A group of researchers from Western Sydney University in Australia and the University of Manchester in the U.K. explored the impact of aerobic exercise on a part the brain called the hippocampus, an area responsible for how the brain processes and retains memories
The scientists reviewed 14 clinical trials that looked at the brain scans of 737 participants before and after aerobic exercise regimens. The group of the trial participants was made up of healthy adults, people who had Alzheimer’s and people with diagnoses of depression and schizophrenia. They ranged in age from ranged from 24 to 76 years old.
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They looked at the effects of a variety of aerobic exercise programs including indoor cycling, walking and running on a treadmill. The frequency of the exercise was an average of 2 to 5 sessions a week.
Looking at the results of those trials, the researchers found that while exercise did not impact total hippocampal volume, it did lead to an increase the size of the left region of the hippocampus in humans. (Brain health in humans declines by 5 percent each decade after people hit 40.)
"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," the study’s lead author Joseph Firth explained in a summary of the findings. "Our data showed that, rather than actually increasing the size of the hippocampus per se, the main 'brain benefits' are due to aerobic exercise slowing down the deterioration in brain size. In other words, exercise can be seen as a maintenance program for the brain."