YOU ARE MESSING UP YOUR OWN CIRCADIAN RHYTHM!!! You get into bed, you're cozy, the TV volume is down, the light from it gently casting shadows on the walls AND KEEPING YOU UP ALL NIGHT LONG! Seriously, in a new study, sleeping with the TV on can cause your brain to not shut off. Apparently our brains "scan for unfamiliar sounds and voices" and outside stimulation while we sleep. Having the TV on can actually cause "micro-arousals" all night, a state where you ALMOST wake up. Basically it's your brain's way of letting you know there might be a threat. So if you fall asleep with "The Terminator" on, you might wake up thinking that you're being chased by an advanced robot assassin.