Sleep disorders are conditions that impair your sleep or prevent you from getting restful sleep and, as a result, can cause daytime sleepiness and other symptoms. Everyone can experience problems with sleep from time to time. However, you might have a sleep disorder if There are more than 100 million Americans of all ages who are not getting an adequate amount of sleep. Sleep is very important. Not getting enough sleep can have untoward consequences on school and work performance, interpersonal relationships, health and safety.