Scientists and doctors have long believed that women’s and men’s brains age differently.
Now researchers have shown that time does affect women and men’s brains differently – men’s brains diminish more quickly than women’s.
As men and women age, their brain size shrinks, and the rate of brain metabolism slows.
Researchers set out to find out exactly how this rate of metabolism changes over time – a factor that could influence how vulnerable someone is to neurodegenerative diseases such as dementia.
A study of 200 men and women, ranging in ages from 20 to 82 years, underwent PET scans to measure the flow of oxygen and glucose to their brains.
The scientists looked at the fraction of sugar committed to aerobic glycolysis – a process associated with metabolism – in different regions of the brain.
The scientists then developed an algorithm to determine the relationship between chronological age and brain metabolism. They calculated the rate for men, and then fed the women’s data into the algorithm.
According to the findings, recently published in the Proceedings of the National Academy of Sciences of the United States of America, women’s brains were on average 3.8 years younger than suggested by their brain metabolism.
They then performed the same calculations but starting with the women’s data, and then feeding the men’s data into the equation. They found that men’s brains were 2.4 years older than their actual age.
A statement from the Washington University School of Medicine in St.Louis said the findings could explain by women tend to stay “mentally sharp” for longer than men.
Senior author of the study, Manu Goyal, MD, an assistant professor of radiology and assistant professor of neurology and of neuroscience at the university’s Mallinckrodt Institute of Radiology, said, “We’re just starting to understand how various sex-related factors might affect the trajectory of brain aging and how that might influence the vulnerability of the brain to neurodegenerative diseases.”
Brains are fuelled by sugar, but how that fuel is used changes as our bodies age. Babies and children use aerobic glycolysis for brain development, and the rest of the sugar is used for thinking and doing. In young adults, much of the sugar is used for aerobic glycolysis, but the proportion declines over time, and is in low amounts by the time people are in their 60s.
The study found that men’s brains actually begin adulthood about three years ahead of women’s, and the gap remains as both men and women age.
“It’s not that men’s brains age faster – they start adulthood about three years older than women, and that persists throughout life,” said Goyal.
“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 currently working on a study to confirm that.”
The statement from the University said older women tended to score better than men of the same age on reason, memory and problem solving tests.
The researchers will now examine if those with younger looking brains are less likely to develop cognitive problems over the course of their lives.
It’s interesting to note that even though women’s brains may appear to be younger than men’s in some aspects, more women are diagnosed with dementia than men.
According to Dementia Australia, women account for 64 per cent of all dementia-related deaths in Australia. This may be related to the fact that women live longer.
So, what is the answer to the question, ‘Do women say mentally sharp for longer than men?’
According to this study, which admittedly only had a small sample size, the answer appears to be ‘yes’.
Please note: The image used to illustrate this article does not refer to actual people or events. Image: iStock.
