Friday Weird Science: Oxytocin and the Big O

Nov 13 2009 Published by under Friday Weird Science

Rounding out Sci's first week of the Great Oxytocin Posting of 2009 (oh yes, there will be two weeks of this, hang tight), we've gotta do something weird. And luckily for everyone, oxytocin does lend itself to the strange types of studies. Like multi-orgasmic studies. Complete with measurements of anal contraction. You know you wanna volunteer for this one.
And luckily for all of you, Sci is the one doing the reading and the retelling of this study. Because reading the methods for this one might cause you to do this: Carmichael et al. "Relationships among cardiovascular, muscular, and oxytocin responses during human sexual activity". Archives of Sexual Behavior, 1994.

Also, we're stuck with another group of people who PUT ALL THEIR DATA IN TABLES!!! AUGH!!! Not only that, all of the tables in the pdf were in landscape, as opposed to portrait, which means Sci spent the entire time reading the paper like this:

Sci will fix for you. She graphs because she loves.
So anyway, as you may know from my previous post on the topic, oxytocin levels change during sexual arousal in women. They ALSO change during sexual arousal in men. In this study, the authors wanted to see whether oxytocin levels correlated specifically with orgasm, and what aspects of orgasm they correlated with.
So take 23 people, 13 women, 10 men. Make sure none of them are uncomfortable about the prospect of masturbating (apparently they have a questionnaire specifically for this, and I hope it also addresses the prospect of masturbating for a bunch of scientists who are going to be taking recordings of all of your physiological parameters). Put them in a sound-attenuated room with a TV (for those who requested porn) and a nice chair. Then, add a blood pressure cuff, a butterfly needle indwelling catheter for continuous blood level monitoring, and anal probes for monitoring of smooth muscle contraction. All these things are on really long leads that go into the next room, so the subjects can get some privacy.
Now, GO! What, you mean that's not comfortable?!
Luckily, they gave them two test sessions, one to get used to the room and surroundings, and another one to get used to the idea of blood sampling and anal probing during self-stimulation. So hopefully the discomfort became less of a factor. Finally, measures were taken twice for each subject, starting 6 minutes prior to self-stimulation, and continuous recording until 5 minutes AFTER.
And he's what they got:

You can see there a graphed representation of anal muscle contractions (a physical sign of orgasm), the volume of the anus at the time (another measure of anal contractions), and systolic blood pressure over the buildup to orgasm and the 5 minutes after. You can see that the blood pressure and anal contractions all peaked very nicely right at orgasm and fell off right after. The blood pressure showed the smallest change, and the APG (the anal volume measure) showed the largest change. The authors found no difference between the time the subjects SAID they were orgasming and the duration of the peak bodily effects, showing that (1) the subjects weren't lying, and (2) that the physical aspects go right along with the subjective experience.
And now we get into the stuff Sci had to look sideways to graph.
oxytocin orgasm 2.png
You can see above the mean duration of orgasm (how long it lasted) in seconds for men (in blue), for women who only had one orgasm (light pink), and for women who had two orgasms (the dark pinks). You can see that duration of orgasm didn't really differ between any of the groups, but hey, at least the multi-orgasmic women got to enjoy it twice. They did have ONE multi-orgasmic man, who had FOUR orgasms prior to actual ejaculation, but he was in a class all his own and I'm not going to bother graphing him if he doesn't come with a standard error and an n higher than one (though I will note that his longest orgasm was along the lines of 47 sec!).
They found that oxytocin levels in men and women peaked with orgasm, and that the oxytocin levels correlated with the "strength" of the orgasm, both in physical measures and in the patient's self-reports.

