Exercise and Youth IV

A pretty interesting article in the LA times on exercise's effect on the brain.  It's a medium-sized effect — but since we're talking about the brain, medium is good," says Michelle Voss, assistant professor of psychology at the University of Iowa and lead author on a 2011 review of the effect of exercise on cognition.

Voss and her team examined more than 100 studies on the topic and discovered some interesting things. Here's one: The brain benefits of resistance training (such as lifting weights) seem to differ from those you get from aerobic exercise. "Aerobic exercise improves ability to coordinate multiple things, long-term planning and your ability to stay on task for extended periods," she said. Resistance training, which is much less studied than the aerobic side of things, "improves your ability to focus amid distracters."

This makes sense: Aerobic exercise such as running involves staying on task for a long time, and if you're training to get better, you need to stick to a plan. Weightlifting requires ignoring the spandex and lousy gym music and focusing enough to prevent the barbell from crushing your trachea during bench press. Perhaps honing the discipline for aerobic exercise and/or learning to tune out gym distractions reaps benefits for the other, non-athletic parts of your life.

The details of what's going on inside the skull are fascinating. Voss explained that MRIs of people in their 60s showed increases in gray and white matter after just six months of exercise. This happens in the prefrontal and temporal lobes, sites that usually diminish with age. With exercise, Voss says, they grow.

Voss also explained that the hippocampus area of the brain, key for memory formation, shrinks 1% to 2% per year in those older than 60, but when people in this age group begin fitness regimens, it grows by 1% to 2% instead.

Beyond growing one's brain, exercise improves the ability of different parts of the brain to work together, Voss says. It talks to itself better, but not in a multiple-personality kind of way.

Simple brisk walking for 45 minutes three times a week gets results.

Going much beyond that won't give your brain much more, Voss added: "There definitely is a law of diminishing returns. The difference between zero and moderate exercise is significant, whereas the difference between moderate and high exercise is much less so."

Exercise also can help if you've got a genetically programmed Alzheimer'stime bomb ticking away. In 2000, Dutch researchers published a study of 347 men, some of whom were genetically prone to Alzheimer's due to a certain gene variant. Adjusting for a number of confounding factors such as smoking, drinking and education, the researchers found that the inactive couch potatoes with the brain-wasting gene variant were four times more likely to develop Alzheimer's than the workout warriors who carried the trait.

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