What Are Heart Rate Zones and How to Determine Yours?

Heart rate zones are a way to describe the intensity of your cardio workout, such as running or cycling. The faster your heart beats, the harder you work. So, a light jog might stay in zone 2 for the entire workout, while a high-intensity interval training (HIIT) session might alternate between zones 1 and 5. Read on to learn what heart rate zones are, how to use them, and some important points to consider when training this way.

Before we begin, let’s clarify: heart rate zones are used for cardio training. Cardio is exercise that involves repeated rhythmic movements , such as running, swimming, or stair climbing. Heart rate zones are irrelevant for strength training , even if you have an app or watch that shows them as if they matter.

What are heart rate zones?

During cardio exercise, your heart has to beat faster to deliver nutrients and oxygen to your muscles. Heart rate is the number of times your heart beats per minute. So, if you can easily measure your heart rate—and fitness trackers and bracelets can—you’ll get a metric that tells you how hard you’re working out.

The exact heart rate values ​​for intense and light workouts vary from person to person, hence the concept of heart rate “zones.” Depending on how your watch or app calculates your heart rate, you might see, for example, “zone 2,” when your heart rate is between 50% and 70% of your maximum. A more intense workout might move you into zone 3. In many systems, the highest zone, for the most challenging parts of the most intense workouts, is zone 5.

Once you’ve identified your zones, you can perform workouts or achieve goals that align with them. For example, you might go for a run and aim to maintain your heart rate in zone 2 for 30 minutes. On another day, you might do a workout where you aim to cycle at an intense pace in zone 4 for a few minutes at a time, with a recovery period where you pedal at an easy pace in zone 1.

Each zone has its own benefits. You’ll most often hear about low-intensity aerobic training in zone 2 or the benefits of tempo workouts, which are primarily done in zone 4. But variety in training across all zones is essential. Every zone is beneficial, even zone 3, which is sometimes mistakenly called the “gray zone” where nothing happens. (Controversial: zone 3 is great , and most of us could use a little more training in it.)

Beginners shouldn’t worry too much about zones.

Before I tell you how to find and use your zones, I’ll start with an important note. You may hear everyone talking about zones, but if you’re new to exercise or heart rate tracking, it’s best to ignore them for now. Pay more attention to how you feel. A workout that’s supposed to be easy should feel easy, regardless of what your heart rate monitor says. A workout that’s supposed to be hard should feel hard.

Over time, if you monitor your heart rate during exercise, you’ll begin to notice which numbers correspond to what sensations. Knowing that you see (for example) 140 on your watch during an easy workout means much more than knowing that your device considers it “zone 2.”

Zone training is difficult for beginners for several reasons:

• Maintaining a healthy heart rate can be challenging, especially in lower zones like zone 2. If your heart rate spikes to zone 4 as soon as you start running, running in zone 2 may simply be impossible.

• Your zones may be calibrated incorrectly. To properly set your zones, you need an accurate maximum heart rate (more on that below), and an age-based formula isn’t guaranteed to be accurate.

• You have more important things to do than stick to the zones! Your body needs to master technique, tempo, and all sorts of physical and mental skills. Every brain cell spent obsessing over the zones is a brain cell unavailable for the more important tasks at hand.

Remember that your watch displays your heart rate because it’s easy to measure and display, not because it’s the most important thing you should pay attention to.

Please note that zones vary across different applications.

There’s not just one, but dozens, if not hundreds, of heart rate zone systems. Some have three zones, others four, others five, and still others even more. Even if two apps or wearables use a five-zone system, they don’t necessarily set the zone boundaries in the same places . For example, some systems set “zone 2” at 60-70% of maximum heart rate, while others use 65-75%.

Different systems also disagree on what exactly these percentages are based on. Sometimes it’s the maximum heart rate, which we’ll discuss below; sometimes it’s the heart rate reserve, which also takes into account the resting heart rate. Less common are zones based on other metrics, such as the lactate threshold.

