What Is Cardio Zone 2 and How Should I Actually Do It?

Low-intensity cardio, sometimes called LISS or “zone 2,” is a previously underappreciated form of exercise. It’s finally coming back into fashion after years of absence while HIIT and lifting-only exercises dominated. But what is cardio zone 2? How to make sure you’re doing everything right? And is it really that bad if your heart rate goes into zone 3?

What is Zone 2 training?

Zone 2 training is cardio performed at a constant low intensity. It’s useful for aerobic training (so you can run faster), anaerobic training (helps you recover faster between reps and sets or between intervals), and is an effective way to burn calories without getting tired .

“Zone 2” is a term borrowed from the five-zone heart rate training system, and the same concept is also known by other names and metrics. For runners, this is “easy pace” or “slow pace for long distances.” For cyclists, this corresponds to zones 2 and 3 of the seven-zone mechanical power system . In other sports such as swimming and rowing, they are often referred to simply as “light” or “low-impact” exercise.

That being said, there is no official definition of Zone 2, and different devices will not necessarily agree with each other . The same heart rate can be in “zone 2” on one device and “zone 3” on another. So please take the following with a grain of salt.

The great thing about zone 2 workouts is that they are relatively slow and done at a steady pace. You’ll be aiming for your heart rate to be around 70%, but that doesn’t mean you should do intervals at 90% and then rest at 50%. This means maintaining a level of 70% throughout the entire workout. Zone 2 cardio can be performed using any sustained, repetitive movement. Popular methods include running, cycling, swimming, rowing, brisk walking, brisk walking, or riding an elliptical machine. (Walking may make a difference if you’re new to exercise; as you get better, you may need to choose a more challenging form of exercise .)

To be clear, it’s still work —it’s not the same as sitting and relaxing—but it should feel like you could keep working forever if you wanted to. You don’t stop a zone 2 session when you’re tired, you stop because you scheduled a 30, 45 or 60 minute session and your time is up.

How do I find my zone 2?

I’ll give you the short answer, but there are some major caveats that I’ll cover below. So consider this formula to give you a ballpark figure, and then I’ll tell you how to adjust it for your own real body (which won’t necessarily match the formulas). There are two steps:

Find your maximum heart rate

Maximum heart rate is literally defined as the maximum speed your heart can beat. (Sometimes people assume that this is a recommendation that you should keep your heart rate below this number. No, if your heart rate is higher than the number you thought was your maximum, it simply tells you that this number is not your maximum.) Here Here are some ways to find out your maximum heart rate:

• Field test for maximum heart rate (best for people with a healthy heart and some pain tolerance) . There are several ways to do this, but basically you will try to push your heart rate to the absolute maximum and see what happens. there is a number. The most common way is to find a long, steep hill and run up it three times, running really hard on the last one. The number you see at the end is a good estimate of your maximum. Of course, don’t do this if you’ve been told you shouldn’t train at high intensity .

• Your personal history (best for athletes with experience using a heart rate monitor) : If you’ve done high-intensity exercise in the past, especially killer efforts that resulted in you collapsing to the floor, this is the highest you’ve ever seen on your body. hours. or the heart rate monitor is probably at or close to your maximum. A 5K race or FTP test will often get you closer to your goal if you’ve really persisted throughout.

• Assessment based on simple exercises (best for non-athletes who have experience using a heart rate monitor) . If you have an idea of ​​what heart rate you see when you train at a steady conversation pace, multiply the largest number you can take into account. conversational at 1.25. This is my own opinion based on studies that have shown that the maximum conversation rate is around 77-79% of the maximum. This is not as good as field testing, but for many people it will give a better result than the formula below.

• Formula . I don’t recommend using the formula if you have the option to use either of the first two real options above. Using a formula to determine your maximum heart rate is like asking ChatGPT for your shoe size. This will give a plausible guess, but it could easily be very, very wrong. In any case, the simplest formula is to subtract your age from 220. (There are other formulas, but frankly, they all have serious inaccuracies. I wouldn’t worry about whether one is “better” than the others. They all suck.)

I talk more about why almost all max heart rate formulas are wrong here , but that’s beside the point for now. If you know your maximum heart rate, you can move on to the next step.

Use a percentage of your maximum as “zone 2”.

Once you know your maximum heart rate (or have an estimate you’re willing to work with), multiply it to get the upper and lower limits of zone 2. Multiply by what? Well, there are several opinions on what Zone 2 should be.

If you’re using a smartwatch or other device, go into settings and set your own heart rate (all major brands can do this – check the instructions to see where this setting is). Zones are usually filled in automatically.

As I wrote earlier, each device has its own idea of ​​what should be considered zone 2 . If you want me to decide the tiebreaker, I would choose a heart rate between 60% and 75% of your maximum heart rate . So, multiply your estimated maximum heart rate by 0.6 to get the lower limit of that zone and by 0.7 to get the upper limit. For example, if your maximum heart rate is 200, your zone 2 is 120 to 150 bpm. If your maximum heart rate is 175, your zone 2 will be between 105 and 132.

What are the benefits of zone 2 cardio?

