Exercise is brain food - slowly, a theory of why

Years ago I was skeptical of research claiming that exercise was not only associated with better memory and perhaps better cognition, but that it also improved memory and cognition.

The results keep coming though, including some interesting animal models. So, I'm starting to believe. The case for building one's life around exercise is stronger than ever.

It would be helpful, though, to have some plausible mechanism for why exercise should help memory. Hand waving about sloshing blood is not persuasive. This is more interesting ...

Exercise and your brain: Why working out may help memory: Scientific American Blog

A new study shows that sugar may not be so sweet for the brain – and may lead to memory problems.

Researchers from four universities report in the Annals of Neurology that people who absorb glucose more slowly than those who metabolize it quickly are more forgetful and are more likely to have a faulty dentate gyrus, a pocket in the hippocampus section of the brain. The hippocampus is involved with learning and memory formation....

... Glucose metabolism naturally slows with age, and memory begins to decline in our 30s, says co-author Scott Small, an associate professor of neurology at Columbia University Medical Center in New York. The new study suggests a possible association between the two, because elevated blood sugar appears to damage the dentate gyrus, Small says.

The dentate gyrus's exact function is unknown. But it's one of several circuits in the hippocampus that, if disrupted, impairs memory, such as a person's ability to learn the names of new people or to remember where they parked their car.

The possible connection between its dysfunction and poor glucose regulation may explain earlier observations that exercise benefits the dentate gyrus, Small says. Until now, scientists believed that physical activity reduced the risk of age-related memory loss by allowing glucose to be absorbed more quickly into muscle cells, but were not sure why. This indicates, Small says, that the dentate gyrus could be the missing link...

Obviously these are incremental results that, in isolation, don't merit a news article. The key is that they're part of a trend focusing on the effects of exercise on glucose update, and how that may alter performance of flaky brain components that are long past their warranty period.

So how do we build our lives around exercise? It's not like there are open slots to fill in -- our family gave up on watching TV in the last century and we really can't do less household work. So other good things have to go - sleep (bad idea), social time, family time, home maintenance, reading, study, work ...