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3 Reasons To Never Trust Estimated Calorie Burn On Cardio Machines

By Pat Koch, CSCS / September 14, 2018

If you’re someone who constantly worries about how many calories you’re burning during your workouts, then this article is for you.

You’re going to learn two important ideas about exercise and estimated calorie burn:

  1. You can’t trust estimated calorie burn on cardio machines, because they are likely inaccurate.
  2. Worrying about calorie burn is not the path towards fitness success over the long term.

Here are 3 reasons why estimated calorie burn on cardio machines is probably incorrect:

Reason 1: Estimated Calorie Burn Includes Your RMR

Imagine that all you did all day was lay down and not move. Your body requires a certain number of calories just to maintain your current body weight. This is called your resting metabolic rate (RMR), and it refers to the number of calories your body uses just to keep you alive (breathing, organ function, etc.). Your RMR is a huge determinant of how many calories you need to consume each day.

Treadmills and other cardio machines include RMR within their estimate of total calorie burn during your workout. This means the calorie estimate you see on display is not just how many calories you have burned during the activity, but also the number of calories you burned by simply being alive during that time. This leads to an overinflation of how many calories you burned by exercising.

For example, if a 175-lb man exercises for 30 minutes at a moderate pace, he will burn around 270 total calories according to his machine. But to get an accurate count, he would need to subtract around 40 calories from the 270 to account for his RMR. That means the number of calories he burned was actually closer to 230 calories.

The greater your workout time and the heavier you are, the more overinflated the number becomes. If you rely on exercise to create a large caloric deficit, you’ll definitely want to take this overestimation into consideration.

Reason 2: Cardio Machines Assume You Are A 180-lb Man

Calculating an estimated calorie burn on machines is very difficult because individuals vary so widely. In order to correctly estimate caloric expenditure, many factors need to be considered. Your total energy cost during exercise depends on your weight, gender, age, height, amount of muscle, and current disease state.

Treadmills rarely take the aforementioned factors into account. If you are exercising on a cardio machine and neglect to input information on your height, weight, or age, your estimates will be very off. Then, the cardio machine will use a default runner based on a typical man weighing about 160-180 lbs. If you weigh less than a typical man, your calorie burn will be overestimated, and vice versa.

Reason 3: Cardio Machines Do Not Take Into Account Exercise Efficiency

Exercise efficiency describes how many calories your body uses to do work. People who workout regularly and are very fit are more exercise efficient. That means they use fewer calories to do more work or exercise.

There are many factors that affect exercise efficiency that may also throw off the estimated calorie burn shown on a machine:

1. Muscle Fiber CompositionFast twitch fibers are less efficient than slow twitch fibers. Thus your efficiency, and potentially the total number of calories burned will depend on your genetic disposition and your overall training history.

2. Exercise Technique – Improved technique leads to fewer extraneous body movements and increased efficiency.

Lets take a competitive swimmer vs. a person who rarely swims as an example. If asked to travel the same distance at similar speeds, the experienced swimmer would burn fewer calories due to smoother strokes and a better understanding of buoyancy, which makes the activity easier for him.

The same applies to cardio machines. Although cardio machines are less technical than swimming, your body adapts to the exercises you do regularly, making them easier over time. As you get better, you burn fewer calories doing the same amount of work.

A relevant example is using the handrails to hold up your body on a machine like the Stairmaster. Bracing yourself with your arms makes the activity easier, yet the machine fails to adjust for this measure.

3. Fitness Level – More fit individuals perform a given task at a higher efficiency because of decreased energy expenditure from non-exercise tasks such as temperature regulation, increased circulation, and waste removal. When you do specific exercises regularly (like running, using the stepmill, or rowing), you improve your cardiovascular fitness level and your muscles adapt to that exercise.

Improved fitness means that you burn fewer calories, unless you continually increase the challenge.

All of this is not meant to deter you from using cardio machines in your quest to lose fat. Increasing your exercise efficiency is not necessarily a bad thing when it comes to fat loss. Usually, an increase in efficiency comes with an increase in ability. For example, more efficient exercisers can usually run further and faster, and push themselves harder.

