Women's Brains Are 'Four Years Younger' Than Men's, Study Finds

Women's brains are nearly four years younger than men's, at least in how they burn fuel, according to scans performed by U.S. researchers. 'Scientists found that healthy women have a 'metabolic brain age' that is persistently younger than men's of the same chronological age,' reports The Guardian. 'The difference is apparent from early adulthood and remains into old age.' From the report: The finding suggests that changes in how the brain uses energy over a person's lifetime proceed more gradually in women than they do in men. While researchers are unsure of the medical consequences, it may help explain why women tend to stay mentally sharp for longer. 'Brain metabolism changes with age but what we noticed is that a good deal of the variation we see is down to sex differences,' said Marcus Raichle, a neurobiologist at Washington University school of medicine in St Louis. 'If you look at how brain metabolism predicts a person's age, women come out looking about four years younger than they are.'

The scientists used a brain scanning technique called positron emission tomography to measure the flow of oxygen and glucose in the brains of 121 women and 84 men aged 20 to 82. The scans revealed how sugar was being turned into energy in different parts of the volunteers' brains. To see how brain metabolism differed between the sexes, the researchers used a computer algorithm to predict people's ages based on brain metabolism as measured by the scans. First, the scientists taught it to predict men's ages from metabolism data gleaned from the male brain scans. The striking result came when the scientists fed metabolism data from the women into the same program. While the program estimated male ages accurately, it judged the women's brains to be, on average, 3.8 years younger than their real ages. 'The scientists then flipped the analysis around,' the report adds. 'They trained the algorithm to predict women's ages from data garnered from their brain scans. This time, when they fed metabolism data from the men into the computer, it estimated them to be 2.4 years older than they were. The way male brains burned sugar made them seem older than female ones of the same age.' The study has been published in the journal Proceedings of the National Academy of Sciences.

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