Markham Heid
The Nuance - Medium
January 6, 2022

At 30, your mental muscles have likely already begun to weaken.

Hemingway’s The Sun Also Rises, a character is asked how he managed to go bankrupt. “Two ways,” he replies. “Gradually and then suddenly.”

For a lot of people, age-related cognitive decline follows a similar trajectory.

At first the loss of mental sharpness is imperceptible. But one day you may wake to find that your memory, concentration, and other mental muscles have grown noticeably, frustratingly weak.

Exactly when this cognitive decline starts is a matter of expert debate. But research in the journal Neurobiology of Aging has found that it may begin as early as your 20s.

“Typically, a person peaks out around their 30th birthday,” says Michael Merzenich, PhD, a professor emeritus and former director of the Keck Center for Integrative Neuroscience at the University of California, San Francisco. Each decade thereafter, the average person’s mental acuity steadily drops off, he says.

This slow-motion cliff dive into the cerebral abyss was once considered an inevitable part of aging. Senility was thought of as a destination, not a disease: live long enough, and sooner or later you’d get there.

But now we know better.

Merzenich is author of Soft Wireda book about brain plasticity. He says that the brain’s toolset usually grows rusty as a result of disuse — not because of unpreventable degradation. “There are about a billion things that contribute to that decline, but one of the principal ones is taking your brain offline,” he says.

In this context, “offline” refers to rote or autopilot activities — the habitual tasks your brain has performed so many times that they’ve become second nature. “This means doing the same things — resting on your laurels and relying on the abilities or skills you acquired at a younger age,” he explains.

During the first few decades of your life, this sort of cognitive coasting isn’t really possible. Each new year presents novel settings and challenges. Grappling with those pumps up your mental muscles.

But once you’ve settled into adulthood — into a profession, a partner, and a set of routines—your day-to-day life may not ask much of your brain’s executive functions, which are the high-level operations that help you solve complex problems and navigate unfamiliar terrain.

Further complicating matters is the fact that your brain, when given the opportunity, would prefer to be in cruise control. Doing what you’re used to doing is both comfortable and easy. Challenging your brain with unfamiliar tasks is taxing. And the older and more set-in-your-ways you become, the more difficult it can be to break out of your habitual ruts.

Fortunately, it’s possible to arrest or even reverse age-related cognitive decline.

Some of Merzenich’s published work has found that “targeted” brain training can help people strengthen their memories, concentration, and high-level processing capabilities. Even among people with mild traumatic brain injury, cognitive deficits are often reversible with proper training, more of his research has shown.

“The key is to constantly engage your brain’s learning machinery with skills or activities that are new to you,” he says. “And watching a new show or playing a new video game are not the kinds of challenges I’m talking about.”

He recommends adopting a new hobby — something that lies well outside the arena of your normal experience and that forces you to learn a new set of skills. It could be studying a foreign language. It could by meditation or gardening. It could be playing a musical instrument or taking up interpretive dance.

“The goal is to expand your understanding in a new way,” he says.

You may have to fumble around to find something that grabs you, but that’s all right. Even if it takes months or years to land on a hobby that captivates you, the process of exploring new activities is doing good work for your brain.

Merzenich also recommends avoiding those crutches or shortcuts that do your brain’s work for it. “Mining your brain’s knowledge to come up with answers on your own — that’s real exercise,” he says. “If instead you use the internet to jump immediately to the answer, there’s a price for that. It adds up to hundreds of thousands of learning moments that are lost every year.”

Whether you’re looking up directions or the name of an actor, taking time to dig that info out of your memory may pay dividends.

Like your body, your brain requires exercise to stay healthy. Challenging it with new hobbies and learning opportunities may be the best way to sustain its fitness.