Calories burned discrepancy

I’m new to Zwift.
I’ve been using Polar H10 heart rate monitor (connected to Polar V800)
after 50 minutes ride Zwift shows 440 calories burnt, whereas Polar is showing 700.
Both platforms have the same statistics set up (age, weight, height etc).
can anyone explain the huge discrepancy?


activity intensity is a factor too… what does this calculator says?

read this one too :wink:

thanks for your response. Based on the calculator in your link Polar is spot on and Zwift is way off.

Zwift uses power (wattage) to calculate calories burned, not heart rate.

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My guess would be that zwift will be closer as it uses power (assuming you have a power meter or smart trainer).

if using calorie estimates for weight loss always pick the lowest. Whichever you use will always have assumptions built into the calculation somewhere and so none will be very accurate.

Do calories really matter? Why is this the metric that people track? We know it is, at best, a complete guess in the first place. Calories in calories out (CICO) has been proven to be an unsustainable and extremely difficult way to lose weight (I assume that is why you are tracking calories, why else would you?). Dr. Jason Fung explains the process here.

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having read that he still says that you need to consume fewer calories than you burn though - just be clever about which calories you consume and when.

If you zwift with a power meter, zwift is correct and polar is way wrong

Calories can’t be tracked accurate just based on hr

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it can’t be with a power meter either, it is far more accurate though. It has to assume how efficient your body is and extra calories are burned depending on how much you move around on the bike/how hot you are etc

but, yes, power meters are a much better indicator


I know I’m late to the party. I’m using the Polar OH-1+ (forearm/bicep heart rate monitor). Map my ride and Polar indicate around the same amount of calories burned when compared to Zwift. Zwift is way off. I weigh myself after my cycling workouts. I can assure you Polar or Map My Ride estimates are probably more accurate based on the article below. I don’t know why Zwift doesn’t give you the option of using data from Polar. Zwifts algorithm for calories is trash.

The researchers evaluated seven fitness-tracking devices with the help of a small group of 60 volunteers and found that six of the devices were accurate for heart rate to within 5 percent. None of the devices were from the Polar brand, but the findings are still helpful for understanding that even when heart rate accuracy was good, the accuracy of measuring energy expenditure was not: The most accurate device was off by 27 percent, and the least accurate was off by a staggering 93 percent.

But with Polar heart rate monitors so often functioning as the gold standard for measuring heart rate, is it possible that they fare better?

The answer is a mixed bag, depending on which model is evaluated and the activity that they were used to gauge. For example, in a study published in a March 2010 issue of the *[British Journal of Sports Medicine], researchers found that the Polar Activity Watch 200 fell within the accepted 10 percent error threshold of calorie estimates — when used while hiking. They didn’t evaluate the AW200 during other activities.