sleep expert dr holger her pain reviews the evidence the key issue is exposure to blue light is on the lips of course short wavelength light between 470 and 480 nanometers it's registered by photo receptors in the eye one consequence is that the production of melatonin and suppressed or other processes are also a factor such as temperature regulation this kind of light disrupts the sleep wake it takes longer to fall asleep and the duration of sleep get shorter. so will the internal clock shift or get out of sync doing the experiment. during the day the sisters who live and work together have pretty much the same routine they work a lot in the fresh air and are tired by the end of the day. if you add up the hours the sisters slept over the course of the week because total is considerably lower than coyotes every night because slept 15 or 20 minutes less than carty. a concentration test shows that this really amounts to a sleep deficit and is not merely because the kid needs less sleep the sisters are told to follow a black dot as it moves around the circle for half an hour occasionally