Aging and Brain Health and How to Preserve It: What Experts Know So Far

Cropped shot of a senior couple exercising together indoors
Gary Small, MD, and Sandra Bond Chapman, PhD, delve into the definition of brain health, how to preserve it at any age, and how to promote brain health to the public.

Preserving brain health is integral to longevity, especially in an ever-growing aging population. The population of people aged 65 and older is projected to increase to 80.8 million by 2040 and 94.7 million by 2060.1

With an aging population comes the prevalence of normal age-related forgetfulness, and although cognitive function is believed to decline with age, clinicians and scientists believe the lifelong practice of using cognitive abilities can have a protective effect on brain aging.

A 2021 study published in Nature Human Behaviour found that when researchers tested the effects of aging on alerting (a state of extra vigilance and readiness to respond to new information), orienting (attending to new information), and executive (inhibitory) (focusing on important parts of a situation) networks in more than 700 participants between the ages of 58 and 98 years, orienting and executive inhibitory efficiency increased until the mid to late 70s, while alerting abilities declined.2 This study challenged the notion that an individual’s mental faculties decline and do not improve with age. Researchers hypothesized that their findings were attributed to the lifelong practice of orienting and executive inhibition—two key brain functions—in everyday life.2

Many but not all cognitive abilities decline during aging. Some even improve due to lifelong experience,” the researchers stated.

On the other hand, the presence of memory problems with aging can be indicative of dementia. Among Americans aged 65 and older, about 6.2 million live with Alzheimer dementia.3

Gary Small, MD, chair of psychiatry, Hackensack University Medical Center, physician-in-chief, Behavioral Health, and H. Hovnanian Family Foundation Endowed Chair in Behavioral Health, in Hackensack Meridian Health in New Jersey, said, regardless of whether someone has a genetic risk for Alzheimer disease (AD), if they do regular exercise, their brain will be in better shape than if they don’t exercise.

“We did a study where we looked at people with a genetic risk for AD. Those who exercised more had less evidence of AD,” says Dr Small.

In the 2016 study, published in the American Journal of Geriatric Psychiatry, Dr Small and his colleagues found significant associations between body mass index (BMI), physical activity, and diet and 2-(1-(6-[(2-[F-18]fluoroethyl)(methyl)amino]-2- naphthyl)ethylidene)malononitrile (FDDNP)-brain positron emission tomography (PET) binding levels in volunteers with subjective memory impairment and mild cognitive impairment (MCI).4

Participants who reported higher levels of physical activity and were classified with a “normal” BMI had lower FDDNP binding levels compared with participants with MCI who were less physically active and were classified with an “above normal” BMI. In addition, following a healthy diet was associated with lower FDDNP-PET binding levels among all participants.

“…Lifestyle behaviors affecting BMI influence AD and related dementia risk, and multifactorial health strategies might delay onset of AD symptoms,” Dr Small and his colleagues concluded.

For a more in-depth look at aging, brain health, and how providers can help their patients preserve it, we spoke with Dr Small and cognitive neuroscientist Sandra Bond Chapman, PhD, distinguished professor and chief director, Center for BrainHealth, University of Texas at Dallas.

Currently, there is no universal definition of “brain health.” How would you define it?

Dr Chapman: The concept of brain health is captured neither by [intelligence quotient] (IQ) nor by memory tests, nor solely by the absence of diseases or pathology in the brain. In the past, brain, cognitive and mental health assessments were deficit-focused, aimed at detecting disease or disorder rather than strengths or potential.

For the past 3 decades, cognitive neuroscience has been radically changing our understanding of the brain’s lifelong ability to change, adapt and get stronger. We translate the new science to define brain health as making the most of one’s brain capacities to thrive in life.This definition is based on the potential and dynamic capacity of the brain rather than a fixed-in-time set of deficits. This conceptualization accords with the best scientific evidence of the human brain’s immense ability to reshape and reorganize itself in response to experience – neuroplasticity.

As people age, there is a greater susceptibility to neurologic disorders, which can make preserving brain health challenging. What approaches can be taken to prevent these conditions?

Dr Small: What happens when someone is in their mid-40s is their cognitive function has declined significantly compared with when they’re in their 20s. People begin to notice these cognitive slips, but this is a normal part of aging. The rate at which brain health declines is determined in part by genetics, [but] nongenetic factors are [also] important, including physical exercise, adequate sleep, consuming a healthy diet, and so forth. For my patients, I try to help them understand those opportunities to preserve their brain health.

