can be best defined as a conscious process of making choices among one or more alternatives with the intention of moving toward some desired state of affairs.

The answer is keep records

Because without physical activity, the body has extra "energy" if you will, and so when it is time for bed you are not tired, so you end up staying up all night. also there is probably an effect on your internal clock, which messes with your melatonin production which goes hand in hand with your sleep cycle