The brain, like any other body part, gets old. However, not all brains age the same way. For example, women's brains may age more slowly than men’s. That is the finding of a U.S. study from Washington University School of Medicine in St. Louis, Missouri. Researchers there wanted to find out how the brain uses sugar. To do that, they studied just over 200 brains of men and women aged 20 to 80. They used PET scans to look at the flow of oxygen and sugar in the brains. The researchers found that the brains of women looked nearly four years younger than the brains of men who were born in the same year. Their findings suggest that the brains of men and women may use sugar differently as they age. But the researchers do not know why. Some scientists suggest that hormones could play a part.