An overwhelming body of research has linked exercise with the development of stronger bones and muscle, but also bigger and smarter brains. Exercise increases a naturally occurring protein called brain-derived neurotrophic factor (BDNF) essential to learning. BDNF is important for the survival and growth of information-transmitting brain cells (neurons), helping them and other parts of the brain take in new information, process it, associate it, remember it, and put it in context.1
The military should take special note of this important science. Too many U.S. warfighters are not exercising regularly prior to entering military service and do not maintain an adequate fitness standard while serving. Thus, based on the research, they may not be maximizing their intellectual prowess. Of the five military branches, only the Marine Corps requires daily exercise, but it has yet to make it part of an inspectable program. The other military services encourage daily exercise but only require semiannual fitness tests.
The Research
The concept that exercise is good for the brain is not new. One of the world’s foremost authorities on the brain-fitness connection, Dr. John Ratey, first identified a causal link between fitness and cognitive performance in the 1970s. A psychiatrist and clinical assistant professor at Harvard Medical School, Ratey has always been interested in methods to make the brain function better. In 1995, his research took a giant leap forward after he read an article by Dr. Carl Cotman that identified a direct biological link between movement and improved cognitive function in mice.2 Cotman discovered that more physically active mice had heavier brains with bigger hippocampi and larger, thicker cortexes—an indication their brain cells had grown and become more connected. Significantly, BDNF was identified as the “master molecule” that caused this growth, and BDNF had increased after just one week of exercise. Cotman’s study more definitively demonstrated that exercise was the “spark” that improved the learning process.3
In the following years, neuroscientists increased their study of exercise and found more evidence that exercise provides a substantial learning stimulus—not just for animal subjects, but human subjects as well. For example, in 2007, German researchers found that people learn vocabulary words 20 percent faster after than before exercise.4 In another study, University of Illinois psychophysiologist Charles Hillman measured the attention, working memory, and information processing speed of fit and unfit children and noted improved executive function in fit children’s brains. “The ability to stop and consider a response, to use the experience of a wrong choice as a guide in making the next decision, relates to executive function, which is controlled by an area of the brain called the prefrontal cortex.”5
While scientists were uncovering the mysteries of BDNF and the learning process in the lab, junior high school physical education (PE) teacher Phil Lawler was discovering the strength of the mind-body connection in Naperville, Illinois. In 1990, bothered by the declining health and increased obesity of his students, Lawler decided to do something about it. Realizing that not all his students enjoyed exercise or actively participated during PE class, he made several changes to his traditional gym class that profoundly improved not only his students’ fitness and health, but also their behavior and learning. In short, Lawler decreased the amount of time students were standing around, increased the intensity of the exercise and the amount of time they were moving, and ensured everyone was participating.
This approach became known as “New PE,” and, over time, Lawler’s entire public-school district adopted similar programs. By 1999, an incredible 98 percent of Naperville students passed international fitness tests, and only 3 percent were classified as obese, compared with the national childhood average of 30 percent.6 Teachers soon noticed students also were performing better on academic tests, especially if those classes took place immediately following a New PE class.
Naperville teachers received permission to compete as their own “country” on the Trends in International Mathematics and Science Study (TIMSS), a worldwide math and science standardized test. This allowed Naperville’s results to be separate from the aggregated results of all other U.S. schools. Historically, the United States ranks just inside the top 20 of approximately 40 countries on TIMSS, significantly behind Japan, Singapore, and China. In the 1999 study, however, the Naperville school district placed first in the world in science and sixth in the world in math, beating China in both subjects. By increasing the duration and intensity of exercise, Lawler and his like-minded peers transformed 19,000 Naperville students into the fittest in the nation and some of the smartest in the world.7
Research and the Military
Given the finding that fitter children have improved cognition, one wonders if a similar phenomenon is occurring in the military. It is well known that Marines with higher fitness scores are selected for promotion and retention at higher rates.8 Critics may believe these statistics prove the Marine Corps is overemphasizing fitness to the detriment of other desired leadership qualities, such as judgment and decision making, or feel only specific job fields require high fitness levels. However, Ratey, Lawler, and others have demonstrated that view to be wrong. Marines with high fitness scores may also be better at judgment and decision making precisely because they exercise regularly and are more fit than their less competitive peers.
