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Tuesday, May 13, 2008

Losing your mind?

Maybe not, if you give it enough oxygen.

I'm always looking for ways to motivate people to exercise, I remember how long it took me to get motivated. This week's TIME has an article on memory and dementia and what scientists know now. Here's the key excerpt:
So why should memory fade at all? The answer may come from the gym.

A decade ago, when neuroscientist Fred Gage of the Salk Institute made the discovery that the adult brain continues to regenerate, the brains in question belonged to mice. Some of the mice had been sedentary, others had been exercising, and the ones that logged the most miles on their wheels produced many more new neurons than did the sedentary ones.

Now it turns out that the same appears to be true for humans. In a paper published last spring, a team led by Gage, Small and Richard Sloan, a psychologist at Columbia University, revealed that after pounding the treadmill four times a week for an hour for 12 weeks, a group of previously inactive men and women, ages 21 to 45, showed substantial increases in cerebral blood volume (CBV)--a proxy for neurogenesis because where there are more cells, there are more blood vessels.

Not only did the CBV profile of the human exercisers mirror that of the mice, but the people who exercised more did better on a slew of memory tests. Other evidence backs this up. In a study of "previously sedentary" older subjects by psychologist Arthur Kramer at the University of Illinois and others at Israel's Bar-Ilan University, investigators found that those who engaged in aerobic exercise did better cognitively than those who stretched and toned but never got their heart rates pumping. What's more, subsequent imaging showed that aerobic exercise "increased brain volume in regions associated with age-related decline in both structure and cognition."

Cerebral blood volume is not the only thing responsible for this brain-boosting. Also at work is the fact that exercise increases what's known as brain-derived neurotrophic factor (BDNF), a protein that stimulates the birth of new brain cells and then helps them differentiate and connect. BDNF also enhances neural plasticity, the process by which the brain changes in response to learning. In diseases like Alzheimer's, depression, Parkinson's and dementia, BDNF levels are low. In people who exercise, BDNF levels rise.
I'm still no good at remembering names though.

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