Heart-rate zones for runners: how to set them, and how to use them.

By Raji Shah · Updated 2026-10-24

Heart-rate zones are useful when they keep easy days easy and hard days purposeful. They only work if the numbers behind them fit you, and most watches start from an age formula that can miss your real maximum by 10 beats or more. This guide covers how to set zones that fit, what each zone is for, and when to follow pace or effort instead.

What heart-rate zones are

A heart-rate zone is a band of beats per minute tied to an intensity. Most watches use five zones, built from one or two personal numbers: your maximum heart rate, your resting heart rate, or your heart rate at lactate threshold. If those numbers are off, every zone is off with them.

Garmin and Polar both default to the same setup: five bands, each 10% of max heart rate wide, starting at 50%. The table shows those bands for an example runner with a max of 190 bpm, with Garmin's own description of how each one feels.

Three ways to set your zones

Every zone system is anchored to one of three numbers. Which one you use changes the beats per minute in each zone, sometimes by 20 or more.

Percentage of max heart rate

This is the simplest method, and the default on Garmin, Polar, Suunto and Apple Watch. Each zone is a fixed share of your max, so you need only one number. That is also the weakness: if the max is wrong, every zone moves with it, and your resting heart rate plays no part.

Heart-rate reserve

Heart-rate reserve is the gap between your max and your resting heart rate. Each zone starts at your resting heart rate plus a share of that gap: resting heart rate + (max − resting) × the percentage. With a max of 190 and a resting heart rate of 50, the reserve is 140 beats, so 60 to 70% of reserve is 134 to 148 bpm, against 114 to 133 bpm for 60 to 70% of max. The method is often called the Karvonen formula. In lab studies, a percentage of heart-rate reserve lined up almost exactly with the same percentage of the body's oxygen-use reserve, while percentages of max heart rate ran well ahead of the matching share of maximal oxygen use: 63% of max heart rate corresponded to only about 40% of VO2 max. WHOOP and Fitbit use it by default, and Garmin, COROS and Suunto offer it as an option. You need an accurate resting heart rate, ideally the overnight figure a watch or band records.

Lactate-threshold heart rate

Your lactate threshold is the intensity at which lactate starts building up in your blood faster than your body clears it; above it, fatigue builds quickly. Zones anchored to it follow your own physiology instead of a percentage that may sit in a different place for you. COROS uses it by default, with six zones running from recovery, below 80% of threshold heart rate, to the hardest efforts, above 106%. Garmin and Suunto offer it as an option. Newer Garmin watches estimate it automatically during outdoor GPS runs, from wrist or chest-strap heart rate, once they have a VO2 max estimate for you; older models need a guided test with a chest strap. When you base Garmin zones on it, your threshold becomes the boundary between Zone 4 and Zone 5. COROS's Running Fitness Test, a guided 25-to-40-minute run, measures threshold pace, threshold heart rate and max heart rate in one go.

Watch estimates are convenient but rough. In a 2025 study of recreational runners, threshold estimates from Huawei, Garmin and COROS watches were close on average, but for individual runners they missed the lab-measured threshold heart rate by about 9 to 11 bpm. Without a watch estimate, a hard, evenly paced 30-minute solo run is a common field test: in a study of 27 competitive runners and triathletes, heart rate in a 30-minute time trial matched heart rate at a standard lab lactate threshold on average, with a typical individual error of about 8 bpm. If you try it, treat the heart rate you hold through the run as a rough estimate, not a lab result. Treat the run itself like a race, with a proper warm-up, and skip it if you are unsure about hard exercise.

How to find your real max heart rate

Max-HR and heart-rate-reserve zones both need a max heart rate, and the usual starting point is a formula. The oldest is 220 minus your age. Two newer ones come from much larger datasets: 208 minus 0.7 times your age, from a pooled analysis of 351 studies and 18,712 people, and 211 minus 0.64 times your age, from a study of 3,320 healthy adults. For a 40-year-old, they give 180, 180 and 185 bpm.

The trouble is the individual error, not the average. In the 3,320-person study, the typical miss was about 11 bpm, which means roughly a third of people sit more than 11 bpm above or below the formula. A comparison of nine formulas against 99 treadmill tests found wide errors for every one of them. Garmin itself says your true max is likely within 12 bpm of 220 minus age. If your real max is 195 and your watch assumes 180, every zone starts too low, and easy runs show up as Zone 3 or 4.

A better number comes from your own data. The highest heart rate from a 5K or 10K race, or from a very hard sustained effort, is a better estimate, and Garmin says that is where a max tends to show up. In one study of 20 college distance runners, the peak heart rate in a hard interval session (207 bpm on average) and in competition (206) was higher than in a lab treadmill test (194). Record the effort with a chest strap if you can, because wrist sensors can produce false highs. A dedicated all-out test is very demanding, so check with a health professional first if you are unsure about hard exercise.

