What happens is after three nights of getting 1-3 hours less sleep per night is that their body isn't disposing of glucose properly. So their blood glucose levels stay elevated. On top of that, insulin, they're not making enough insulin to lower the blood glucose levels and so you get this double whammy almost looking like insulin resistant, or pre-diabetic, if you were to just look at the hard numbers ... This is just from not getting enough sleep for three nights in a row...