What Are METs on a Treadmill?

1. What Are METs on a Treadmill? The Short Answer

METs (metabolic equivalents) on a treadmill show how hard you are working as a multiple of your resting energy use: 1 MET is sitting quietly, so 4 METs means roughly four times your resting rate. The console typically estimates the figure from the belt speed and incline using standard equations, not from anything it measures about you.

As rough landmarks, the standard equations put a 3 mph walk on the flat at about 3.3 METs, a 3.5 mph walk at a 5% incline at about 6 METs, and a 6 mph run on the flat at about 10 METs. The full table is below. Activities between about 3 and 6 METs are conventionally classed as moderate intensity, and 6 METs and above as vigorous.

Because a MET is defined per kilogram of body weight, the figure on the display is the same for a light person and a heavy person at the same settings. That is what makes it handy: it describes the settings, not the person. It is also what makes it a rough guide, because two people at 6 METs may find the session very different depending on their fitness.

To turn METs into calories, multiply by your weight in kilograms and the time in hours: 6 METs for 30 minutes at 160 lb (about 72.6 kg) is roughly 6 × 72.6 × 0.5, or about 220 calories. The sections below show where all of these numbers come from.

2. What Exactly Is a MET?

A MET is a unit of energy use equal to the rate at which an average adult uses oxygen sitting quietly at rest, conventionally set at 3.5 millilitres of oxygen per kilogram of body weight per minute. That works out at roughly one kilocalorie per kilogram of body weight per hour.

The idea is to describe activities as multiples of rest. If an activity is rated at 5 METs, it uses about five times as much oxygen, and therefore about five times as much energy, as sitting still. Writing it that way has two useful consequences:

• It is independent of body size. Because the unit is per kilogram, a walk at a given speed and grade has roughly the same MET value for anyone, and body weight comes back in only when you convert to calories.
• It is comparable across activities. A MET value for a treadmill walk can be compared with one for cycling, gardening or climbing stairs, which is why physical activity guidelines and research use it.

Where the "1 kcal per kg per hour" comes from. Using oxygen releases energy at roughly 5 kilocalories per litre of oxygen. At 3.5 ml/kg/min, one hour is 210 ml per kilogram, or 0.21 litres, and 0.21 × 5 is about 1.05 kilocalories per kilogram per hour. Rounding that to 1 is a convenient approximation, and it is why the two common calorie formulas below give slightly different answers.

The 3.5 is a convention, not a measurement of you. Real resting energy use varies from person to person with body composition, age, sex and other factors, and for many people it sits somewhat below the conventional figure. That does not make METs useless — they are a standard scale, like a ruler — but it is one reason that converting METs into calories for a particular person is an estimate.

3. Why Does My Treadmill Show METs?

Treadmills show METs because it is a standard, weight-independent way of describing exercise intensity, used in exercise physiology, clinical exercise testing, cardiac rehabilitation and public health guidelines — and because the console can calculate it from the two things it knows, speed and incline.

The treadmill is where much of the science of exercise intensity was worked out, and treadmill exercise tests often express a person's capacity in METs. Rehabilitation programmes sometimes give patients a MET range to work within. If someone has been told by their clinical team to exercise at, say, 3 to 4 METs, a treadmill that displays METs makes that instruction easy to follow — with the caveat that the console figure is an estimate, and the clinical team's advice on how to use it comes first.

For everyone else, the MET display is mostly a convenient intensity readout. It answers the question "how much harder is this setting than that one?" in a way that speed alone cannot, because it combines speed and incline into a single number. A 3 mph walk at a 10% grade and a 5 mph jog on the flat look very different on the speed display; the MET figures show they are in the same broad range of effort for an average person.

Not every console shows METs, and those that do may label the field differently or show it only in certain modes. Your manual will say whether it is there and how it is calculated, though many manuals do not explain the calculation at all.

4. How Are Treadmill METs Calculated?

Treadmill METs are typically calculated from belt speed and incline using metabolic equations like the American College of Sports Medicine (ACSM) walking and running equations, which estimate oxygen use per kilogram from speed and grade and then divide by 3.5 to give METs. We cannot see inside any particular console, but these published equations are the standard approach and are the basis for every figure on this page.

The two equations

Both equations give oxygen use (VO₂) in millilitres per kilogram per minute. Speed is in metres per minute (1 mph is 26.8 m/min) and grade is the incline as a decimal (5% is 0.05).

• Walking: VO₂ = 0.1 × speed + 1.8 × speed × grade + 3.5
• Running: VO₂ = 0.2 × speed + 0.9 × speed × grade + 3.5
• METs = VO₂ ÷ 3.5

Each equation has three parts. The first term is the cost of moving horizontally — and running costs about twice as much per metre as walking in this model. The second term is the cost of climbing, which depends on how fast you are rising. The final 3.5 is the resting component, the one MET you would use anyway.

