Did you know that no two people may burn the same amount of calories for the same workout? In addition to different workouts having different intensity levels, people can be of different sizes or weights and have a unique resting metabolism. METs, or metabolic equivalents, were developed by physiologists to help us understand and calculate an exact value for caloric expenditure for each person.
Highlights
- MET is a number used to show the difference between your working metabolic rate and your resting metabolic rate, the number indicates the intensity of a given physical activity,
- The MET for an activity, you can also estimate how many calories you burn in a minute by applying a simple formula,
- METs help us really gauge how effective a workout is, be it standing up from a chair or running on a treadmill.
METs are a great way to measure exercise intensity, by using this method, you can save your brain from a long cardio session of calculating the energy burned during exercise.
In this article, we’ll see how METs work and how to accurately calculate and implement them to improve your exercise and its results. So let’s start with this cardio, shall we?
What are METs?
A MET is a number used to show the difference between your working metabolic rate and your resting metabolic rate. (4) Put more simply, the number indicates the intensity of a given physical activity, with one MET being the energy you spend sitting at rest. If a workout uses eight METs, it means your body uses eight times the amount of energy than when you’re at rest.
We have mentioned a few times that METs are a measure of the relative difficulty of a physical activity, but what are they really measuring? Well, to understand this, we need to grasp how our body uses energy. Our cells use oxygen to create energy and this energy is used as fuel for contraction in our muscles. One MET for most individuals at rest is equal to 3.5 millilitres of oxygen per kg of the body per minute. (10) Now, if that is confusing, you can just think of it as how much oxygen your body is consuming. The harder your muscles work, the more oxygen they need, and the higher your MET score.
Complicated as they may sound, METs are numbers that you might have seen more frequently than you think. They appear on wearable fitness devices and even on your treadmill while you are running.
You may not have given them much thought, but METs could be your best friend. They help us really gauge how effective a workout is, be it standing up from a chair or running on a treadmill.
Ideal MET scores
Now that we understand the meaning of a MET score, you may be asking what kinds of exercise MET scores correspond with and what your goal should be.
MET scores are often split into three subsections: light, moderate or vigorous.
According to the Centers for Disease Control and Prevention, USA, activities burning 3.0 to 6.0 METs qualify as moderate-intensity, while those using more than 6.0 METs are vigorous. (9)
Shown simply:
<3.0 METs = Light intensity
3.0–6.0 METs = Moderate intensity
6.0 METs = Vigorous
It’s recommended by health experts such as the American Heart Association that individuals should do a minimum of 150 minutes of moderate aerobic activity weekly to achieve their best cardiovascular health. This amount of exercise is equal to approximately 500 MET minutes per week. (4)
You can meet these scores through any variety of activities, from running to biking and even kayaking, among others.
How are METs calculated?
As a practical tool, METs allow for a general comparison of different activities and relative intensities.
As mentioned earlier, activities are split into three different categories based on light, moderate and vigorous intensity. (9)
Also, our muscles use oxygen to help create the energy needed to burn calories. One MET is the energy required for an average adult to sit still and equals this approximate 3.5 ml of oxygen per kg of body weight per minute. (9) An example of a 2 MET activity would be one that requires double the metabolic energy expenditure, and this trend would continue as the MET numbers increase.
This means that the energy cost of an activity can be calculated by taking the relative oxygen cost for a particular activity (ml o2/kg/min) by 3.5. (11)
METs and calories
When it comes to fitness, you might be more familiar with calories than METs. Calories are a measurement of energy expenditure, scientifically defined as the energy needed to raise the temperature of 1 gram of water through 1°C. But what does this have to do with METs? The human body will burn around 5 calories to convert 1 litre of oxygen into energy. So the more oxygen we consume, the more calories we burn. (10)
But, here’s how METs differ from calories. If two people who weighed the same were to cycle the same distance and course, they would burn an identical number of calories. However, if one of these individuals weighed double the other, they would burn almost double the calories. Using METs helps us factor in the differences without all the complicated caloric calculations.
So once you have the MET for an activity, you can also estimate how many calories you burn in a minute by applying a simple formula. This formula can also help you make decisions about whether you should increase the level of intensity or duration to achieve a specific goal, like weight loss. (4)
Formula:
METs x 3.5 x Body weight (kg) / 200 = Kcal/min.
Both METs and calories are useful. You’ll find calorie counts listed all over food packaging and part of many fitness routines, making them seem like a requirement for engaging in any fitness goals. However, it can be incredibly confusing when trying to figure out the amount of calories burned in a given day or workout. This is where METs can be a fundamental tool for creating a baseline way of tracking your workout intensity and caloric burn.
MET score for common activities
So far, we have been focusing predominantly on how MET scores relate to workouts or slightly higher-intensity physical activity, but METs can be useful at any stage of your fitness journey. Whilst it can be laborious to calculate the calories burned on a walk or while doing chores, it can be much easier to remember your MET score for these kinds of activities. And as mentioned above, this can help contribute to your weekly activity or MET goals!
You may be surprised by the MET scores of common activities that are not strictly ‘workouts’. Any activity that is more strenuous than sitting can have a MET score.
Common light-intensity MET activities: (9, 10, 11, 12)
- Putting away laundry – 2.3 METs
- Standing at your desk – 1.8 METs
- Sitting and reading – 1.3 METs
- Washing dishes – 2.2 METs
- Going for a slow walk – 2 METs
Common moderate MET activities: (9, 10, 11, 12)
- Walking to the store – 3.5 METs
- Walking with your dog or a stroller – 3.8 METs
- Mowing the lawn/yard work – 5.0 METs
- Weeding your garden – 3.8 METs
- Playing with your kids – 3.5 METs
In comparison to these activities, MET scores for high-intensity activities/workouts, like running or bicycling, range from 8 to 11.5. (9, 10, 11, 12).
Conclusion
Overall, METs effectively help in calculating the intensity and progress of your active routine. The more effort, and thus oxygen, an activity requires, the higher its MET value. METs can be especially useful if you don’t like to use measurements such as heart rate or calories burned. They can also help you calculate your calories burned in a simple way.
However, METs are not always accurate, especially if you use a chart based on an average person of ‘normal’ weight (in many cases 70 kg/154 lbs). The intensity of a specific workout and the calories burned in a day are largely based on your gender, age, height, weight and lean body mass. For example, inexperienced or overweight individuals may exert more oxygen than an advanced athlete when going for a run or doing physical activity.
Aiming for good health using METs as an indicator is not as limiting as looking at calories in and out. One can aim for at least 500 MET minutes a week for ideal cardiovascular health, and that can be achieved through a variety of activities.
Disclaimer: The contents of this article are for general information and educational purposes only. It neither provides any medical advice nor intends to substitute professional medical opinion on the treatment, diagnosis, prevention or alleviation of any disease, disorder or disability. Always consult with your doctor or qualified healthcare professional about your health condition and/or concerns and before undertaking a new health care regimen including making any dietary or lifestyle changes.
References
- https://www.precor.com/en-us/what-are-mets
- https://www.sciencedirect.com/topics/medicine-and-dentistry/metabolic-equivalent
- https://www.latimes.com/archives/la-xpm-2005-oct-24-he-mets24-story.html
- https://www.healthline.com/health/what-are-mets
- https://www.webmd.com/fitness-exercise/what-is-a-met-score#
