Move, It Makes You Smarter

... but there is another, easy-to-achieve, scientifically proven way to make yourself smarter. Go for a walk or a swim. For more than a decade, neuroscientists and physiologists have been gathering evidence of the beneficial relationship between exercise and brainpower. But the newest findings make it clear that this isn't just a relationship; it is the relationship. Using sophisticated technologies to examine the workings of individual neurons - and the makeup of brain matter itself - scientists in just the past few months have discovered that exercise appears to build a brain that resists physical shrinkage and enhance cognitive flexibility. Exercise, the latest neuroscience suggests, does more to bolster thinking than thinking does.

Whatever the activity, though, an emerging message from the most recent science is that exercise needn't be exhausting to be effective for the brain. When a group of 120 older men and women were assigned to walking or stretching programs for a major 2011 study, the walkers wound up with larger hippocampi after a year. Meanwhile, the stretchers lost volume to normal atrophy. The walkers also displayed higher levels of B.D.N.F. in their bloodstreams than the stretching group and performed better on cognitive tests.

Gretchen Reynolds writes the Phys Ed column for The Times's Well blog. Her book, ''The First 20 Minutes,'' about the science of exercise, will be published this month. Editor: Ilena Silverman