And scientists at Washington University in St. Louis thought the same thing might be true of a person's brain.
They found that, based on these metabolic levels, women's brains appeared about three years younger, on average, than men's brains of the same chronological age. The difference is consistent from early adulthood into the senior years, reports the Guardian. "I think this could mean that the reason women don't experience as much cognitive decline in later years is because their brains are effectively younger, and we're now working on a study to confirm that", he explained. The difference is a metabolical one, and it may serve to explain why women seem to stay mentally sharp longer than men. The brain's metabolism slows as people grow older, with pensioners using less glucose for brain development and more to complete everyday tasks. We find that throughout the adult life span the female brain has a persistently lower metabolic brain age-relative to their chronological age-compared with the male brain.
While interesting, it is hard to see what practical implications this study has in terms of improving public health and preventing degenerative conditions such as dementia.
Scientists have just found a new distinction between the brains of the two sexes: age-related changes to the brain occur more slowly in women than in men. "We're being very cautious in not speculating on what this means in terms of downstream dementia and so forth". Our recent multitracer PET brain imaging data demonstrate that as the brain ages, its resting metabolism gradually shifts away from a mixture of nonoxidative and oxidative use of glucose to predominantly oxidative metabolism (4, 5). They found that on average, women's brains are 3.8 years younger than men's. To sort through the data, the researchers used machine learning to calculate each of the participants' brain age based on their metabolism. One explanation could be that the genes involved in energy use could be less impacted by age in women, or that women don't experience the same loss of blood flow in the brain after puberty than men.
Women may have the advantage over men when it comes to brainpower.
When the study was reversed - by training the algorithm on women's data and applying it to men - it produced a slightly different result.
And while metabolic brain age might be useful to predict the risk of cognitive decline or identify factors that potentially could improve or worsen the trajectory of brain aging, the findings need to be validated in other cohorts, the researchers added. But the metabolic brain age was on average 3.8 years younger in women than in men.
Pointing to existing research, the team surmised that women's brains could be free from neurocongitive decline for longer for a number of reasons.
The finding is "great news for many women", says Roberta Diaz Brinton, who wasn't connected with the study and directs the Center for Innovation in Brain Science at the University of Arizona Health Sciences.
The new research focused on metabolic processes that have a major influence on brain performance and ageing. "I think this could mean that the reason women don't experience as much cognitive decline in later years is that their brains are effectively younger, and we're now working on a study to confirm that".