Being comfortable during training can feel pretty uncomfortable if you ask us. We’ve been conditioned to crave the heart-racing, sweat-dripping intensity of HIIT for so long, that now any cardio that leaves us feeling anything less than this, almost feels like a cheat.
But times have changed and as one trend fades, a new one emerges: Enter zone 2 training: a lower intensity sesh, that we think will be here for the long run (literally). Why? Because it comes with many benefits to overall health and performance, whilst being much less tiring! With zone 2 training you feel like you could keep going forever – you don’t stop as you collapse on the floor after going HAM on the rower. You stop when the time is up, feeling like you still have more in the tank. It’s easy, but hard at the same time, if you know what we mean.
So if you’re ready to get into the zone, then listen up. We’re going to give you everything you need to know about zone 2 cardio, the benefits, how to calculate zone 2, and how to include it in your routine – Trust us, you’ll be off and running in no time.
Contents:
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What Is Zone 2 Cardio?
Zone 2 training is one of the five heart rate zones used to define the intensity of activity, zone 1 being easy (e.g. walking or carrying groceries), and zone 5 being the absolute max you can push to.
Zone 2 falls into the lower end of the scale, performed at 60-70% of your max heart rate – it’s slow, it’s steady, but it’s still work. Runners might call it an ‘easy pace’, cyclists might refer to it as a zone 2 in a 6-7 zone scale, and the weekend warriors may know it LISS (low-intensity steady-state cardio). To us, it’s easy exercise: you’re moving and your heart rate is above resting, but you can talk to your friend, or sing along to your favorite song as you go.
The Benefits of Zone 2 Cardio
Training in zone 2 can cause several questions to pop up as you’re running along: Am I working hard enough? Is this exercise actually helping at all? Trust us, Zone 2 cardio may feel strange at first, but it’s worth persevering, as it comes with many benefits that make this type of training very beneficial:
1. Less Fatigue, Faster Recovery
Finish a HIIT session, hill sprints, or a tough CrossFit WOD and your body will be feeling the impact. Zone 2 cardio, however, is much kinder on your body, placing less stress on your musculoskeletal system and causing less fatigue. If you find yourself feeling tired or sore after a high-intensity session, add some zone two cardio into the mix. It won’t negatively impact your other training, and can actually help speed up recovery [1].
2. Better Performance At Higher Intensities
Many of us are used to training in higher heart rate zones for shorter periods of time. This uses our anaerobic training system, utilizing carbohydrates for fuel. But that doesn’t mean that you have to train within that heart rate zone to improve high intensity exercise: in fact, training in zone 2 improves performance at higher intensities too. This is because zone 2 cardio builds a solid fitness base and improves your body’s ability to switch between using fat to fuel activity and carbohydrates – called ‘metabolic flexibility’. If you’re a runner trying to improve your 10K time, incorporating longer, slower zone 2 training will allow you to extend the duration of time you are able to run for, which will in turn, improve your 10K time.
3. The Ideal Fat-Burning Zone
Training at moderate intensity of this kind means the body relies mostly on fat for energy – so if fat loss is your goal, zone 2 training can help you get there. Train any harder, and your body will start to use carbohydrates, in the form of glycogen, for energy [2]. Zone 2 offers a sweet spot where you can still put in effort, but without crossing over into an anaerobic heart zone that prioritizes carbohydrates for fuel, not fat.
4. An All Round Health-Booster
Zone 2 training increases mitochondrial size, number, and function [3]. These are the ‘powerhouse’ of our cells – giving them energy and fuel to work. Mitochondria dysfunction has been linked to metabolic syndrome, type 2 diabetes, cardiovascular disease, and more [4]. Improving your zone 2 cardio will boost your mitochondria, decreasing the risk of health conditions.
5. Improved Mental Health
That euphoric feeling you get after a run? Yep, that’s the endorphins kicking in. It won’t surprise you then to know that aerobic exercise is proven to boost self-esteem and social functioning, whilst decreasing anxiety, depression, and insomnia [5].
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Zone 1 Vs Zone 2 Cardio
If zone 2 is easy, then zone 1 is very easy. Sitting around 50-60% of your max heart rate, zone 1 training includes warm up, recovery, or very light exercise such as stretching or slow walking: you’ll be doing zone 1 training without even realizing and when you prepare and cool down from exercise. Zone 1 doesn’t improve cardio fitness, but it does promote blood flow through the muscles. As the intensity is so low, it doesn’t require any recovery time and you could perform zone 1 exercise for a very long time.
Zone 2, takes it up a notch, entering base training level. A recovery ride or an easy run: you are intentionally exercising but it’s easy and doesn’t require a ton of recovery after.
