Which is a condition that is typically related to malfunction of the pancreas? skin conditions
early onset of puberty
irregular sleep patterns
high levels of blood sugar

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