Garmin and WHOOP both raise your stored max automatically when they detect a higher reading; Garmin first checks that the reading looks reliable. That helps if your max was set too low, but it can also lock in a false spike. If your zones suddenly shift after one run, check whether the new max came from a real effort or a sensor glitch, and correct it by hand.

Why the same percentage isn't the same effort for everyone

Even with a correct max, a fixed percentage doesn't put everyone at the same intensity. You have two thresholds. The first, where blood lactate first rises and breathing deepens, marks the top of easy running. The second, close to the lactate threshold your watch estimates, is where fatigue starts building quickly. Both sit at different percentages of max for different people. In a lab study of 100 adults, the first threshold fell anywhere from 60% to 90% of max heart rate. In a group of trained male runners, the first threshold sat at about 77 to 81% of max heart rate on average and the second at about 91 to 93%, and individuals spread well beyond those averages.

So a percentage zone can be an easy jog for one runner and a threshold effort for another. A review of exercise-intensity methods concluded that fixed percentages of max heart rate or VO2 max have "little merit" for targeting a specific intensity. In trials with previously inactive adults, zones built from each person's thresholds improved fitness more, and in more of the participants, than standard percentage zones, although the threshold groups often trained harder too. None of these trials involved trained runners.

You don't need a lab to act on this. If your watch estimates your threshold, try zones based on it, but check them against the talk test either way, since watch estimates can miss by about 10 bpm: in one study, people could still read aloud comfortably at about 82% of max heart rate on average, but individuals varied by several percentage points either way. Our guide to running by feel covers the talk test and perceived effort in more detail.

Zone 2 running, and why it can feel too slow

"Zone 2" means different things in different places. On Garmin's default settings, it is 60 to 70% of max heart rate, which Garmin describes as a comfortable pace where conversation is possible. On heart-rate reserve systems such as WHOOP, the same label covers higher heart rates. In sports science, Zone 2 usually means training just below your first threshold: a 2025 panel of 14 sport scientists and coaches described it as exercise "immediately below the first lactate or ventilatory threshold". In trained male runners, that first threshold sits at about 77 to 81% of max heart rate on average, so the research version of Zone 2 falls mostly inside Garmin's default Zone 3.

That gap is one reason a 70% cap can feel painfully slow, especially if your max comes from an age formula and is set too low. You don't have to stay inside a watch's Zone 2 to run easy: a conversational effort is easy running whatever zone your watch shows. Newer runners have a different problem: on average, runners need roughly the same oxygen to hold a given pace whatever their fitness, so for someone with a lower aerobic ceiling, even a slow jog uses a large share of it and pushes heart rate up. Walk breaks are a legitimate way to keep easy runs easy while fitness builds.

Zone 2 isn't magic, either. A 2025 review concluded that the evidence doesn't support it as the best intensity for building the muscles' aerobic machinery or fat-burning capacity in the general population, and that prioritizing harder work is key to getting the most heart and metabolic benefit, especially when training time is limited. The scientists' panel likewise noted that its benefits "might not be unique to zone 2". Easy running earns its place because it lets you run more without wrecking your hard days, not because one heart-rate band unlocks special adaptations.

How much time to spend in each zone

Most of your running should be easy, and the research on how athletes train is consistent on that point. Competitive endurance athletes who train 10 to 13 times a week typically keep about 80% of sessions easy and build about 20% around hard work. Measured in minutes, the hard share is smaller still: in one six-month study of eight subelite runners, about 71% of training time was below the first threshold, 21% between thresholds and 8% above, and the runners who spent more time easy ran a faster 10 km cross-country race.

Recreational runners tend to follow a similar pattern. In a 12-week study of 48 recreational marathon and half-marathon runners, about 69% of training time was easy, 17% moderate and 14% hard. Trials comparing training plans for recreational runners have not found one clear winner, but a review of how distance runners train concluded that at least 70% of training should be low intensity.

In practice, that means one or two quality sessions a week, a long run at easy effort, and easy running in between. Our Zone 5 guide covers what to do in the hard sessions. Your watch's time-in-zone chart will make hard days look smaller than they were: warm-ups, recoveries between reps and heart-rate lag all land in lower zones. In one study of elite skiers, counting minutes in zone recorded about a third as much high-intensity work as counting sessions by their goal. Judge a week by its sessions first and its zone chart second.

How Garmin, Apple Watch, COROS, Polar and others set zones

Each platform has its own defaults, so the same run can land in different zones on two devices. This is how each one sets zones out of the box, according to its own documentation.

The differences matter when you compare devices: for the example runner above, WHOOP's Zone 2 sits 15 to 20 bpm higher than Garmin's default. If you wear two devices, enter the same max and resting heart rate in both and use the same method. Our guide to wearing WHOOP and a Garmin together covers that setup.

To change zones on the most common platforms:

• Garmin: on the watch, go to Watch Settings, User Profile, Heart Rate & Power Zones, then Heart Rate.
• Apple Watch: on the watch, go to Settings, Workout, Heart Rate Zones, then Manual. On iPhone, the same option is in the Watch app under Workout.
• COROS: in the COROS app, go to Profile, Settings, Heart Rate Zone, then Zone Types.
• Polar: in Polar Flow, open Sport profiles, edit a profile and switch its heart-rate zones from Default to Custom.