This is the second major graph, showing the strength of anal muscle contraction during orgasm for men, mono-orgasmic women, and multi-orgasmic women. You can see that the men appear to have the strongest anal muscle contraction by a good bit, while the women peak at about the same whether they have single or double orgasms.
But what's really cool about this study? What it actually LOOKED LIKE (no, not that, sicko)

Here you can see the simultaneous recordings for two different types of orgasm (apparently they were able to separate the orgasms easily into two different types). It shows very nicely how the muscle contractions and volume (the APG and EMG) go right along with the subjective measures of orgasm (the tick marks in 1 sec intervals. I really hope they didn't make the subjects fill out a sheet during or that's going to be one heck of a confound, maybe they just said "oh, right then!"?). You can also see that there's a little burst of muscle activity right before orgasm, and while the muscle contractions are pretty rhythmic, there are some pauses as well. You can also see that the EMG and APG measures correlated with each other in little bursts.
In measures of the two different types of orgasm, it appears that the second type (classified as type B) was generally longer (26.9 sec vs 16.3 sec), but had the same number of muscle contractions, so I guess you could call it "slower" as well.
Interestingly, in subjective measures afterward, the subjects all reported brief or long orgasms to be equally satisfying, despite the differences in the physical measures. So there were some subjective differences involved. But overall, the subjective measures of WHEN the orgasm occurred, the physical responses, and the hormonal responses (the peaks in oxytocin) all correlated very well.
The authors concluded several things:
1) Based on previous studies as well as the current one, blood pressure goes along with oxytocin levels, and some studies have shown that injection oxytocin increases blood pressure. So oxytocin could be having direct effects on blood pressure.
2) That oxytocin helps to stimulate the muscle contractions that occur with orgasm. Oxytocin is known to stimulate muscle contraction (like in the alveoli during lactation and in the uterus during birth), and so this isn't a particularly big stretch. Not only that, knowing that oxytocin can help stimulate the muscle contractions that occur with orgasm could help those who have problems with it, perhaps using supplemental oxytocin as the next Viagra (I really hope I didn't get people ideas with that one, I'm going to assume someone's thought of it already).
The take home message? For your next orgasm, thank oxytocin. It's about time it got credit for something fun.
Carmichael, M., Warburton, V., Dixen, J., & Davidson, J. (1994). Relationships among cardiovascular, muscular, and oxytocin responses during human sexual activity Archives of Sexual Behavior, 23 (1), 59-79 DOI: 10.1007/BF01541618

20 responses so far

  • A multi-orgasmic male? Life's soooo unjust sometimes ;-(
    Great post anyway, Sci! πŸ™‚

  • AK says:

    Question: how were the two types of orgasm distributed? Did everybody have only one type, or were there some (or all) who experienced both types? How distributed between sexes?
    BTW, the owl is cute, but I hope you know there's a button you can click in Adobe to rotate the page.

  • Scicurious says:

    AK: ummm...Sci didn't know that...where is this magical button? My neck still hurts. Stupid small numbers...even at 150% they were so small!!!
    I actually looked for the n's on that (just looked again) and I don't think they were stated. This is odd as they gave mean and SEM...

  • I wonder how would oxytocine levels be affected by foreplay - in both sexes, of course πŸ™‚ This particular study involved single persons, but maybe somebody will try to measure all those parameters during an intercourse? We know already that nipple stimulation plays an important role in females - so how about males? And other sensitive body areas?

  • becca says:

    I am disappointed to see only this use of "magical button" on a post about orgasms.

  • Catharine says:

    Very interesting, lively, and stimulating! But I'm wondering about possible differences in oxytocin in small, weak orgasms compared to more substantial ones -- the question doesn't necessarily have to do with the length of the orgasm but the quality. And why are some orgasms qualitatively different than others? If orgasm is a discrete event, there is something about that difference that doesn't make sense. Are there reasons other than side-effects of medications? (I don't think this is a purely subjective fact, that is, I bet the physical/chemical measurements of weak orgasms are quantitatively less than good, strong orgasms.) Also, how would you explain feeling the chemical rush of oxytocin in breasts (the same feeling as when your milk "lets down") many, many years after breastfeeding (but never before) in situations in which you are either sexually aroused or maternally aroused, so to speak (like feeling a gush of emotion when you see an infant). To add a little more confusion to this series of questions, why would somebody feel it (the rush) in only one breast?

