To the sleep disorders that afflict many people is added that of “sexsomnia” that few know about.

During it, the person engages in sexual acts in his sleep and the next morning when he wakes up he remembers nothing.

Although many people think they are dreaming, many parasomnias occur when the brain is not in a dream state, explains Dr. Carlos Schenck, professor and senior psychiatrist at Hennepin County Medical Center at the University of Minnesota.

“These are arousal disorders,” said Schenck, who has studied insomnia for decades. “They most often occur during the slowest, deepest stage of sleep, called delta sleep. It’s like an alarm or a trigger going off in the central nervous system.

“Your consciousness is fast asleep, but your body is activated,” Schenck said. “This is dangerous because then one starts walking and running and engages in activities while sleeping.”

It is difficult to study her sexual insomniabecause unless people are self-harming, many have no idea about their unconscious sexual activity until a partner tells them.

A 2010 study looked at 1,000 randomly selected adults in Norway and found that about 7% had experienced sexual parasomnia at least once in their lifetime, while almost 3% were currently living with the condition.

“There are some people who will engage in sexual activity with their partner and it doesn’t bother either of them. So it’s possible that this is consensual for some,” said Jennifer Mundt, assistant professor of sleep medicine, psychiatry and behavioral sciences at Northwestern University Feinberg School of Medicine in Chicago.

“There are definitely cases where it’s worrying for the partner and for the person doing it once they realize what they’ve done.”

What triggers sexual insomnia?

As experts explain, there is no way to predict that you will develop parasomnia. “Some people who talk or walk while they sleep as children develop sexsomnia or other parasomnias as adults, but many others do not,” Schenck said.

“We don’t know the ultimate cause, but there is a genetic component,” he said. “If you have at least one first-degree relative with parasomnia, it is more likely that someone will develop sleep disorders. In fact, the more first- or second-degree relatives with parasomnia, the more likely the condition will persist into adulthood or recur.”

Obstructive sleep apnea can also be a trigger. Also called OSA, obstructive sleep apnea is a serious sleep disorder in which breathing stops for 10 seconds to two minutes several times an hour each night. The condition occurs mainly in men, although the percentage of women is rising.