The Messy Science of Wet Dreams

It’s not just teens who wake up in a cold, uh, sweat.

The Messy Science of Wet Dreams

Wet dreams — more formally known as nocturnal emissions — are both euphoric and depressing: One moment you’re fooling around with the sex partner of your literal dreams; the next you’re all alone in a tangle of bedsheets and your own, well, y’know.

But what’s the actual science behind this sticky phenomenon? And is there any rhyme or reason as to when (and why) we experience these nocturnal emissions?

For answers, we sought out sex researcher David Ley, author of Ethical Porn for Dicks: A Man’s Guide to Responsible Viewing Pleasure, to help us better understand what’s going on beneath the sheets during a wet dream.

What Causes Wet Dreams?
Generally speaking, a wet dream occurs when we experience sexual arousal during sleep. This is especially common in men, since we naturally experience erections during the REM (rapid eye movement) phase of sleep. Combine that with an erotic dream, and there’s a good chance you’ll wake up in a (wet) spot of bother.

There’s also some utility to wet dreams: “For men, nocturnal emissions are a way for the body to clear out old sperm,” Ley explains. “Sperm has an expiration date, and if you haven’t ejaculated in a while, your body gets rid of the old stuff to ensure the sperm on tap is fresh and ready to hit the field of play.”

Or your bedsheets, in this case.

When Do They Happen?
Wet dreams are most common during puberty, when testosterone (the hormone responsible for sperm production) levels are at their highest. This doesn’t mean there’s something wrong if you wake up with sticky briefs well into middle age, though. “Men can remain virile late into their lives — Charlie Chaplin, for instance, fathered a child when he was in his 70s — and as long as you remain virile, your body still needs to clear out old sperm,” Ley explains.

Wet dreams are also linked to ejaculation frequency, according to Ley. “Going without orgasm for a few weeks increases the likelihood of nocturnal emission,” he says. “The NoFap trend and the idea that those in sex-addiction treatment are to remain abstinent for 60 to 90 days both dramatically increase the likelihood of nocturnal emissions.”

How Does It Actually Work?
While it’s possible to blow your load without any sort of physical stimulation, Ley believes nocturnal emissions are more often a result of sleep-humping: “Oftentimes, the sleeper unconsciously masturbates or grinds himself into the bed.”

Just when we thought nothing was more embarrassing than sleep-talking

Do Women Get Them, Too?
Yes! Women may experience nocturnal orgasms less frequently than men, but a 1986 study published in The Journal of Sex Research suggests that as many as 85 percent of women will experience a wet dream by the age of 21. And it’s likely that wet dreams among women are even more widespread than that: The study based their numbers on a small sample of college women during the 1980s — a relatively conservative time, sexually speaking.

So it seems what they say is true: Most people never stop thinking about sex — even when we’re fast asleep.