Working in zone 2 builds your aerobic base. When you do cardio at such an easy pace, your body adapts by increasing the number of capillaries (tiny blood vessels) to more efficiently deliver oxygen and nutrients to your muscles. You get more mitochondria to power each muscle cell (you have thousands of mitochondria per cell) and you produce more enzymes that convert food into usable energy. Your heart and lungs become more efficient at absorbing oxygen and delivering blood to your muscles, and your muscles become able to store more carbohydrates (in a form called glycogen), so more of the carbohydrates you eat are ready to go. jogging or traveling.

For runners, Zone 2 work, often referred to as “easy pace,” should make up the majority (some say 80%) of your weekly mileage. The fitness you achieve from easy running is what allows you to benefit and recover from harder efforts like interval training.

For people whose primary sport is more strength-oriented (like me), Cardio Zone 2 strengthens the same body systems that help us recover between sets and even between reps. This increases our productivity, allowing us to get more work done overall. If you eat enough, adding cardio to your daily routine will allow you to do more work in the gym, not less. (And no, cardio doesn’t kill your results .)

And for people who only exercise for health reasons, Cardio Zone 2 is the ideal “moderate” exercise that we should all be doing at least 150 minutes a week . It’s good for the heart, and even people with medical conditions that limit their ability to exercise can often do low-intensity cardio exercise safely . (Of course, check with your doctor to be sure.)

It is important to note that zone 2 training is very low fatigue . More time-efficient forms of cardio and conditioning like HIIT, hill sprints, or CrossFit WODs are great for your aerobic fitness, but these workouts have to be high-intensity to work, and you’ll be pooping afterwards. They are good in small doses, but they need to be taken in small doses.

On the contrary, working at an easy pace is practically free. You can do easy zone 2 workouts every day in addition to your regular workouts and feel good. Once you get used to it, you will be able to do zone 2 work on your “rest” days without defeating the purpose of the rest day. If you have the time for it, it’s kind of a cheat code for achieving aerobic results.

How do you know if you are in zone 2?

The best way to know if you’re in zone 2 is to pay attention to your efforts and how they feel. Even though “zone 2” is defined in terms of heart rate, there are so many caveats to determining your maximum and defining the boundaries of the zone that I don’t recommend that beginners first calculate it based on their heart rate percentage. Unless you’ve actually pushed your heart rate up to your maximum effort level and know what that number is, you won’t actually know your maximum heart rate .

Instead, let’s talk about how it should feel. On a scale of 0 to 10, where 0 is nothing and 10 is sprinting, low-intensity cardio is about a 3 to 5. You’re working out, but not very hard. If your breathing is getting erratic or you feel like you’re tired as hell and can’t wait for it to end, you’re probably somewhere around 7+ and you’re definitely training too hard for a zone 2 workout.

The Zone 2 pace is conversational , and is sometimes called the “conversation test.” If you could tell a friend about your day while working out, you’re probably on the right level. This doesn’t mean spitting out a few words here and there, but speaking in complete sentences without getting out of breath. If you find yourself stopping to catch your breath or feel like you need to take a break, you’ve overdone it. (However, part of zone 3 is also in this conversation zone, but that’s okay —zone 3 is still good for you .)

However, it shouldn’t feel too easy: Zone 2 is more like a brisk walk or light jog than a leisurely stroll. If you stop, you should feel like you’ve taken a break from something. Maintaining the pace requires some work and focus.

Running

Runners often have trouble with this as the dividing line between walking and running is sometimes too high to maintain an easy pace while running if you are a beginner. The next best option is to jog as slowly as possible, and when you feel out of breath, switch to a brisk walk. For some people, brisk walking throughout your workout is an ideal zone 2 workout. As you get fitter, light jogging will be possible.

Here’s a real-world example of how to maintain a zone 2 pace: If I’m going for an easy run, I start at a nice, easy pace. But I live in a hilly area, so pretty soon I’ll be walking up a hill and I’ll notice my breathing getting heavier. At this point, if my heart rate gets higher than I’d like for that workout, I switch to power walking. Running on flats and walking uphill is a great way to maintain a consistent level of effort, rather than accidentally turning an easy run into a hill sprint.

Cycling

Cyclists often measure their training using a seven-zone system, which is based on how much power, in a physical sense, you put into your bike’s gears. These are called Coggan Power Zones , and cycling training systems like Zwift and Peloton use the same basic idea. To calibrate these zones, you’ll take an FTP (functional threshold power) test—essentially a 20-minute race against yourself. From here, you (or your workout app) calculate power ratings for your zones.

Zones 2 and 3 in this system generally correspond to our “zone 2” cardio. (By the way, your heart rate at the end of the FTP test will be pretty close to your maximum heart rate if you really went all out.) If you’re training with both a heart rate monitor and a bike power meter at the same time, don’t worry if they don’t match exactly. Riding in power zones 2 and 3 will satisfy your low-intensity cardio needs, even if your heart rate starts in zone 1 and skyrockets to zone 3 by the end.

Other cardio

For other forms of cardio, go by sensation or heart rate if you actually know your heart rate percentages. When you’re on the elliptical, rowing, or airbike, you should feel like you can easily continue a conversation and stop because time is up, not because you’re running out of gas.

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