Here is something nobody mentions: while you are asleep, contributing nothing, your body is busy.
Sleep runs in cycles of roughly 90 minutes, and each cycle ends in a stretch of REM. During REM your brain is nearly as active as it is when you are awake, but the signals that reach your muscles are blocked, which is why you do not physically act out your dreams. That same shift changes what your blood vessels are doing.
The alert, fight-or-flight side of your nervous system quiets down, and the rest-and-recover side takes over. In genital tissue, that means the vessels relax and blood flows in. Engorgement, lubrication, heightened sensitivity. This happens in every REM period, so three to five times a night, and it has almost nothing to do with what you are dreaming about. Someone having a filthy dream and someone dreaming about an airport queue show the same physical pattern.
As for why your body bothers: the leading explanation is oxygen. Erectile and vulvar tissue relies on regular blood flow to stay elastic and healthy. In men there is reasonable evidence that when nocturnal engorgement stops happening, the tissue gradually stiffens and scars. In women the same mechanism is assumed and far less studied, which is a recurring theme in this entire subject.
Sometimes the process tips over into orgasm and you wake up during it, or just after. That is a wet dream, though nobody uses the phrase about a grown woman. It is not the point of the process, it is an occasional byproduct, and how often it happens to women is genuinely unknown. The most quoted number still comes from Kinsey. In 1953.
One practical use for all this: doctors can measure nocturnal engorgement to work out whether an arousal problem is physical or psychological. If the body manages it reliably during sleep but struggles when you are awake, the circulation is fine and the cause is somewhere else.
How to protect it
- Sleep the whole night, especially the end of it. REM periods get longer as the night goes on, so most of your REM is in the final couple of hours. Waking up early cuts the part that matters most.
- Keep alcohol away from bedtime. It suppresses REM in the first half of the night, so a nightcap costs you cycles.
- Move during the day. Nocturnal blood flow depends on general vascular health, so anything good for your circulation is good for this.
- Do not count. Most nocturnal arousal is never remembered, and frequency of sleep orgasms is not a measure of anything.
- Know what is actually worth attention. A persistent, noticeable change in your waking arousal is worth raising with a doctor. An uneventful night is not.
Your body has been doing this every night since puberty without asking your permission or requiring your participation. The least you can do is go to bed on time.
Xoxo,
Cerē