According to several recent studies, the human body is both exceptionally gross and fantastically weird, and never more so than when it is engaged in the act that makes new human bodies. Despite exceptional amounts of popular interest, the physical effects of intercourse on the body have historically proven somewhat difficult to study.
For many years, religiously-motivated concerns about morality prevented studies from happening, and even when a study finally gets underway, other problems presented themselves. “The Observer Effect” states that it is impossible to stick a bunch of electrodes on a couple, set up a bunch of recording and monitoring devices, and watch them having relations from behind a two-way mirror and yield identical results.
Despite all of those obstacles, we have managed to learn a few things about what happens to your body while having sex. Here is a list of some of the gross, weird, fun, awesome, hilarious, and confusing things that humans do when they’re doin’ it.
Breasts Grow During Arousal
Increased blood flow to the area can cause a woman’s breasts to swell to up to 25 percent larger than in their non-aroused state, which men should file away under extra incentives to take their time before “doing the deed” (as if they didn’t have enough already).
Stimulation promotes circulation in general and encourages blood flow to the “sensitive” zones (such as the chest and nipples) in particular. Women’s breasts may change in color slightly, with redness or blotchiness appearing on the chest and the areolas and nipples darkening. As the nipples harden and the areolas become enlarged, the whole area becomes far more sensitive to the touch. Play your cards just right and some women can even climax from nipple stimulation alone.
Your Brain Gets You High
Let’s face the facts: we’re all addicts. Maybe you’re not hooked on the “traditional stuff,” but admit it: you’re addicted to something. The body is just one big series of chemical reactions, and historically, one of humanity’s favorite drugs to experiment with happens in the bedroom.
During the arousal process, the brain stem releases the pleasure chemical dopamine, your adrenal glands start producing adrenaline, and the hypothalamus secretes even more happy juice into the blood in the form of oxytocin and prolactin. Once you start reaching climax, however, the secreting stops and the full-on flooding begins. Dopamine, prolactin, and oxytocin, plus phenylethylamine, vasopressin, serotonin, and other endorphins are all released during climax, creating that blissful, euphoric feeling that keeps people coming back for more.
Your Immune System Gets a Boost from Frequent Booty
This just in: the drive to be healthy starts with a healthy and regular “bedroom routine.”
According to one study, sexually active people are healthier overall and take fewer sick days than their celibate co-workers (not that that excuse would fly if your boss caught you and the hottie from accounts receivable in the coat closet enjoying a little afternoon delight).
Having regular intercourse boosts your immunoglobulin A (IgA) levels, with higher levels correlating to greater duration and satisfaction – so it’s not just quantity of booty that does a body good, it’s the quality, too. Intercourse also helps your body’s production of lymphocytes, which are a key part of the process of fighting off infections, and it increases immunoglobulin antibody levels which help your body ward off viruses, bacteria, and other invasive microbes.
So go ahead, get down tonight – for your health.
Female Genitals Suck
You kids today with your Tinders and your cosplays and your buttstuffs sometimes forget that intercourse, at its most basic level, is a biological function for procreation. As much as you might think that you’re just having a nice recreational goofaround, it’s hard to tell female genitalia that, so it’s going to keep doing everything in its power to increase the chances of conception.
One of the vagina’s tricky little moves is that it is constantly trying to suck up any and all sperm that gets inside of it. During the early phases of the arousal process, it begins “tenting,” which moves the vagina and the cervix closer together and helps create a suction that pulls sperm inward. Then, during climax, the muscular contractions that a woman experiences are, in part, the genital tract further sucking inward, radically increasing the chances of sperm retention.
Your Sense of Smell Increases as You Climax
When you reach climax, one of the many chemicals released into your drug-addled brain is prolactin. Prolactin has a number of effects, including supporting the immune system, fighting cell death, and makin’ you feel gooood.
Prolactin also has the unique side effect of totally opening up the part of the brain that interprets smells, known as the olfactory bulb. This allows for better processing and storing of olfactory data and may help people – especially women – to better assess their mates for genetic health and future identification. These olfactory imprints are stored long-term, and the arousal instinct can be triggered in the future just by getting a whiff of a lover’s pheromones. You literally think differently about the smell of someone that makes you reach climax.
Fun scientific fact: there is no bone in a lady boner.
During the arousal process, the glans and shaft of the clitoris fill with blood, making it stiffen and swell, sometimes up to double its non-aroused size. The clitoral hood also engorges, mostly to protect the highly sensitive clitoris from too much direct contact, and after climax, everything returns to normal within about 10 minutes. If a woman becomes aroused and doesn’t reach climax, the blood will remain trapped in the region possibly for hours, which many women can find irritating, uncomfortable, or frustrating.
Your Pain Tolerance Skyrockets
“Pain don’t hurt,” said Dalton, the zen philosopher and epic throat-ripper portrayed by Patrick Swayze in the 1989 trashsterpiece Road House, and given how hot Swayze was in the late ’80s, one can only assume he was talking about pain thresholds during sexual arousal.
During intercourse, the body’s ability to tolerate pain increases dramatically, especially so among women; as women approach climax, their pain threshold is almost 100% higher than it is during non-stimulated times. Those sensations aren’t just dulled, however. They can also be re-framed as pleasure.
The insula and anterior cingulate are the areas of your brain that manage pain, but they also become highly active during intercourse and, for some reason, treat many sensations that would be classified as unpleasant under other circumstances as very pleasant indeed. This may explain why people tend to contort their face into expressions that very strongly resemble pain during intercourse, and it almost certainly plays a role in why some people enjoy S&M.
You Get That Post-Coital ‘Glow’
It’s true, good intercourse can make you glow.
