Scientists still lack hard data about how long it takes men to recharge after sex. But for years they thought they were at least had an explanation as to why the standstill was necessary.
It may be time to retract the existing explanation why back-to-back ejaculations are a biological battle.
The prevailing explanation for the “refractory period after ejaculation” (the idea that men have to wait after orgasm before being aroused again) called a hormone prolactin. Prolactin is perhaps best known for stimulating milk production in women during pregnancy, but it also has deep bonds with orgasms (usually accompanied by ejaculation, but not always).
High levels of prolactin have been linked to low sexual desire. Studies have also shown that prolactin rises during ejaculation and orgasm, indicating that it is the hormone that causes the body to demand a break afterwards. One notable exception stems from a case study involving a man who was repeatedly able to orgasm. In one trial, he only needed two minutes between orgasms – he also did not see a typical prolactin uptake after release in the control group.
But research from the past may have sent scientists in the wrong direction, explains Susana Lima, the first author of a new study published this week in Communication Biology. Lima is a researcher at the Champalimaud Research Center for the Unknown, a private biomedical research institution.
In a study on two types of mice, she found that it had to do with prolactin levels no effect over the male refractory period.
“It means it was just a correlation,” says Lima Reverse. “The cause has never been tested.”
How the study worked – This study is based on the sexual experiences of two types of mice: one type with a short refractory period and one with a long recovery period lasting several days. The male and female mice were first kept separate and then introduced to each other.
The team took blood samples from the male mice on four occasions: Before meeting their female counterparts, after the mice initially pulled up their sexual mates (demonized), to a certain number of mounters (five for one type of mouse and three for the others, if you must know), and then after the mice have ejaculated.
The scientists could see that the mice ejaculated when they displayed ‘stereotypical shivering’ and fell over.
The detailed blood samples showed that prolactin did increase during sexual activity. But subsequent trials illustrated this did not affect the refractory period.
In follow-up experiments, the team artificially manipulated the level of prolactin in the blood of each male mouse. previously they had sex. These higher levels did not change their sexual behavior. If prolactin had inhibited sex, the mice would have had less sexual desire, the authors explain.
The authors also blocked the release of prolactin after orgasm to see if it could inspire more sexual activity by shortening the refractory period. They found no significant increases.
A mouse study may not completely spell out the end of prolactin theory, but because prolactin has similar functions in humans and mice, Lima says she expects these results to remain in humans.
“I think we can consider our results as strong evidence against prolactin and the refractory period in men,” she says.
What is the new explanation? – If this study does not completely discount the idea that prolactin contributes to the refractory period, it suggests that scientists should also support other ideas. These ideas probably combine different systems and hormones in the body rising and falling, not just one smoke gun, Lima says.
“Most likely both central systems and peripheral systems work in coordination… “
She in turn explains that there two main systems probably the refractory period: a central brain mechanism and a ‘peripheral’ – a mechanism that deals with the physical elements such as the penis, glands and other organs that ‘support erection, emission and ejaculation’. The central brain mechanism has more to do with behavioral elements, such as sexual desire.
In short, a lot happens in the brain and body during ejaculation, and understanding why it takes time for the body to recover can amount to learning the intricacies of each action.
“Most likely, both central systems and peripheral systems work in coordination so that the male does not have an erection without desire or desire without being able to stand up straight,” says Lima.
For now, the true cause of the male refractory period is still a mystery – just like the female orgasm.
Summary: In many species, ejaculation is followed by a state of diminished sexual activity, the refractory period after ejaculation. Several pieces of evidence have suggested that prolactin, a pituitary hormone released during ejaculation in humans and other animals, plays a decisive role in determining the refractory period. However, data supporting this hypothesis are controversial. We used two different strains of the house mouse, a wild derivative and a classical laboratory strain that differ significantly in their sexual performance, to investigate the involvement of prolactin in sexual activity and the refractory period. First, we show that there is release of prolactin during sexual behavior in male mice. Second, using a pharmacological approach, we show that acute manipulations of prolactin levels, which mimic the natural release during sexual behavior, or inhibit its occurrence, do not affect sexual activity or shorten the refractory period, respectively. Therefore, we show compelling evidence that refutes the idea that prolactin released during copulation is involved in the establishment of the refractory period, a long hypothesis in the field of behavioral endocrinology.