Wednesday, September 24, 2008

Science and your long life brain

Let’s start with the bad news about brain ageing and then see why, for the vast majority of us aged forty-five or older, it’s really not bad news after all!

As we age our brain changes, for one thing it shrinks. In youth it weighs around 1.5 kg (approximately 3lbs) but by the time we celebrate our 65th birthday its weight may have dropped to 1.2 kg.

Furthermore the natural gaps between the folds of the outer layer of the brain - the neocortex - widen and two large spaces within the brain (the ventricles) also enlarge.

Unhelpful structural changes also take place, including the spread of neuritic plaques and neurofibrillary tangles, the latter formed from the remains of dead brain cells. Since the density of neuritic plaques is directly related to a decline in mental ability and since both plaques and tangles are implicated in Alzheimer’s disease, this is potentially very bad news indeed.

Finally, from early adulthood onwards we lose brain cells, especially in the crucial frontal regions, responsible for most of what makes up both our unique individual personality and our intellectual ability reside.

So, you may be asking, where is the good news?

Well, for a start, neuritic plaques and neurofibrillary tangles are by no means an inevitable consequence of aging. Studies of people who have lived well into their nineties, for example, have found no trace of them.

What about brain shrinkage and cell loss?

Surely such physical deterioration and the death of millions of posmitotic (i.e. irreplaceable) brain cells must have a drastic effect on function.

The reassuring answer is not necessarily.

It is certainly true that brain cells die in large numbers every day from around the age of twenty onwards, with some 50,000 perishing daily and contributing to the shrinkage of between 10 and 15 percent, described above.

Fortunately we have such a superabundance of cells, estimated at 100 billion, that even this seemingly high rate of attrition is of no practical significance provided we protect those billions of cells remaining through a health promoting lifestyle.

Furthermore some parts of the brain continue to grow throughout life, the dendrites (thread like extensions of the neurons which make contact with other cells) are continuously replaced. So too, recent research has shown, are some of the neurons in regions crucial to forming, retaining and recollecting memories.

Just a few of the reasons by previous pessimism among many gerontologists (specialists in ageing) and neuroscientists specialising in brain ageing, is giving way to optimism and an increasing acceptance of the idea that, with good housekeeping, the brain can continue to function healthily and at a high level far, far, longer than was previously believed.

What do I mean by ‘good housekeeping’?

Certainly more than just challenging the brain with mental workouts, vital as those are.

While constant intellectual stimulation, based on the familiar ‘use it or lose it’ approach to maintaining a long life brain is a necessary – indeed essential – precondition to what I have termed braingevity, such an overly narrow approach cannot, on its own, maintain the brain in peak condition and slow the consequences of ageing.

A holistic approach that takes account of such health promoting - as opposed to a life limiting – aspects of lifestyle – is no less important.

The key factors here include enjoying adequate sleep and continued social involvement, a sensible diet and regular, vigorous, exercise, the ability to relax deeply and manage stress efficiently, the capacity to remain hopeful and the determined to stay optimistic even in the face of loss and adversity.

PS: Don't forget to try our Free Brain Age Test!

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