Is Age-Related Cognitive Decline Inevitable?

More worrisome is not being able to perform activities of daily life, such as bathing, doing laundry, cooking and cleaning — “things that you were normally able to do but now find challenging, but not because of a physical impairment,” Holland says. It might be worrying “if you were able to balance a checkbook and now you’re having trouble doing it, for instance. I get concerned when someone is not remembering how to get home.”

A dimming of your senses — hearing or vision loss, specifically — can accelerate cognitive decline. The distorted or muted input of “data” requires your brain to do more to process it, Holland says. Plus, “you start self-isolating, and the loss of socialization can lead to an increase in cognitive decline,” he says.

Evaluating cognitive function

There is no single test for cognitive decline. Tests including the Mini-Mental State Examination (MMSE) and Montreal Cognitive Assessment (MoCA) are commonly used to screen for issues with memory, thinking and problem-solving skills.

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“Then we move on to actual cognitive tests and a cognitive battery,” Holland says. The health care provider will also check for causes beyond dementia, such as depression, vitamin deficiencies or medication side effects. In addition, neuropsychological testing may be used to identify whether changes in a person’s cognition are consistent with normal aging among healthy adults of the same age.

There are tests for genetic factors, particularly a gene mutation called APOE4, that increase the risk for Alzheimer’s disease. “If you inherit one copy of the gene, it doubles your risk, compared to somebody who doesn’t carry APOE4,” says Dr. Charles Bernick, staff neurologist with the Cleveland Clinic Lou Ruvo Center for Brain Health in Las Vegas. Having two copies of it (one from each parent), confers an even higher risk. 

But having APOE4 doesn’t mean a person will definitely get Alzheimer’s disease, according to the National Institutes of Health. And APOE4 doesn’t appear to have the same effects in nonwhite populations.

Genetic testing isn’t recommended for people without Alzheimer’s symptoms. Knowing if a person has a genetic risk comes into play when a person with the disease considers taking one of the new disease-slowing drugs. “If you carry one copy of APOE4, it puts you at a little higher risk of having side effects,” Bernick says, “and if you carry two copies, you have an even higher risk.”

Shoring up your cognitive reserve

Regardless of whether someone feels their cognitive abilities have started to slip, there’s usually an opportunity to maintain their current level of mental functioning, Holland says. “The big idea behind a lot of the interventions, especially those lifestyle factors, is to prevent the onset of cognitive decline to start with,” he says. “And if someone … has, say, mild cognitive impairment, we want to pause it at that point and prevent progression.”

Whether lost cognitive abilities can be regained is an open question, Holland says. “We now know that there is neuroplasticity, which is the capability to create new neural pathways to potentially regain that functionality.”

Preventing dementia

Part of the reason cognitive decline is not inevitable is the good news that nearly 50 percent of dementia cases could be prevented or delayed by tackling 14 risk factors. According to a 2024 report in The Lancet, you can optimize your brain function by doing things like getting active, treating depression, improving high blood pressure and high cholesterol, getting control of diabetes, limiting alcohol and quitting smoking — and the earlier that changes are made, the greater the potential for risk reduction.

In fact, multicomponent interventions in particular show significant potential. A landmark study of older adults from Finland found that those assigned to a program that included a combination of tactics — physical exercise, a healthy diet lots of fruits and vegetables, whole grains, olive oil, lean protein), brain stimulation like learning a new language, and control of risk factors like high blood pressure and high cholesterol — improved or maintained their cognitive functioning. Those who received health education alone did not. The same approach was found to be effective in the U.S.-based POINTER study as well.

A recent review of studies in The Lancet Healthy Longevity also found that a multipronged approach to preventing cognitive decline was effective. But it also showed that physical activity and cognitive training, by themselves or combined, yielded important benefits.

Other research shows regular physical activity, like brisk walking, is particularly potent. It can plump up brain volume, which shrinks with age, improve the brain’s processing speed and promote the production of a substance called brain-derived neurotrophic factor (BDNF), which is like fertilizer for the brain, Fillit says. In healthy individuals, “preventive lifestyle management types of intervention can actually modify the course of what we currently think of as normal cognitive aging,” he says.

Even in people with higher genetic risk, lifestyle changes can “at least modify the onset of symptoms,” Bernick says. The key to these strategies is to start now. Says Holland, “Intervening as early as possible is ideal.”