##### What is a MET?

Tweet###### Brian Bambl B.S. Exercise Science 2012-01-20

If you’ve ever ran on a treadmill, ridden a recumbent or upright bike, used an elliptical, or used any other cardio machine then chances are that you’ve seen the word **MET** on the console of those machines. Have you ever wondered what a **MET** is?

Well, **MET** stands for **Metabolic Equivalent of Task**and thus is used to evaluate the metabolic level (energy cost) of a given activity. The measurement system of METS keeps the metabolic measurements simple and makes it possible for exercise scientists to easily relate the energy level of one activity to another and to the amount of energy that a person uses at rest. For example, while at rest you’re energy cost/metabolic rate is equivalent to 1 MET.

The energy cost of 1 MET is equivalent to burning 1 Kilocalorie (1 **C**alorie that you see on a nutrition label) per kilogram of body weight per hour. 1 MET is also equivalent to your body using 3.5 milliliters of oxygen per kilogram of body weight per minute (3.5 ml O_{2} *kg^{-1}*min^{-1}). This is where we can connect METS to exercise. The measurement of the amount of oxygen that your body uses is directly related to the number of Calories that you’re burning. This is due to the fact that oxygen is an important component in the metabolism process and there is a linear relationship between how much oxygen your body uses and the number Calories that you burn That is, for every 1,000 milliliters of oxygen (1 Liter) that your body uses, you burn 5 Calories/Kilocalories. This is one of the reasons that your breathing rate increases as you run, your body needs more oxygen in order for that Calorie burning process/metabolism to continue.

Now, let’s look at METS as it directly relates to cardio. We’ll use running in our example. If we were to measure how much oxygen a 150 lb. (68.1 kg) individual uses running at a speed of 6 MPH, we would see that while running they would be using 2,452 milliliters of oxygen per minute. Then after doing the math we could see it more simply put it as them working at a level of 10.29 METS. The 10.29 METS allows us to easily relate this person’s metabolic level as being 10.29 times greater than when at rest. Now, you must remember that METS is relative to your body weight and that is one of the reasons that exercise machines will ask you to enter your body weight. Entering your body weight allows the machine to accurately tell you how many Calories that you’re burning/burn.

Well, we don’t have a machine to do the math for us, but I have done it. In doing the math we can see that a 150 lb. individual would burn 122.76 Calories during this run. Remember, the number of Calories that an individual burns at 10.29 METS is relative to THEIR body weight.

If you don’t feel like doing the math then you can use our Running calorie calculator on this page.

Here is the math step by step, assuming we could measure the individual’s oxygen use during their run.

2,452 milliliters of oxygen / 3.5 ml of Oxygen * 68.1 kilograms = 10.29 METS

10.29 METS * 3.5 ml of Oxygen * 68.1 kilograms * 10 minutes= 24,555 milliliters of oxygen.

Remember that for every 1,000 milliliters (1 Liter) of oxygen that your body uses, you will burn 5 Calories.

So, 24,555 milliliters / 1,000 milliliter = 24.55 Liters of oxygen.

24.55 liters of oxygen * 5 Calories = 122.7 Calories