Nightmares occur during R.E.M. sleep, when the brain's suppression systems relax and allow us process our feelings.

It's a kind of stress response called "learned helplessness" that renders the individual passive in the face of stress.

Sleep deprivation increases risk for a host of lifestyle disorders and shortens life spans.

Study participants who woke to a harsh, mechanical alarm reported feeling more groggy.

This biological rhythm controlled by the brain also influences appetite, body temperature, hormone levels, and blood pressure.

A stop-and-start breathing pattern may cause a sudden drop in blood oxygen levels, raising blood pressure and exerting the cardiovascular system.

After scary dreams, the emotional control regions of the brain respond to threats much more effectively, a study has found.

Research says when you nap, and for how long, often determines how rested you feel after.

New research sheds light on how some people can sleep 3-4 hours per night and still function at full potential.

Your age and the quality of your sleep determine whether the 8-hour prescription applies.

Pregnancy insomnia is common but should be addressed because it leaves women tired when they really need rest.

Dreaming might only be a privilege for those with air purifiers.

Mirroring others' actions is an indicator of how empathetic we are.

To lower stillbirth risk, study authors advise pregnant women to sleep on their side.

From longer life spans, to less sleep, to more stress, the risk factors are uniquely female.

Turning my sleep paralysis into controllable lucid dreams helped me deal with stress.

Comfort objects are nothing to be ashamed of.

A study suggests it would help us sleep more deeply and improve memory.