About a third of people in the United States don't get enough sleep, according to the Centers for Disease Control and Prevention

About five million people suffer from a sleep disorder that has them feeling exhausted, even after getting a full night of sleep. 

Now scientists are getting to the root cause of these sleep disorders in order to redefine rest.

"Sleep is the VIP service everybody needs. Regardless of age, sleep is so important to our system. It affects basically every area of our life," Certified Sleep Consultant Leandre Schoeman said.

Stress, insomnia, chronic fatigue, sleep apnea, restless legs, age, all of these things can cause a restless night's sleep, but have you ever had a full eight hours and still woke up exhausted?

There's a name for it.

Scientists are studying Idiopathic Hypersomnia, which means unexplained sleepiness.

One in 70 people experience it on a regular basis. The main symptom, chronic daytime sleepiness, even after a nap. People also have difficulty waking up and when they do wake up, they are disoriented.

The condition can make day-to-day activities a challenge.

Scientists at the University of Wisconsin-Madison now believe it may be caused by a hormonal imbalance that acts like an all-day sleeping pill that throws off a person's circadian rhythm, or the body's sleep-wake cycle.

There's no cure, but treatments include stimulant medications, like Provigil or Alertec, to help people stay awake during the day, helping you get the rest you need.

There is no test to diagnose Idiopathic Hypersomnia, it's commonly diagnosed by elimination of other sleep disorders.

Experts recommend adults sleep between seven and nine hours a night.