Dr Chapman: [As] you might expect of this most valuable asset and complex organ, there are additional brain-specific recommendations for strengthening and maintaining brain health even in the face of brain disease, insult, or injury: [mental stimulation, efficient orchestration of the brain’s networks, ensuring downtime for the brain, keeping stress under control, and connect socially].

In a previous study published in Trends in Cognitive Sciences, researchers noted the brain scans of some 70-year-olds resembled that of 30-year-olds.5 What did these brain scans actually reveal?

Dr Chapman: Nyberg [and colleagues] reviewed the structure and function of the brains of older people who perform similarly to younger persons on memory measures and identified a number of structural differences where there was less atrophy (shrinkage) in key memory and other parts of the brain.5

Other studies show increases in brain blood flow in older vs younger adults during mental activation tasks, suggesting greater recruitment of more brain regions and the possibility that an older brain is able to reorganize and “work harder” to achieve a similar level of performance [compared with] younger brains. Most of the research, however, has been in cross-sectional rather than longitudinal [studies], and at this stage these findings are not conclusive as to what steps can be taken to keep a younger functioning brain as we age.

What is the role of stress in brain aging?

Dr Chapman: Stress is the perception that the demands made on a person exceed their ability to cope with them, and the resulting emotion is anxiety. When anxiety is high and long-lasting, the high cortisol levels in the brain can impair certain circuits in the brain, particularly related to memory function in the hippocampus. Anxiety can also increase the neurotransmitter norepinephrine to levels that impair the ability of different networks in the brain to communicate smoothly with each other, resulting in a difficulty in thinking clearly and causing a negative spiral.

What are the mechanisms behind the beneficial effects of exercise on brain health?

Dr Chapman: This works in a number of different ways. First, aerobic exercise causes your brain to increase hormones including brain-derived neurotrophic factor (BDNF) that is essentially like a brain “fertilizer” that strengthens connectivity, particularly in the crucial hippocampal memory center.

Second, finishing a workout gives you a sense of achievement, and that success experience is associated with an increase in dopamine activity in the brain’s reward network – this is essentially like a little mood-lifting antidepressant.

Thirdly, exercise [helps you] focus you on a goal and action, and so your attention is harnessed to delivering this. This means that your mind is less likely to go walkabout to unresolved problems or worries that can drag your mood down and lift anxiety.

What are the most effective approaches neurologists can use to promote brain health among their patients?

Dr Chapman: The medical establishment can play a major role in promoting preventive, proactive brain fitness, like cardiologists do for the heart.

Individuals can start taking charge of their brain health at a young age, without waiting for something to go wrong. They should employ science-backed strategies and healthy brain practices. A good place to start is by joining The BrainHealth Project – it is free to join, confidential, and backed by rigorous science.

Dr Small: Educating people about the connections of what they do and how their brain functions is an effective approach. As a practicing physician, it’s important not only to look at physical illness, but to ask about behavior, their sleep, their stress levels, and then get them on a program that’s practical and effective.

Disclosure: Dr Small has declared affiliations with biotech, pharmaceutical, and/or device companies. Please see the original reference for a full list of his disclosures. 


1. Administration for Community Living. Projected future growth of older population. Updated May 25 2021. Accessed January 21, 2022.

2. Veríssimo J, Verhaeghen P, Goldman N, Weinstein M, Ullman MT. Evidence that ageing yields improvements as well as declines across attention and executive functions. Nat Hum Behav. Published online August 19, 2021. doi:10.1038/s41562-021-01169-7

3. Alzheimer’s Association. Alzheimer’s facts and figures report. Accessed January 21, 2022.

4. Merrill DA, Siddarth P, Raji CA, et al. Modifiable risk factors and brain PET measures of amyloid and tau in non-demented adults with memory complaints. Am J Geriatr Psychiatry. Published online May 13, 2016. doi:10.1016/j.jagp.2016.05.007

5. Nyberg L, Lövdén M, Riklund K, Lindenberg U, Bäckman L. Memory aging and brain maintenance. Trends Cogn Sci. Published online April 30, 2012. doi:10.1016/j.tics.2012.04.005

This article originally appeared on Neurology Advisor