For both men and women, there is a physical resolution after orgasm. This is when the body returns to its normal, pre-excitement state — muscles relax, and blood pressure and heart rate drop.
How long does a man have to wait?
In men, the penis loses its tumescence, and sexual desire, having been satisfied, disappears, according to the International Society for Sexual Medicine. During this refractory period, a man is incapable of becoming hard again and doesn't respond to sexual stimulation.
The refractory period is thought to be triggered in men by a surge of prolactin, a hormone secreted by the pituitary gland, along with a drop in testosterone (per Men's Health). Together, along with the involvement of the nervous system, these hormones cause a physiological state of being unable to have an erection.
How long the refractory period lasts depends on a variety of factors, with a salient one being age. Young men in their 20s may only require a few minutes before they can have another erection, while men in their 30s and 40s may need 30 to 60 minutes or longer. It also varies from man to man, as well as the kind of sexual activity that led to orgasm.
How long does a woman have to wait?
One study found that the surge of prolactin released after orgasm was 400 percent higher when the orgasm resulted from intercourse than when it resulted from masturbation. This could mean that climaxing after intercourse may lead to a longer refractory period than one after self-pleasure.
It's known that women also experience a surge of prolactin after orgasm, suggesting there might be a physiological refractory period. One study of 174 university students found that 96 percent had clitoral hypersensitivity after orgasm, which made them averse to further clitoral stimulation (per The Canadian Journal of Human Sexuality). This is similar to the penile sensitivity men experience after climaxing. Despite these findings, women can be multi-orgasmic.