Over the past 100 years, the average lifespan has almost doubled. At the turn of the 20th century, in the industrialised West, you could expect to live until your 40s, on average. In the modern-day United States (and the figures are similar for other Western nations), the typical man can anticipate remaining on this Earth until he is 75. If you’re a woman, you can expect a few more years.
Although this is obviously a welcome development – largely brought about by improvements in healthcare and the defeat of infectious diseases – it is a double-edged sword. The body could well keep going throughout all these decades, but the brain might not; and, if you are left able-bodied but with a permanently compromised brain, then you will be in an unenviable position. Such is the concern that a recent survey by Alzheimer’s Research UK showed that, for almost half of the respondents, dementia is the condition they fear the most, rising to more than 60 per cent among those aged over 65.
I have worked in the area of brain health for almost 20 years in my role as a psychiatrist, and one of my major areas of interest is dementia (a progressive loss of brain function due to an illness, such as Alzheimer’s disease). I’ve come to believe that everyone should be thinking about their brain health much earlier than the age of 65. That’s because there are ways to substantially reduce your risk of dementia and cognitive impairment, and the earlier you address problematic lifestyle choices and health conditions, the more successful you are likely to be.
Avoiding dementia is only one consideration, however. Of equal importance is optimising brain function throughout your lifespan – allowing this vital organ to function at its best in the many decades before dementia becomes most relevant. Doing this will help you enjoy greater productivity, happiness and life satisfaction.
Ageing changes the brain, but it’s not all bad news
When considering ways to optimise your brain health, it’s useful to be aware of the forces acting in the opposite direction. In general, the brain fails for a number of reasons:
•When it does not receive optimal fuel for growth and maintenance – both in the form of oxygen and vital nutrients. This could be due to diminished blood supply or an inadequate nutrient consumption.
•Through the accumulation of ‘debris’. Debris builds up in the brain over time as a byproduct of metabolic processes, and its presence is magnified by things we do and don’t do with our lives. This debris can be inflammatory in nature – ie, produced as a response to a perceived threat to the brain – and this inflammation accelerates with age – a process known creatively as inflammaging. Inflammation underpins multiple chronic health conditions including dementia.
•When it is damaged by physical injury. Even relatively innocuous events, such as heading a soccer ball can, if frequent enough, cause long-lasting cognitive problems (more on this in the next section).
•Through lack of training. The brain, like a muscle, can be trained. Unfortunately, just as our bodily muscles wither if we don’t use them, this also means a lack of training and mental activity can lead to a loss of cognitive function and brain failure.
The longer you live, the more time there is for these forces acting against brain health to accumulate. So what does that mean for the ageing brain, even one that manages to avoid injury or illness? Well, there is good news and bad.
The bad news is that you should anticipate some decline in ‘brain-power’ as you grow older, potentially as early as your 30s:
•Forgetfulness can occur, but perhaps the most obvious problem is a loss of processing speed. I’m in my mid-40s and can definitely attest to this. I can usually get to the right answer in the end, but it takes me longer. Playing quick-fire trivia with my teenage son is a lost cause.
•There is also a deterioration in ‘executive skills’ with age, including those governed by the prefrontal cortex (at the front of the brain), which can compromise your ability to plan and organise yourself, and to solve complex problems. Again, this is worse when you are under pressure of time. These changes in cognition are correlated with changes in the brain – shrinkage (which is a proxy of neuronal loss) – and changes in blood supply.
The good news is that certain cognitive skills do not decline drastically with age: your vocabulary and language ability are likely to remain relatively intact (aside from more ‘tip of the tongue’ moments probably related to our slowed processing speed). Likewise, your visuospatial skills will probably survive well with ageing. These enable you to know where you are in relation to other things in our environment – handy when you are driving! Increasing wisdom and experience can also offset a number of the age-related deficits – leading to better decision-making.