Zone 2 Vs Zone 3 Cardio
Zone 3 (70-80% of your max hr or 7 out of 10 RPE) is more challenging than Zone 2. Whilst you may still be able to speak, sentences will feel choppy and you’ll feel out of breath.
Zone 3 training is often referred to as the ‘Grey Zone’ of training: It’s too hard to reap the benefits of zone 2 (aerobic work that uses fat as its primary energy source), but too easy to reach ‘race pace’ in Zone 4+ (which will boost lactate threshold, anaerobic capacity and high-intensity training for competitions). With Zone 3 also comes lactate acid response making the training feel harder on your muscles and requiring longer recovery compared to Zone 2.
In recent years, there has been a move towards polarized training (balancing low-intensity efforts with high-intensity training), which has been found to improve running speed and VO2 max [6, 7]. Zone 3 unfortunately doesn’t fall into either of these categories, being too hard for a recovery, and too easy for max effort. That’s not to say that no one intentionally trains in Zone 3 (if you’re on a tempo run, or cycling in a group over a long distance, you may find yourself in Zone 3), but the general consensus is to stay out of the ‘danger zone’: either stick in Zone 2 for your recovery sessions, or push yourself into Zones 4+ for those days when you really want to challenge yourself.
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Zone 2 Cardio Examples
Whether you are a short distance runner trying to improve your 5K time or a triathlete training for endurance over long distances, zone 2 cardio benefits both higher intensity work and endurance performance by improving fuel utilization. Zone 2 training allows you to set a solid aerobic foundation, not only improving the amount of time you can run, swim, cycle (or whatever your choice of sport), but the speed you can go at shorter distances too.
So how do you train in zone 2? The good news is, you can use any low-intensity cardio method for zone 2 training – from running outdoors, to rowing on the erg. The most common modes of zone 2 training are:
Zone 2 Running
A long run, easy run, or recovery run are all suited to zone 2 training. Yes, these runs are slower, but in some ways, they’re not easier. Getting your heart rate within the right zone and keeping it there can be a challenge in itself. If you’re used to pushing yourself and keeping a fast pace, reining things in and resisting the urge to speed ahead can be hard. If you aren’t used to running, even a gentle jog could cause your heart rate to spike, surpassing the 60% sweet spot. Wearing a heart rate monitor or fitness tracker will allow you to check your heart rate and adjust your speed accordingly. You may need to start with a brisk walk or planned rest periods during your run to prevent your heart rate from creeping into zone 3.
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Zone 2 Cycling
Another popular type of zone 2 cardio is cycling. For cyclists, zone 2 training falls in the range of 55% to 75% of their Functional Threshold Power (which is the highest average power you can sustain for one hour, measured in watts). But you don’t need to be a seasoned cyclist to make use of this mode of training – hop on a spin or watt bike in the gym, to reap the benefits of this low-impact zone 2 method. As with running, this is a slower pace that you should be able to sustain for longer and talk whilst you’re doing it.
Zone 2 Walking
We’ve mentioned ‘easy’ a lot – but zone 2 shouldn’t be too easy. That’s not to say that walking can’t be a form of zone two cardio – it certainly can, but we’re more referring here to a brisk walk or even a hike, rather than a leisurely stroll. Again, if you don’t exercise regularly, a stroll might be enough to push you into zone 2 initially, but for the most part, you’ll need to put in a little bit of effort here.
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What Is My Zone 2 Heart Rate?
The pace of exercise required to push you into zone 2, or keep you within it, will vary from person to person depending on individual fitness levels and genetics. Whilst one person may find a brisk walk brings their heart rate up sufficiently, someone who has a strong engine may find they need to be taking a light jog to raise their heart rate into the 60% zone. You’ll be the judge (or your smartwatch will).
There are two main methods you can use to judge your heart rate zone:
Calculating zone 2 using your max heart rate
Using the RPE scale to identify zone 2
It’s worth noting that sometimes we do need to take these calculations with a pinch of salt. Genetics play a role in heart rate, meaning that each heart rate zone will vary from person to person. If you feel like your watch is constantly telling you a heart rate zone that doesn’t align with how you feel, then you may want to use the RPE scale instead to make your own assessment of your heart rate zone, instead of relying solely on these calculations.
1. How To Calculate Max Heart Rate
The first way to identify zone 2 heart rate is to calculate your max heart rate, and then use that to find your zone 2 heart rate.
To calculate your max heart rate, follow the calculation: 220 - your age
For example, if you are 30, your max heart rate would be 220 - 30 = 190.
Zone two would then be around 60% of your max heart rate, making it 114 in this case.
