January 17, 2011

Q&A: Do Women Experience Nocturnal ‘Erections’ Similar To Men’s?

You may be surprised by some of what researchers know about sleep and sex. Starting in the 1960s, researchers began looking at genital arousal during sleep.

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Question: Do women experience nocturnal ‘erections’ similar male nocturnal erections? I understand the male version has little to do with feeling sexually aroused but is more associated with REM sleep, and may help keep the penis healthy with oxygenated blood supply during the night. If this is true, isn’t it likely that women’s bodies do something similar?

Studying In Your Sleep

You certainly have good instincts – and you may be surprised by some of what we know about sleep and sex. Starting in the 1960s, researchers began looking at genital arousal during sleep and found that men experience erections during the rapid eye movement phase, more commonly known as the REM phase, of sleep.

In the years that followed, researchers began studying women to see if something similar happened. Studying female genital arousal is often more challenging than studying male genital arousal.

After all, the presence or absence of a man’s penile erection is more easily detectable than measures of female genital arousal, such as changes to the clitoris or genital temperature during sleep. In the 1960s and 1970s, researchers attempted both of these types of studies of female genital arousal during sleep but found them to be challenging and inconclusive.

Excitement In Your Sleep

Researchers ultimately focused on studying changes in blood flow to women’s genitals during sleep. They found that women experienced increased in blood flow to their genitals during REM sleep, just as men experience increases in blood flow to their penis, which contributes to their erections.

People also experience increased blood flow to their genitals during sexual excitement and arousal when they’re awake. If you’ve ever felt warm and tingly in your genital area when you’ve been excited about someone, that’s due to increased blood flow.

Scientists have found that blood flow to the genitals increases anywhere from just a little during REM sleep to about as much as it increases when women masturbate or watch erotic films. In other words, it may be that, some of the women, REM-related genital arousal feels similar to waking sexual arousal. This makes sense given that many women report waking up from deep sleep only to find themselves feeling highly aroused, or having just experienced an orgasm, just as some men do during sleep.

Dream A Little Dream Of Me

REM sleep is also the phase of sleep in which people dream, which begs the question of what it is that people are dreaming about. Given that men and women very frequently experience REM-related genital arousal, some people wonder how often we have erotic or sexual dreams without remembering them.

In one study, scientists noted that a woman experienced an orgasm while sleeping. The next day, she told the scientists about a sexual dream she remembered having had the night before, and that the dream involved another woman being sexual with her. In her dream, the woman then turned into a man. She was perplexed by this dream, given that she said she had never had any sexual interest in or sexual experiences with other women.

However, dreams about sex may be linked to people’s genital arousal or orgasm, and sexual dreams be random and not reflective of people’s waking interests in sex.

Someone, for example, once told me that his first wet dream came about while he dreamt about the Smurfs! He was a young boy, close to puberty, and had little knowledge about sex but for some reason a non-sexual dream about the Smurfs provoked his first ejaculation. Anything is possible in the world of dreams.

Also, although scientists who study sex can clearly show that genital arousal happens during sleep, we cannot say why it happens. Some scientists have suggested that perhaps genital arousal during REM sleep is our bodies’ way of keeping our genital tissue healthy by delivering oxygen to it through regular increases in blood flow.

More Information

You can learn more about the science of studying orgasm in The Science of Orgasm and more about genital response and sexual pleasure in Because It Feels Good: A Woman’s Guide to Sexual Pleasure and Satisfaction.

Reviewed July 2017.

Next Question: Clitoral Stimulation – Pain, Tickling And Discomfort

Whenever I try to stimulate my girlfriend’s clitoris whether orally or with my hand she says it tickles or hurts. I have never experienced anything like this with past relationships. Any suggestions to help her become comfortable with clitoral stimulation?

Read Dr. Debby Herbenick’s response.

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