Zone 2 is the heart rate range where your body burns fat and builds aerobic fitness without exhaustion

Zone 2 is roughly 60 to 70 percent of your maximum heart rate, the pace where you can hold a conversation but feel like you're working. To find your Zone 2 range, subtract your age from 220 to estimate your maximum heart rate, then multiply that number by 0.60 and 0.70. A 40-year-old would have a maximum heart rate of 180, making Zone 2 between 108 and 126 beats per minute.

This calculation gives you a starting point, but the real Zone 2 is where your body shifts from burning carbohydrates to burning fat for fuel — a metabolic threshold that varies by fitness level and genetics. The math gets you close; your own breathing and effort tell you when you've found it.

Key Takeaways

  • Zone 2 sits between 60 and 70 percent of your maximum heart rate, which you can estimate by subtracting your age from 220.
  • The formula gives you a range to start with, but your actual Zone 2 depends on your fitness level and how your body responds to sustained effort.
  • A heart rate monitor or fitness watch shows you the numbers in real time, but the talk test — being able to speak in short sentences — is the simplest check.
  • Zone 2 training builds aerobic capacity and fat-burning ability without the recovery demands of harder workouts.
  • Your Zone 2 range may shift over weeks and months as your fitness improves, so recalculating every few months keeps your targets accurate.

The basic formula: age-predicted maximum heart rate

The standard equation is straightforward: 220 minus your age equals your estimated maximum heart rate. A 35-year-old would have a predicted max of 185 beats per minute. A 55-year-old would have a predicted max of 165. This number is an average across the population, not a measurement of your actual maximum, but it works well enough for setting training zones.

Once you have your maximum, multiply it by 0.60 to find the bottom of Zone 2 and by 0.70 to find the top. A 35-year-old with a max of 185 would have a Zone 2 range of 111 to 130 beats per minute. That range is where most of your aerobic training should happen if you're building endurance or fat-burning capacity.

The formula works for most people, but it's less accurate if you're very fit, very sedentary, or taking medications that affect heart rate. If your calculated maximum feels wildly off — if you can easily exceed it during hard exercise, or if you can't come close — your actual maximum is different from the prediction.

Why the formula is a starting point, not the final answer

The 220-minus-age equation predicts an average, and you are not average. Your actual maximum heart rate depends on your genetics, your fitness level, and how your nervous system responds to stress. Two people of the same age and fitness can have maximum heart rates that differ by 20 or 30 beats per minute.

Zone 2 is defined not just by heart rate but by metabolism — it's the intensity where your body can sustain fat burning and aerobic work for hours without tipping into harder effort. That threshold happens at different heart rates for different people. A trained endurance athlete might hit their aerobic threshold at 65 percent of max; a sedentary person might hit it at 55 percent. The formula gives you a range to test, not a may provide.

This is why fitness apps and watches that know your training history can refine your zones over time. They see where you actually work hard, where you recover, and where you seem to shift between fuel sources. Your own perception — how hard you feel like you're working — is equally important information.

Using the talk test to verify your Zone 2

The simplest check for Zone 2 is whether you can speak. In Zone 2, you should be able to say a short sentence — "I'm working but not struggling" — without gasping. You can't sing or chat freely, but you're not breathless. If you can't finish a sentence, you're too hard. If you could recite a paragraph, you're too straightforward.

The talk test works because it reflects what's actually happening in your body. When you cross from aerobic work into harder effort, your breathing pattern changes sharply. You shift from nose breathing to mouth breathing, from steady to ragged. Your body is telling you before your heart rate monitor does.

Combine the talk test with your heart rate number. If your watch says you're at 120 beats per minute but you're gasping, your Zone 2 top is probably lower than the formula predicted. If you're at 100 beats per minute and could easily talk, your Zone 2 might start lower than 60 percent of max. Trust both signals together.

How to measure your actual maximum heart rate

If you want a more accurate maximum than the formula gives, you can measure it. The most reliable way is a maximal effort test: warm up for 10 minutes, then run, bike, or row as hard as you can for 3 to 5 minutes, pushing until you can't go harder. The highest number your monitor records is close to your true maximum.