A worked example: 3.5 mph at 5%

• Speed: 3.5 mph × 26.8 = 93.9 m/min.
• Horizontal: 0.1 × 93.9 = 9.4.
• Vertical: 1.8 × 93.9 × 0.05 = 8.4.
• Resting: 3.5.
• Total: 9.4 + 8.4 + 3.5 = 21.3 ml/kg/min.
• METs: 21.3 ÷ 3.5 = about 6.1.

A worked example: 6 mph on the flat

• Speed: 6 mph × 26.8 = 160.9 m/min.
• Horizontal: 0.2 × 160.9 = 32.2.
• Vertical: 0.9 × 160.9 × 0 = 0.
• Total: 32.2 + 3.5 = 35.7 ml/kg/min.
• METs: 35.7 ÷ 3.5 = about 10.2.

Notice that body weight appears nowhere. The console does not need to know it to show METs; it only needs your weight for the calorie field. That is why the MET display can be roughly right even when the calorie display is badly off because nobody entered a weight.

5. Treadmill METs by Speed and Incline: An Estimate Table

The tables below are calculated from the ACSM equations above, rounded to one decimal place. They are estimates for an average person walking or running hands-free at the stated settings, not measurements. Use the walking table for walking and the running table for running, whatever the speed — the next section explains why that matters between 4 and 5 mph.

Walking (estimated METs)

Running (estimated METs)

Two patterns stand out. First, incline moves the number much more for walkers than speed does: going from 3.0 to 3.5 mph on the flat adds about 0.4 METs, while raising the grade from 0% to 5% at 3.0 mph adds about 2.1. That is the arithmetic behind the popularity of incline walking, which our guide towhat incline to walk onputs into practice. Second, in the running equation each percent of grade adds relatively little — the climbing coefficient is half the walking one — so for runners, speed is the bigger lever.

Treat the extreme corners of the tables with extra caution. Steep grades at the faster walking speeds and fast running speeds are where the equations are furthest from the conditions they were built for, and where individual differences are largest.

6. Which Equation Applies Between 4 and 5 mph?

Between about 4 and 5 mph, use the equation that matches what you are actually doing — the walking one if you are walking, the running one if you are jogging — because the two give very different answers at the same speed.

At 4.5 mph on the flat, for example, the walking equation gives about 4.4 METs and the running equation about 7.9. Neither is wrong; they describe different movements. Running involves a flight phase and more vertical bounce, and the running equation's horizontal term is twice the walking one to reflect that. A fast walk at 4.5 mph is awkward and hard for many people, and the walking equation probably understates it; a slow jog at the same speed is comfortable for many runners.

The equations are usually described as most accurate within certain ranges: the walking equation for speeds of roughly 1.9 to 3.7 mph, and the running equation for speeds above about 5 mph, or lower if the person is genuinely jogging rather than walking. Our 4.0 mph row sits just outside the walking range and should be read with that in mind.

This creates a practical problem for consoles. A treadmill cannot see whether you are walking or running at 4.5 mph, so a console that uses equations like these has to make an assumption — for example, switching from one equation to the other at a fixed speed. If yours does, its MET figure can jump noticeably as you cross that threshold even though your effort barely changed. If your console's MET reading leaps between two adjacent speeds, this is a plausible explanation. For walkers who want a harder session, the cleaner route is usually to add incline at a comfortable walking speed rather than pushing into the awkward zone; see our guide towhat speed to walk on a treadmill.

7. How Do You Convert METs to Calories?

To convert METs to calories, multiply METs by your body weight in kilograms and by the time in hours: calories ≈ METs × kg × hours. For weight in pounds, divide by 2.2 first. This is the same arithmetic behind most calorie estimates, including many console figures.

Example. A 160 lb person (about 72.6 kg) walking at 3.5 mph and 5% for 30 minutes: 6.1 × 72.6 × 0.5 ≈ 221, so roughly 220 calories. The same session for a 200 lb person (about 90.7 kg): 6.1 × 90.7 × 0.5 ≈ 277, so roughly 275 calories. A 6 mph run on the flat for 30 minutes at 160 lb: 10.2 × 72.6 × 0.5 ≈ 370 calories.

The per-minute version. Another common form is calories per minute = METs × 3.5 × kg ÷ 200. It gives figures about 5% higher than the simple version, because it uses roughly 5 kilocalories per litre of oxygen instead of rounding to 1 kcal per kg per hour. For the 3.5 mph, 5% example it gives about 7.7 calories a minute, or roughly 230 for half an hour. The difference is a reminder of how much precision these numbers really have: two respectable versions of the same formula disagree by more than ten calories on a half-hour walk.

