What is Zone 2 cardio and is it right for you?
Zone 2 cardio might sound like something made up by your smartwatch, but it actually just means a low-intensity workout.
What is Zone 2 cardio?
Your heart rate can be neatly fit into five zones, with varying effects on the body.
Zone 2 is the lowest intensity heart rate zone that can still be considered exercise - imagine going for a jog while still being able to hold a conversation with someone running next to you - and is used to build or maintain cardiovascular endurance.
Zone 2 also keeps your heart rate and muscular response in what some people call the fat-burning zone, where your body will be creating ATP (Adenosine Triphosphate) by combining glucose from body fat (as opposed to carbohydrates) with oxygen.
Zone 2 training is any aerobic activity that puts your heart rate into this zone - around 60-70 per cent of your maximum heart rate.
How to calculate your max heart rate
You can undertake a more accurate max effort fitness test at the gym with a trainer, which will usually record your VO2 max (the maximum amount of oxygen you can make use of during intense exercise) and performances on the treadmill or bike.
If you don't have a trainer to hand, there are several other ways to get a close estimation of your max heart rate:
Subtract your age from 220: to work in Zone 2 at the age of 30, for instance, you're looking for 60-70 per cent of a max heart rate of 190bpm, which comes out at between 114bpm and 133bpm.
The Maffetone method, which calculates the upper threshold of your Zone 2 training by subtracting your age from 180 - for the same 30-year-old, that would be an upper limit of 150. Some trainer will then add or subtract 5, depending on a client's general state of health and fitness.)
The Karvonen formula: ([maximum heart rate – resting heart rate] x % intensity) + resting heart rate = training zone.
Zone 2 cardio benefits
Zone 2 training can bring major benefits to your overall health.
As Zone 2 relies on aerobic rather than anaerobic training, it strengthens your cardiovascular system and makes it more efficient, helping to deliver oxygenated blood to different parts of our body and reducing lifestyle-related diseases such as obesity, heart disease and type II diabetes.
For athletes, Zone 2 also leads to improved mitochondrial growth, improving fat utilisation during exercise and allowing the body to preserve glycogen to be used later during more intense periods of a race. You also are less likely to overtrain - which can lead to fatigue and injuries - if you mix up Zone 2 training sessions with more taxing workouts.
Low-intensity exercise is also great for the mind because it helps reduce stress and anxiety enabling an endorphin release, which is the ‘feel good’ hormone.
Is Zone 2 cardio good for fat loss?
Yes, but only as part of a wider fitness and nutrition routine - as the saying goes, you can’t outrun a bad diet.
When in Zone 2, your body will use fat as its primary fuel source, rather than carbohydrates, so this means that you're burning more of your calories from stored fat. But you will burn relatively fewer calories because your training intensity is lower. And when it comes to fat loss and exercise, it’s the number of calories burnt that is the key.
So while Zone 2 cardio can help you burn calories and fat, it's also important to create a calorie deficit through a combination of diet and exercise in order to lose weight.
Is Zone 2 training right for you?
If you're looking to improve your overall fitness, then Zone 2 can form a solid cornerstone of that goal. But strength training is also an important component of any fat loss program because as it helps build lean muscle mass, which can increase your metabolism and help you burn more calories at rest.
Aim to incorporate both Zone 2 cardio and strength training into your fitness routine for optimal results.