It is also well established that fitter individuals get injured and sick less frequently and that exercise improves resiliency and psychological health, mitigating stress, anxiety, depression, and attention deficit.9 Healthier, fit individuals miss less work—and it is less expensive to prevent injuries and illness than to treat them. Finally, exercise itself need not be expensive.
Mandatory Exercise
All service members must be required to exercise regularly. Something this important must be institutionalized. In addition, commands should be held accountable in formal inspections for maintaining minimum physical training (PT) standards. Even though the Marine Corps has the strongest fitness culture and most robust fitness policies, many units cite a lack of time for daily PT. However, if the careers of commanding officers could be negatively affected by an inspection, the lack-of-time excuse would disappear. If a program is important, it should be inspected.
Military unit exercise programs should include at least 30 minutes of moderate aerobic exercise five or more days a week to improve attention, memory, and thinking.10 Moderate intensity is defined as approximately 70–75 percent maximum heart rate, enough aerobic activity to raise the heart rate and increase the body’s need for oxygen. Any type of aerobic exercise will do, but the more varied and complex, the greater the benefit. Using different muscles releases different hormones that affect the brain differently, and the more complicated the movement, the more it stimulates thinking. Complex motor skills produce more BDNF than simple aerobic exercise alone.11 Finally, any exercise is better than no exercise. If time is of the essence, studies show that even quick four to eight–minute bursts of exercises such as push-ups, jumping rope, and burpees will improve cognition.
Exercise protects and creates new brain cells and activates the learning process, which is essential to outthinking and outsmarting adversaries. Exercise is so beneficial for the body and mind, it should be a near-daily, mission-essential task for all military units. If the approximately 1.4 million active-duty personnel followed Naperville-style physical training, the next generation of warfighters would be healthier, fitter, and smarter.12 Brains and brawn traditionally have been trained separately, and policy makers inherently mistrust simple solutions to complex problems. One country that needs no convincing, however, is China. Aware of the Naperville story, China has joined other countries in consulting New PE experts. In fact, in September 2019, Dr. Ratey traveled to China at the behest of President Xi Jinping to help him establish a national New PE program.13
This should be a wake up call for the Navy and Marine Corps team. Time is of the essence, if it wishes to have the personnel physically and mentally prepared to confront a peer competitor such as China.
1. John J. Ratey, MD, and Eric Hagerman, Spark: The Revolutionary New Science of Exercise and the Brain (New York: Little Brown and Company, 2008), 45.
2. Ratey and Hagerman, 42–44.
3. Ratey and Hagerman, 43–44.
4. Bernward Winter, Caterina Breitenstein, Frank C. Mooren, Klaus Voelker, Manfred Fobker, Anja Lechtermann, Karsten Krueger, Albert Fromme, Catharina Korsukewitz, Agnes Floel, and Stephan Knecht, “High Impact Running Improves Learning,” Neurobiology of Learning and Memory 87, no. 4 (May 2007): 597–609.
5. Ratey and Hagerman, Spark, 26.
6. Paul Zientarski, phone interviews with author; Ratey and Hagerman, Spark, 8.
7. Ratey and Hagerman, Spark, 8, 10.
8. Talent Management Operational Planning Team, Marine Corps Force Innovation Office, Deputy Plans Officer, MAJ M. J. Posey, USMC, Quantico, Virginia, 2014.
9. Ratey and Hagerman, Spark, 1–7.
10. Ratey and Hagerman, 54.
11. Ratey and Hagerman, 55–56.
12. Ratey and Hagerman, 32.
13. Dr. John J. Ratey and Paul S. Zientarski, phone interviews with authors.
