes it worse. Wingo had seven active men run at 60% of VO2max in 95 °F, and their heart rate rose 19% between minute 15 and minute 45. Lafrenz had trained cyclists ride at about 59% of VO2max in the heat and in mild air, over the same stretch: +11% at 95 °F, +2% at 72 °F. Dehydration adds to it.
So on easy days, treat the top of zone 2 as a cap. With that Karvonen setup, stay under 145 and let the pace slow down as needed. Short intervals are the exception: heart rate lags the effort by a minute or two, so you run those by pace.
Setting it up in Garmin Connect or Polar Flow
- Use a max you’ve measured, or the estimate from the max heart rate calculator until you have one.
- Enter it with your resting heart rate in the heart rate zone calculator and compare the two methods.
- In the app, pick the same method you used (% of max or % of reserve) before typing the boundaries in. Mix them up and none of the numbers match.
- After a month, compare your easy runs’ average heart rate against the top of zone 2. If runs that felt easy sat above it, your max is set too low.
Sources
- Karvonen method: Karvonen, Kentala and Mustala, Ann Med Exp Biol Fenn 1957;35(3):307–315.
- Heart rate reserve and oxygen uptake reserve: Swain and Leutholtz, Med Sci Sports Exerc 1997;29(3):410–414.
- ACSM intensity guidelines: Garber et al., Med Sci Sports Exerc 2011;43(7):1334–1359.
- Tanaka formula: Tanaka, Monahan and Seals, J Am Coll Cardiol 2001;37(1):153–156.
- Error of age formulas: Nes et al., Scand J Med Sci Sports 2013;23(6):697–704.
- Cardiovascular drift: Coyle and González-Alonso, Exerc Sport Sci Rev 2001;29(2):88–92.
- Drift while running in the heat: Wingo, Stone and Ng, Med Sci Sports Exerc 2020;52(9):1924–1932.
- Drift at 35 °C against 22 °C: Lafrenz et al., Med Sci Sports Exerc 2008;40(6):1065–1071.
- Training split of Norwegian skiers: Seiler and Kjerland, Scand J Med Sci Sports 2006;16(1):49–56.