Zone 2 Heart Rate: How to Calculate Yours (5 Methods)

"What should my Zone 2 heart rate be?" is one of the most common questions in endurance training, and it deserves a better answer than the single number most articles give you. The quick version — 60 to 70% of your maximum heart rate — is a fine starting point, but it hides a genuinely important detail: there are at least five different ways to calculate your Zone 2 heart rate, and for the same person they can disagree by 20 to 30 beats per minute. Pick the wrong one and you can spend months training in the wrong place.

This guide walks through every method that matters — the percentage-of-max shortcut, the more personalised Karvonen (heart rate reserve) formula, Phil Maffetone's MAF 180, threshold-anchored zones, and lab testing — with worked examples for each. Then it shows you exactly how far apart they land, which one to trust, and the free field test that beats all of them. By the end you will have a Zone 2 heart rate range you can actually train to today.

What a "Zone 2 heart rate" actually is

Zone 2 is the second of the five heart rate training zones, sitting between easy recovery (Zone 1) and tempo effort (Zone 3). Your Zone 2 heart rate is the band of beats per minute that keeps you in sustained, comfortable aerobic exercise — the pace at which your body burns predominantly fat for fuel and produces very little lactate. In the standard five-zone model it is conventionally defined as 60 to 70% of your maximum heart rate.

Physiologically, the top of true Zone 2 is your aerobic threshold (sometimes called the first lactate threshold, LT1, or the first ventilatory threshold, VT1) — the effort above which lactate begins to accumulate faster than your body can clear it. Everything below that line is territory you can sustain for a very long time. The whole point of calculating your Zone 2 heart rate is to find, as closely as possible, where that line sits for you. If you just want to know what Zone 2 is and how to train it, start with our Zone 2 beginner's guide — this article is specifically about pinning down the number.

Method 1 — Percentage of your maximum heart rate (the default)

This is the method almost everyone starts with, and it is what your Apple Watch uses out of the box. It has two steps.

Step 1 — estimate your maximum heart rate. The classic formula is HR max = 220 − your age.

Step 2 — take 60 to 70% of that number. That band is your Zone 2 heart rate.

Worked example for a 40-year-old:

• HR max ≈ 220 − 40 = 180 bpm
• Lower bound: 180 × 0.60 = 108 bpm
• Upper bound: 180 × 0.70 = 126 bpm

So this person's estimated Zone 2 is roughly 108–126 bpm. Fast, free, and no equipment required — which is exactly why it is the default.

The weakness is accuracy. The 220-minus-age formula carries a standard deviation of about ±10–12 bpm, so a 40-year-old's true max could plausibly sit anywhere from 168 to 192 bpm. Because every zone is a slice of that max, the error propagates straight into your Zone 2 numbers. Research-grade alternatives like the Tanaka formula (208 − 0.7 × age) track real data a little better, especially past 50. If you want to get your max right rather than estimate it, our max heart rate guide covers field testing, and our heart rate zones by age chart lists the percentage-based Zone 2 band for every decade.

Method 2 — The Karvonen (heart rate reserve) method

The percentage-of-max method has a blind spot: it ignores your resting heart rate, which is one of the clearest signals of your individual fitness. Two 40-year-olds with the same 180 bpm max but resting heart rates of 45 and 70 are physiologically very different people, yet Method 1 hands them identical zones. The Karvonen formula fixes this by working from your heart rate reserve — the gap between your resting and maximum heart rate.

The formula is:

Target HR = ((HR max − resting HR) × intensity) + resting HR

For Zone 2, you run it at 60% and 70% intensity. Worked example for a 40-year-old with a resting heart rate of 60 bpm:

• Heart rate reserve = 180 − 60 = 120 bpm
• Lower bound: (120 × 0.60) + 60 = 132 bpm
• Upper bound: (120 × 0.70) + 60 = 144 bpm

Notice how different that is: 132–144 bpm versus the 108–126 bpm the percentage method gave the same person. The Karvonen method almost always lands higher, because it folds your resting heart rate back into every calculation. Many coaches consider it a more realistic estimate of easy-aerobic effort for people with an average or low resting heart rate — and it partly explains why so many trained people find the percentage-of-max Zone 2 feels absurdly, uselessly slow.

To use Karvonen well you need an accurate resting heart rate. Measure it first thing in the morning, before you get out of bed, ideally averaged across several days. An Apple Watch records your resting heart rate automatically in Apple Health, which is the easiest reliable source.

Method 3 — The MAF 180 formula

Endurance coach Dr. Phil Maffetone built the MAF 180 formula specifically to keep aerobic training genuinely aerobic. Instead of working from your maximum, it gives you a single aerobic ceiling — a heart rate to stay at or below during base training.

Start with 180 − your age, then adjust for your health and training history:

• Subtract 10 if you are recovering from a major illness or surgery, or take regular medication.
• Subtract 5 if you are injured, have regressed in training, get more than two colds or flus a year, have asthma or allergies, or are just getting back into exercise.
• Keep 180 − age if you have trained consistently for up to two years without any of the above.
• Add 5 if you have trained consistently for more than two years, making progress and staying injury-free.

