Waking up during the night is frustrating, but it’s often completely normal—until it crosses a specific threshold that ...

Sleep Cycles: One rapid eye movement (REM) stage and three non-REM stages that altogether last about 90 to 120 minutes Benefits: Physical and mental recuperation and memory consolidation Disorders: ...

It is not just a habit or a lifestyle choice; experts confirm that shifting sleep patterns are driven by biological changes in your brain and eyes that alter your internal clock.

A restful night alternates in cycles between non-rapid eye movement (NREM) and rapid eye movement (REM) sleep states. The study from UNIL shows that a brain region called the "locus coeruleus" (in ...

A simple guide to returning to your schedule when travel, late nights, or seasonal shifts affect your shuteye.

This article was reviewed by Felix Gussone, MD. "Stiffness" is often considered a sign of male arousal, but it’s not uncommon to experience it even when you’re not turned on. Nocturnal arousal refers ...