Why Do Heart Rate Zones Matter When You Exercise?

Step into most gyms or fitness classes and you’ll likely see at least a few people wearing heart rate monitors. These exercisers aren’t just wearing these gadgets to look cool. They’re doing it because they want to stay in their ideal heart rate zone. Let’s take a look at what these zones are and how they can influence your exercise results.

About the Heart Rate Zones

Professionals divide up your maximum heart rate into five major zones. The first zone is warm-up or maintenance, which involves very light to moderate activity. In this zone, your heart rate does not exceed 60% of its max. 60 to 70% is the weight control or fat burn zone. 70 to 80% represents the aerobic zone, which is where most people want to be when they do traditional cardio exercises. From 80 to 90%, you are in the anaerobic or hardcore training zone. In this zone, the muscles have to rely on reactions that don’t require oxygen in order to keep functioning. The final zone is known as VO2 max. VO2 refers to the maximum rate of oxygen you use during exercise and is a measure of how fit you are.


Sure, you probably want to get ripped when you work out (or at least fit into some skinny jeans), but these types of results are not the biggest reason to look at heart rate zones. Safety is. The heart simply is not designed to go for extended periods at ultra-high intensity levels. It’s made more to work at a max for a brief interval and then rest–think of your ancestors running away from a lion here. This is why High Intensity Interval Training (HiiT) has gained such momentum in recent years. If you push your heart too hard for too long, you engage physiological inflammatory responses that, over time, can hurt your heart tissue and even lead to heart attack. When you see your heart rate is too high, you can slow down, decrease the amount of weight you’re working with or increase the length of your rest intervals.

Heart Rate Training Zone Chart

Shaping the Body

In the fitness world, most people look to work in the aerobic and anaerobic heart rate zones. With aerobic exercise, your body turns to glycogen and fat as primary fuel sources. You are able to get lean and lose weight as a result. By comparison, anaerobic exercise burns mainly glycogen. It results in the production of hormones such as epinephrine, human growth hormone and testosterone, which not only build fat, but which also help build muscle. Pushing yourself a little further when you workout, therefore, can give you a more toned look and is better at improving your endurance and performance. Neither of these is necessarily “better,” per se, and most experts would say you should get into both zones through varying your workouts for optimum fitness, but depending on what you’re looking to achieve physically, you might want to concentrate a little more on one area or the other.

Finding Your Personal Target Heart Rate Zone

Fitness gurus say you should subtract your age from 220 to get your maximum heart rate (MHR). From here, you multiply your heart rate max by 0.6 and 0.8 to get the lower and upper limits of your target heart rate zone–this will show you where you’ll be sitting in terms of beats per minute if you are working in the weight loss or aerobic zones. The common recommendation is that, if you’re a beginner, you aim to stay on the lower end, working in the weight loss zone until your heart gets a little stronger. Once you know what your target zone is, you might want to stray from it occasionally as your fitness improves. For instance, you can work out longer if you keep your heart rate below 60%, but going over 80% once in a while for brief intervals can give your performance a boost by improving your VO2 max level.


Keeping Your Eye on Your Heart Rate

One of the best ways to make sure you’re not overdoing it or are working in a zone that accommodates your primary fitness goals is to use a heart rate monitor. All of them feature a watch-like device, but the best ones are designed to sync with a chest strap. The strap “talks” continuously to the wrist monitor, giving you a much more accurate picture of what’s going on. You can get additional features such as calorie tracking, workout summaries and more on higher-end models. If you can’t afford a monitor, don’t fret. Manually testing occasionally during your workout by finding your pulse on your wrist or neck works, too.


Heart rate zones are important to monitor not only for safety, but also for results in physical appearance and performance. Once you’ve calculated your max heart rate, simple tools like a heart rate monitor are very helpful in helping you reach your goals.


Harvard Health Publications (2008). Glossary of Exercise Terms.

MyFoodDiary.com (2013). Aerobic vs. Anaerobic: What’s the Difference?

National Emergency Medication Associtaion (2013). What You Should Know About Your Heart Rate or Pulse.\

HeartQ Heart Rate Monitor

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