Zone 2 cardio, explained: How it works and why you should try it

Heard of zone 2 training and wondering what all the fuss is about? Here’s what you need to know about it, as well as some of the reasons to add it to your exercise regimen.

What is zone 2 cardio?

Cardio exercise can be broken down into 5 zones, 1 being the lowest and 5 the highest.

The zone system is based on how intense the exercise is and, as a result, how much each zone impacts your heart rate.

For instance, zone 1 training is fairly gentle and has a minimal effect on your heart rate, while zone 5 can elevate it quite significantly. Each zone is determined by the percentage of your maximum heart rate that it reaches. 

This brings us to zone 2 cardio. When you’re in zone 2, your heart rate increases to about 60-70% of its maximum rate.

This means you’re likely doing low-moderate intensity aerobic training, such as a light jog, brisk walk, or cycling. 

When you’re in zone 2, you can usually continue holding a conversation and stick with the exercise for a minimum of 30 minutes. Think of it as a consistent and controlled effort that focuses on endurance rather than high-intensity training that leaves you feeling depleted.

You might also hear zone 2 referred to as “base training”. This is because many fitness experts recommend focusing the bulk of your workouts on zone 2 cardio — potentially around two-thirds of your total training time.

For reference, here’s what the remaining 4 heart rate zones look like:

• Zone 1: This includes low-intensity cardio like slow walking or yoga, which typically get your heart rate to about 50-60% of your maximum.
• Zone 3: Also known as moderate-high intensity exercise, zone 3 gets you to 70-80% of your maximum heart rate and includes activities like running and cycling.
• Zone 4: Zone 4 gets your heart rate to 80-90% of the maximum, with exercises like high-intensity fitness classes and running intervals.
• Zone 5: This is the highest zone, where your heart rate can get up to 90-100% of its maximum. Zone 5 covers intense workouts such as high-intensity interval training (HIIT), sprinting, and burpee sessions.

The benefits of zone 2 cardio

You might think lower-intensity aerobic exercise doesn’t offer the same benefits as a more vigorous workout, but that’s not necessarily the case.

In fact, there are plenty of (proven!) health benefits to zone 2 training, which is why so many fitness experts endorse it.

(We should also add that all forms of exercise are valuable — it’s really just about moving your body in a way that works for you.)

Zone 2 cardio can burn fat

Your body uses different fuel sources depending on the zone you’re training in. When you’re doing zone 2 cardio, your body predominantly relies on fat rather than carbs as its fuel, helping to promote fat loss.

In fact, research shows that maximal fat oxidation occurs when your maximum heart rate is between 60.2 and 80% [1].

It can boost your cardiovascular fitness

Because zone 2 cardio requires steady oxygen use, it’s able to boost your body’s VO2 max — i.e. the highest amount of oxygen your body can use and a key measure of your fitness.

This is a win for your cardiovascular health because a higher VO2 max can reduce your risk of several heart issues [2][3].

It builds endurance

An additional advantage of a stronger aerobic system is that it builds your endurance, allowing you to sustain longer workouts at higher intensities.

Using zone 2 as a base can also make it easier to level up to higher zones.

It improves mitochondrial function

Zone 2 cardio can improve the health of the mitochondria in your body [4]. These are tiny organelles that support energy production.

It can support recovery

If you're used to doing high-intensity exercise, zone 2 is an ideal level for recovery days because it’s much less demanding on your body.

It can reduce your risk of overtraining

Because zone 2 is fairly low-intensity, you may have a smaller chance of sustaining an injury or overtraining.

It’s accessible to lots of fitness levels

Zone 2 can work for all kinds of people, from exercise newbies to experienced athletes.

Examples of zone 2 cardio activities

The other great thing about zone 2 is that lots of exercises fall into it, making it an accessible and adaptable way to work out.