This test is hard and not necessary for most people. The formula works well enough for training. But if you're an athlete, if you're older and want accuracy, or if your calculated max feels obviously wrong, a maximal test takes 20 minutes and gives you a real number to build zones from.

A gentler alternative is a step test: find a staircase or step, step up and down at a steady pace for 3 minutes, rest for 1 minute, then repeat at a faster pace for 3 minutes. Your heart rate during the second round gives you a rough estimate of your aerobic capacity and can help you sense where your zones actually sit.

Recalculating Zone 2 as your fitness changes

Your Zone 2 range shifts as you get fitter. When you first start aerobic training, your heart rate at a given effort is higher — your heart has to work harder to deliver oxygen. After weeks of consistent training, your heart becomes more efficient. The same pace now happens at a lower heart rate, which means your Zone 2 range drifts downward.

This is a sign of progress, not a problem. It means your aerobic system is adapting. But it also means your training zones need updating. If you calculated your zones three months ago and you've been training steadily, recalculate now. Your maximum heart rate may have shifted slightly, and your actual Zone 2 threshold has probably moved.

A straightforward way to track this: every 8 to 12 weeks, do the same straightforward workout — a 20-minute run or bike at what feels like Zone 2 effort — and note your average heart rate. If that number is dropping while the effort feels the same, your fitness is improving and your zones are shifting. Recalculate using the formula or adjust your zones downward by a few beats per minute.

Zone 2 on different devices and apps

Most fitness watches and apps calculate zones automatically once you enter your age and sometimes your resting heart rate. Apple Watch, Garmin, Strava, and others all use variations of the 220-minus-age formula as a starting point. Some apps let you enter your actual maximum heart rate instead, which overrides the formula with your real number.

The zones these apps show you are estimates. They're useful for seeing whether you're in the ballpark, but they're not precise. If your app says Zone 2 is 110 to 130 beats per minute, that's a reasonable range to test — but your actual Zone 2 might be 105 to 125, or 115 to 135. Use the app's numbers as a guide and adjust based on how you feel and how your body responds.

Some apps, like Whoop and Apple Fitness+, refine your zones over time by watching your training data. They see your patterns — where you consistently work hard, where you recover, where your heart rate spikes — and adjust their estimates. If you use one of these apps regularly, let it learn your patterns for a few weeks before trusting the zones completely.

Frequently Asked Questions

What if my calculated Zone 2 doesn't match how hard I feel like I'm working?

Trust how you feel first. If your formula says Zone 2 is 110 to 130 beats per minute but you're gasping at 125, your actual Zone 2 is lower. If you're at 110 and could easily chat, your Zone 2 probably starts lower. The formula is a starting point; your body's response is the real data.

Should I use my resting heart rate to calculate zones?

Some formulas use resting heart rate to refine zone calculations, which can be more accurate than age alone. If your app asks for resting heart rate, provide it — measure it first thing in the morning before getting out of bed. But the basic 220-minus-age formula works without it.

Does Zone 2 change if I'm sick or stressed?

Yes. Illness, stress, poor sleep, and dehydration all raise your resting heart rate and shift your zones upward. If you notice your heart rate is higher than usual at the same effort, you're probably not recovered. Skip the hard workout and do straightforward Zone 2 work instead, or rest entirely.

Can I train in Zone 2 every day?

Yes. Zone 2 is low enough intensity that daily training is sustainable and builds aerobic fitness without requiring long recovery. Many endurance athletes do most of their training in Zone 2 and add harder work only once or twice per week.

What's the difference between Zone 2 and Zone 1?

Zone 1 is below 60 percent of maximum heart rate — very straightforward, almost a warm-up pace. Zone 2 is 60 to 70 percent, where you're working but still aerobic. Zone 2 is where most of your training time should go if you're building fitness; Zone 1 is for recovery days and warm-ups.