REPRODUCTIVE potential could be higher in those proficient at long distance running, research suggests. Pre-birth levels of testosterone have already shown several beneficial advantages for men, such as increased sex drive, sperm count, cardiovascular efficacy, and spatial awareness. Research now suggests that those exposed to higher levels of testosterone in the womb are also better at distance running.
In order to test this theory, researchers analysed 542 runners participating at the Robin Hood half marathon, Nottingham, UK, by photocopying their hands and recording their running times and other factors just after runners crossed the line; they used a digit ratio, which showed that those exposed to more prenatal testosterone had a longer ring finger (4th digit) than index finger (2nd digit). Results showed that the 10% of men with the most masculine digit ratios were on average 11 minutes and 59 seconds faster than the 10% with the least masculine digit ratios. This correlation was also found in women, but was more pronounced in men, suggesting stronger evolutionary selection in men for running ability.
Dr Danny Longman, lead author, Department of Archaeology and Anthropology, University of Cambridge, Cambridge, UK, explained that prenatal testosterone exposure has very little influence on running ability; however, their unparalleled sample size of over 500 subjects enabled researchers to gather conclusive evidence. “This may sound crazy, but when a hunter is relatively fit the amount of energy they expend is actually tiny compared to the energy benefits of an antelope-sized animal, for example. Before the domestication of dogs, persistence hunting may have been one of the more efficient forms of hunting, and as a consequence may have shaped human evolution,” said Dr Longman. Dr Longman added: “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.”
Long distance running may have been a positive signal of desirable male genetics, as men able to run such distances would have made better family providers; the athleticism needed to acquire food would also be a desirable trait to pass on to future generations.