Exercise maintains brain size, new research finds

Exercise increases brain size, new research finds
Credit: University of Western Sydney

Aerobic exercise can improve memory function and maintain brain health as we age, a new Australian-led study has found.

In a first of its kind international collaboration, researchers from Australia's National Institute of Complementary Medicine (opens in new window) at Western Sydney University and the Division of Psychology and Mental Health at the University of Manchester in the UK examined the effects of aerobic on a region of the called the hippocampus, which is critical for memory and other brain functions.

Brain health decreases with age, with the average brain shrinking by approximately five per cent per decade after the age of 40.

Studies in mice and rats have consistently shown that physical exercise increases the size of the hippocampus but until now evidence in humans has been inconsistent.

The researchers systematically reviewed 14 clinical trials which examined the brain scans of 737 people before and after aerobic exercise programs or in control conditions.

The participants included a mix of healthy adults, people with such as Alzheimer's and people with a clinical diagnosis of mental illness including depression and schizophrenia. Ages ranged from 24 to 76 years with an average age of 66.

The researchers examined effects of aerobic exercise, including stationary cycling, walking, and treadmill running. The length of the interventions ranged from three to 24 months with a range of 2-5 sessions per week.

Overall, the results – published in the journal NeuroImage– showed that, while exercise had no effect on total hippocampal volume, it did significantly increase the size of the left region of the hippocampus in humans.

Lead author, NICM postdoctoral research fellow, Joseph Firth said the study provides some of the most definitive evidence to date on the benefits of exercise for .

"When you exercise you produce a chemical called brain-derived neurotrophic factor (BDNF), which may help to prevent age-related decline by reducing the deterioration of the brain," Mr Firth said.

"Our data showed that, rather than actually increasing the size of the hippocampus per se, the main 'brain benefits' are due to slowing down the deterioration in . In other words, exercise can be seen as a maintenance program for the brain."

Mr Firth said along with improving regular 'healthy' ageing, the results have implications for the prevention of ageing-related neurodegenerative disorders such as Alzheimer's and dementia – however further research is needed to establish this.

Interestingly, is one of the very few 'proven' methods for maintaining brain size and functioning into older age.

More information: Joseph Firth et al. Effect of aerobic exercise on hippocampal volume in humans: A systematic review and meta-analysis, NeuroImage (2017). DOI: 10.1016/j.neuroimage.2017.11.007

Journal information: NeuroImage
Citation: Exercise maintains brain size, new research finds (2017, November 13) retrieved 28 March 2024 from https://medicalxpress.com/news/2017-11-brain-size.html
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