It is well known that many men nod off straight after sex and now scientists conducted research which involved scanning the brains of men during and after orgasm.

In the case of the latter, they found that the cerebral cortex – which plays a vital role in attention, consciousness and perceptual awareness – shut down almost immediately after orgasm.

Serge Stoleru, a French government scientist, said that the research offers the “first hints” of what happens in the brain during sex.

He told the Sunday Times: “For women, it seems to be different.

“They don’t seem to have such a strong refractory period and may be asking for more when their partners just want a rest.”

Scientists have found that man’s cerebral cortex shut down almost immediately after orgasm

The study also showed that the brain switched off almost all sexual desire after orgasm.

And as well as this, men have a further reason for feeling drowsy: their brains become flooded with sleep-inducing chemicals such as serotonin after they have had sex.

Earlier studies have also suggested that men aren’t to blame for wanting to take a well-earned break after sex.

In 2005, research found the blood rush after climax depletes the muscles of energy-producing glycogen.

And because men typically have higher muscle density than women, they become more tired after sex.

The survey showed the majority of men did feel more relaxed straight after sex.

80% of men said they felt able to drift off without any problems after making love, compared with just 46% of women.

They were amongst 10,000 adults surveyed by organizers of The Vitality Show, Europe’s largest health and beauty exhibition.

The survey also found 48% of men had actually fallen asleep during the act itself.

And whilst scientists might have rescued men from a telling off for sleeping straight after orgasm, it seems perhaps understandable that the latest research won’t do the same for those who doze before reaching climax.