Rethinking aging as it applies to the brain

Contrary to the popular belief that dementia is inevitable, steps can be taken by individuals and societies to reduce the risk of dementia and, simultaneously, increase brain ability.

Research published in the past decade has upended what has long been taught on this subject – making it more important than ever to review what is known about the brain and how it changes as we live longer.

Doctors who graduated before 2000 were taught that the brain only developed during childhood but that after age 20 brain cells died off. This was part of the theory that won Santiago Ramón y Cajal the Nobel Prize in 1906; however, we now know he was wrong. There is continued debate over whether we can renew brain cells in adult life as mice do or as our own kidney and liver cells do, but we do know that we can develop new brain circuits. This is called “neuroplasticity” and there is evidence that new circuits can be formed at any age if the brain is asked to do so, either by external stimulation or by physical activity.

Dementia is not a disease like rheumatoid arthritis that can be confirmed with a blood test. It is better described as a condition that can be observed by people, including people without a medical degree. There are four changes that indicate dementia is becoming more conspicuous and need to be taken seriously. These include:

  •   failures of self-care, for example failure to wash or get to the toilet in time with apparent disregard for the consequences;
  •   failure to look after one’s home properly, such as leaving the gas or the water on;
  •   problems with driving;
  •   problems with money.

These signs are different from normal aging. It is unhelpful to talk about pre-dementia or MCI (mild cognitive impairment) although some do use these terms. Instead, the emphasis should be on the fact that dementia is different from normal aging.

Some changes occur in the brain as a result of the normal aging process but these do not cause major problems. For example, people notice memory slips as they age – inability to remember where they put their keys, the name of someone they met yesterday or the name of a book that had an influence 20 years ago – but these are not signs of early dementia, they are problems with filing and recovering pieces of knowledge.

Aging is too often blamed for the changes taking place in our bodies and minds, when in actuality, the normal biological process of aging does not have a substantial effect on the brain. We now know that three other processes are important in determining what happens to us and how quickly we decline.

Many problems formerly considered to be entirely due to the aging process are instead influenced by the ageism that dominates our society.

First, there are changes in the way the brain works due to loss of what could be called “brain fitness.” As we live longer, our brain is often challenged less. For example, if we retire from a challenging job and do not substitute that challenge with other challenging activities, our brain becomes less “fit.” Techniques for examining how the brain works reveal how new circuits form when the brain is asked to perform a new task. The task may be physical, such as dancing, or cognitive, such as learning a language, or a combination of cognitive and emotional, for example sitting on the committee of a voluntary organization. This runs contrary to ageist assumptions that as people live longer, they need less stimulation and are less capable of responding to stimulation.

Second, many diseases affect the brain other than Alzheimer’s, such as secondary cancers in the brain. Recent research highlights the contribution of vascular causes of dementia, namely dementia due to impairment of the blood and oxygen supply to the brain. Risk of vascular dementia can be reduced by at least a third.

Aging, fitness and disease are well understood. So too are the factors that affect the mind, the way we think and feel. This is affected not so much by aging as by the attitudes and behaviours of other people, particularly what could be called “ageism” – consistent under-expectation of what people in their 60s, 70s, 80s and 90s can achieve based on incorrect beliefs, for example, that all intellectual functions deteriorate with age. New research shows that problems formerly considered to be entirely due to the aging process, such as memory loss, hearing decline, and cardiovascular events, are instead influenced by the negative age beliefs that dominate our society.

What we need is a cultural revolution to rethink aging, and to find out how we can increase our brain ability whatever our age, and how we can reduce our risk of dementia. There is no guarantee, of course, because Alzheimer’s remains the single most common cause of dementia and we do not know yet how to prevent or treat it, but there are many other causes, and therefore many other actions, that can be taken by individuals and society at large.

What can individuals do? 

Find a friend and explain to them the difference between dementia and normal aging.

What can the community do?  

Society needs to educate all members about the difference between dementia and normal aging and the cause of dementia, and the fact that, in the words of The Lancet, “… it is never too early and never too late to reduce the risk of dementia.”

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1 Comment
  • Dr. Ronald Worton says:

    Hey Larry, I have always appreciated your wisdom and clear thinking. Thank you for this article that resonates with this 80 year old who still sits on a couple of non-profit Boards and spends 6-8 hours per day reading and writing about science.


Larry W. Chambers


In addition to being a science advisor to the Alzheimer Society of Canada, Larry W. Chambers is Director, Research and Scholarship of the Niagara Regional Campus, Michael G. DeGroote School of Medicine, McMaster University, and maintains appointments at Bruyere Research Institute; Faculty of Health, York University; and ICES.

Madeleine Smith


Madeleine Smith is a medical student at the Niagara Regional Campus, Michael G. DeGroote School of Medicine, McMaster University.

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