Or to put it another way, if you're looking to keep your brain big and healthy, exercise could be your silver bullet.
In a first of its kind worldwide collaboration, the new study was led by researchers from Australia's National Institute of Complementary Medicine at Western Sydney University along with the Division of Psychology and Mental Health at the University of Manchester in the UK.
Regular exercise can increase the size of the human brain, a landmark Australian study has found.
All the trials examined the brain scans of almost 737 people before and after aerobic exercises.
Exercise! Study after study touts the enormous benefits exercise has to offer, the latest confirming that aerobic exercise can improve memory function and maintain brain health as we age.
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.
The subjects ranged in age from 24 to 76 with an average age of 66 and included both healthy participants as well as those with mild cognitive impairments (like Alzheimer's) and those with a clinical diagnosis of mental illness (like depression and schizophrenia).
The researchers examined effects of aerobic exercise, including stationary cycling, walking, and treadmill running. The length of interventions ranged from three to 24 months, with almost two to five sessions of exercises every week.
"Our study provides some of the most definitive evidence to date on the benefits of exercise for brain health", Dr. Firth said.
Commenting on the findings, Joseph Firth, from the National Institute of Complementary Medicine (NICM) at Western Sydney University said, "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". 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 programme for the brain", he added.
Firth says that the study could have implications for the prevention of age-related neurodegenerative disorders. However, so far physical exercise is one of the very few "proven" ways maintaining brain size and functioning into older age.