A man’s brainpower, scientists say, can be damaged by sharing a bed. When they spend the night with a partner, their sleep patterns are disturbed, whether they make love or not.

This leads to poorer mental agility the next day.

Women do not suffer from the same problem. They have disturbed sleep if they share a bed, but tend to get better quality rest when they do drop off and their brain power remains undiminished.

The findings suggest if a man has an important day ahead he would be best to head off to the spare room rather than share the marital bed.
The research, featured in New Scientist magazine, was presented to the Forum of European Neurosciences in Vienna last week.
The study also found sharing a bed can impact on dreams.

Typically, women remembered more of their dreams after sleeping alone, while men recalled the most after sex.

And while most men believed having a partner helped them to drop off, most women felt they slept better when alone.

This could be because men were more often blamed for some of the obvious causes of disturbed sleep, such as snoring, "tossing and turning" and "hogging the doona".

Over-heating because of the extra warmth generated by sleeping beside another person may be just as blameworthy for a sleep-deprived night as other factors.