An global collaboration of researchers from Western Sydney University and the University of Manchester reviewed 14 clinical trials that examined the brain scans of 737 people before and after an aerobic exercise program, as well as a control group.
Brain health decreases as we age, with the average brain shrinking by approximately five percent per decade after the age of 40.
Overall, the results 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.
The participants, aged between 24 to 76 years, included a mix of healthy adults, people with mild cognitive impairment such as Alzheimer's and people with a clinical diagnosis of mental illness including depression and schizophrenia.
The researchers did a meta-analysis of 14 studies and examined the brain scans of 737 people before and after aerobic exercise programs or in control conditions.
The researchers looked at the effects on the participants of various exercises including cycling on an exercise bike, walking and running on a treadmill for between three and 24 months, with sessions taking place between 2 and 5 times a week.
A new study suggests aerobic exercise can increase the size of a region of the brain that plays an important role in consolidating memories, among other functions.
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 brain health. Animal studies have shown that exercise actually increases the size of the hippocampus, but until now proof that the same occurs for humans has been inconsistent. "In other words, exercise can be seen as a maintenance program for the brain".
This is all due to a chemical your brain creates when you do any type of aerobic exercise called brain-derived neurotrophic factor (BDNF), Firth says.
"Firth also added that as well as helping to boost regular"'healthy" aging, the results of the new research could have implications for preventing aging-related neurodegenerative disorders such as Alzheimer's and dementia, although further research is needed.
Interestingly, physical exercise is one of the very few "proven" methods for maintaining brain size and functioning into older age.