You’ve reached content that’s exclusive to AARP members.

To continue, you’ll need to become an AARP member. Join now, and you’ll have access to all the great content and features in Staying Sharp, plus more AARP member benefits.


Already a member?

Want to read more? Create an account on

A healthy lifestyle helps protect the brain. Make brain health a habit and register on to access Staying Sharp.

Login to Unlock Access

Not Registered?

Your Brain in Your 40s

Brain health is important to monitor as we age


Add to My Favorites
My Favorites page is currently unavailable.

Add to My Favorites

Added to My Favorites


Forty may be the new 30 for your brain. In AARP’s Brain Health Research Study, people ages 69 to 75 said they think that the brain peaks at 40. By middle age, our brains excel at reasoning and using experience to reach strong conclusions, says David S. Knopman, M.D., professor of neurology at the Alzheimer's Disease Research Center at Mayo Clinic. Emotional intelligence is also strong: The brain’s ability to evaluate people’s emotional states peaks in the 40s and 50s, researchers at MIT found.

Around age 45, however, our mental abilities begin to decline, according to a 10-year study in the British Medical Journal. Blood flow diminishes, neural connections shrink, and people often notice “subtle changes in their ability to remember new names or do more than one thing at a time,” the American Psychological Association reports. And while Alzheimer’s disease is rare in people under 50, the biological changes associated with it, such as the development of amyloid plaques, often happen 15 to 20 years before the onset of symptoms, says Jennifer Rose Molano, M.D., associate professor in the Department of Neurology and Rehabilitation Medicine at the University of Cincinnati College of Medicine. But take heart: Research is finding that what you do now can protect your brain from the buildup of the plaques that can rob you of your memory later. 

Here are some strategies that may help keep your brain humming.

  • Lower your risk of heart disease. Heart disease risk factors in midlife — such as smoking, high blood pressure and diabetes — were linked to late-life dementia in a study from Johns Hopkins University. Middle-aged smokers had a 41 percent higher dementia risk than nonsmokers or those who kicked the habit, and people with high blood pressure had a 39 percent higher risk.

  • Reduce your odds of diabetes. People who have diabetes in midlife have a 77 percent higher dementia risk than those without diabetes, the Hopkins study found. Diabetes can also affect brain performance. People scored lower on memory tests two years after being diagnosed with the disease, according to a study in the journal Neurology. The reasons for the diabetes-dementia link aren’t entirely understood, but type 2 diabetes can affect blood flow to the brain, and problems such as poor blood sugar control and inflammation may affect the brain, as well.

  • Get off the couch. Exercise, particularly in midlife, may be an important step towards ensuring healthy brain aging, researchers at Boston University School of Medicine found. They studied people whose average age was 40, giving them a treadmill test. Twenty years later, participants were retested and underwent a brain scan. Those who were gasping on the treadmill (their blood pressure and heart rate were high) were more likely to have smaller brain volumes than those who were fit. Smaller brain volume is linked to problems with memory and thinking skills.

  • Lose your belly fat. Roughly 40 percent of Americans ages 40 to 59 are obese, and that extra weight could affect your brain as you age. A high body mass index (a measurement of body fat) was associated with less gray matter in the part of the brain that focuses on memory, a study at the Max Planck Institute for Human Cognitive and Brain Sciences showed. Further, a Kaiser Permanente study discovered that people ages 40 to 45 who had large stomachs were more likely to suffer from dementia in their 70s than those who didn’t. “Midlife is when pounds can creep on,” says Cynthia Green, president of Total Brain Health in Montclair, N.J. “And we know that weight around the midsection is associated with increased risk for dementia.”

  • Don’t work so much. Working more than 25 hours per week can diminish your brainpower, but working 25 hours or less might improve it, according to a study of people age 40-plus conducted by the University of Melbourne. And since heart disease is linked with dementia, schedule a vacation. In the Framingham Heart Study, one of the largest studies ever on cardiovascular disease, men who didn’t take vacations for several years were 30 percent more likely to suffer heart attacks than those who did. Traveling also challenges your mind, which “promotes brain health and builds brain resilience across the life span,” a travel report from the Global Coalition on Aging notes.

  • Hang out with friends. Conversation seems simple, but it’s a complex activity, and that’s good for your mind. In a 2017 AARP survey, adults age 40-plus with large social networks reported better brain health than those with small networks. Another great way to socialize? Volunteer. People over 40 who volunteer experience higher levels of “mental well-being” — from lower anxiety to better sleep — than nonvolunteers, according to University of Southampton professor Faiza Tabassum, coauthor of a volunteering study published in the journal BMJ Open.

  • Increase your sack time. Sleep is important for clearing out toxins in the brain, including amyloid, the protein linked with Alzheimer’s disease. “In midlife you want to decrease some of the risk factors associated with late-life dementia,” Molano says. “I expect the more that people are having chronic sleep issues, the more it interferes with optimizing brain health.” People with sleep apnea may also experience a decline in memory earlier in life than those who don’t have sleep disorders, she adds.

Read more articles about how your brain changes through the decades.

Up Next

Added to Favorites

Favorite removed

Added to Favorites

Favorite removed

Added to Favorites

Favorite removed