A good night's sleep—everyone needs it, but not everyone gets it. We stay up late and get up early, and then wonder why we always feel tired.

Sleep is essential to physical and emotional health. Adequate sleep may also play a role in helping the body recover from illness and injury.

Do you have sleep debt? Lack of sleep, or "sleep debt," can leave you feeling tired, listless and sleepy on a daily basis.

If you experience difficulty falling asleep, staying asleep, or enjoying a restful night's sleep, you may be suffering from insomnia.

Insomnia, trouble falling asleep or trouble sleeping, is a growing problem in the United States.