Why the Zone 2 methods disagree
Each method anchors Zone 2 to a different number. The %HRmax rule takes 60 to 70% of your maximum heart rate and ignores your resting heart rate. Karvonen takes 60 to 70% of your heart-rate reserve (max minus resting) and adds resting HR back, which always lands higher: at age 40 with a resting HR of 60, it sits 24 bpm above %HRmax at the bottom of the zone and 18 bpm above it at the top.
Both depend on HRmax, and an age formula like Tanaka (208 minus 0.7 times age) misses an individual by 10 bpm or more. MAF 180 skips HRmax entirely and uses 180 minus age, adjusted for health and training history. Friel's method anchors to your lactate-threshold heart rate (LTHR) from a 30-minute test, so it moves with your fitness instead of your birthday.
None of these is wrong. They are different estimates of the same physiological line, your first lactate threshold (LT1), measured with different amounts of information about you.
Which method to trust
Rank them by how much of your own physiology goes in. A lab LT1 or VT1 from a lactate or gas-exchange test is the real boundary: Seiler's three-zone model puts it at the top of Zone 1, and Friel puts it at the top of Zone 2. Next comes LTHR from a field test, then Karvonen (it knows your resting HR), then %HRmax with a measured max, then anything built on age alone, including %HRmax with an estimated max and MAF.
The calculator marks the most reliable method your inputs unlock. Add a resting HR, an LTHR or a lab LT1 and it moves up that ladder.
What the consensus band means
The highlighted band is the heart-rate range that the most methods contain at the same time. If every method overlaps, it is simply their shared overlap. If they split into separate clusters, it is the range covered by the biggest cluster; ties go to the wider range, then to the lower one. At least two methods must agree, otherwise the calculator says there is no consensus instead of inventing one.
Every method counts equally in that band, which is why it sits next to the trust ranking rather than replacing it. With a lab LT1, stay at or below it, even if the band reaches higher.
How Zone 2 should feel
Zone 2 is conversational. You can speak in full sentences without gasping between them. If you can only manage a few words at a time, you are above it. That talk test is a useful cross-check on any number: when heat, poor sleep or a long session push your heart rate up, the feel tells you more than yesterday's zone chart.
Heart rate also drifts upward over a long steady session. Starting at the bottom of the band leaves room for that drift.
How much of your training belongs in Zone 2
Seiler's review of elite endurance athletes found roughly 80% of training sessions below the first threshold and about 20% at or above it. For most amateurs that means the large majority of weekly time easy, with one or two hard sessions, not every run in the middle.
Zone 2 in watts is Coggan's Endurance zone, 56 to 75% of FTP. For runners the matching pace is Daniels' Easy pace, 59 to 74% of VDOT. Enter an FTP or a recent race below the heart-rate inputs to see both.
How it works
- 1Enter your age. Age gives an estimated max heart rate (Tanaka) and your MAF 180 ceiling. Add a measured max heart rate if you have one.
- 2Add resting heart rate. Measured lying down on waking, it unlocks the Karvonen heart-rate-reserve method.
- 3Add test results if you have them. An LTHR from a 30-minute time trial unlocks Friel's Zone 2; a heart rate at LT1 or VT1 from a lab test sets the ceiling.
- 4Read the overlap. Each method gets its own bar on one heart-rate axis. The highlighted band is where the most methods agree; the badge marks the most reliable one.
- 5Check it by feel. On your next easy session, hold the band and confirm you can still talk in full sentences.
Frequently asked questions
What is my Zone 2 heart rate by age?
By the 60-70% of max heart rate rule with Tanaka's estimate, Zone 2 is 112 to 131 bpm at age 30, 108 to 126 bpm at 40 and 104 to 121 bpm at 50. Age-only numbers can be off by 10 bpm or more, so add a resting heart rate or a test result to narrow it down.
Why does my watch show a different Zone 2?
Most watches default to 60-70% of an age-predicted max heart rate, while others use heart-rate reserve or LTHR. Those methods can put Zone 2 20 bpm or more apart for the same person. Check which method your watch uses and compare it with the matching row here.
Is MAF 180 the same as Zone 2?
Close, not identical. MAF sets a ceiling of 180 minus your age, adjusted for health and training history, and trains in the 10 bpm below it. For many people that lands inside Zone 2 by heart-rate reserve and above Zone 2 by %HRmax.
Is Zone 2 the same as LT1?
Zone 2 sits just below LT1, the first rise in blood lactate. Friel places LT1 at the top of Zone 2, and Seiler's three-zone model uses it as the ceiling of Zone 1. If you have a lab-measured LT1, keep Zone 2 at or below it.
What is Zone 2 in watts and running pace?
In watts it is Coggan's Endurance zone, 56 to 75% of FTP: 139 to 188 W for an FTP of 250 W. For runners it is Daniels' Easy pace; a 20:00 5 km gives about 4:54 to 5:53 per km.
Sources
- Tanaka, Monahan & Seals (2001) Age-predicted maximal heart rate revisited. J Am Coll Cardiol 37(1):153-156.
- Karvonen, Kentala & Mustala (1957) The effects of training on heart rate; a longitudinal study. Ann Med Exp Biol Fenn 35(3):307-315.
- Joe Friel A quick guide to setting zones (LTHR zones, LT1 at the top of Zone 2).
- Philip Maffetone The MAF 180 Formula.
- Seiler (2010) What is best practice for training intensity and duration distribution in endurance athletes? Int J Sports Physiol Perform 5(3):276-291.
- Andrew Coggan Power training levels (Zone 2 Endurance, 56-75% of FTP).
- Jack Daniels Daniels' Running Formula: VDOT and Easy pace (Daniels-Gilbert equations).
Last updated 6 September 2026.