Remember to Exercise … and Don’t Forget!

Exercise is good for you. I think we’ve all heard that often enough. But some new research adds yet another factor to the many benefits offered by exercise.

Researchers at the University of Nottingham Medical School have found a mechanism by which healthy physical activity might protect against alzheimer’s disease (Corticotropin-Releasing Factor Receptor 1 Activation During Exposure to Novelty Stress Protects Against Alzheimer’s Disease-Like Cognitive Decline in AβPP/PS1 Mice). It has been known from past research that physical and mental activity may reduce the likelihood of developing Alzheimer’s Disease. However, why these are beneficial is still being investigated. In their recently published paper, authors Scullion, Hewitt & Pardon note an apparent paradox (emphasis mine):

Susceptibility to stress is a risk factor for AD but positive lifestyle factors effective in delaying AD progression in mouse models (e.g., exercise, environmental enrichment) improve stress resistance despite inducing a number of markers of chronic stress …

What this means is that we know that stress increases the risk of Alzheimer’s Disease, and we know that exercise causes stress. Despite this, exercise decreases the risk of Azheimer’s Disease. The researchers explored a hypothesis for why this is the case by blocking a particular receptor in mice that have a known susceptibility to alzheimer’s-like dementia.

The theoretical underpinnings of this research are quite involved, examining a complex relationship between stress, stress hormones and specific brain receptors involved how we respond to stress. Their published findings were beyond my capacity to understand, but thankfully the University has provided a more easily digested press release. The press release reports (emphasis again mine):

… in mice with Alzheimer’s a repeated regime of moderate exercise restored the normal function of the CRF system [a hormonal system involved in the stress response] allowing its memory enhancing effects. The results are in line with the idea that regular exercise is a means of improving one’s ability to deal with everyday stress in addition to keeping mental abilities keen.

Finally, their study showed that the switching on of this particular brain receptor during exercise increased the density of synapses, which makes the connection between nerve cells, the loss of which is thought to be responsible for the early memory loss seen in Alzheimer’s patients.

Dr Pardon said: “This is the first time that researchers have been able to identify a brain process directly responsible for the beneficial effects of exercise in slowing down the progression of the early memory decline characteristics of Alzheimer’s disease.”

I particularly like that this research not only demonstrates that exercise may be protective against development of Alzheimer’s disease, but that it potentially does so by improving our ability to cope with everyday stress.

Additionally, this is not just a case of “exercise while you are young to help your mind when you are old” – their findings indicated a restorative effect of exercise on neurological pathways in mice already susceptible to development of memory loss. Exercise may not only reduce risk of Azheimer’s, but could also slow down progression of the disease.