According to a study published in 2011 in the Proceedings of the National Academy of Sciences, exercise can improve the size of your hippocampus. And a decline in the size of this part of the brain is known to lead to dementia and Alzheimer’s later in life.
To quote from the research paper, which found that one year of exercise produced a 2 per cent larger hippocampus that an equivalent group undertaking no exercise:
‘The hippocampus shrinks in late adulthood, leading to impaired memory and increased risk for dementia. Hippocampal and medial temporal lobe volumes are larger in higher-fit adults, and physical activity training increases hippocampal perfusion, but the extent to which aerobic exercise training can modify hippocampal volume in late adulthood remains unknown. Here we show, in a randomized controlled trial with 120 older adults, that aerobic exercise training increases the size of the anterior hippocampus, leading to improvements in spatial memory.