Gross versus net. Both versions give gross calories, which include the one MET you would have used sitting on the sofa anyway. If you want the extra calories the session cost, use METs minus one: (6.1 − 1) × 72.6 × 0.5 ≈ 185 calories for the example above. The difference matters most at walking intensities, where the resting component is a larger share of the total.

For tables of calorie estimates across speeds, inclines and body weights, see our reference ontreadmill calories burned; for why the console figure often runs high, see whethertreadmill calories are accurate.

8. What Are MET-Minutes, and How Many Do You Need a Week?

MET-minutes are METs multiplied by minutes of activity, and the US physical activity guidelines' recommendation of 150 to 300 minutes of moderate activity a week is commonly expressed as roughly 500 to 1,000 MET-minutes a week.

The arithmetic is simple. Thirty minutes at 3.3 METs is 99 MET-minutes. Thirty minutes at 6.1 METs is about 183. The point of the unit is that it combines intensity and time into one number, so a shorter, harder session and a longer, easier one can be compared.

Where 500 to 1,000 comes from. The Physical Activity Guidelines for Americans recommend that adults get at least 150 to 300 minutes of moderate-intensity aerobic activity a week, or 75 to 150 minutes of vigorous activity, or an equivalent mix. Moderate activity is conventionally 3 to just under 6 METs. One hundred and fifty minutes at 3 to 6 METs is 450 to 900 MET-minutes, which is why the weekly target is often framed as roughly 500 to 1,000 MET-minutes. Vigorous minutes count roughly double, which the MET arithmetic captures naturally.

Treadmill examples. Using the table estimates:

• Five 30-minute walks at 3.0 mph, flat: 5 × 30 × 3.3 ≈ 495 MET-minutes — right at the lower end.
• Five 30-minute walks at 3.5 mph, 5%: 5 × 30 × 6.1 ≈ 915 MET-minutes.
• Three 25-minute runs at 6 mph, flat: 3 × 25 × 10.2 ≈ 765 MET-minutes.

Two cautions. The guidelines are about the total amount of activity across the week, and the MET-minute figure is only as good as the MET estimate underneath it. And the guidelines are written for the general adult population; if you have a medical condition, how much and how hard you should exercise is a question for your doctor. For planning a week around the number, our guide tousing a treadmill every daycovers spreading sessions and recovery.

9. What Is a Good MET Number on a Treadmill?

There is no single good MET number on a treadmill; the right figure depends on your fitness and what the session is for. As a broad guide, about 3 to 6 METs is moderate intensity and 6 or more is vigorous, but the same MET figure can be easy for one person and very hard for another.

That is the main limitation of METs as an intensity guide. They measure the absolute cost of the settings, not how hard that cost is for you. A 6-MET incline walk may be a comfortable conversational effort for a trained runner and close to the limit for someone who has been inactive for years. Both are using roughly the same oxygen per kilogram; what differs is how close that is to their maximum.

For deciding how hard to work, relative measures usually serve better:

• The talk test. At moderate intensity you can talk in full sentences but not sing; at vigorous intensity you can only manage a few words at a time.
• Heart rate, measured with a chest strap or a reasonably fitted watch, interpreted against your own zones. Our guide totreadmill heart rate zonesexplains how to set them and their limits.
• Perceived effort, rated honestly on a simple scale.

METs are best used alongside these: as a way of seeing that a session got harder or easier, of comparing settings, and of adding up weekly totals. If a clinician has given you a MET range, use it as they instructed, remembering that the console figure is an estimate for an average person and that your heart rate and symptoms come first.

10. How Accurate Are Treadmill METs?

Treadmill METs are reasonable estimates for an average person, but they are not a measurement of you: they assume average movement efficiency, a conventional resting rate, hands-free walking and an accurate speed and incline display, and any of those can be off.

• Individual efficiency. People differ in how economically they walk and run. Two people at the same settings can use noticeably different amounts of oxygen, and the equations give both the same figure.
• The resting convention. The 3.5 ml/kg/min definition of one MET is a standard value, not your resting rate, which affects any conversion into calories.
• Holding the rails. The equations assume you support your own weight. Gripping the rails, especially on an incline, reduces the real cost while the MET display stays the same. Our guide toholding the handrailsexplains the effect.
• Display accuracy. The console calculates METs from the speed and incline it thinks it is running at. If the belt is slow or the incline is off, the MET figure is off with them; our guide totreadmill calibrationcovers checking both.
• The walk-run switch. As explained above, the equations differ sharply between walking and running, and the console has to guess which you are doing.
• Steady state. The equations describe steady effort. In the first minutes of a session, or during short intervals, the displayed figure changes instantly while your body takes time to catch up.

None of this makes the figure useless. A MET display that consistently describes the settings is a good way to compare sessions on the same machine and to see the effect of incline. It becomes less trustworthy when you compare across machines, convert to precise calorie counts, or treat it as a personal measurement.

11. Frequently Asked Questions