7. Hypersomnia
People with hypersomnia feel really sleepy during the day – so sleepy that they have to duck out for a nap even during meals, while working, or at other inappropriate times. But the naps tend not to provide much relief from the fatigue. Some people with hypersomnia are unable to hold down jobs or have a normal social life. Source: National Institute of Neurological Disorders and Stroke.
8. Sleep Apnea
People with sleep apnea stop breathing repeatedly during sleep, waking up partially in order to catch their breath. In the morning, there is typically no recollection of the wakening. Most cases of sleep apnea are caused by the relaxation of soft tissue in the throat, which shuts off the airway. Source: American Academy of Sleep Medicine.