Unexpected things can happen after you have an orgasm, and research shows that a variety of strange post-climax — or peri-orgasm — responses are more common than you may think. Some women experience an altered state of consciousness, develop a headache, or start sneezing. I recently had an uncontrollable urge to laugh that lasted for about 30 minutes.

But while there isn’t a ton of information out there to explain why, there is science to back it up. When you have an orgasm, your body is flooded with hormones, including oxytocin (the cuddle hormone), dopamine (the feel-good hormone), epinephrine, adrenaline, and serotonin — which give you a nice high feeling, says Tammy Nelson, a sex and relationship therapist and author of Getting The Sex You Want. She says that while many women feel a rush of intimacy or joy after sex, others might experience reactions like spontaneous crying, or even yelling at their partner.

No one has figured out the exact cause of my post-orgasm giggles, but it definitely happens and isn’t a cause for concern, says Dr. Anna Reinert, a fellow in minimally invasive gynecological surgery and chronic pain at Dignity Health in Phoenix. She and her colleagues searched through the literature to investigate the complicated world of human sexuality by gathering case studies of some reported, but understudied, things that can happen after sex and orgasm.

Here are some of their most interesting findings, broken down by different post-sex behaviors and sensations.

Crying
Dr. Reinert says it’s not uncommon for women to report postcoital dysphoria, which could include crying, depression, anxiety, and aggression. Symptoms can last up to an hour after sex — with or without an orgasm — and often occur in women in a stable relationship.

Crying or getting sad after sex isn’t a sign of depression or psychological distress, says Dr. Reinert. “It’s just something that can happen in the context of all the neuroendocrine effects following orgasm,” she explains.

Foot sensations
The part of the brain that processes bodily sensations for the genitals and feet are close together, says Dr. Reinert. Basically, if you look at a map of the brain, your feet and vagina are next to each other. This can cause some cross wiring that can lead to orgasm, and sometimes, pain in the feet after sex.

Headache
Headaches that occur after an orgasm tend to be explosive and show up on both sides of the head. Intense pain can last anywhere from a minute to 24 hours, with moderate pain lasting up to three days.

If the pain is severe and doesn’t subside, check with your doctor to make sure you don’t have a bleed. “We always tell people if you’re having the worst headache of your life, make sure it’s not a subarachnoid hemorrhage, which can be lethal,” says Dr. Reinert.

Body weakness 
Everyone experiences a little muscle relaxation after an orgasm, says Dr. Reinert, but patients who have a history of narcolepsy or a sleep disorder can experience post-orgasmic cataplexy, or orgasmolepsy. This sudden onset of weakness usually lasts for less than 30 seconds, but can include a complete loss of muscle control.

This can happen because the amygdala — the part of the brain that processes emotion — fires persistently with orgasm, creating a feedback loop where it disinhibits neurons in the medulla, which controls some of the bodies automatic responses like breathing, heart rate, and blood pressure. This can lead to atonia, or lose of muscle tone, explains Dr. Reinert.

Suddenly going limp can be dangerous, especially if you fall and hit your head. Talk to your doctor about medication — including anti-cataplectic drugs or antidepressants — if this is a common experience for you.

When should you worry?
There’s a lot of variety in orgasms, and why one experience is different from the next is hard to say. Most unusual symptoms only happen occasionally and subside along with the post-orgasm glow. While things like a debilitating headache or crushing chest pain — a possible sign of a heart attack — warrant a trip to the doctor, most other experiences are no reason to worry.

“You want to make sure that there’s not something more dangerous going on, especially if this is something that keeps happening,” says Dr. Reinert. “Ultimately, the goal is to be able to appropriately reassure patients that this is not a more dangerous entity. It is something that happens sometimes in some people.”

Keri Wiginton is a writer and photographer focusing on issues related to women's health, mental well-being, and feminism. Her work has appeared in the Chicago Tribune, Washington Post, Austin-American Statesman, Tampa Bay Times and Houston Chronicle. Follow her work at www.keriwiginton.com or on Twitter at @keriphoto.