The evidence is in: Exercise your brain for mental fitness
by Jack L. Groppel, Ph.D., FACSM, USPTA Master Professional
Question: I was recently reviewing the updated Web site, www.tennis-health.com, and was fascinated to read how playing tennis affects the brain. To me, this is yet another incredible reason to get people to our facilities and on our tennis courts. Would you please go into more detail on this?
Answer: I, too, have been fascinated by what the scientific community is discovering about the effects of exercise, interval training, and, in some specific cases, tennis, on the brain. As I developed my answer to your question, it soon became clear that I will need two columns to give your question the energy it deserves. This column will concern itself with exercise in general and will then introduce some tennis-specific research, while my next column will deal solely with research observations on why tennis is the best activity in the world, for young and old alike.
Let me begin my answer with this news conference quote from Arthur Kramer, a neuroscientist at the University of Illinois and author of a review from the Association for Psychological Science, published in 2009: "... there's enough evidence to launch a public policy campaign that includes an endorsement of exercise to improve brain function." The obvious next question is "Why?" And then, I'll begin the discussion of "Why tennis?" The "Why tennis?" portion will be concluded in my next column.
First, a human being is designed to move, not to be sedentary! According to John Medina, in his book, "Brain Rules" (2009), the human brain evolved under conditions of almost constant motion. He reported on a study citing two elderly populations who led different lifestyles, one sedentary and one active. It was observed that exercise positively affected executive skills, spatial tasks, reaction times and quantitative skills. Thus, Rule No. 1 in his book (out of 12 rules) is that "Exercise Boosts Brain Power." Specifically, he cites two reasons for improved cognition through exercise:
1. Exercise increases oxygen flow into the brain, which reduces brain-bound free radicals. One of the most interesting findings of the past few decades is that an increase in oxygen is always accompanied by an uptick in mental sharpness.
2. Exercise acts directly on the molecular machinery of the brain itself. It increases neurons' creation, survival, and resistance to damage and stress.
In early 2008, the Cochrane Library published a survey of research that determined that aerobic exercise improves many forms of cognitive function such as auditory and visual attention, motor function, cognitive speed, and memory. To truly understand the mechanism behind this, you will have to bear with me as I discuss what the neuroscientists are saying. And, their observations begin with animals.
An article in U.S. News and World Report in 2008 reported that studies in rodents determined that running led to an increase in brain cells, specifically in the hippocampus, a part of the brain that is concerned with learning and memory. Now, I know what you are thinking: Tennis players are not rodents! Please bear with me just a moment, as the following work directly relates to this previous study, but does involve people. Arthur Kramer, with Kirk Erickson from the University of Pittsburgh, conducted a study of 165 adults to measure the hippocampus. Kramer said, "The higher fit people have a bigger hippocampus, and the people that have more tissue in the hippocampus, have a better spatial memory."
In an article in the journal, Cerebral Cortex, published in 2008, the authors observed many chemical changes that occur in athletes while running, endorphins being one of them. We all know about endorphins, or the natural 'high' that one gets after a great workout, but there is much, much more. John Ratey, Harvard psychiatrist and author of the revolutionary book, "SPARK," (and himself an avid tennis enthusiast) is quoted as saying, "Endorphins are not the only change occurring; so is norepinephrine, serotonin, dopamine, and brain-derived neurotrophic factor (BDNF)." I am not trying to 'wow' you with big words but, again, let's follow the trail.
BDNF is a very important growth factor in the brain. Some authors have said that it provides an almost 'fertilizer-like' growth effect on specific neurons in the brain, while keeping existing neurons healthy (a great attribute for those of us who 'might' be getting older). Other research findings regarding aerobic exercise include increased blood flow to the brain, supposed to reduce free radicals, as well as many other growth factors (FGF2, if you want to look it up) and molecules (nitric oxide), all of which support brain growth and resilience. What, now, does all this mean? For one, and at the absolute elementary level, one study observed that inactive individuals are two times as likely to develop mental disabilities compared to active individuals. But, there continues to be much more to this, for you and I as USPTA Professionals! And, a lot of it has to do with intensity of exercise.
John Ratey has said that there might be more benefits to interval training, short bursts of intense activity followed by brief rest periods (sound like a game of tennis?) It has actually been shown that intense exercise enables the brain to produce more of the above-mentioned growth factors. According to Ratey, "When you exercise more intensely, your brain produces growth hormone that cuts belly fat, increases muscle, and pumps up the brain volume. It also produces more nitric oxide (see previous paragraph) than steady training!" Then, Ratey, referring directly to tennis, in the February 19, 2008 issue of USA Today, said, "I recommend [people] work out five or six days a week. A heart-thumping game of tennis ... can keep the brain in top shape."
Now, let's even look at the mental exercise of 'anticipating' a tennis movement. In a 2007 issue of the International Journal of Psychophysiology, Wright and Jackson studied adult novice tennis players, using magnetic resonance imaging, to see how they anticipated the direction of a player's serve (this done while watching a video). Numerous regions of the brain were activated in detecting the stimuli of the server's motion and ball flight. If you combine this information with the fact that new cells are seen in the brain with exercise, it begins to become obvious how powerful tennis can be in helping the brain grow and also keeping it healthy. And consider that, in February 2008, Cerebral Cortex reported that expert tennis players experienced increased corticospinal facilitation (increased nervous system activity) when mentally practicing a tennis stroke. This was not seen when practicing a golf swing or table tennis stroke.
To close this initial column, let me describe a research study that sounds like an episode of the award-winning TV show, "HOUSE" (where Dr. House always seems to solve an unsolvable medical condition). In February of this year, an article was published in The Guardian, out of the United Kingdom, reporting on the case study research of brain-injured patients. The article was entitled, "Think Tennis for Yes, Home for No: How Doctors Helped Man in Vegetative State." A 29-year-old man had lain in a hospital bed for seven years, showing no signs of consciousness. Using a high-tech scanner, his doctors managed to 'read' his thoughts, but the physicians had to come up with a unique way of getting a response. When asked a yes/no question, he was instructed that a 'yes' answer was to "think of playing tennis" (a motor activity that 'activates' a certain part of the brain). A 'no' answer would be indicated if he thought about wandering from room to room in his home. An interesting aside to this is that 'wandering from room to room' is still a motor activity but not as 'active' as playing tennis. His doctors were "amazed when the patient gave a series of correct answers about his family." To quote directly, "Not only did these scans tell us that the patient was not in a vegetative state, but more importantly, for the first time in five years, it provided the patient with a way of communicating his thoughts to the outside world."
In my next column on the effects of exercise on the brain, I will detail the plethora of research that specifically examines our great game and demonstrates that, across the age continuum, tennis excels as the best activity in which one could participate.
Send questions to jgroppel@LGEPerformance.com.