We already know sex is really good for you, and can basically double as medicine. I mean, it increases your immunoglobulin A levels and makes your immune system stronger, protects against certain cancers, helps you sleep better, and it relieves stress and keeps your mental health in check.
That said, it’s no surprise that an activity as healthy and fun as sex leaves you feeling happy and serene, in something commonly known as the sexual “afterglow.”
According to research published in the scientific journal Psychological Science, it turns out that splendid post-coital “glow” is actually all emotional, and comes from the happiness you feel courtesy of the "love hormone" oxytocin.
This actually makes a lot of sense, considering most would argue that a solid romp in the sheets leaves you a sweaty, drained, sleepy mess, even though you feel pretty damn amazing on the inside.
For their research, scientists analyzed the results of two separate studies that each surveyed 100 newlywed couples, where the couples filled out sex diaries for two weeks and recorded how many times they had sex, and how they felt about their relationships in the days following sex.
Not surprisingly, the couples reported increased sexual satisfaction on the days they fooled around, but more importantly, it was discovered that they had higher feelings of intimacy and happiness, a.k.a. the “afterglow,” that lasted for two whole days after a roll in the hay.
Furthermore, the researchers discovered that during the afterglow phase, a man’s sperm quality actually decreases, but begins to recover after the third day.
It’s believed that this 48-hour afterglow and the two day decrease in sperm quality work together as an evolutionary remnant intended to keep the happy couple together for at least two days after a good lay, since sperm can only survive for a maximum of two days in the female reproductive tract. And when you can’t bust a high-quality nut for two days, it gives the previously deployed sperm a better chance of reaching the egg.
Did you get all that?
What’s more is that the researchers had the couples reevaluate their relationships four to six months later, and found that those who felt the strongest afterglows were more satisfied with their relationship months later, meaning the better the sex is, the better the relationship. But that’s not too surprising, is it?
"Our research shows that sexual satisfaction remains elevated 48 hours after sex," says lead author, Dr. Andrea Meltzer. "The afterglow appears to last approximately the same length of time that it takes for peak sperm concentration to be restored.
“And people with a stronger sexual afterglow — that is, people who report a higher level of sexual satisfaction 48 hours after sex — report higher levels of relationship satisfaction several months later.”
To conclude, let's sum up the entire study into one simple sentence: You feel sexually satisfied for two whole days after sex, and it's only because you subconsciously want to knock up your lady with your high-quality sperm. The end.