Cognitive Decline With Age Is Normal -- But It's Not Inevitable, Study Says

Ever forget where you put your keys? Researchers say memory troubles are common as you grow older, but they aren't necessarily an inevitable part of aging.

Following a close look at biochemical processes in the brain, researchers say cognitive decline is well under way by the age of 40 and picks up speed after that. But the good news is that it may not have to be that way.

“These are biological processes, and once we fully understand what is going on, we may be able to slow or prevent it,” said Kathy Magnusson, a neuroscientist at Oregon State University and a professor in the Linus Pauling Institute, in a press release. “There may be ways to influence it with diet, health habits, continued mental activity or even drugs.”

The research into cognitive decline is complex. A study by Oregon State University found that a genetic therapy in laboratory mice -- which involved restoring a building block in what's known as the NMDA receptor -- helped improve the animals' memory and cognitive functions.

Within the NMDA receptor are various subunits, and Magnusson said that research keeps pointing back to the GluN2B subunit as one of the most vital. Infants and children have lots of them, and as a result can soak up memories and learn new things like a sponge. But they gradually dwindle in number as one grows older, and studies have found those that remain work less efficiently over time.

“You can still learn new things and make new memories when you are older, but it’s not as easy,” Magnusson said in a press release. “Fewer messages get through, fewer connections get made, and your brain has to work harder.”

Even so, she said, the one thing that seems fairly clear is that cognitive decline is not inevitable.

“It’s biological, we’re finding out why it happens, and it appears there are ways we might be able to slow or stop it, perhaps repair the NMDA receptors," she said in a press release. "If we can determine how to do that without harm, we will.”

Magnusson encouraged people to work their brain while also enjoying lots of social interaction and physical exercise.

Exercise also has been known to slow memory loss in those at risk of getting Alzheimer's.