Women's orgasms are even more fascinating than we fathomed

Some women tense up, others moan and some... sneeze?

The female orgasm is a complex physiological process that involves everything from muscle contractions to flushed skin to hormone release. And while most women's bodies respond to orgasm in similar ways, some experience rare reactions, including sneezing and hallucinating, according to a recent paper published in the Sexual Medicine Reviews journal.

In "Did You Climax or Are You Just Laughing at Me?" Rare Phenomena Associated With Orgasm, researchers looked at past studies and reports of men and women who experienced peri-orgasmic phenomena, defined as an unusual physical or psychological symptom experienced in response to orgasm. They unearthed reports of people crying, hallucinating, getting headaches and even experiencing orgasmic sensations in one foot.

These reactions are rare and fascinating but what happens to most women during orgasm is equally curious.

To understand more about the physiology behind the female orgasm, we asked the experts, Dr. Lori Brotto, registered psychologist and professor of gynecology at the University of British Columbia, and Jessica O'Reilly, a sex and relationship expert in Toronto, to walk us through the female body's response to the big O.

The Brain

At the point of orgasm, the brain releases massive amounts of oxytocin and dopamine, said Brotto. Oxytocin or the "love hormone" is thought to promote feelings of connection and bonding with a partner after orgasm, and dopamine is a "feel-good" neurotransmitter connected to the reward centre of the brain, she said. Other changes take place in the brain during orgasm, but the release of dopamine and oxytocin are the most significant, Brotto said.

The Muscles and Heart

During orgasm, muscles throughout the body may contract, spasm and tense up involuntarily, said O'Reilly. "For some women, they'll describe it as a pulsing (feeling)…followed by a feeling of release," she said. The contraction of anal, uterine and pubococcygeus muscles – which reach from the pelvic bone to the tail bone – may result in feelings of tightness along the pelvic floor, she said. Blood pressure, respiration rate and heart rate can also increase during orgasm, she said.

The Genitalia

The main changes in genitalia occur during high levels of arousal preceding orgasm, with much of the changes revolving around the clitoris – a sex organ much bigger than what meets the eye, said Brotto. Specifically, during arousal the clitoris can become erect and expand in size as it fills with blood. The vestibular bulbs – clitoral tissue under the surface of the labia skin – also fill with blood, in turn making the labia appear puffy and engorged, she said. At the point of orgasm, there's a release and the bulbs return to their flaccid state, said Brotto. For some women, they will also expel a fluid or "squirt" during orgasm, she said.

The Skin

A woman's skin often becomes more sensitive to touch leading up to and during orgasm, with erogenous zones such as nipples becoming particularly sensitive, said Brotto. Some women may also experience a "sex flush" during orgasm where the skin on the chest and face appears pink or red due to increased blood flow, said O'Reilly.

The Voice

Humans often make verbal sounds in response to feelings of intense pleasure, said O'Reilly. However, many of the sounds we make during sex and orgasm are dictated by cultural and gendered norms and are influenced by porn, she said. For instance, a woman may moan rather than grunt during orgasm, knowing it's more culturally appropriate for women to moan. "All of us, myself included, adjust our sounds to match what we think we're supposed to sound like," said O'Reilly. "Our sounds are not always the most genuine."

Katrina Clarke is a Vancouver- and Toronto-based journalist who writes about relationships, health, technology and social trends. Find her on Twitter at @KatrinaAClarke