In the middle of sex, most of us probably aren’t thinking, “Wow, my pituitary gland’s really lighting up now!” But that’s precisely what’s happening. That and a slew of other bodily functions and processes you’re probably not aware of — nor thinking about — during your romp in the hay. The truth is, your brain and body are going through one heck of a roller coaster in order for you to experience as much pleasure as possible.
“Both men and women go through four sex-response cycles,” Dr. Diana Ramos, OB-GYN and cochair of the National Preconception Health and Health Care Initiative, tells SheKnows. “Excitement, plateau, orgasm and resolution — in no particular order or amount of time for each.”
Each stage comes with its own set of bodily changes and responses, some trippier than others.
During this stage, your body undergoes a variety of visible changes. “Increased blood pressure and flow along with your body releasing more nitric oxide can cause a woman’s vagina to change shades of color or swell,” says Ramos. “Breasts and other sensitive areas become tender and aroused, and it’s also why heart racing and muscle tension occurs.”
Also during this stage, the penis may become erect and the testes elevate as the scrotum contracts, she adds. And don’t forget about that sex flush, which is a result of blood flowing to the surface of the skin.
Here, the signs of excitement are even more visible according to Dr. Jess O’Reilly, host of the Sex With Dr. Jess podcast.
The clitoral glans may retract beneath its hood. In addition, the outer third of the vagina may swell, and the uterus may continue to tilt upward, she tells SheKnows. Muscular tension, heart rate, breathing and blood pressure continue to increase. The testicles may elevate closer to the body, and muscles may begin to spasm.
Though the heart is often thought to represent matters of love and sex, O'Reilly says the heart’s involvement in sexual processes is minimal in comparison to that of the brain and the nervous system.
“The pituitary gland lights up. The nucleus accumbens and ventral tegmental areas are activated. The hypothalamus goes into overdrive. And the center of reasoning and behavior shuts down entirely as you spiral into the euphoria of sexual pleasure,” she explains. “All this activity may sound like sensory overload, but this is actually your brain… on sex.”
PET scans of the brain during sexual activity and orgasm reveal that its reward circuit lights up with a flurry of activity during sex, O'Reilly says.
“These scans confirm anecdotal reports that sex is both a physical and emotional experience, as the amygdalae, which control emotion as well as the area which manages muscle function, are activated,” she adds.
Additionally, during sex, the levels of dopamine and epinephrine are on the rise, says Ramos. “When your heart rate, breathing and blood pressure are at their peak, there’ll be a spike in the production of oxytocin, which tends to cause the climax,” she notes.
This, as O'Reilly points out, all leads back to the brain. “Brain studies also explain why sex is so pleasurable from a chemical perspective, as the areas related to dopamine release become hotbeds of sexual activity resulting in increased levels of this feel-good neurotransmitter,” she says. “And as the pituitary gland is activated, the release of endorphins, oxytocin and vasopressin promote pain reduction, intimacy and bonding.”
What also might be happening during this stage? According to O'Reilly, quite of few things are going through your body as it experiences orgasm.
Some might experience a dilation of pupils in response to the oxytocin release into the spinal cord area that controls this response. You might also experience involuntary muscular contractions throughout the pelvic region, including the vagina, uterus, anus, penile base, prostate and pelvic floor. These contractions are spaced at an average of 0.8 seconds apart, says O'Reilly, beginning at 0.6 seconds and slowing down thereafter. Some might also ejaculate, which refers to the expulsion of fluid through the urethra.
The resolution stage
Post-climax, Ramos says all the hormones and neurotransmitters will begin to resolve, and your body will return to its normal state, including swelled and erect body parts as well as body parts that might have changed in color.
While you might experience these sensations during sex, O'Reilly points out, “It’s very important to note that these reactions are not universal and the process is not linear. For example, you may not orgasm every time you have sex, and that’s OK.”
She adds, “I really want to emphasize that you don’t have to experience all of these bodily responses to enjoy sex.” But if you do, at least now you know what's going on.