Physical exercise and your brain

Physical exercise and your brain

The benefits of exercise for our physical health and overall well-being are well documented, but did you know that keeping fit might also have a positive influence on your mind? We explore the relationship between exercise and cognition and find that getting your body into shape can have all sorts of great side effects for your brain.

It doesn't seem particularly surprising that taking care of your body should have a beneficial effect on your mind. After all, the brain, for all its fancy functions and mysterious machinations, is very much a bodily organ, so it stands to reason that if exercise is good for your heart, lungs and waistline, it's probably also good for those little grey cells.

But think again. Why should it be that simple? After all, exercise can have harmful effects on the body – think of the damage to muscles and joints, for example. Is it possible that exercise might have harmful effects on the brain as well? Perhaps we need to think about different kinds of exercise in this context, too. The example of damage to muscles and joints applies more clearly to high-impact sports than low-impact ones; it's possible that such differentiations exist for the effects of exercise on the brain, too.

Furthermore, the brain is enormously complex. When we talk about cognition, or thinking skills, we're actually using an umbrella term for a huge variety of functions – including, but not limited to, our ability to concentrate, process information quickly, remember events and information, and make complex analyses using a mixture of reasoning and gut instinct. So when we consider the effects of exercise on cognition, we need to define our terms very carefully.

As one recent review put it, cognitive performance may be enhanced or impaired depending on when it is measured, the type of cognitive task selected, and the type of exercise performed. That's quite a complex list of variables to keep in mind. Here's a brief, user-friendly overview of recent research into the relationship between physical exercise

In the short term, gentle exercise can boost cognitive performance... but it's complicated!

Studies of people doing short bursts of exercise have shown short-term facilitative effects on mental tasks. It is thought that this has to do with overall levels of increased arousal, including increased blood flow (and therefore nutrients) to the brain. Although cognitive functioning dips during the first twenty minutes of exercising, participants tend to perform better on tasks of concentration and processing speed, and remember more of what they've learned, after a brief (one hour) session of aerobic exercise. These effects are acute but persist for some hours. Interestingly, more intense and prolonged exercise tends to lead to poorer performance on these same tasks – an effect that is thought to be connected to fatigue and dehydration. There are also some task-specific effects: Higher-level reasoning does not tend to improve as much as memory, for example. To complicate things further, it seems that different forms of exercise have different effects – one study found that cycling was associated with enhanced performance during and after exercise, whereas treadmill running led to impaired performance during exercise and a small improvement in performance following exercise.

Exercise helps children's cognitive functioning enormously

It seems that pretty much all children concentrate and learn better if they exercise regularly. There have been numerous programmes of exercise interventions in schools that show such improvements, and results have been reported not just in terms of performance on cognitive tests but also in brain activation. Scientists have concluded that regular physical exercise benefits cognitive development in children struggling with obesity or attention deficit problems, as well as those without any such issues.

Exercise is important for maintaining good cognitive functioning as you age

There are two facets to this body of research. One is the finding that people with life-long habits of physical exercise are less likely to suffer from degenerative diseases like Alzheimer's and Parkinson's, which all involve a decline in cognitive functioning. At a population level, physical exercise protects the brain from both normal effects of ageing and age-related diseases that impair cognitive function. The second facet involves using physical exercise as an intervention for people who are already suffering from degenerative diseases. Here, a small but positive effect has consistently been shown, thought to be due to exercise improving biochemical processes in the brain. The fact that it is small isn't trivial – the benefits of drugs that are currently available to slow the progress of degenerative diseases are also generally small.

This is just a brief glimpse of the vastly complicated research that has been conducted into the relationship between exercise and cognition. Of course we mustn't be hasty in drawing conclusions that are not warranted on the basis of the available data. However, it seems safe to offer the following tips for people who want to experience the cognitive benefits of exercise:

-         An hour of relatively gentle aerobic exercise can help if you need to concentrate and remember, so it's time well spent if you are revising for exams or preparing for a tricky presentation at work.

-         Exercise is particularly important for children's cognitive development. Be a good role model to your children and get them active!

-         If you want to keep the effects of ageing at bay, exercise is a good option. Regular, gentle aerobic exercise has a protective effect if it's a long-term habit. It can also be a beneficial intervention for people already suffering from a decline in their cognitive abilities, so if someone close to you is suffering from a degenerative disease like Alzheimer's, consider taking them for regular walks.

Finally, although this is a complex area of research, one overarching conclusion is that exercise is generally a Good Thing as far as your thinking skills are concerned. Yet another reason to get off that sofa!


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