Worked example for a healthy 40-year-old who trains consistently: 180 − 40 = 140 bpm aerobic ceiling. Maffetone treats this as the top of the range, with the working band sitting in roughly the 10 beats below it — about 130–140 bpm here. The MAF number is deliberately cautious about intensity, but because it is anchored to 180 rather than your max, in bpm terms it usually lands well above the percentage-of-max Zone 2 and close to the Karvonen estimate. It is an excellent option if your problem is the very common one of training your easy days too hard.

Method 4 — Anchor to your lactate (aerobic) threshold

The three methods above are all shortcuts for the thing that actually defines Zone 2: your aerobic threshold. A more direct approach skips the max-heart-rate guessing entirely and anchors your zones to a threshold you measure.

The practical version is the 30-minute threshold field test, popularised by coach Joe Friel. After a thorough warm-up, run or ride as steadily hard as you can sustain for 30 minutes, solo. Your average heart rate over the final 20 minutes is a good estimate of your lactate threshold heart rate (LTHR) — the top end of hard-but-sustainable effort. Your easy aerobic Zone 2 work then sits well below that number.

Different coaching systems draw the exact line in slightly different places, so rather than chase a single contested percentage, use this rule of thumb: your true easy-aerobic ceiling typically falls somewhere around 20 to 30 beats below your LTHR, and it should always pass the talk test. Threshold-anchored zones are more individual than any age formula because they are built from your own physiology on the day — the trade-off is that you have to do the (fairly unpleasant) test and repeat it as you get fitter.

Method 5 — Lab testing (the gold standard)

If you want the real number rather than an estimate, a laboratory metabolic test measures it directly. In a graded exercise test, a technician takes blood-lactate samples (or analyses your expired air for the ventilatory thresholds) while ramping your intensity. The heart rate at your first lactate turn-point — around 2 mmol/L, the marker Dr. Iñigo San Millán uses in his well-known work with elite cyclists — is the true top of your Zone 2.

Lab testing removes the guesswork of formulas: it accounts for your genetics, training history, and individual physiology in one measurement. The downsides are cost and access — expect to pay for a session at a sports-science lab or performance clinic — and the fact that the result drifts as your fitness changes, so it is a periodic check rather than a one-time answer. For most people it is overkill, but for a serious athlete it is the most accurate Zone 2 heart rate you can get.

The methods disagree — here is how much

Here is the uncomfortable truth laid out side by side. Every estimate-based method below is calculated for the same person: a 40-year-old with a resting heart rate of 60 bpm.

That is a spread of more than 30 beats per minute between the lowest and highest estimate for one individual — the difference between a brisk walk and a steady jog. So which is right?

The honest answer is that none of the formulas is exact, because your true Zone 2 ceiling is individual and only a threshold or lab test can measure it. But there are sensible defaults. The percentage-of-max method tends to run conservative (low) for people with an average resting heart rate, which is why it so often feels too slow to be doing anything. The Karvonen and MAF methods usually land closer to real easy-aerobic effort for most trained people. If you have no test data, a reasonable approach is to start with Karvonen or MAF, treat the result as a ceiling rather than a target, and then let the talk test make the final call.

The talk test: the free validator that beats every formula

Whatever number you calculate, one field check overrides all of them, costs nothing, and needs no device. In genuine Zone 2 you should be able to speak a full sentence out loud without gasping, but you would not be able to sing comfortably. The instant your speech fragments into short, clipped phrases, you have climbed into Zone 3 and need to ease off.

A close cousin is nose breathing: many people can sustain Zone 2 breathing only through their nose, and the moment you have to gulp air through your mouth you are above the zone. Elite coaches use the talk test to sanity-check athletes who do not trust their numbers, precisely because it reflects your actual physiology on the day — accounting for heat, fatigue, sleep, and stress in a way no formula can. If your calculated Zone 2 and the talk test disagree, trust the talk test and adjust your number.

Which method should you use?

• Total beginner, no data: use percentage-of-max (Method 1) or MAF 180 (Method 3) to get a ballpark today, and lean hard on the talk test.
• You know your resting heart rate: use Karvonen (Method 2) for a more individual estimate — it is the best bang-for-buck upgrade over the basic formula.
• You train your easy days too hard: use MAF 180 as a strict ceiling — its conservative-on-intensity design is built for exactly this problem.
• You are a serious, data-driven athlete: do a 30-minute threshold test (Method 4) or a lab test (Method 5) and anchor your zones to your real physiology.
• Everyone, always: validate with the talk test. It is the tiebreaker.

