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It is difficult to avoid advice to exercise more. But many of us have no desire or ability to run, or join a gym. But did you know that walking can prevent all manner of conditions including depression, Alzheimer’s disease, cancer, diabetes and memory loss? One doctor even prescribes walking to his cancer patients.
Size matters – at least in your brain
As we age our brains shrink in size, with resultant reduction in function. Hence it becomes harder to remember things and it takes us longer to do things. In Alzheimer’s this reduction in brain size is accelerated well beyond the normal shrinkage seen with age.
Researchers have found evidence that declines in a substance called brain-derived neurotrophic factor (BDNF) could also be important in memory loss, depression and shrinkage of the hippocampus.
Walking maintains the hippocampus
The good news is that research has shown that moderate intensity aerobic exercise (brisk walking) is not only associated with maintenance of BDNF levels and hippocampal size, but could also reverse shrinkage. It was found that in the walkers the size of the hippocampus increased by 2% - making it equivalent in size to those in people 1 to 2 years younger.
They also found that those in the control group (who didn’t do the exercise) who were fitter at the start of the study had less hippocampal shrinkage than those who were less fit. This showed that even previous exercise had a protective effect on brain size.
Other studies have also shown a protective effect of exercise in warding off Alzheimer’s Disease. The earlier in life people develop Alzheimer’s the worse the disease and outcomes are. This research shows that at any age, walking as exercise can help put off or possibly avoid decline in memory and onset of Alzheimer’s.
It has also been found that depression is also associated with reduced levels of BDNF and shrinkage of the hippocampus. This may help explain the known link between depression and Alzheimer’s disease. But since depression can occur at any age, this is worrying as it would seem to predispose people with depression to early onset of Alzheimer’s.
Other researchers have found significant improvements in people with depression who walked, and that walking had a similar effect to other forms of exercise.