In fact, the best fat loss strategies generally encourage you to increase the intensity of your cardio workouts, not necessarily the duration.

How Do You Accurately Estimate Calorie Burn From Exercise?

Overall, there’s too many factors that affect your individual calorie burn during exercise to get an accurate estimate from a cardio machine. If you really need to know the number of calories you burned during your workout, you might want to consider using a fitness tracker like a Fitbit, but keep in mind that it has its own limitations.

At the end of the day, if you want to lose fat and keep it off long-term, it’s critical to get your diet in check so that you don’t rely on the “burn it off” mentality. You can’t out-train a bad diet. No amount of exercise will get you a lean and strong body if you’re not paying attention to your nutrition.

Also, consider weight training or interval training if you’re serious about burning fat. Throw in steady state cardio between your strength training days if you don’t want to limit your workouts to strength training. All in all, remember – don’t trust the machine.

For more ideas on the best nutrition, exercise, and lifestyle strategies to lose weight, check out these 101 Proven Tips to Lose Weight Fast.


  • Alexander says:

    Once again, thanks for the advice given. I didn't know about reason #1 previously.

  • warren says:

    A very informative article, when it comes to loosing weight and tracking your process counting calories burned was very important to me.

    I was counting the calories I eat and also the calories I burn, the reason for this was that I would eat back maybe half or all of the calories burned. In the beginning it seemed accurate and was working as I was shedding the fat, dropping pounds and my BF% was dropping.

    Where it starts to get difficult is when you hit the dreaded plateau. After tinkering with my diet and trying to accurately calculate my burn I noticed that if I tighten up my diet and record calories I eat more accurately and not bother with eating back the burned amount I will continue to drop the pounds and BF.

    So far I dropped 21lbs and reduced my bf% by 8% however I'm finding it harder at this moment in time to keep up with dropping 2lbs a week. I have continued to increase the intensity of my workouts and changed them up and my bf% seems to keep going down (if I trust the machine which calculates it for me.)

    This website has played in big part in educating me to do and eat the right things...

    Keep it up!

  • Patrick Koch says:

    Warren, congrats on the hard work.. In my experience weight loss is rarely linear. You are taking all the right steps though. Keep arming yourself with knowledge. And I'm glad Builtlean has helped.

  • Krassi says:

    Thank you Pat for the light brought to this always disputable gym matter.
    I knew that the treadmills were not accurate because each one (different model) gives me different readings for the same exercise, but so are the bicycles.
    Not that I really bother how much calorie I burn, but I need to track and measure somehow my exercises.
    What do you think about the heart rate monitors? Are they any closer to the truth?
    Thank you again.

  • Patrick Koch says:


    I have had trouble finding information on the formulas the heart rate monitors use. My intuition tells me they are slightly better but its hard to say. This could be a good question to ask a company rep.

  • Krassi says:

    Thanks Pat,
    I also have the feeling that they might be a bit better indicator, but what I found strange is when I do moderate cardio I hardly break a sweat, but my heart rate is 140/150. When I do streingth training I hardly breath and my sweat runs like a river, but my heart rate is 120/130.
    I do not think I burn more calorie keeping the treadmill turning.
    Thank you for the article and for the advice. I will check with Suunto rep here about the formula.

  • Daniel says:

    Every instance of the word "then" in this article should have been a "than". Please learn the difference and fix the article. "Then" refers to a sequence of events, as in "first work, then play". "Than" is a comparison, as in "this is better than that". I was extremely annoying to read an article that constantly got this wrong. Please hire writers that know basic grammar and spelling. The job of a writer is to write. Please find someone who knows how to do it.

    • Kristin says:

      Truly, thanks for pointing that out Daniel. I read over and edited the article, correcting a lot of the grammatical errors that you pointed out. If you ever notice errors on any of our other articles, please feel free to let us know and I'll make sure to update them. This article has now been updated, so hopefully you find it a lot easier and more enjoyable to read.

      -Kristin, BuiltLean Coach & Managing Editor

      • Daniel says:

        Thanks. Sorry for the harsh tone of my first post. Thanks for being cool about it and making changes to the article. That's very nice of you.