The Apple Watch, Activity app and resting calories

I agree, resting calories seems odd. My understanding is that the resting calories should not vary, yet mine do by a large margin. Resting calories for me are just over 2000, as I understand it they basically mean the amount of calories I'd burn during a period at complete rest. I assume, maybe wrongly that the period is 24 hours. If this is the case, why do my resting calories change daily? Of course active calories will change, but why resting?

I Read an article on WebMD explaining how resting calories should be calculated. While not complex it was complicated. The article ended by saying a roughly estimate for your daily resting calories is your weight x 11. It was pretty close in the activity app for me.

When sleeping, your heart rate is about 8% lower. If you don't wear the Apple Watch when you sleep, could this be the cause of the Activity app's incorrect estimate of resting calories? Meaning, the Activity app presumably extrapolates a 24-hour calorie burn from only your waking resting heart rate as captured by your Apple Watch when you wear it. Maybe try sleeping with your Apple watch on and see what that does to the data. Consider, also, maybe it is actually more accurate than you think. Factor in that there can be periods of high calorie burn even during periods where you think you're resting. My heart rate can go up playing video games or at work when working out thorny problems. Try sifting through the heart rate data in the Health app to see if your heart rate was up more than you thought (it's captured every 10 seconds throughout the day while wearing the Watch). The brain burns a lot of calories, too, when it lights up (and brain activity can increase heart rate, I'm not sure of the exact correlation, but that would be captured by the Apple Watch).

Well, resting calories are not another term for BMR, if anything, they are a totally separate calculation, called RMR. BMR only deals with your metabolism while you're awake (look it up), but who knows what Apple means by "resting calories." I know your metabolism and its related calorie burn has nothing to do with heart rate, but what I'm saying is that maybe there are calories being burned on top of your metabolism, like when you are sitting down but playing a crazy video game or watching a scary movie, not working out (running, biking, elliptical, etc), and that is what Apple is adding on top and calling resting calories. Why else would it vary from day to day?

Nevermind, I see that resting calories in the Activity app do not change from day to day. They are based on the info you enter in (age, weight, sex),

My resting calories should be around 1500. The Activity app gives me around 2000 resting calories every day, so it's off by quite a lot.

On the other hand, active calories seem to have the opposite problem and are greatly underestimated. Some people have reported getting numbers half of what they should be. In my experience, it's been about 2/3 of what it should be for most outdoor and indoor activities. The only one that's been close so far has been the stair-stepper, but if I remember correctly the 1.0.1 update corrected the calorie estimate for that type of exercise. However I can run 6 miles over 50 minutes and come out with 400 active calories. That certainly seems off by 50% (2/3 of what it should be).

so, you need to keep the watch on while sleeping? Wont that drain the battery faster, like mine did. Didnt last more than 24 hours.