  • becca says:

    The chemical rush of oxytocin could possibly be expected for other bonding type moments, I think the feeling is probably the contraction of the muscles. The milk comes more from the cell's response to prolactin, getting it out is the job of oxytocin, if I understand correctly.
    My Mother, long past menopause, said she definitely got the tingle from her grandchild so I'm guessing it has relatively little to do with estrogen/progesterone (not that those couldn't modify the effect, just that they aren't necessary). Why it can happen in only one side, I haven't figured out. I do know many women report much more production on one side compared to the other. Aside from the muscles getting more work on one side (if the infant tends to be held slightly differently, one one side vs. the other), I haven't heard a good explanation for that.

  • Gwenny says:

    I remember when I first learned that some women only have one orgasm. I read it in a book when I was about 14 or 15. I was like, really, just one . . not five or six. How sad.

  • raja says:

    My dr. treats me for anorgasmia since several months back with a nasal spray of oxytocin.
    It works most of the time but not always.
    I had previously been a multi-orgasmic male before prostate surgery (bph + turp) ruined that.
    Urologists do not think of the prostate as part of the sexual
    mechanism, as they should.
    I regret deeply the surgery as I went in for a tuip and lost something valuable to gain a better stream.
    I believe men can learn to be multi-orgasmic, but it takes dedicated practice and effort.
    Maybe one day... again....with practice.

  • Katie says:

    Interesting study and a great explanation! I'm wondering about the possible confounding effects of the uh, anal probe. Since the anal region is also stimulatory, having something sitting around in there might have an effect on the type, length, and strength of orgasm, don'tcha think?

  • AK says:

    In my version of standalone Adobe Reader 9 it's in the menu at View/Rotate View (Alt+V, Alt+V), or use hot-keys Shift+Ctrl+Plus for clockwise, Shift+Ctrl+Minus for counter-clockwise. I haven't checked but IIRC it's the same for the reader in a browser window, and I would assume it's the same for other releases of the Reader. (O.K., it's not really a button, I stand self-corrected.)

  • bumerry says:

    Katie, my thought exactly! IME, anyway!
    Also, I wondered if the more intense anal contractions in males might have to do with anatomy and a more expanded contraction anatomy for women, leading me to think that vaginal contractions, labial movement and clitoral swelling should be measured in future work. Maybe not all at once though - how would your participant masturbate?!

  • Sci, your introduction to that was so funny I nearly fell off my chair!!!

  • Big Al says:

    I gave my wife 30 orgasms one night. I wish I'd read this 1st, so I could have been thinking about oxytocin levels while I was waiting for my turn. At 30 it got a bit weird so we stopped.

  • [...] Oxytocin does have effects on pair bonding, but that’s usually associated with sexual activity and orgasm, not during flirting. Though oxytocin does increase what we call “affiliative behavior” [...]

  • Dylan says:

    I am a little confused about something...maybe I missed it, but what was the actual finding regarding oxytocin? I don't see it, I'll just have to add the paper to my "to read" list.

    • scicurious says:

      The finding is in there: "They found that oxytocin levels in men and women peaked with orgasm, and that the oxytocin levels correlated with the "strength" of the orgasm, both in physical measures and in the patient's self-reports."

  • Both of these types of IUDs work in the same way by interfering with the movement of the sperm and not allowing it to fertilize the egg

  • I have been browsing online more than three hours today, yet I never found any interesting article like yours. It’s pretty worth enough for me. In my view, if all website owners and bloggers made good content as you did, the web will be much more useful than ever before.

  • Sorry, I probably should have posted my question here. I had already glanced at some of your other articles, titles, but went for a more recent article.

    As you can see, here again, the focus is on sex, and yet I keep reading about various other activities that apparently raise one's level as well.

    Thanks again.

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