Why your heart rate reads higher or lower than usual

Zones assume a heart rate means the same thing every day, and it doesn't. At the same pace, heart rate can sit above or below normal for reasons that have nothing to do with your fitness:

• Drift and heat: on a steady run, heart rate starts creeping up after 10 to 20 minutes as the heart pumps less blood per beat, and more so in heat. By one estimate, it rises about 7 bpm for every 1% of body weight lost to sweat. On long runs, decide in advance whether you will slow down to hold your zone or let heart rate rise a little at the same pace.
• Altitude: thinner air raises heart rate at the same effort. In one lab study, breathing air with 12% oxygen, roughly what you would breathe above 4,000 m (13,000 ft), raised heart rate by about 20 bpm at the same workload. At altitude, expect a higher heart rate at your usual pace, or a slower pace at your usual heart rate.
• Illness and fever: a fever raises heart rate by roughly 8 bpm for every 1 °C (1.8 °F) rise in body temperature, and the rise shows up during sleep too. If your heart rate is unusually high for an easy pace and you feel off, illness is one possible reason; our guide to running with a cold covers when to rest.
• Accumulated fatigue: heavy training can push heart rate the other way. In a study of triathletes who became overreached after three weeks of overload, peak heart rate fell from 182 to 176 bpm, and heart rate dropped faster after exercise, which can look like better fitness. If you can't reach your usual heart rate in hard sessions and you feel flat, you probably need more recovery, not more effort.
• Caffeine and lost sleep: neither changes heart rate much at a set pace. A meta-analysis of 26 studies found caffeine had no effect on heart rate during steady exercise at a fixed intensity, though it made the effort feel easier. After a night without sleep, heart rate at a set intensity was unchanged, but people covered less distance in a 30-minute run at the same perceived effort.
• Medication: beta-blockers and some other medications lower heart rate. In one trial, two weeks on a common beta-blocker lowered heart rate by 15 to 22 bpm at rest, at threshold and at max, while the work people could do at their thresholds didn't change. If you take one, zones set before you started no longer apply, so ask your doctor what targets make sense.
• Sensor errors: a wrist sensor can lock onto your step rate instead of your pulse, or lose contact when the band is loose or your skin is cold. In one study of 50 adults, a chest strap agreed almost perfectly with an ECG, while most wrist devices did well on a treadmill but varied widely in other exercise. Our guides to optical heart-rate accuracy and WHOOP heart-rate errors cover the fixes, and our Zone 5 guide walks through the checks if your watch shows Zone 5 on easy runs.

See a doctor if a high heart rate comes with chest discomfort, palpitations, shortness of breath, dizziness or fainting, or if it doesn't come down when you stop.

Heart rate, pace or effort: which to follow

Heart rate is one of three ways to steer a run, and it is the best of the three only some of the time. It is slow to react, it drifts upward on long or hot runs, and it runs higher on race day: one review estimated that heart rate during a 10K race is about 20 bpm higher than at the same speed in training. Use it where those weaknesses matter least.

Short reps are hard to steer by any single number. In one study of 37 recreational runners, heart-rate targets kept them in the planned zone for 85% of a 45-minute easy run, against 69% with race-pace targets. In five 800 m reps with 90-second recoveries, both methods struggled: 41% of the time in zone with heart-rate targets and 27% with pace targets. Because heart rate is still climbing for the first minute or so of each rep, it can't tell you in real time whether a short rep is right, so decide the target pace or effort in advance and use heart rate afterward to judge the session. Our guides to running by feel, pacing hilly races and running power cover the other two tools.

When to update your zones

Zones need updating less often than you might think, but they do drift:

• Max heart rate changes little with training. A review found training or detraining can shift it by about 3 to 7%, and it tends to fall slightly as fitness rises. Update it when a race or a hard session, recorded with a chest strap, shows a higher reliable reading, and recheck it if a season of hard races never gets close to it.
• Resting heart rate falls with endurance training, by about 3 to 6 bpm on average across controlled studies, and by about 9 bpm in beginners who trained for a year, all of it within the first six months. If you use heart-rate reserve zones, update it every month or two, or let a device that measures it overnight do it for you.
• Threshold heart rate tends to stay fairly stable in trained athletes as fitness rises, while pace at threshold improves. In professional cyclists followed across a season, heart rate at both thresholds barely changed while power at those thresholds rose. So expect faster paces in the same zones, not new zones. Retest after a long break or illness, and recheck if easy, conversational runs keep landing in Zone 4.
• A new device: copy across the same max, resting heart rate and zone method, so your history stays comparable.

Bottom line

Heart-rate zones are only as good as the numbers behind them. Replace the age formula with a real max, add your resting or threshold heart rate if your watch supports it, and set every device you wear the same way. Then use zones where they work best, as a ceiling on easy runs and a check on steady ones, and switch to pace and effort for short, hard reps.

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