杏吧原创

Women have younger brains than men the same age. A study basing age on metabolism rather than birth date found an average 3.8 year difference between聽men and women. The discovery may help explain why women are more likely than men to stay mentally sharp in their later years.

All brains get smaller with age, and it was already known that men鈥檚 tend to shrink at a faster rate.聽To investigate the differences further,聽Manu Goyal at Washington University School of Medicine in St Louis and colleagues聽looked at聽the brains of 205 men and women ranging in age from 20 to 82.

They used positron emission tomography, an imaging technique that helps uncover brain聽metabolism by measuring the flow of oxygen and glucose. The brain consumes large amounts of glucose for energy, but the pattern of use alters with age.

They found that metabolic brain ageing correlated聽with chronological ageing in both men and women, but that at any given age women鈥檚 brains were younger, metabolically speaking, than men鈥檚.

鈥淚t鈥檚 not that men鈥檚 brains age faster 鈥� they start adulthood about three years older than women, and that persists throughout life,鈥� says Goyal. 鈥淲hat we don鈥檛 know is what it means. I think this could mean that the reason women don鈥檛 experience as much cognitive decline in later years is because their brains are effectively younger, and we鈥檙e currently working on a study to confirm that.鈥