Brain Benefits of Exercise

Before you skip another workout, you might think about your brain. A provocative new study finds that some of the benefits of exercise for brain health may evaporate if we take to the couch and stop being active, even just for a week or so.

I have frequently written about how physical activity, especially endurance exercise like running, aids our brains and minds. Studies with animals and people show that working out can lead to the creation of new neurons, blood vessels and synapses and greater overall volume in areas of the brain related to memory and higher-level thinking.

Presumably as a result, people and animals that exercise tend to have sturdier memories and cognitive skills than their sedentary counterparts.

Exercise prompts these changes in large part by increasing blood flow to the brain, many exercise scientists believe. Blood carries fuel and oxygen to brain cells, along with other substances that help to jump-start desirable biochemical processes there, so more blood circulating in the brain is generally a good thing.

Exercise is particularly important for brain health because it appears to ramp up blood flow through the skull not only during the actual activity, but throughout the rest of the day. In past neurological studies, when sedentary people began an exercise program, they soon developed augmented blood flow to their brains, even when they were resting and not running or otherwise moving.

But whether those improvements in blood flow are permanent or how long they might last was not clear.

So for the new study, which was published in August in Frontiers in Aging Neuroscience, researchers from the department of kinesiology at the University of Maryland in College Park decided to ask a group of exceedingly fit older men and women to stop exercising for awhile.

“We wanted to study longtime, serious endurance athletes because they would be expected to have a very high baseline” level of aerobic fitness and established habits of frequent exercise, says J. Carson Smith, an associate professor of kinesiology at the University of Maryland and senior author of the study. If these people abruptly stopped exercising, he says, the impacts could be expected to be more outsized than among people who worked out only lightly.

The researchers eventually found 12 competitive masters runners between the ages of 50 and 80 who agreed to join the study. All had been running and racing for at least 15 years and still regularly ran 35 miles a week or more.

At the start of the experiment, the runners visited the researchers’ lab for tests of their cognitive skills. They also had a special brain M.R.I. that tracks how much blood is flowing to various parts of the brain.

The researchers were particularly interested in blood flow to the hippocampus, a portion of the brain that is essential for memory function.

But for now, the study’s message seems fairly straightforward. For the continued health of your brain, try to keep moving.