Almost all dreams occur during REM sleep. Scientists do not understand why dreaming is important. One theory is that the brain is either cataloging the information it acquired during the day and discarding the data it does not want, or is creating scenarios to work through situations causing emotional distress. Regardless of its function, most people who are deprived of sleep or dreams become disoriented, unable to concentrate, and may even have hallucinations.

Why do people snore and how loud can snoring be?

Snoring is produced by vibrations of the soft palate, usually caused by any condition that hinders breathing through the nose. It is more common while sleeping on the back. Research has indicated that a snore can reach 69 decibels, as compared to 70–90 decibels for a pneumatic drill.