How to Stay Mentally Sharp Into Your 80s and Beyond

Vernon L. Smith, 97, is a very busy man. 

The economist at Chapman University just finished writing a book about Adam Smith and works about eight hours a day, seven days a week in his home office in Colorado Springs, Colo. He enjoys chatting with friends on Facebook and attending concerts with his daughter. 

“I still have a lot of stuff to do. I want to keep at it,” said Smith, who won the Nobel Prize in economics in 2002. 

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Recent memory flubs by President Biden, 81, and former President Donald Trump, 77, have kindled debate about how to stay mentally sharp into your 80s and beyond. 

There isn’t a silver bullet to maintaining mental acuity or warding off dementia, scientists of aging say. But a combination of genetics, healthy lifestyle habits and factors such as cleaner air and good education have been linked to prolonged mental agility. 

Three of Smith’s grandparents lived into their 90s, and an ancestor on his mother’s side lived to 105. But genetics are a small piece of the puzzle, scientists say. Smith has never smoked, eats healthy food, and is physically active and socially engaged—all behaviors linked to longevity and maintaining mental sharpness into later life. 

“The healthier you are in the whole body, the better your brain responds to the aging process,” said Dr. David Wolk, a neurologist at the University of Pennsylvania.

Cognitive performance peaks in healthy adults in their 20s and 30s, Wolk said. Over time, the brain shrinks, its outer layer thins, deeper regions become scarred, and communication between neurons can become less efficient.

Stay engaged

These brain changes can cause memory, reasoning and other cognitive skills to erode. But some people can stave off cognitive decline better than others, said Yaakov Stern, a neuropsychologist at Columbia University. 

Their brains might be more resilient to change or have better “cognitive reserve,” the ability to adapt to brain changes, Stern said. Genetics is thought to play a role in brain maintenance, as does diet, exercise and a person’s risk of vascular disease. More education, mental stimulation and social connectivity have been associated with improved cognitive reserve.

Better brain maintenance and cognitive reserve might help keep symptoms of dementia at bay. Almost 50% of people 40 and older think they will likely develop dementia, according to a 2021 AARP survey. The actual number of U.S. adults 65 and older with dementia is closer to 10%, a 2022 study found. 

Many people don’t know that healthier habits can lower the risk of developing dementia, scientists say. Some 40% of cases globally could be delayed or prevented by lifestyle or environmental changes, including reducing obesity and limiting exposure to air pollution, according to a 2020 report in the medical journal the Lancet.

Try tai chi

Sleeping too little—or too much—can also lead to cognitive problems. Activities including yoga and tai chi, the Chinese martial art, could help improve cognitive function, research suggests. 

Hearing loss is a risk factor for dementia, too. Lost hearing might cause the brain to atrophy more quickly and can make people more isolated, said Dr. Dung Trinh, chief medical officer of the Healthy Brain Clinic. Hearing aids can help preserve mental fitness.

“Our brain is like a muscle. Use it or lose it,” he said.

Researchers studying “super agers,” people over 80 who have mental faculties of people decades younger, said strong social relationships are important for keeping brains sharp.

The same is true for people who live beyond 100, said Stacy Andersen, a behavioral neuroscientist at Boston University and co-director of the New England Centenarian Study.

“They have a purpose. They have things they want to go out and do every day,” Andersen said. 

Smith says his work and his family keep him motivated and driven. 

“I want to go to at least 106,” he said.

Write to Dominique Mosbergen at dominique.mosbergen@wsj.com