How to find your Zone 2 heart rate on Apple Watch

Once you have a target range, your Apple Watch makes it easy to train to. It samples your pulse every second during a workout via its optical sensor, so you can watch your live heart rate and keep it inside your Zone 2 band in real time. To set it up well:

1. Confirm your date of birth in the Health app — Apple uses it to estimate your max heart rate, and a wrong year quietly throws every zone off.
2. Let the watch learn your max over time from your hardest efforts, which can beat a flat 220 − age estimate.
3. Optionally set custom zones. watchOS lets you switch from automatic to manual heart rate zones, so you can plug in the Karvonen or MAF numbers you calculated above.
4. Start sessions in the Workout app for continuous, every-second sampling, and glance at the colour-coded zone view to stay in Zone 2.

For the full walkthrough, see our Apple Watch heart rate zones setup guide.

Common mistakes when calculating Zone 2

• Trusting one formula as gospel. Every age-based formula is an estimate with real error bars. Treat your number as a hypothesis and let the talk test confirm it.
• Using a stale resting heart rate. Karvonen is only as good as your resting HR — measure it properly, first thing in the morning, and update it as you get fitter.
• Setting the number and never revisiting it. Max heart rate falls by roughly a beat a year, and your resting HR and threshold shift with fitness. Recalculate every year or two.
• Ignoring medication. Beta-blockers and some other drugs lower your heart rate and blunt your max, making every formula unreliable — if you take them, rely on the talk test and your clinician's guidance.

The training-side mistakes — drifting into the grey zone, refusing to walk to stay in range — are covered in our beginner's guide.

A note on accuracy and health

Every method here is an estimate meant for healthy people planning general exercise — it is not medical advice. Heart rate response varies with heat, hydration, caffeine, sleep, stress, and altitude, so even a perfect number moves around day to day. If you have a heart condition, take medication that affects your heart rate, or are new to vigorous exercise, talk to your doctor before using maximal tests or hard training, and treat professional guidance as the final word over any formula.

Let Underdog do the zone maths for you

Calculating your Zone 2 heart rate once is easy. Remembering to stay in it session after session, and tracking whether you are actually accumulating enough Zone 2 time each week, is the hard part — and it is exactly what Underdog is built for. Underdog reads your heart rate data automatically from Apple Health after every workout, breaks each session down by zone, and turns your time-in-zone into a weekly points score. Because it rewards time rather than pace, a patient 60-minute Zone 2 session finally shows up on the scoreboard instead of feeling like "just easy cardio."

Those weekly points drop you into a league against other people, with promotion and relegation, so the unglamorous Zone 2 grind becomes something you can actually compete at. It works with any workout type and any Apple Watch that syncs to Apple Health. Download Underdog free on the App Store and let your Zone 2 minutes start counting.

FAQ

What is a good Zone 2 heart rate?

There is no single universal number — it depends on your age, resting heart rate, and the method you use. As a rough guide, Zone 2 is 60–70% of your maximum heart rate, which is about 108–126 bpm for a 40-year-old using the basic formula. The Karvonen method, which factors in resting heart rate, often puts the same person's Zone 2 higher, around 132–144 bpm. Use the talk test to confirm: if you can speak full sentences but not sing, you are in the right place.

How do I calculate my Zone 2 heart rate?

The quickest way: estimate your max heart rate as 220 minus your age, then take 60–70% of it. For a more individual number, use the Karvonen formula: ((max HR − resting HR) × 0.60 to 0.70) + resting HR. Both are estimates — validate the result with the talk test and adjust as needed.

Is Zone 2 60% or 70% of max heart rate?

It is the whole band from 60% to 70% of your maximum heart rate. The lower end (around 60%) is easy aerobic effort; the upper end (around 70%) is the top of Zone 2, right before you cross your aerobic threshold into Zone 3. Staying under the 70% ceiling is what keeps the session genuinely aerobic.

Why does my calculated Zone 2 feel too slow?

Usually because you are using the percentage-of-max method, which tends to run conservative for people with an average or low resting heart rate. Try the Karvonen (heart rate reserve) method instead — it accounts for your resting heart rate and typically produces a higher, more realistic Zone 2 range. If it still feels too slow, that is often the training working as intended: true Zone 2 is meant to feel easy.

Does resting heart rate matter for Zone 2?

It does if you use the Karvonen method, which builds your zones from your heart rate reserve (max minus resting). A lower resting heart rate — a common sign of good aerobic fitness — shifts your calculated Zone 2 range upward. The basic percentage-of-max method ignores resting heart rate entirely, which is one reason the two methods disagree.

What is the Karvonen formula for Zone 2?

Target heart rate = ((maximum HR − resting HR) × intensity) + resting HR, run at 60% and 70% intensity for the two ends of Zone 2. Example for a 40-year-old with a max of 180 and resting HR of 60: lower bound (120 × 0.60) + 60 = 132 bpm; upper bound (120 × 0.70) + 60 = 144 bpm.

How accurate is the 220-minus-age formula?

It is a reasonable starting estimate but not precise — its standard deviation is around ±10–12 bpm, so your true max could be more than 10 beats different. Since Zone 2 is derived from your max, that error carries through. For an accurate number, do a field or lab test, or let your Apple Watch refine your max from your workout history.