The five cardio zones
Did you know that there are five target heart rate zones or “cardio zones”? You may have been hearing more about Zone 2 cardio lately as it has been having a (much deserved) moment. Why is Zone 2 so special and what about the other zones? Let’s nerd out!
Each cardio zone corresponds to a specific range of a percentage of your maximum heart rate. You can estimate your max heart rate by taking 220 minus your age (i.e. 220 - 30 = 190 beats per minute), give or take about 5 bpm depending on your fitness level. The higher your heart rate, the higher the intensity you’re working at, and the higher the zone that you’re in. If you have a way of measuring your heart rate (like a smart watch), you can use this guide to see what heart rate zone you’re training in.
Zone 1: 50-60% heart rate (HR) max
This zone is the lightest intensity zone (sometimes called the “recovery zone”). You should be able to sustain a Zone 1 intensity for many hours while comfortably carrying a conversation. Most activities of daily living (ADLs) fall into Zone 1. Think walking, running errands, etc.
Zone 2: 60-70% HR max
While this intensity is slightly higher than Zone 1, we should still be able to spend at least 2-3 hours in Zone 2 while being able to sustain a conversation. Zone 2 is considered aerobic training. Examples include lower intensity hiking, jogging, cycling, and swimming. The benefits of doing Zone 2 cardio regularly (ideally 1-3 hours per week) include improved recovery, endurance, resting heart rate, metabolism, and more.
Training in Zone 2 can be challenging because it’s a much lower intensity than many of us think of when we think about training, and it may not feel like you’re doing “enough,” but you are! When it comes to building endurance and aerobic capacity, training in Zone 2 is actually more beneficial than training in higher zones.
Zone 3: 70-80% HR max
Zone 3 brings us into more anaerobic training. A Zone 3 pace can’t be sustained for as long as Zone 2, and holding a conversation without panting will start to get difficult here. Think intervals, tempo work, or a race pace. Training in Zone 3 can be beneficial, but generally, Zones 2, 4, and 5 have greater benefits for developing endurance, speed, and power.
Zone 4: 80-90% HR max
Zone 4 is getting into higher intensity anaerobic training. Typically, a Zone 4 pace is difficult to sustain for over a minute. An example of Zone 4 training is higher intensity intervals of running, rowing, cycling, swimming, etc. Benefits include being able to sustain faster paces and higher intensities for longer periods of time.
Zone 5: 90-100% HR max
Zone 5 cardio is training at very high intensities for very short periods of time. A Zone 5 cardio pace is difficult for even elite athletes to sustain for 30 seconds. This is where maximum effort sprints can come into training. Training in Zone 5 can improve speed and power output, and while it’s beneficial to train in Zone 5 sometimes, it is difficult to recover from and shouldn’t be used all the time.
How do you apply these zones to your training?
How much time you should spend in each zone each week largely depends on your goals. If you’re training for a marathon or endurance sport, you might spend a lot of time in Zones 2 and 3. If you’re training for sprints or power output, you’ll likely need to spend more time in Zones 4 and 5. Everyone–regardless of specific training goals–can benefit from spending a good amount of time in the lower zones and a little bit of time at the higher heart rate zones for a healthy heart and lower resting heart rate.
Next time you’re doing cardio, take a look at what zone(s) you’re in! If you don’t have a way of measuring your heart rate, you can estimate what zone you’re in based on how challenging the effort feels. Think of Zone 1 as a 6 or 7 out of 10 and Zone 5 as a 9 or 10 out of 10 effort. This 1-10 scale is called the rating of perceived exertion (RPE) scale and can be used to track intensity for both cardio and strength training efforts.
