Long-distance running may be a lonely pastime - but academics say that men who can run for miles may find it easier to attract women.

People who are better at running half marathons are likely to have been exposed to high levels of testosterone in the womb, researchers from Cambridge University said.

This means they not only have better cardiovascular efficiency but also a strong sex drive and high sperm count - suggesting that historically they were chosen by women as more desirable mates.

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Men who run long distances tend to be fitter, have a strong sex drive and higher sperm count, and attract women more easily, a study found. Ryan Reynolds (left) and Harry Judd (right) are seen running marathons

Lead author Dr Danny Longman, from the university’s division of biological anthropology, said: ‘The observation that endurance running ability is connected to reproductive potential in men suggests that women in our hunter-gatherer past were able to observe running as a signal for a good breeding partner.’

His team found that the best half marathon competitors tended to also have longer ring fingers - a signal that they had seen higher levels hormone exposure in the womb.

They said the finding suggests females had selected mates for athletic endurance.

This may be because ‘persistence hunting’ - exhausting prey by tirelessly tracking it - was a vital way to get food.

It means that men who could run long distance were more attractive to women - a trait the researchers say has persisted through the generations.

And the same link to testosterone does not necessarily apply to those who are better at sprinting short distances - because in hunter gatherer societies endurance would have been more useful than brute force.

HOW A PERSON'S FINGER CAN REVEAL IF THEY WILL BE FAITHFUL Forget witty chat-up lines or a perfect physique – the key to finding your ideal partner is in their hands. Those whose ring fingers and index fingers are the same length are more likely to be faithful lovers, research suggests. In contrast, those with a longer ring finger, pictured, could be more likely to cheat. It is thought exposure to high levels of testosterone – a hormone linked to sex drive – in the womb has a long-lasting effect on finger length. Those with a longer ring finger are likely to have been exposed to more testosterone. The researchers said that while hormone exposure could not predict the behaviour of every individual, the link meant finger length could help identify people who are likely to be more promiscuous. Advertisement

Persistence hunters may also have possessed other qualities, like intelligence and generosity, which women looked for in a mate.

Dr Longman said: ‘It was thought that a better hunter would have got more meat, and had a healthier - and larger - family as a consequence of providing more meat for his family.

‘But hunter-gatherers may have used egalitarian systems with equal meat distribution as we see in remaining tribes today.

‘In which case more meat is not a factor, but the ability to get meat would signal underlying traits of athletic endurance, as well as intelligence - to track and outwit prey - and generosity - to contribute to tribal society. All traits you want passed on to your children.’

Dr Longman said that while training and muscle strength were more important than hormone exposure in running performance, the size of the study meant the findings were ‘conclusive’ evidence of a predisposition.

He added: ‘Humans are hopeless sprinters. Rabbits, for example, are much faster sprinters, despite being fat and round. But humans are fantastically efficient long-distance runners, comparable to wolves and wild coyotes.

‘We sweat when most animals would overheat. Our tendons and posture are designed to propel our next strides - there was likely a selective pressure for all these benefits during our evolution.’

‘Hunters will deliberately choose the hottest time of day to hunt, and chase and track an antelope or gnu [a large dark antelope] over 18 to 25 miles for four or five hours.’

The team, from Cambridge and University College London, analysed 542 runners at the 2013 Robin Hood half marathon in Nottingham by photocopying hands and taking run times and other key details just after runners crossed the line.

The study found marathon runners tended to have long ring fingers. Previous research found men whose ring fingers and index fingers are the same length are more likely to be faithful lovers

They found that the 10 per cent of men with the most masculine finger ratios were, on average, 24 minutes and 33 seconds faster than the 10 per cent of men with the least masculine digits.

The correlation was also found in women, but was much more pronounced in men.

Scientists have previously demonstrated that men who have a longer ring finger than index finger are more likely to have higher levels of testosterone.

Having a long ring finger is linked to being more attractive, promiscuous, extroverted and having a greater likelihood of playing a musical instrument.