Calories Burned While Sleeping

Hi,

I use to sleep with my watch because I want everything to be measured, however I have to take it off while sleeping now cause I get very bad rashes. I checked calories burned when I woke up and started the watch and it said 540. When I slept with it and checked on the morning it said 558 but it had also counted 13 steps while I was in bed. I got to bed and got up from bed at the same time. What I wonder is if it is better to sleep with the watch or take it off if I want calories burned to be accurately calculated during sleep?