Researchers at Columbia University Medical Center used magnetic resonance imaging to show that even small rises in blood sugar levels can reduce blood flow to the dentate gyrus, the part of the brain that controls memory (Annals of Neurology, December 2008). This may give us the explanation for memory loss that occurs with aging and why exercise helps to prevent memory loss.
The brain gets more than 98 percent of its energy from a steady supply of sugar circulating in the bloodstream. When blood flow is reduced, the brain is deprived of its source of energy and oxygen, causing injury to brain cells.
When you eat, sugar goes from your intestines into your bloodstream. The rise in blood sugar calls out insulin that drives sugar from your bloodstream into cells, keeping blood sugar levels steady. However, with aging, the body starts to lose its fine ability to control blood sugar, and blood sugar levels can rise too high. However, you are protected when you exercise because contracting muscles draw sugar so rapidly from the bloodstream that your blood sugar level doesn’t rise very high and your pancreas doesn’t need to release very much insulin. This rapid withdrawal of sugar from the bloodstream by exercising muscles is dramatic during exercise and can last up to eighteen hours after you finish exercising.
Hundreds of other studies show that 1) exercise slows loss of memory with aging, 2) diabetes markedly increases risk for dementia, 3) diabetes damages the dentate gyrus, 4) exercise helps to prevent the rise in blood sugar after eating and the associated age-related loss of mental function, 5) regular exercisers suffer far less from age-related memory decline, 6) obesity markedly increases risk of age-related loss of mental function, and 7) exercise helps to prevent and treat obesity. This new study should encourage you to exercise to save your mind.
Dr. Gabe Mirkin is a Villager. Learn more at www.drmirkin.com
