Medically speaking, sleep is a recurring state of absent or decreased consciousness, and reduced awareness of the environment. Sleep is usually characterized by a recumbent posture and reduced movement associated with decreased body movements. Human sleep consists of two distinct types 1) rapid eye movement (REM) sleep and 2) non-rapid eye movement (NREM) sleep. These two types of sleep alternate 3 to 6 times throughout the night at intervals of 60 to 120 minutes. The majority of dreaming occurs during REM sleep, heart rate becomes irregular and the breathing rate becomes shallow and irregular. NREM sleep is divided into three stages, N1, N2, and N3, which roughly corresponds to depth of sleep; N3 is considered to be the deepest sleep in humans in which it is the most difficult to awaken the individual. Heart rate and breathing are regular during NREM and mental activity is less and more thought-like.
Articles in this section
- How does sleep relate to weight?
- How much sleep do I need?
- What is a Pre-Bed Routine?
- What should I avoid before bed?
- What are some good pre-bed activities?
- Why is sleep important?
- Do energy drinks affect sleep?
- How do nicotine and smoking tobacco affect sleep?
- How does nutrition affect sleep?
- Should I read or watch television in bed?