Can exercise promote healthy brains?
Exercise may be a protective factor against the mental decline that comes with ageing. Just like a muscle, the brain needs to be “exercised” both in thought and also in the physical sense.
While the mechanisms aren’t clear, it’s known that the people who remain physically and mentally active into old age have a lower chance of developing diseases such as Alzheimer’s and dementia.
This suggests that physical activity, possibly through increased blood flow to the brain or production of neural growth factors, may help support and preserve normal brain function.
In a 12-week study, researchers from the United States recruited 30 inactive people aged between 61 and 88 to be part of an exercise regimen. The exercise program included moderate intensity walking on a treadmill four times a week for 12 weeks. Fourteen of the adults were showing some signs of mild cognitive impairment at the start of the study.
As expected, participants saw an improvement in fitness with heart and lung health enhanced by about 8%.
Comparing brain scans from before and after the exercise program showed an increase in the thickness of the cortex with the greatest growth in cortex size seen in those who showed the most improvements in physical fitness.
The cortex is the outer layer of the brain that typically shrinks with Alzheimer’s disease. The thickening was seen in both healthy people and those with mild cognitive impairment.
The study can’t prove definitively that exercise leads to brain gains. Previous studies, however, have found that exercise can benefit other areas of older adults’ brains.
Even though this was a small study, it builds a case for it ‘never being too late’ to help arrest brain deterioration with age, even if a person is showing some early signs of memory failure.
Last Reviewed: 26/08/2019
Norman Swan Medical Communications
Reiter K et al. Improved cardiorespiratory fitness is associated with increased cortical thickness in mild cognitive impairment. Journal of the International Neuropsychological Society 2015;21:757-767.