Calibrating battery...

I'm going to calibrate the battery of my MacBook for the first time. It's already 100% charged, I'm only going to leave it on for a few hours (I'm going out). My question is: is it ok to leave the computer on (the battery will be draining) and disable sleep mode so when I come back the battery will be nearly drained? I know the sleep function is very handy, but in times like this, I guess it'd be best to disable it for a while.

Thanks...