Exercise can change brains for the better, study finds…
We know the effect of exercise on physical health, and are discovering more about the effect of exercise on mental health. But the effect of physical exercise on brain health has remained somewhat mysterious.
“Whether exercise can change the structure of your brain is quite a contentious issue,” says Joseph Firth, of Western Sydney University and the National Institute of Complementary Medicine (NICM). “There have been a lot of studies either way – some studies show it did have an effect and some studies showed it didn’t.”
As well as consistency, the type of exercise we do may make a difference to brain health.
In a new study published in the journal NeuroImage, Firth led a team in reviewing the body of research in order to “gain a more definitive answer and answer the question – does it actually change the brain size?”
Firth, whose own research has explored the effect of exercise for people with psychiatric conditions such as schizophrenia, found that exercise “can indeed” change the way our brain is structured.
“If we look at the effect of exercise across the brain, we see that there’s no significant change of total hippocampal volume and there’s no change in the right-hand side,” he explains. “But if we look specifically in the left-hand side of the hippocampus, then that particular area seems to be particularly sensitive to exercise and that does significantly increase.”
Why the left side and not the right is affected is unclear, Firth says, as “they serve similar functions” in terms of cognitive function, specifically in relation to making memories, mental health and emotional regulation.
“They are both implicated equally in most functions, so why that side would be more sensitive to exercise we don’t really know,” Firth admits, “but the reason why the brain changes from exercise is probably because exercise releases something called BDNF – which is a neurotrophic factor – and when you exercise, your brain releases more of that chemical, and the hippocampus in particular is sensitive to that and it causes regenesis, telling the brain to grow, so it’s the BDNF response to exercise that causes the changes in brain volume.”
The BDNF response may also help to explain some of the potential benefits of exercise on the brain.
“Even a healthy brain, past the age of 40, deteriorates by about 5 per cent per decade,” Firth says. “That’s partly due to less BDNF in the brain. Exercise regulates the BDNF and prevents it from deteriorating.”
This means, if we exercise regularly (the studies they analysed typically met the guidelines of either 90 minutes of intense exercise per week or 150 minutes of more moderate exercise per week) it can help prevent your brain from deteriorating over time.
As well as consistency, the type of exercise we do may make a difference. One study from last year by University of Sydney researchers found that resistance training was particularly effective for improving cognitive function.
“It’s likely hormones that contribute to muscle strength gains are also causing cognitive improvement,” lead author Dr Yorgi Mavros, from the faculty of health sciences, told Fairfax.
“As research progresses, resistance training probably will emerge as a more effective exercise for improving brain health,” Firth says. “It’s looking like it does have really positive effects, not just on the way your brain is structured, but also on the neural connectivity between the different areas of the brain, which is really important for maintaining functioning over time. Aerobic training is what we typically consider the cornerstone of health, but resistance training for brain health is emerging as more promising.”
Also promising are the possibilities such research opens up about ways of addressing brain and mental health. “With something like psychosis or schizophrenia, a lot of the neural deterioration that occurs happens in the very early stages of illness, and no one has really looked at yet whether you could use exercise to prevent that,” Firth says. “Could you actually prevent the neural changes that occur with schizophrenia and psychosis? We’re doing trials at the moment … it’s quite an exciting area. Rather than reverse it … which might be impossible, we could use it to prevent deterioration.”
Similarly, for the rest of us who want to grow into our old age with healthy bodies and brains, Firth assures that exercise does help to maintain your brain health and prevent age-related decline. “It might even help to prevent Alzheimer’s and dementia from occurring,” he adds. “It doesn’t look like it can reverse those changes for people who have had those conditions for a long time – exercise might not be effective enough to cure somebody, but if it can prevent it from happening then that’s just as important. ”
This Article was written by Sarah Berry from “The Age” on 15th November 2017
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