What heart rate zones are
Heart rate zones are intensity bands, each defined as a percentage of your maximum heart rate, that describe how hard your cardiovascular system is working during exercise. Most systems use five of them. The lowest is an easy effort just above resting, and the highest is close to all-out. Because your heart rate rises in a fairly predictable way as effort increases, these zones give you a practical dial for pacing a workout.
The value of the zones is that different intensities train different things. Easy aerobic work builds the base that lets you sustain effort; harder work raises your ceiling. Spreading training across zones, rather than doing everything at one middling pace, is the reason coaches and wearables put so much weight on them.
Zone models are estimates built on a formula, though. The most individual version comes from measuring where your body actually shifts gears. During its in-lab VO2 max test, Different Health sets training zones from measured ventilatory thresholds, the points where breathing changes as intensity climbs, rather than from an age formula. That distinction matters more than it first appears, and we come back to it below.
The five heart rate zones
The table below shows a widely used five-zone model based on percentage of maximum heart rate, along with how each zone tends to feel. The "talk test" is a simple cross-check that the American Heart Association and Mayo Clinic both mention: the harder the zone, the fewer words you can get out.
| Zone | % of max HR | How it feels | What it develops |
|---|---|---|---|
| Zone 1 | 50–60% | Very easy; can talk or sing | Warm-up, recovery, general movement |
| Zone 2 | 60–70% | Easy, conversational | Aerobic base and endurance |
| Zone 3 | 70–80% | Moderate; can talk but not sing | Aerobic capacity, steady tempo |
| Zone 4 | 80–90% | Hard; only a few words at a time | Threshold and sustainable speed |
| Zone 5 | 90–100% | Near-maximal; can't talk | Top-end power and VO2 max |
A common five-zone model as a percentage of maximum heart rate. Zone structure per Houston Methodist; effort cues per American Heart Association and Mayo Clinic. Different systems set the boundaries slightly differently.
Zone 2 is the easy aerobic range often nicknamed the fat-burning zone, and it has become the headline of a lot of training advice; we cover its specific benefits and the fat-burning question in separate guides. Zones 4 and 5 are where short, hard intervals live, the kind used to raise VO2 max. For this article, the point is the framework itself: knowing which band you are in tells you what a session is actually training.
How to find your maximum heart rate
Your maximum heart rate is the highest number of beats per minute your heart reaches at full exertion, and every zone is a percentage of it. The most common estimate is 220 minus your age, so a 40-year-old lands near 180 beats per minute. This is the number most any max heart rate calculator uses by default.
That formula is a population average, not a personal measurement. Mayo Clinic uses a refinement, 208 minus 0.7 times your age, in its own worked examples, which tends to fit older adults better. Harvard Health is blunter about the limits: estimating maximum heart rate from age gives only a ballpark, and determining it accurately requires a cardiopulmonary exercise test that tracks how your heart, lungs, and muscles respond to a graded challenge.
This is one place a lab assessment earns its keep. A Different Health VO2 max test measures your response to rising intensity directly, so the zones that come out reflect your physiology rather than a formula tied only to your birthday.
How to calculate your zones
Once you have a maximum heart rate, the simplest method is to multiply it by each zone's percentage. For a 40-year-old with an estimated maximum of 180, Zone 2 (60 to 70 percent) works out to roughly 108 to 126 beats per minute. A heart rate zone calculator automates exactly this arithmetic.
A more individual approach is the heart rate reserve method, also called the Karvonen method, which factors in your resting heart rate. Mayo Clinic lays out the steps: subtract your resting heart rate from your maximum to get your heart rate reserve, multiply that reserve by the intensity percentage, then add your resting heart rate back in. In Mayo's worked example, a 45-year-old with a resting heart rate of 80 has a maximum of about 176 (using 208 minus 0.7 times age) and a heart rate reserve of about 96, giving a vigorous 70-to-85 percent zone of roughly 148 to 162 beats per minute.
The reserve method matters most if your resting heart rate is unusually low or high, since it anchors the zones to your actual starting point. Your resting heart rate is worth knowing on its own, and we cover healthy ranges by age in a separate article.
Heart rate zones by age
Because estimated maximum heart rate declines with age, the beats-per-minute numbers for every zone drift downward over the years even though the percentages stay the same. The table applies the American Heart Association's approach, a 50-to-85 percent target zone of a maximum estimated as 220 minus age, to show how heart rate zones by age shift across adulthood.
| Age | Est. max HR (bpm) | Target zone, 50–85% (bpm) |
|---|---|---|
| 20 | 200 | 100–170 |
| 30 | 190 | 95–162 |
| 40 | 180 | 90–153 |
| 50 | 170 | 85–145 |
| 60 | 160 | 80–136 |
| 70 | 150 | 75–128 |
Estimated maximum heart rate and 50–85% target zone by age, using the 220-minus-age method. Figures are averages and general guides. Source: American Heart Association.
These are starting points, not personal limits. The American Heart Association also notes that some medications, including beta blockers, lower both maximum heart rate and the target zone, so if you take heart medication or have a heart condition, your numbers will differ and are a question for your clinician. This article is educational and is not a substitute for personal medical advice.
