Why men fall asleep after sex

Men cannot help but fall asleep straight after indulging in sexual activity because their brains are ordering them to do so, a new study has revealed.

In the research, scientists have claimed the male brain is programmed to switch off after orgasm.

In contrast, women stay alert so are more likely to be left staring at the ceiling in frustration.

Men were scanned during and after climax and it was found that the entire cerebral cortex, the brain's "thinking" part, shut down during orgasm.

Then two other areas, the cingulate cortex and amygdala, triggered the deactivation of all sexual desire.

"These experiments give us the first hints as to what happens in the brain during orgasm," the Mirror quoted Serge Stoleru, a French government ­scientist, as saying.

"For women it seems to be different," he said.

Stoleru said that women do not have such a strong refractory period - which is a recovery phase when the body calms down.

That leaves them wondering why their partners have lost all interest when they want more of it.