Sleep Part III Finally, the other elephant in the room related to sleep is STRESS. Stress alters the function of the hormone cortisol and can significantly alter night sleep function. There are three major chemicals that affect sleep: cortisol, adenosine and melatonin. In normal conditions, adenosine rises during the day making you sleepy, cortisol hits its low point at night and melatonin rises as the sun goes down. This combination puts pressure on you to feel sleepy and want to go to bed. Unfortunately, modern life has made many of us feel stressed and sympathetically fired up which affects cortisol function. Instead of being at its nadir at night, the stress response causes cortisol to rise at inappropriate times disrupting sleep onset and maintenance. Couple this stress with facebook addiction and screen induced melatonin suppression and you have a recipe for insomnia and disrupted sleep. (Hanson et. al. 2010)....Plus, a section on cellphones and driver knowledge. Enjoy, Dr. M