The next time you’re running and your thoughts flit from what to have for breakfast and this afternoon’s work deadlines to who played Chief on Get Smart,* don’t worry that you’re becoming scatterbrained. In fact, the aerobic fitness you get from running makes you better able than sedentary people to sustain mental focus.

That’s the takeaway from research conducted at the University of Granada in Spain and slated for publication in Medicine & Science in Sports & Exercise.

For the study, researchers gathered 22 triathletes, who trained eight or more hours a week, and 20 people who they classified as having low aerobic fitness. The subjects performed a dull but demanding task for one hour. Sitting in front of a black computer screen, they were to react as quickly as possible when they saw a full red circle, which appeared at intermittent intervals. (The average test involved reacting to about 400 circles.)

The researchers measured the subjects’ reaction times and brain activity in 12-minute segments during the one-hour test. In the first 36 minutes, the triathletes had quicker reaction times than the less-fit subjects. Throughout the test, the triathletes’ brains showed greater brain activity associated with allocating mental resources to a task, as well as brain activity associated with a preparatory response to a task. Taken together, the researchers wrote, the results “demonstrated a positive association between aerobic fitness, sustained attention, and response preparation.”

Other studies have shown that fit people perform better in tests of mental skills such as processing speed, cognitive control, and memory. This research complements those findings with its findings on the ability to focus.

“Sustained attention is the ability to maintain performance over a long period of time, which depends on maintaining vigilance, the ability to detect the stimulus, and resistance to distraction,” Antonio Luque-Casado, the lead author of the study, told Runner’s World in an email. “A reduced ability to monitor significant sources of information directly affects all cognitive abilities (i.e., slow responses and/or failures to respond to target stimuli). Therefore, sustained attention is an inherent function [of] general cognitive performance that is critical to cognitive abilities in humans.”

Luque-Casado said that being able to sustain mental attention is important in both everyday activities, such as driving and absorbing a presentation at work, and intricate professional tasks, such as performing surgery or handling air-traffic control.

Fit people’s better ability to sustain attention most likely comes not from practicing focus while exercising, but as a side effect of regular aerobic workouts. Studies on animals and humans have shown that exercise promotes the growth of new neural pathways in the brain, prevents some degeneration, and causes the growth of blood vessels in key parts of the brain, thereby increasing the supply of nutrients and energy to those areas.

Luque-Casado said that his findings are relevant not only for people such as his triathlete subjects who get several hours of aerobic exercise each week. Training enough to produce what Luque-Casado called “a robust and permanent physiological profile,” or an observable level of aerobic fitness, is likely sufficient.

“From our study, we cannot know an exact point of aerobic fitness from which we can observe changes at cognitive level,” Luque-Casado said. “However, most research so far points to the regular practice of extensive aerobic exercise, such as running, as the most suitable type of exercise to elicit beneficial long-term changes in brain structures and, consequently, in cognitive performance.”

Studies have found improvements in cognitive function after just six weeks of three or four weekly aerobic workouts, according to Luque-Casado.

While this research didn’t test the ability to focus immediately after a workout, “there are studies suggesting a positive effect of a single bout of acute exercise on cognitive performance,” Luque-Casado said. “In general terms, [workouts of] 20 to 30 minutes at intensities around 75 percent of the anaerobic threshold seem to benefit performance in some cognitive functions” in the short term, he said.

Lunch run, anyone?

*Edward Platt played Chief on Get Smart.

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Scott Douglas

Scott is a veteran running, fitness, and health journalist who has held senior editorial positions at Runner’s World and Running Times. Much of his writing translates sport science research and elite best practices into practical guidance for everyday athletes. He is the author or coauthor of several running books, including Running Is My Therapy, Advanced Marathoning, and Meb for Mortals. Scott has also written about running for Slate, The Atlantic, the Washington Post, and other members of the sedentary media. His lifetime running odometer is past 110,000 miles, but he’s as much in love as ever.