HELP!!! Cals burned?!!

[Rikarogg]

Ok, so I have a kinda higher resting heart rate (like 85-95) and during hard aerobic exercise my heart rate can get up to 165 (which is maxed, but ok for my age, 39). These cardio exercises are typically zumba or cardio dance. I also do bodypump which is obviously not as hard cardio wise. With hard exercise it says I am burning 600-750 cals. Even though I am seriously sweating my booty off, how accurate is this actually? I was wondering if I should assume maybe 25-50% less than the Fitbit says? I have a charge 3 btw. I am 5'6 and 225 lbs. Any ideas or suggestions would be GREATLY appreciated! Thank you!!!!

[Dominique]

You didn’t mention the duration of your cardio workouts, but let’s assume it’s 45 minutes (which is quite long for high-intensity exercises). Your calculated BMR is 1665 (I used this online calculator), so BMR per minute is 1665/1440 (there are 24 x 60 = 1440 minutes in a day). I selected the most intense form of aerobic in the Compendium of Physical Activities: "aerobic dance wearing 10-15 lb weights", which has a MET of 10.0. If you did that for 45 minutes, you would burn 10 x 1665 x 45 / 1440 = 520 calories. So, yes, Fitbit’s estimate of 600-750 is likely on the high side.

However, if you are interested in calories burned for the purpose of weight loss, what really matters are calories burned over the entire day (TDEE). Fitbit provides you with an estimate of that too. Of course, that too may be inflated (you must keep in mind it’s an estimate). You can get a "second opinion" by using the aforementioned calculator, with your average step count as a proxy for your activity level.

Bottom line: if you intend to use Fitbit as a tool to help you losing weight, you may want to shoot for a higher deficit (as estimated by Fitbit), e.g. 1000-1250, understanding the actual deficit may be significantly lower, e.g. 250-500. Over time, the scale should tell you by how much Fitbit calories are off, and you can adjust accordingly.