Another effect of all this increased blood flow is your skin both eliminates toxins and gets more oxygen, which helps your dermis look younger, softer, and brighter. It also boosts collagen production, which helps stave off age spots and sagging. Intercourse can also be helpful to those that suffer from chronic acne because it can potentially regulate some of the hormone imbalances that cause acne in the first place (although telling that to a zit-faced teen may just frustrate them even further). Additionally, all the hubbub helps your body produce human growth hormone, which keeps the skin looking and feeling youthful and elastic.
Perhaps most strangely, during the arousal process, the skin’s electrical resistance increases, heightening sensitivity. This galvanic skin response controls sweat production and pore size. The higher the degree of arousal, the higher the skin conductance. Curiously, this is also what Scientologists are measuring with their “E-meters” in their “auditing sessions.”
Now, everyone knows about lady boners, but did you know that dudes can get boners too? Shocking news to be sure, but you can totally look it up.
Much like its female counterpart, the lesser-known “clitor-his” is the product of an increase in blood circulation during the arousal process, especially within a certain region known to doctors and researchers as the “bone zone.” Within the bone zone is the penis, which, when compared to other erogenous areas on the body, is definitely the silliest. Within the penis is a network of corporal sinusoids – a kind of spongy tissue that absorbs and retains blood during arousal, allowing it to (hopefully) grow and harden. While not quite capable of the growth that the glans of the clitoris is, the erect penis is still capable of growing 25-50 percent larger than its flaccid length.
During arousal the brain tells its friend, the neurotransmitting chemical nitric oxide, to tell the smooth muscle enzymes guanylate cyclase to get their buddy, cyclic guanine monophosphate (cGMP), to increase the size of the blood vessels that carry blood into the penis and decrease the size of the blood vessels that carry it out. Then tunica albuginea, the bouncer of the penis-club, slams the door behind the blood, trapping it inside. This turns into a hostage situation where cGMP won’t let tunica open the doors until the brain gets its climax – or until the brain finally loses interest in the club; whichever comes first.
Fertility Is Increased If You Have Frequent Intercourse
Ok, here’s a no-brainer: did you know that having intercourse makes a woman more likely to conceive?
Yes. Yes, you did know that.
But did you know that doing it during times in the menstrual cycle when a woman cannot conceive makes her more likely to get pregnant during the times that she can?
Maybe. You might’ve known that, you might not have – who knows what you know?
A recent study showed that women that engage in frequent coitus during their infertile periods have higher levels of type 2 T-cells – the helper cells responsible for making sure a woman’s body doesn’t kill all the sperm at once, increasing her chance of getting pregnant. That combines with the body’s increased ability to fight off diseases that may impede conception to make conditions as conducive as possible for fertilization.
You Go into Reward Mode
The brain treats intercourse like a bonus level on a video game: once it’s activated it just starts trying to grab everything it can in the short time that it has.
The reward circuit is what’s activated when your brain wants to reinforce a certain behavior. In order to start building positive associations with a given action, your brain stem releases a heavy dose of the pleasure drug dopamine. We get similar hits when we eat food our body says it likes, when we win at the casino, or when we snort those giant rails of cocaine our body tells us it wants (reward mode doesn’t always make the best long-term choices).
For men, the brain goes into reward mode with very little sexual provocation – just the glimpse of something moderately alluring can be enough to get the dopamine flowing. Women tend to have a higher threshold for activation when it comes to intercourse, as the consequence centers of their brains are far more active than those in men. Visual stimuli alone is rarely enough to start the chemical chain reaction, however, women tend to be highly reactive to touch and smell.
Once the reward center is activated, regardless of gender, all humans tend to turn into dope(amine) fiends that won’t stop until they get their fix – or the time on their bonus stage runs out.
Your Blood Pressure and Temperature Rise
Music historians have noted that songs about love and intercourse are rife with references to pumping blood and rising temperatures. The reason for these repeated themes isn’t just that songwriters are unrepentant hacks, but rather that they have a finely tuned understanding of the biological underpinnings of the arousal process. The reality is that intercourse actually does get the blood pumping harder, thus increasing your temperature – so thank you, Foreigner, for helping us understand ourselves just a little bit better.
From the moment you first get turned on all the way through your post-coital bliss, the whole sexual cycle involves the circulatory system. Initially, when you just start getting aroused, your adrenal gland begins hitting your bloodstream with adrenaline, speeding up your heart and dilating your blood vessels. Blood is the main component of the erectile process, and most ED medications are just glorified circulatory drugs. After all, why do you think our symbol for love is the heart?
Those that are good at it may have noticed that, when done correctly, the act is a bit of a workout. There’s all that thrusting, the contorted positions, the flexing in the mirror – the sheer athletic endeavor of it all increases heart rate and blood pressure by 50-60 percent. While the long-term effects of all this cardio exercise have been shown to lower blood pressure overall, those with heart or circulatory issues have to be careful how enthusiastic they get in the moment – overly robust intercourse can actually triple your heart attack risks. Talk about your broken hearts! Hey-O!
Men Get Sleepy After Doing The Deed
When men fall asleep right after, it’s not just because you’re doing it late at night. In a bed. Maybe after a few cocktails (although any or all of these may be contributing factors). It’s not even just that intercourse is hard f’ing work, so to speak.
The major reason that men get sleepy after intercourse, regardless of time of day or sobriety level, is that the oft-mentioned post-coital chemical flood includes prolactin, norepinephrine, serotonin, oxytocin, and vasopressin – all chemicals associated with relaxation, happiness, and, you guessed it, drowsiness. So, ladies, it’s not that your guy is lazy, insensitive, or trying to get out of cuddling – heck, he just got flooded with oxytocin too, he’d probably love a good spoon sesh. It’s just that he just OD’d on happiness and needs a quick nap in order to recover from feeling so great.