Formulas vs. measured zones
Formula-based zones are convenient and good enough for general fitness, but they carry real error. Individual maximum heart rates commonly sit above or below the 220-minus-age estimate, and a wearable adds its own uncertainty because it infers a maximum from your age and reads your pulse at the wrist. The zones on your watch are a useful trend rather than a precise prescription.
Estimating maximum heart rate from age gives only a ballpark; accurately determining it requires a cardiopulmonary exercise test that tracks how the heart, lungs, blood vessels, and muscles respond to exercise.
— Harvard Health, drawing on Massachusetts General Hospital's Cardiovascular Performance Program
Measured zones close that gap. In a lab VO2 max test, ventilatory thresholds mark where your breathing shifts as effort rises, and those points define zone boundaries that are specific to you. This is the method Different Health uses, and its dashboard also folds in data from wearables like Whoop and Oura so your day-to-day tracking lines up with the measured baseline. A team of MDs and PhDs then turns that profile into a training plan, so the zones become a program rather than just a chart.
How to train using your zones
A practical way to use zones is to make most of your training easy and a smaller share hard, rather than living in the moderate middle. The sample week below is illustrative, not a prescription; adjust the volume and days to your own fitness and goals, and build up gradually if you are new to structured training.
| Day | Session | Zone |
|---|---|---|
| Monday | Easy aerobic, 40 min | Zone 2 |
| Tuesday | Intervals (e.g., 4 × 4 min hard / 3 min easy) | Zone 4–5 |
| Wednesday | Recovery walk or rest | Zone 1 |
| Thursday | Easy aerobic, 45 min | Zone 2 |
| Friday | Tempo, 25 min | Zone 3 |
| Saturday | Long easy session, 60–75 min | Zone 2 |
| Sunday | Rest | — |
Illustrative week mixing easy and hard zones. Example only; adjust to your fitness and goals.
If you would rather not watch a monitor, the talk test tracks intensity well: comfortable conversation means easy zones, clipped sentences mean you have crossed into hard work. Whichever way you gauge it, the goal is to match intensity to purpose, so each session trains what you meant it to.
Key takeaways
- Five zones: heart rate zones run from very easy (Zone 1) to near-maximal (Zone 5), each a percentage of your maximum heart rate.
- Start with max HR: the common estimate is 220 minus age; Mayo Clinic uses 208 minus 0.7 times age as a closer fit for older adults.
- Two math methods: percentage of max heart rate is simplest; the heart rate reserve (Karvonen) method adds your resting heart rate for a more individual result.
- Zones shift with age: because estimated max heart rate falls over time, the bpm ranges for each zone decline even as the percentages hold.
- Formulas are estimates: a true maximum heart rate requires a cardiopulmonary exercise test, per Harvard Health, and measured ventilatory thresholds give the most individual zones.
- Train with intent: mostly easy work with some hard sessions develops both endurance and top-end fitness.
Frequently asked questions
How do I calculate my heart rate zones?
Start by estimating your maximum heart rate, usually as 220 minus your age, then take percentages of it for each zone. For a more individual number, the heart rate reserve method (also called Karvonen) subtracts your resting heart rate from your maximum, multiplies the difference by the intensity percentage, and adds your resting heart rate back in, as Mayo Clinic describes.
What are the five heart rate zones?
In a common model based on percentage of maximum heart rate, Zone 1 is very easy (about 50 to 60 percent), Zone 2 is easy aerobic (60 to 70), Zone 3 is moderate or tempo (70 to 80), Zone 4 is hard or threshold (80 to 90), and Zone 5 is near-maximal (90 to 100). Different systems draw the lines slightly differently.
Are heart rate zone calculators accurate?
A heart rate zone calculator applies a formula such as 220 minus age or the heart rate reserve method, so it is only as accurate as that estimate. The American Heart Association calls these figures averages and a general guide. Harvard Health notes that pinning down a true maximum heart rate requires a cardiopulmonary exercise test.
What are heart rate zones by age?
Because maximum heart rate falls with age, the beats-per-minute numbers for each zone shift down over time. Using the American Heart Association's approach, a 30-year-old has an estimated maximum near 190 bpm and a 50-to-85 percent target zone of about 95 to 162 bpm, while a 60-year-old's estimated maximum is near 160 bpm with a zone of about 80 to 136 bpm.
Which heart rate zone burns the most fat?
Lower-intensity work, often the Zone 2 range, uses a higher percentage of fat for fuel, which is why it is nicknamed the fat-burning zone. Higher zones burn more total calories per minute, so the best zone depends on your goal. Our fat-burning heart rate guide covers this trade-off in detail.
Are the heart rate zones on my smartwatch accurate?
Wearables estimate your zones from an age-based maximum heart rate and a wrist sensor, so they give a useful trend but can be off for any one person. A lab-measured maximum from a cardiopulmonary exercise test, or zones set from measured ventilatory thresholds, is more individual than a formula or a watch estimate.