Treadmill and calories

I was in the Precor treadmill at the gym today, it's the kind with hand sensors to monitor your heart rate. I walked pretty fast for with a 14% incline at 3.1 speed (I guess that's mph). I was at 70% of my max heart rate for almost 40 minutes. At the end of it the machine said I burned 400 calories!!! Is that even possible.

I'm trying to eat back my exercise calories because I don't want to lose weight, but I don't want to over eat either.

Thoughts?

Replies

  • JenMc14
    JenMc14 Posts: 2,389 Member
    I take treadmill readouts with a grain of salt, especially if they don't ask your weight. I use a treadmill calculator that accounts for incline, use one of the uphill entries on MFP and even hit Spark People sometimes, then take an average of the three.
  • heybales
    heybales Posts: 18,842 Member
    That HR is merely used for display, not calculating calories. They may use it for a HR type program too, vary the speed and incline according to limits you input.
    But because it may disappear when you let go, not used in calculations.

    More accurate formulas are used for calories actually, as long as your weight was in there, and incline was only up to 5, and walking speed is between 2-4 mph, or running between 5-6.3 mph.
    More accurate than HRM's actually.
    http://www.myfitnesspal.com/topics/show/774337-how-to-test-hrm-for-how-accurate-calorie-burn-is

    Confirm what it gave you here. Machine, HRM, database like MFP, would all be giving Gross estimates, so use that to actually compare.
    For purpose of eatback, you'd use the Net estimate.

    http://www.exrx.net/Calculators/WalkRunMETs.html
  • bmancanfly
    bmancanfly Posts: 6 Member
    That was a great link thanks!

    I calculated using the websites in your link and the calories came out exactly the same. Hmmm. Maybe I did burn 400 calories.

    Probably best to err on the side of caution though.

    I need to get one of those HR monitors and compare the results.
  • bmancanfly
    bmancanfly Posts: 6 Member
    More accurate formulas are used for calories actually, as long as your weight was in there, and incline was only up to 5, and walking speed is between 2-4 mph, or running between 5-6.3 mph.
    More accurate than HRM's actually.

    Just curious, why does the incline change the accuracy.
  • heybales
    heybales Posts: 18,842 Member
    More accurate formulas are used for calories actually, as long as your weight was in there, and incline was only up to 5, and walking speed is between 2-4 mph, or running between 5-6.3 mph.
    More accurate than HRM's actually.

    Just curious, why does the incline change the accuracy.

    Personal efficiency of going up incline can change a whole lot more than walking level.

    Same reason why elliptical's have no good study formula's, the design of them, the incline, the method of how you move the feet, too many variables besides how the person actually does it. I've stood and moved my legs like I was standing on bike going up hill, compared to trying to keep body position level and just moving legs. Same everything else, wow what a difference. Give me a bike for sure!
  • omma_to_3
    omma_to_3 Posts: 3,265 Member
    My treadmill (despite linking with my polar HRM) displays nearly double the calories burned to what my HRM reads.
  • heybales
    heybales Posts: 18,842 Member
    My treadmill (despite linking with my polar HRM) displays nearly double the calories burned to what my HRM reads.

    Wow, what is your HRM make and model?

    Have you ever adjusted the HRmax stat for what you've seen in reality, or the VO2max stat if it's a better one?

    Because that's pretty bad for the HRM. One study showed a nice Polar on women being 30% off using default values, prior to using lab tested figures of HRmax and VO2max, then at least down to 12% off.
    http://www.myfitnesspal.com/topics/show/459580-polar-hrm-calorie-burn-estimate-accuracy-study