By Melissa Dahl

It is something of a cliché among runners, how the activity never fails to clear your head. Does some creative block have you feeling stuck? Go for a run. Are you deliberating between one of two potentially life-altering decisions? Go for a run. Are you feeling mildly mad, sad, or even just vaguely meh? Go for a run, go for a run, go for a run.


The author Joyce Carol Oates once wrote in a column for the New York Times that “in running the mind flees with the body … in rhythm with our feet and the swinging of our arms.” Filmmaker Casey Neistat told Runner’s World last fall that running is sometimes the only thing that gives him clarity of mind. “Every major decision I’ve made in the last eight years has been prefaced by a run,” he told the magazine. But I maybe like the way a runner named Monte Davis phrased it best, as quotedin the 1976 book The Joy of Running: “It’s hard to run and feel sorry for yourself at the same time,” he said. “Also, there are those hours of clear-headedness that follow a long run.”

A good run can sometimes make you feel like a brand-new person. And, in a way, that feeling may be literally true. About three decades of research in neuroscience have identified a robust link between aerobic exercise and subsequent cognitive clarity, and to many in this field the most exciting recent finding in this area is that of neurogenesis. Not so many years ago, the brightest minds in neurosciencethought that our brains got a set amount of neurons, and that by adulthood, no new neurons would be birthed. But this turned out not to be true. Studies in animal models have shown that new neurons are produced in the brain throughout the lifespan, and, so far, only one activity is known to trigger the birth of those new neurons: vigorous aerobic exercise, said Karen Postal, president of the American Academy of Clinical Neuropsychology. “That’s it,” she said. “That’s the only trigger that we know about.”

The other fascinating thing here is where these new cells pop up: in the hippocampus, a region of the brain associated with learning and memory. So this could help explain, at least partially, why so many studies have identified a link between aerobic exercise and improvement in memory. “If you are exercising so that you sweat — about 30 to 40 minutes — new brain cells are being born,” added Postal, who herself is a runner. “And it just happens to be in that memory area.”

Other post-run changes have been recorded in the brain’s frontal lobe, with increased activity seen in this region after people adopt a long-term habit of physical activity. This area of the brain — sometimes called the frontal executive network system — is located, obviously enough, at the very front: It’s right behind your forehead. After about 30 to 40 minutes of a vigorous aerobic workout – enough to make you sweat – studies have recorded increased blood flow to this region, which, incidentally, is associated with many of the attributes we associate with “clear thinking”: planning ahead, focus and concentration, goal-setting, time management.

But it’s this area that’s also been linked to emotion regulation, which may help explain the results of one recent study conducted by Harvard psychology professor Emily E. Bernstein. Like Postal, Bernstein is also a runner, and was curious about a pattern she saw in her own mind after a run. “I notice in myself that I just feel better when I’m active,” she said. She started to become really interested in the intervention studies that have popped up in recent years that suggest if you can get people who are having trouble with mood or anxiety to exercise, it helps. “But why?” she wanted to know. “What is exercise actually doing?”

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