When it comes to sex men are better on theory than they are in practice.
The favoured option
A survey has confirmed the long-held belief that men spend much of their time day-dreaming about sex.
But the fast pace of modern life leaves them too tired for the real thing.
In fact, given the chance of an extra hour in bed, most working men say they would rather spend it asleep than having sex.
The survey, for vitamins company Berocca, found that more than six out of ten men say that work is the most demanding part of their life.
And it seems to take a heavy toll. More than half said they were simply too tired for a social life, or to have sex when they got home after a busy day.
Thinking of sex
However, most men were not too tired or stressed at work to fantasise about sex - even at inappropriate times.
One in five men admitted they thought about sex within a minute of the start of a business meeting.
Christine Northam, a counsellor for the charity Relate, said the survey was a good sign that people were starting to consider the impact of long working hours on emotional health.
"Lots of people are suffering from stress as the result of working long hours, and the lack of security in employment.
"When people are completely shattered and stressed they don't feel very sexy.
"But sex is a very important part of a loving, intimate relationship.
"If we value stable relationships as a foundation of society, then society needs to change. We need to get away from the culture of working too long and hard, being too materialistic and driven by money."
The survey also found that more than three-quarters of men cannot stay alert throughout the working day - in fact the average man said he was only sharp for around three hours.
This may be in part due to a poor diet. Seven out of ten of the 650 men who took part in the survey admitted they did not eat properly.