How hard should you be working during cardio exercise? Most fitness beginners have no idea how hard they need to exercise in order to burn calories, burn fat and lose weight. They call it “working” out for a reason: you need to put some effort into your cardio routines in order to get any benefits out of them. But how do you find that line between “not enough” and “too much”?

There are a few simple methods to measure the amount of effort you’re expending during physical activity. Let’s look at the famous Talk Test, Perceived Exertion and your Target Rate Zone.

How The Talk Test Works

The first method of measuring exertion is the simple “Talk Test”. There is a direct correlation how hard you are working and how difficult it is to speak. In essence, the harder you exercise, the more oxygen your muscles require, leaving less oxygen available for conversation.

During cardio exercise, you should never push yourself past the point where you are able to speak. Not only does this help keep you in the target heart rate zone, it is also a safety consideration. You just never know when you’re going to have to shout out “Quick, call 911”.

But if you find yourself singing show tunes while chugging away on the treadmill, you need to pick it up a notch – actually, a couple of notches. Moderate effort should allow you to have short conversations, while vigorous effort will reduce those conversations to short sentences. So now you know that exercise buddies who use their treadmill time to “catch up” on the kids’ latest accomplishments, aren’t working as hard as need to be.

How Perceived Exertion Works

The concept of perceived exertion attributes a numerical value to the level at which you think you’re working. The scale ranges from 1-10, with 1 corresponding to a level of exertion you could maintain forever (like laying in bed watching reality TV), and 10 corresponding to maximum exertion just short of passing out. Your cardio workouts should require an exertion level in the 5-8 range.

So if you’ve been jogging for 3 miles every day at an exertion level that feels like an 8, and you realize one day that you’re feeling like a 4, then you know you can start pushing yourself a bit harder during your workouts.

The following chart will help you determine your perceived level of exertion. You may want to print this page and tape the chart on the wall next to your treadmill.

Scale of Perceived Exertion

10: You can’t talk. Sweat is pouring out of every pore. You’re light-headed and heart feels like it will burst out of your chest.

9: The activity you’re performing is extremely challenging, but not impossible to continue. You’re heart is pounding. You can barely speak a few words.

7-8: You can continue, but you don’t like it. You’re on the edge of your comfort zone. You’re sweating and breathing very hard, but you can still speak in short sentences.

4-6: You feel like you could keep up this pace for quite a while. Your heart is beating fast and you’re sweating, but you can hold a short conversation.

2-3: You could keep moving like this for a long time without much effort. Your heart rate is slightly elevated and you have broken a slight sweat, but you can easily hold a conversation. Many treadmill buddies get stuck in this range, too busy to talking to notice they aren’t really working.

1: You aren’t moving at all, but doing some completely sedentary activity like watching TV or surfing the internet.

The Karvonen Method Of Measuing Target Heart Rate

One last method to measure your level of exertion is to measure your heart rate. The idea is to work out hard enough to elevate your heart rate to a certain level and then keep it there for the duration of your cardio session.

The standard formula for measuring the target heart takes into account your age, but not your current level of fitness. But the Karvonen method also takes into account your resting heart rate, which typically is lower as you become more fit. This method requies a little bit more math, but is still very easy to calculate.

1. Subtract your age from 220 to find your estimated maximum heart rate


2. Subtract your resting heart rate (the number of times your heart beats in one minute) from your maximum heart rate.

3. Divide the answer in Step 2 by 2 and add your resting heart rate back in to determine the low end of your target heart rate zone.

4. Multiply your answer in Step 2 by .85 and add your resting heart rate back in to determine the high end of your target heart rate zone.

Let’s look at an example for a 40-year old woman with a resting heart rate of 60 beats per minute:

(1.) 220-40 = 180


(2.) 180-60 = 12o

(3.) 120 / 2 = 60

60 + 60 = 120

(4.) 120 X .85 = 102

102 + 60 = 162

From this example, our 40-year old woman knows that she can push herself to a maximum heart rate of 162 beats per minutes. Most of the cardio machines at the gym includes a heart rate monitor so you can easily keep track of your heart rate during your cardio workout. In fact, the best cardio machines for home use also include this type of technology. If you like to jog for cardio exercise, invest in a watch that includes a heart rate monitor.

There really is not excuse for not working out at the proper intensity level. In fact, if you are going to invest time in your fitness schedule, make sure you are working hard enough to achieve your goals, whatever they happen to be. If you goals include a maximum level of fitness, hang up your cell phone and work out. If socializing is your primary reason for going to the gym, why not skip the gym and meet your friend at the coffee shop? The folks on the treadmills next to you will appreciate it.