I just got my charge HR on Saturday. I've been pretty much ignoring the first few days as I read they are not reliable. Today was my first day going to the gym and logging a workout. I pressed the button at the beginning of class and at the end. When i finally got the fitbit to link to my laptop, it says i burned 203 calories in my 55 minute class. This is a pretty intense interval training class (alternating between bursts of cardio and strength training with weights (lunges) and without (squats) as an example. Do I need to add in some additional calorie burn, because I think the # it calculated must just be on the cardio bursts? My instructor said the class burns an average of 600 calories usually....unless she is way wrong. I'm confused!

I also do not understand the calorie burned symbol on the fit bit: right now it says 1091. What exactly does that # mean? Also, My fitness pal has now dropped my calories burned to 90, but earlier said the 203 that the fitbit dashboard stated. I am so confused. Please help. I have read through some of these posts, but I am still not wrapping my brain around this.
Thanks in advance!