Immune system <– which is why you get sick easy
Furthermore, unhealthy conditions, disorders and diseases can also cause sleep problems, including:
Hypertension and elevated cardiovascular risks (MI, stroke)
Emotional disorders (depression, bipolar disorder)
Obesity; metabolic syndrome and diabetes
Alcohol and drug abuse
Groups that are at particular risk for sleep deprivation include night shift workers (aka Creatives), physicians (average sleep = 6.5 hours a day; residents = 5 hours a day), truck drivers, parents and teenagers. (American Academy of Sleep Medicine and National Heart, Lung, and Blood Institute Working Group on Problem Sleepiness. 1997).