Question

1. Briefly discuss dreams and REM vs. NREM sleep.

Answer 1

Dream

A dream is a succession of images, ideas, emotions, and sensations that usually occur involuntarily in the mind during certain stages of sleep. The content and purpose of dreams are not fully understood, although they have been a topic of scientific, philosophical and religious interest throughout recorded history.

Sleep is beneficial to your overall health. Getting a good night's sleep aids in memory recall, appreciation of loved ones and mental alertness. When sleep doesn't happen it can lead to lethargy, irritability and an increased risk of certain diseases. Learn tips for getting good sleep and the impact of sleep deprivation on your overall health.

REM sleep
Rapid eye movement sleep is one of the deepest of all the stages of sleep. It usually takes up about 25 percent of your sleep time. REM comes in short bursts at first and lasts for only a few minutes but then it gradually stretches into longer time segments. REM is good for your memory. When in REM the brain takes information from the short term memory and moves it to the long term memory. The body is paralyzed at this stage. The eyes will move from side to side very quickly even though they are closed. Heavy dreaming activity is going on.

During REM sleep, the body and brain go through several changes, including:

• The rapid movement of the eyes.
• Fast and irregular breathing.
• Increased heart rate (to near waking levels).
• Changes in body temperature.
• Increased blood pressure.
• Brain activity similar to that seen while awake.
• Increased oxygen consumption by the brain.
• Sexual arousal in both men and women.
• Twitching of the face and limbs.

NREM sleep
NREM includes all of the stages of sleep other than REM. The body is able to move and the eyes remain still. These stages of sleep vary in depth from stage 1 (lightest) to stage 4 (deepest). Stages 3 and 4 are considered deep sleep and this is where most of the physical restoration occurs. The growth hormone is produced and cellular repair begins in NREM.

Before entering the REM sleep phase, the body goes through each of the stages of non-REM sleep. Each stage of NREM lasts for 5-15 minutes.

Stage 1 non-REM sleep - a person in this stage is between being awake and asleep or is in a state of very light sleep.

Stage 2 non-REM sleep - this stage is characterized by a slightly deeper sleep. Body temperature drops and heart rate slows down.

Stages 3 and 4 non-REM sleep - a state of deep and restorative sleep known as slow-wave sleep, or delta sleep. The muscles relax, the supply of blood to the muscles increases, and the body repairs and grows tissue. Hormones are released and energy stores are replenished.

As people age, they tend to get less NREM sleep. Those under 30 usually experience 2 hours of restorative sleep nightly while older adults may get just 30 minutes.