Calories Burned: Do Cardio Machines Lie to Us?

Measuring Cardio Output

Have you ever wondered if that little “calories burned” readout on your cardio machine is for real? I tested 6 of the most common machines for accuracy, and you might be surprised at the results.

Not everyone cares about counting, but I’m a numbers kind of gal. Those flashing numerals on the console of my cardio machine have a serious power over me. My favorite readout is the “calories burned” counter. I think it’s because calories are a measure of energy that I can really wrap my brain around. If I see that I’ve burned 350 calories, I know that’s about equal to 3.5 bananas. I know that once I get above 500 calories, I’ve pushed myself into the weight loss zone. I know that if I’ve burned 1000 calories, I’m having pizza for dinner. Yesssssssss.

But is that for real? They’re just numbers that a machine spits out. Sometimes I can enter my weight, and I guess that makes it more accurate. But sometimes I feel like I’m working really hard and the calorie counter is super low. Or I feel like I haven’t even broken a sweat and the readout is super high. I’m always wondering which machine is really the most efficient fat blaster. What’s the best machine to spend my time on if I want to burn the most calories?

To set the record straight, I strapped on a heart rate monitor and hit up the gym with a pen in my top knot and my trusty notebook under one sweaty pit. The HR monitor I used was absolutely fantastic. It’s a Polar FT7, and if you’re at all interested in knowing the hard data of your workouts, I would highly recommend it for accuracy, ease of use, and comfort.

To set up the experiment, I exercised on 6 cardio machines for 5 minutes at a time at a medium intensity. I didn’t go all out, but I didn’t take it easy either. On non-motorized machines that I propelled myself (elliptical, open tread, bicycle), I aimed for a steady 160 BPM. I put each machine on its middle setting. For example, the fastest setting on the stair climber was 20, so I set it on 10. Then I recorded the calories burned from the cardio machine’s read out, the calories burned from my HR monitor, and my average heart rate during each exercise period.

Here are the hard numbers. Let’s see who’s been scamming us.

1. Elliptical Trainer

  • Machine: 65 Calories
  • HR Monitor: 49 Calories
  • Average HR: 160 BPM

2. Open Tread

  • Machine: 79 Calories
  • HR Monitor: 51 Calories
  • Average HR: 160 BPM

3. Treadmill 

  • Machine: 70 Calories
  • HR Monitor: 57 Calories
  • Average HR: 174 BPM

4. Rowing Machine

  • Machine: 45 Calories
  • HR Monitor: 46 Calories
  • Average HR: 147 BPM

5. Stair Climber

  • Machine: 55 Calories
  • HR Monitor: 55 Calories
  • Average HR: 166 BPM

6. Bicycle (spinning bike)

  • Machine: 58 Calories
  • HR Monitor: 52 Calorie
  • Average HR: 160 BPM

As you can see, the stair climber and treadmill are the clear winners for efficiency. Those are the machines I feel the most strain on as well. I often have to get off of the stair climber because there’s so much sweat pooling on the steps. It’s a similar story with the treadmill. The reason my HR was so high was because I had the incline jacked. The highest setting is 14. I set it at 7, which doesn’t sound crazy, but was a pretty steep climb.

  • Lesson Learned: The more climbing you do, the more calories burned.

When you look at the numbers you might think they all look about the same. There’s only a 10 calorie difference between the rowing machine at 46 cals and the stair climber at 56 cals. But keep in mind that I only spent 5 minutes on each machine. Over time those extra 10 calories really rack up. Imagine if you spent an hour on each machine. You’d burn 552 calories on the rowing machine. The stair climber would have you at 672. 120 calories = a big difference!

  • Lesson Learned: All of these machines burn calories. But if you want to make every minute count, go where you sweat.

The stair climber, rowing machine, and bicycle were pretty accurate. The treadmill, open tread, and elliptical were WAY off, overshooting calories burned by up to 28 false calories. Yikes.

  • Lesson Learned: Maybe it’s the brand of machine, or the electronics are old and dusty, but I’m never trusting one of those readouts again. I think it’s interesting that none of the machines were under the HR monitor’s readings. I think it would be naive of us not to consider that the more calories people think they’re burning, the more popular a machine is. And the more popular a machine is, more gyms will buy it. If these readouts matter to you, don’t put your trust in a hunk of sweat-stained metal. Get a HR monitor for accurate counting and obsess to your heart’s content.

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Image: Sarah Olive Bergeson