The most common five-zone system

I know you won’t rest until I show you a table with numbers, so here it is. This isn’t the only zone system, but it works well for most purposes, and you’ll find versions of it in several different apps and wearables. It’s not the best, but it’s probably the simplest. You need to know your maximum heart rate (MHR), and then you can calculate percentages of it to determine your zones:

• Zone 1 : 50% to 60% of your maximum heart rate (MHR), although some systems can reach 65%.

• Zone 2 : 61% to 70% of your maximum heart rate; some systems can reach 75%.

• Zone 3 : 71% to 80%, or possibly 76% to 85%.

• Zone 4 : 80% to 90%, sometimes 85% to 95%.

• Zone 5 : up to 100%

In these systems, Zone 1 is for warming up or very light recovery between intervals. Zone 2 is for light aerobic exercise, like a light jog—something you can sustain for several hours if you’re fit enough. Zone 3 is for moderate-intensity exercise, like a fast jog, which will tire you out if you do it for more than an hour but can be maintained fairly steadily. Zone 4 is when the workload becomes intense, usually for just a few minutes at a time, and you’ll only be in Zone 5 for a few seconds during the most challenging intervals. You won’t be able to sustain work in Zone 5 for much longer.

How to determine your maximum heart rate

Now that you know the zones, you’re only missing one thing: your maximum heart rate, which is the basis for all of these zones.

Typically, these systems recommend subtracting your age from 220 to determine your maximum heart rate. Sometimes they use a different formula. But these formulas are often incorrect , as they give the same number for everyone of the same age. We’re supposed to believe that all 43-year-olds have a maximum heart rate of 177 beats per minute, but in reality, there are plenty of 43-year-olds with maximum heart rates above 200, and it’s not uncommon to find 43-year-olds with maximum heart rates in the 150s. (Similar caveats apply at any age.) Someone with a maximum rate of 200 beats per minute will wonder why they’re always in “zone 4” when they feel like they’re in zone 2, and someone with a maximum rate of 150 beats per minute will wonder why they feel like they’re dying when they’re in “zone 3.”

So, don’t rely on the formula, especially if you see zones that don’t correspond to how you feel during your workout. Ideally, you’ll conduct a maximum heart rate test , as I describe here , or make an educated guess by looking at the highest heart rate recorded by your device during one of your most intense workouts.

What sensations should occur in each heart rate zone?

You can test your comfort zones a bit to make sure they feel right. Here’s what they should feel like:

• In zone 1 you will feel very light, with virtually no physical exertion.

• In the second zone, you will begin to feel hot and sweaty, but you will still be able to easily carry on a conversation.

• In zone 3, your breathing will increase slightly. The lower limit of zone 3 still allows for conversation, but closer to the upper limit of this zone, you’ll only be able to utter a few words at a time.

• In Zone 4, you’re working hard and not in the mood for conversation, but you probably feel like you could keep it up for a little while longer—or at least a few minutes.

• Zone 5 is your absolute top speed, and you can only sustain it for a few agonizing seconds.

If you’re unsure of your maximum heart rate, try using this resistance level guide for a while. When you reach a workout that requires zone 5, go all out—and then check your heart rate monitor.

How do I stay in zone two?

You can learn more about Zone 2 here , including what it is, how to do it, and why it may be a bit overrated. Zone 2 is an easy effort that can be continued almost indefinitely. For a beginner, walking might be a Zone 2 workout. For an athlete, Zone 2 might be a brisk jog that they can maintain for several hours. The best indicator of Zone 2 training is that you stop because time is up, not because you’re too tired to continue.

There’s nothing special about maintaining zone 2, other than the fact that it doesn’t cause extreme fatigue, so you can do it a lot. If you notice your heart rate gradually rising to zone 3, that’s perfectly normal . The more you train, the more attention you need to pay to intensity. Athletes who train 10 hours a week need to make sure some of their workouts are light exercise. But if you’re doing a few 30-minute runs or attending a fitness class, any intensity is fine, as long as you feel good after most of your workouts, not completely exhausted.

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