However, some research shows that major stressors may increase REM sleep but reduce deep sleep. REM rebound, which is when we ...

"Deep sleep builds your immune system, and REM sleep regulates and fine-tunes it," says Darwall-Smith agrees. During deep ...

Most people spend a third of their lives sleeping, but you may need more or less than eight hours a night. The amount of ...

Sexual activity—whether partnered or solo—improves sleep efficiency and reduces night-time wakefulness, according to a pilot ...

REM sleep behavior disorder is characterized by acting out dreams, which may include shouting, kicking and punching during sleep.

Heart rate variability (HRV) status2: See last night's average HRV and the smartwatch will establish a personal baseline and ...