Using a fitness tracker or heart rate monitor whilst you exercise will allow you to see if you are within your zone two heart rate range.
2. How To Assess RPE
If you don’t have a device to monitor your heart rate, using the RPE scale is a great way to assess your heart rate zone based on your own judgment of how hard you are working.
RPE is rated on a scale of 0 - 10, where 0 is no effort at all, such as lying on the sofa, and 10 is the hardest you can push, for example, if you are running and feel totally out of breath. Zone 2 should sit at around a 3: You’re moving, you’re putting in a little effort, but it’s not strenuous.
When you are exercising, think about how much effort you are putting in on a scale of 1-10: If your heart rate is not elevated at all, you are likely going too easy, but if you’re short of breath and struggling to hold a conversation, it’s a sign to rein things back. You should feel like you are doing moderate exercise, with a slightly elevated heart rate, but nothing too strenuous. You should be able to sustain the activity for a long period without difficulty.
FAQs:
Research suggests that athletes should stick to the 80-20 rule: That means about 80% of training should sit in zone 2, and the rest in higher intensity (anaerobic) range. This ratio is known as polarized training, which mixes lower-intensity training with short periods of high intensity.
Ideally, you would perform 3-4 zone 2 sessions a week, but for beginners, this may be less. It’s important to remember that zone 2 training will take up more time (45-60 minutes+) compared to higher-intensity sessions, which are usually shorter. The trick during zone 2 cardio is to not push too hard – you don’t want to up the intensity and move into zone 3, 4, or even 5, as lactate starts to build up, you’ll begin to tap into a different energy system for fuel. Entering the higher heart rate zones will also increase recovery time, which is not what we are trying to do here!
Zone 2 training isn’t called the fat-burning zone for nothing: Training within this heart rate range uses fat as the primary source of fuel, rather than carbohydrates. However, whilst you may be using fat as the main fuel source in zone 2, you will burn fewer calories (and therefore less total fat) than if you were training at a higher intensity. Research supports this, proving that whilst steady-state endurance over a longer period (45 minutes, 5 days a week) burns fat, shorter, less frequent high-intensity sessions burn nine times as much fat [8]. Yes, zone 2 does burn fat, but training at higher intensities burns more calories per minute, making it a better option if weight loss is your goal.
The magic of zone 2 training is that you can do it with just about any cardio method – one isn’t better than the other. Jogging in the park, swimming in the sea, or watching Netflix on the Cross Trainer (We’re all guilty of it once in a while…): the best cardio for zone 2 is whatever you enjoy the most. Indoor or outdoor, zone 2 cardio can be done anywhere. Just remember to remain aware of your heart rate (or check it on your fitness tracker) whilst you exercise – you’ll be surprised how easy it is to slip into zone 3 or 4!
The worry about the trade-off between cardio and strength training is real. You may have clocked on already to the fact that the two have some effect on each other. In fact, studies have conducted research into this and come up with the ‘Interference effect’, which states that combining strength and endurance training harms performance, strength gains, and muscle growth [9]. Cardio leads to muscle breakdown and if you try and hit a 1 rep max after a long cardio session, chances are you’ll struggle.
So does cardio really kill your gains? Not necessarily. A more recent study concluded that aerobic training does not impact muscle hypertrophy or strength gains [10]. In fact, zone 2 cardio has many benefits, including improving muscular endurance, which allows you to perform more reps and sets during weight training, increasing muscle gains over time.
That being said, you need to be conscious of session timing: Where possible, perform longer stints of cardio in a separate session from heavy lifting [11]. This will ensure you still have enough energy in the tank for your big lifts, allowing you to reap the benefits that zone two cardio brings to muscle tissues and aerobic capacity, without impacting your strength gains.
Looking to excel in both cardio and lifting? Here’s Everything You Need To Know About Hybrid Training
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In It For The Long Run
Zone 2 has been on the sideline for a long time, but it’s back, and it’s here to stay. Running, cycling, swimming, rowing – you pick your method, and your heart rate will decide the pace. That doesn’t mean you need to neglect HIIT entirely, but it’s time we stop doing it on the daily. Adding a little low can help feed your high, so it’s time we start prioritizing zone 2 – for our health, our hearts, and overall performance.
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WRITTEN BY: Alex Kirkup-Lee
Alex is an inhouse Content Writer for Gymshark’s Health & Conditioning categories. A qualified Personal Trainer, CrossFit Level 1 and Functional Fitness Coach, Alex is experienced in training clients from a range of sporting backgrounds. With a passion for functional training, her favorite workout is anything that includes deadlifts, rowing, or wallballs.
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