If you are someone who is really serious about their workouts or if you simply want to achieve the most with the limited amount of time you can set aside for working out, you need to know a little bit about the science. You cannot just run out on your first day and sprint like a maniac for 15 miles without stopping or collapsing which is the more probable outcome. In my case, for sure. You need to know how much you can exert yourself and you need to know how far you can push yourself. That is where Cardio Workout Zones come in.

 What are the cardio workout zones?

Cardio workout zones are actually representations of the intensity of your cardio training. The lowest, Zone 1, is considered to be the lightest cardio workout zone, the one where you exert yourself the least while Zone 5 is the toughest and something that should never be attempted without first consulting a physician or a professional of some kind. However, before we get into explaining cardio workout zones, we need to take some time to talk about the various heart rates that you will need to be aware of in order to organize and schedule your cardio workouts according to the cardio zones.

Heart rates explained

The first of the heart rates that you will need to determine your cardio workout zones is the Maximum Heart Rate (MaxHR). The maximum heart rate is considered to be the number of beats that your body is capable of churning out at the most. In short, your heart cannot beat faster than this. The most precise way to find out your MaxHR is to visit a doctor and to have an electrocardiogram test done. However, since most of us do not have the time, the money or the means to get this test done, we need to employ any of the formulas that have been devised to calculate or at least approximate the MaxHR. We will get to this later.

The second of the heart rates you need to be aware of is the Target Heart Rate. As you may have guessed from its name, it is the heart rate that you are going for when working out. You target this particular heart rate during your workout because it is a great representation of how intense the workout is. It is the most precise representation when cardio training is in question. You get your Target Heart Rate by calculating the percentage of your Maximum Heart Rate. We will also get to this later, after the introduction.

Recovery Heart Rate is the third of the heart rates we are concerned with here and it represents the difference between your heart rate during the workout and the heart rate you experience after one to two minutes have passed from the workout. This is important because you can see how fit you are by calculating the recovery heart rate. For example, if the difference is only slight (meaning that your heart is beating pretty much the same 2 minutes after you have stopped working out), you are not very fit. The bigger the difference, the fitter you are. A common recovery heart rate is somewhere around 20-30 beats per minute.

How to calculate your predicted maximum heart rate?

As we have already mentioned, the best and the most precise way to get your MaxHR is to have an electrocardiogram test done. Fortunately, there are other ways you can do this, employing one or more of the different formulas that have been devised for this purpose specifically. We will introduce the most popular of them here but you need to keep in mind that approximations may be off, sometimes even up to 10-15 bpm. There is definitely no shortage of calculators that you can use for this that you can find for free online but we would also like to give you a few of these formulas here.

The simplest is the Age Predicted Formula, or Age-Based formula. According to this formula, you simply subtract the number of your age from 220 and you get your MaxHR.

So, if you are 35, you subtract it from 220, 220-35 and you get the MaxHR of 185. You should keep in mind that this formula tends to be less precise when the person is over the age of 40.

A more complex formula is the Edwards Age and Weight Predicted Formula. This formula also factors in the body weight. The formula goes as following:

For Women: 210 – half of age – 5% of body weight

For Men: 210 – half of age – 5% of body weight + 4

Let’s say that you are a woman, aged 40, weighing 150 lbs. That would be 210 – 20 (half the age) – 7.5 (150 * 0.05) + 182.5. For a man of the same age and the same weight, the MaxHR would be 182.5 + 4 = 186.5

The Karvonen Formula is also one that is often used but it can get quite complicated. Instead, you can, for instance, check out the calculator here that will help you find your MaxHR.

Cardio Workout Zones

Once you have calculated your Maximum Heart Rate, it is easy to find your target heart rate which will indicate in which Cardio Workout Zone you are and this will let you know how intense the workout is and what effects you can expect. Although some experts mention only four zones (see image below) dividing them into five zones is considered as more precise.

Zone 1 is also called the Healthy Heart Zone. It is the perfect zone for the newcomers to fitness training. In addition to this, this zone is also for warming up and cooling down. In this zone, you are working out at 50-60% of your MaxHR. This means that if your MaxHR is 180 bpm, the Zone 1 would be between 75 and 108 bpm. By working out in this zone, you will decrease your body fat somewhat, as well as your blood pressure and blood cholesterol levels. You will make yourself healthier, but you will not be losing too much weight or increasing your cardiorespiratory endurance.

Zone 2 is the Fat Burning Zone or the Temperate Zone. This zone is perfect for people with average fitness levels who wish to gain some muscle mass, train their bodies to burn fats more efficiently and improve the health of the heart. This zone can be reached by jogging slowly. In this zone, you are working out at 60-70% of your MaxHR.

Zone 3, or the Aerobic Zone is at 70-80% of MaxHR. This is the zone you get in by running and where you start to sweat. By working out in Aerobic Zone, you will enhance the ability of your heart to pump blood and you will also increase the capacity of the lungs. Workouts in this zone will decrease your heart rate and improve the cardiovascular fitness. If you are going for an endurance event in the future, you need to hit this zone in your training.

Zone 4 is also known as Anaerobic Threshold and it is a high-intensity workout zone. Some people also call it the Performance Zone. In it, you are working out at 80-90% of MaxHR. In this zone, you will burn even more calories and you will also increase your VO₂ Max. Work outs in this zone should only be done in short intervals.

Zone 5 or the Red Line Zone is the most intensive one and you need to be cleared by the physician before you even attempt to work out in this zone. It occurs at 90-100% of MaxHR and only the professional athletes or those who are at the peak of physical fitness can work out in this zone, and even they for a very short time. Working out in this zone often leads to injuries.

And there you have it, cardio workout zones explained in short. Keep in mind that the MaxHR can change over the years and because of the fitness training that you have been doing. Also, keep in mind that there are other ways in which you can approximate in which zone you are, such as the Talk Test, for example. However, if you keep these various cardio zones in mind, you might just find that golden work out intensity that will satisfy your needs and provide you with the results that you have been looking for.

Author profile:

Goran Bogunovic’s fitness career started some fifteen years ago and it was really love at first sight. Since then he has been learning and testing his knowledge on himself. Now he can say that he has substantial experience in fitness, strength training, nutrition and supplementation and he wishes to share what he has learned with you.