The goal is to increase your heart rate to 60-70% of your maximum, so the ideal activity and exercise intensity may look different for you depending on your fitness level. Here are some ideas to try:

• Jogging: A light jog can bring your heart rate to the zone 2 target and allow you to maintain it.
• Walking: If jogging isn't exactly your speed, or you want to start with something a little gentler, you’ll be glad to know that walking can absolutely be categorised as zone 2. It’s just about getting your heart rate to that target percentage. To up the intensity, walk at a brisk pace or add a gentle incline.
• Cycling: Cycling is great because it’s low-impact and you can maintain a steady pace for a long period. You could opt for road cycling or even stick to the stationary bike at the gym.
• Swimming: Strokes like freestyle, breaststroke, and backstroke can easily get you to zone 2.
• Dancing or aerobics: Low-impact aerobics classes and dance workouts like Zumba are solid ways to get your heart rate into zone 2.
• Working out at the gym: Several pieces of equipment are perfect for zone 2 training, including the elliptical trainer, rowing machine, treadmill, and stairclimber.

One thing to be aware of is that your heart rate should ideally stay consistent throughout your workout.

Consistency allows your body to fully utilise oxygen and burn fat efficiently — two of the primary goals of zone 2 training.

To achieve this, try to maintain a steady pace and incline, and regularly monitor what your heart rate is doing (more on how to track it below!). If your heart rate is rising above or dipping below the zone 2 target, adjust your speed, resistance or exertion accordingly.

How long should your zone 2 cardio workouts be?

Zone 2 cardio workouts should last for a minimum of 30 minutes to reap all the benefits to your fitness and health. Ideally, though, you want to aim for 45 minutes to 1 hour per session.

You should also try to complete 2-4 zone 2 workouts per week, for around 3-5 hours total.

If you’re still building up your fitness, you don’t need to dive in headfirst. Start with 2 hours of zone 2 cardio each week and work your way up.

How do you know if you're in zone 2?

There are a few ways to figure out if you’re in zone 2. 

One involves using a heart rate monitor or smartwatch that can determine your pulse.

You first need to work out your maximum heart rate, which you can do using your age [5]. Deduct how old you are from 220 to get an estimate of your max heart rate.

For instance, if you’re 30, your maximum heart rate would be 190 beats per minute (220 - 30 = 190). If you’re 50, your maximum heart rate would be 170 bpm (220 - 50 = 170).

Using the zone 2 target of 60-70%, zone 2 in the first example would be a range of 114-133 bpm and in the second example, it’d be a range of 102-119 bpm.

You can then use your heart rate monitor or smartwatch to see if your heart rate is sitting in zone 2.

Another way to find out if you’re in zone 2 is to use the calculation above but check your pulse manually. Simply count how many times your heart beats in one minute.

The final way is to use the talk test. In zone 2, you’ll usually feel slightly out of breath but still able to speak a full sentence comfortably.

How to get started with zone 2 cardio

Ready to kick off your zone 2 workouts? Thanks to zone 2’s accessibility, it’s relatively easy to get started. Here are a few tips:

Figure out your target heart rate

Once you’ve figured out the zone 2 range you should be aiming for, you’ll have a clearer idea of what to achieve and how to track your progress.

Choose your zone 2 activities

There are lots of ways to get your heart rate into zone 2, from dancing to swimming. If you’re unsure which activity is right for you, try a few of them before figuring out which ones you like most.

The goal is to pick something you enjoy so you’re more likely to stick with it.

Start slowly

While the ideal scenario involves up to 5 hours of zone 2 training each week, you don’t have to start with that — especially if you’re still building up your fitness.

Go easy on yourself and begin by doing 30-minute sessions a couple of times each week and increase as your aerobic fitness improves.

Make sure to warm up and cool down

Warming up your body so it’s ready for a workout and cooling it down afterwards are both crucial for reducing the risk of injury and helping your body's ability to recover.

Spend 10-20 minutes on low-intensity exercise (something like walking or slow cycling) first to warm up, then spend an additional 10-20 minutes stretching once you’re done.

Add recovery days

You don’t necessarily need to undertake a zone 2 workout every day of the week.

Give yourself rest days when you just do something as simple as a light stretch or alternate your zone 2 training days with low-impact exercise days.

Build a broader workout routine

The best exercise regimens combine different types of movement so you’re giving your body a comprehensive workout.

Zone 2 training can be complemented by strength training, intense exercises like HIIT and sprints, and gentle movements like walking and yoga.

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