Learn about MET and how this simple ratio will change the way you evaluate your physical exercise.

A common scenario

I’m a heavier set guy. I wouldn’t say fat, but if I could just lose those pesky few kilos, I know my joints would love me more and I’d be running a trim faster. The funny thing is after going out for my typical 20km run down the Limmat (the river here in Zurich), and posting the run details from dacadoo on my Facebook profile, I get a lot of comments from girls saying things like: “Wow, you burned a lot of calories!” and “I wish I could burn that many calories during one of my runs.” Is dacadoo tracking this correctly?

Or are these numbers just really wrong? I can assure you that dacadoo is accurately tracking your calorie usage, even more so if you use a heart rate monitor. Why we don’t all burn the same amount of calories has to do with our size, and most specifically our weight. The girls that comment on my posts are generally 15kg if not more lighter than I am. They weigh less, so they need less energy to move themselves.

The math behind MET

Though you might think that’s unfair, don’t forget that we all consume different amounts of calories as well. Nonetheless, a scientific figure is needed to measure the intensity of a workout and bring people onto a level playing field. That number is called MET (The Metabolic Equivalent of Task, or simply metabolic equivalent). Unless you’re a mathematics major the exact calculation might not be that interesting, but here it is: 1 MET = 3.5 ml O2·kg−1·min−1 or put another way: 1 MET = 1 kcal·kg−1·h−1. Now that might not say much to you, but what MET really allows us to do is assign a value to different activities, because not all activities are created equal and 1 hour of walking is different than 1 hour of running. By using MET, you can better compare the total health benefits of different activities amongst different people.

Image: The dacadoo health platform enables the tracking of over 95 fitness workout activities (outdoor and indoor sports) either over the mobile dacadoo tracker app or via manual entry. The dacadoo energy models are based on MET (metabolic equivalent of Task)* which measures the intensity of a physical activity. *Compendium of Physical Activity, Stanford University

Application of MET

Now that we understand where MET comes from we can apply it to our physical activities. Because MET is a mathematical ratio (intensity and rate), there is also the idea of a MET- minute. The MET-Minute allows us to compare apples and oranges if you will — that is different people doing different activities. Let’s look at an example to drive this point home: Megan works long hours in the office, but takes time three times a week to go running for 30 minutes. Ralph is self-employed and doesn’t much like doing too much sport on his own but plays tennis on Saturdays for 90 minutes. Both are doing 90 minutes of sport a week, but they have different weights, heights and are different genders, so their calorie burning will be different. No problem.

MET Calculation:

We can therefore see that Jane is doing more for her general health with her activity three times a week. She may not be burning more calories overall, but the sport she is doing burns more calories compared to her weight than what Ralph is doing. You will also want to note that the health benefits of increasing the number of MET-minutes will only plateau at very high levels, and for most people, there will be no diminishing returns. In general you want to increase your total number of MET-minutes.

MET Intensity

Here is a table of some common activities and their MET value. As you can see sleeping is less intense than sitting awake. Though your metabolism works through the night and in a deep sleep works most efficiently, MET is a separate calculation and does not take your metabolic rate into consideration. The MET scale goes from 0.9 (sleeping) to 23 (running at 22.5km/h or a 4:17 mile pace).

Physical activity MET

Conclusion

MET provides a statistical formula for comparing different activities based on their intensity. Using MET you should be able to build more variation into your fitness routine. In the coming weeks we’ll feature posts on the specific health benefits of MET activities in the light, moderate, and intensive intensity groups.

Example picture:

To really make the point about MET clear, consider this last example: Riding your bike to work has a MET value of 4 and running has a MET value of 8. That means you need to bike at the easy city pace twice as long as you run to get the same benefit.

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