Ask the Doctors: Fainting During Orgasm

I have a good friend who recently told me that his girlfriend sometimes faints when they’re having sex. Specifically it sounds like it happens when she comes. He didn’t seem too worried about it, although the sound of it made me a little nervous — I feel like I’ve heard about headaches when people come, is this related? Should I warn him there might be a problem?
–Concerned Friend

Let me put it this way: Fainting at the point of orgasm doesn’t raise as much concern among the medical pros as some kinds of passing out, but as I researched your question, everyone who addressed fainting –the medical name for it is syncope (pronounced “sin’-co-pee”)– seemed to agree that sometimes it’s a sign of, or can result from, a serious condition. So I don’t think you’re concerned for absolutely no reason, and if Girlfriend-of-Friend has never told a doc about this, I’d recommend she do so — to rule out these problems or to catch them early.

Fainting — loss of consciousness including a lack of awareness of one’s surroundings — can include loss of muscle tone, so that often a person also falls or slumps over. Usually it happens because the brain doesn’t get the blood-borne oxygen and nutrients it needs. To quote the nice doctors on “Decreased blood flow to the brain can occur because 1) the heart fails to pump the blood; 2) the blood vessels don’t have enough tone to maintain blood pressure to deliver the blood to the brain; 3) there is not enough blood or fluid [or, I would add, oxygen or nutrients] within the blood vessels; or 4) a combination of reasons one, two, or three above.”

It can be very transient, or repetitive; especially when it’s repetitive, it’s good to establish its cause to make sure it’s not a sign of something very medically problematic or even life-threatening. Although the cause of fainting is often something benign, it is not normal. And there are a good many possible causes and related factors.

Vasovagal response: When the vagus nerve is overstimulated (which many types of physical and emotional stimuli can do), blood vessels can dilate and the heart can slow. One writer in my research called it an “anti-adrenaline effect,” in which a surge of the chemical acetylcholine has slowed you down, doing the opposite of adrenaline’s wake-up, fight-or-flight effect.  Various kinds of common physical effort can cause vasovagal syncope, including a hard cough or straining to pee¦ and orgasm, especially the kind where the person bears down powerfully.

Cardiac syncope:  This happens when the rhythm of the heart is interrupted — tachycardia, or fast heartbeat, doesn’t allow the heart to fill with enough blood to pump out to the brain, while abnormally slow heartbeat can cause too-low blood pressure. An electrical problem with the heart — its inability to beat properly — can be extremely dangerous. Some heart meds can also cause blood pressure issues that can result in cardiac syncope. Obstructive cardiac problems (such as blockages or lesions) can cause the response, also. This one, I think it’s obvious, is a possible cause of fainting that must be taken quite seriously.

Systemic loss of blood pressure: Both of the above causes of fainting can include a significant drop in blood pressure, but note that it can also be associated with shock (including anaphylactic shock, and this, although rare, is a response that happens when a person is profoundly allergic to latex or other substances).

Seizure disorders including epilepsy: While fainting can be part of a seizure, there can be more to a seizure than syncope. Any fainting episodes that include movements (jerking, etc.) might point to this, but there are many types of epilepsy and other seizure disorders. An affected person would need to be assessed by a neurologist.

Something called BPPV (benign paroxysmal positional vertigo) could be related, according to the nice folks at the Mayo Clinic. This is associated with the position a person is in, and changing that position. As the name suggests, this response is not really dangerous, but would be associated with, for instance, sitting up–if a lying-down person comes and passes out, it’s not BPPV, it’s something else.

With a severe headache, the experience of fainting can be related to migraine and possible increased risk of stroke. There are other ways that sex headaches manifest themselves — that’s a topic for another day — and headache and syncope don’t always happen together, fortunately.

Other things to consider: anemia, dehydration, hypoglycemia, diabetes, high blood pressure, smoking, various kinds of drugs (including some recreational ones like speed, cocaine, and alcohol), pregnancy, vertebro-basilar arterial disease, some forms of lung disease. Some of these elements might also be made more serious by age, and/or older people may be more likely than younger ones to have the underlying heart and other conditions that may result in syncope.  (Fainting can still be problematic in a younger person, however.)

In many, if not most, cases, a person who’s fainted will “come to” more quickly and easily if their head is down, because adequate blood flow to the brain can then resume. The best practice here is to turn the affected person on her side, just in case she throws up.

FYI: Though your question has to do with fainting upon orgasm, I should note that syncope can absolutely also happen during BDSM play, and if someone is in standing bondage when it happens, it will be important to get them down right away. People who are going to do bondage should take this into account–just in case your friend and his GF are kinky that way. People who are placed in standing bondage should attempt to maintain some motion in their legs (this assists in pumping the blood back up), rather than locking their legs stiffly. If a person is wearing anything tight, like a corset or hood, it should be loosened/removed.

lso, “vanilla sex” of long duration, involving lots of energy expenditure and too little hydration or nourishment might set up the conditions for transient syncope. As the Wiki page says, syncope can be caused by “physical exercise in excess of the energy reserve of the body” — if that’s not an excellent description of the “too-into-fucking-to-eat” syndrome, I don’t know what is.

If the fainting person doesn’t eat or drink much before they have sex, locks their legs out stiffly when they get aroused, engages in any sort of breath play (from a partner holding their throat to just holding their breath intensely), or if their breathing gets short and quick and they hyperventilate, and particularly if their sexual response includes powerful bearing-down in their buildup to orgasm or the orgasm itself: any of these elements might be relevant to a spell of fainting. If the room’s too warm or stuffy it may also contribute to the likelihood of fainting.

This may be WAY too much information for a chat over beers, but you might want to share this Q&A with your friend and his partner. And she should, if she’s hasn’t done so already, see a sex-positive and sexuality-knowledgeable doctor. None of what I’ve told you is medical advice, just informed research, so the next step is to compare all this to the fainting woman’s experience and current knowledge. It’s possible she’s already been to the cardiologist and everything’s cool, but if she hasn’t, why not err on the side of caution?

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Dr. Carol Queen

Carol Queen has a PhD in sexology; she calls herself a "cultural sexologist" because her earlier academic degree is in sociology: while she addresses individual issues and couple's sexual concerns, her overarching interest is in cultural issues (gender, shame, access to education, etc.). Queen has worked at Good Vibrations, the woman-founded sexuality company based in San Francisco that turned 35 years old in 2012, since 1990. Her current position is Staff Sexologist and Good Vibrations Historian; her roles include representing the company to the press and the public; overseeing educational programming for staff and others; and scripting/hosting a line of sex education videos, the Pleasure-Ed series, for GV’s sister company Good Releasing. She also curates the company's Antique Vibrator Museum. She is also the founding director of the Center for Sex & Culture, a non-profit sex ed and arts center San Francisco, and is a frequent lecturer at colleges, universities, and community-based organizations. Her dozen books include a Lambda Literary Award winner, PoMoSexuals, and Real Live Nude Girl: Chronicles of Sex-Positive Culture, which are used as texts in some college classes. She blogs at the Good Vibes Magazine and at SFGate's City Brights bloggers page and contributes to the Boston Dig. For more about her at

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