Deep sleep is the mentally and physically restorative stage of sleep. How much of it do you actually need?

The feeling of having had “a good night’s sleep” lies not only in how much we slept, but also in the subjective impression of having slept deeply and without interruption. But what constitutes the ...

Vivid dreams make sleep feel deeper - even when the brain is more active, suggests new research. The discovery of a "key" relationship between dreaming and the feeling of having had a good rest may ...