Exercise Your Brain

Some of the greatest thinkers in history made exercise an integral part of their lives and attributed their daily physical activity to their success.  Aristotle, the Greek philosopher who was a pupil of Plato and the teacher of Alexander the Great, would give lectures while walking.  His students would follow him as he spoke, his academy was called the peripatetic (walking about) school and lessons took place in the Lyceum (a gymnasium and public meeting place in Athens).  Henry David Thoreau was a famous walker whose most noted work, Walden, is a book about natural history, philosophy and simple living in a natural setting. It was written when he lived, explored and walked Walden Pond for a two-year period. Aristotle and Thoreau are two famous examples of men who realized and utilized the benefits of exercise while thinking. What can the great thinkers teach us about the effects of exercise on the brain?

Regular exercise is good and is known to reduce the risk for heart attack, stroke, atrial fibrillation, colon cancer, hypertension, diabetes, depression, and obesity. Exercise will lower total cholesterol, raise good cholesterol (HDL), and lower stress levels. Exercise can even help us live longer. Daily moderate walking will extend life by one and one half years and more strenuous exercise will extend it by three years. Any amount of exercise will decrease the risk of dying from heart disease compared to the sedentary individual, who has the highest risk for cardiac disease and death. The recommended amount of exercise for adults is 150 minutes per week (35 minutes per day) of moderate intensity or 75 minutes per week (20 minutes per day) of vigorous intensity exercise.  Moderate intensity exercise includes walking at 3 miles per hour, bicycling less than 10 mile per hour, water aerobics, doubles tennis, and general gardening. Vigorous exercise is walking uphill, race walking, bicycling faster than 10 miles per hour, singles tennis and heavy gardening. People performing moderate to vigorous physical activity can reduce their risk for cardiac death by 20% or more. Exercise has no side effects and relatively low cost. If exercise were a medication, it would be a blockbuster!  However, can exercise make us smarter? Can it reduce the risk for dementia?

To decide whether students were smarter when they exercise during their classes, researchers studied 500 second and third graders. Half of the students received traditional lessons; they were taught sitting at their desks. The other half was taught incorporating physical activity into their lessons. For example, students did eight jumping jacks to solve the multiplication problem 2 times 4.  After two years, the students in the physically active group scored significantly higher in math and spelling than their non-exercising peers. It was felt that exercise during learning reinforces concepts and increases concentration since the brain and the body were working together.  Perhaps high school students should do jumping jacks or play a game of Ping-Pong before the SATs to improve their scores. That would be an interesting study.

Even for those who have finished high school, exercise has been shown to improve brain function. One study of inactive, overweight 49 year olds involved baseline cognitive tests, such as remembering pairs of numbers.  The patients then started a four-month exercise regimen. At the end of the four months, the patients had lost weight and improved their cognitive function.  The study concluded that the more patients could exercise, the more weight was lost and the sharper they became.  Another study compared sedentary middle-aged patients to endurance trained middle agers. The fit adults had better cognitive performance. It was felt that exercise improves blood flow to the brain, preventing midlife vascular disease associated with cognitive decline later in life. Dementia is a decline in mental ability severe enough to interfere with daily life. It is caused by permanent damage or destruction of brain cells. The incidence of dementia is increasing worldwide and the risk of dementia increases with increasing age.  Exercise may substantially reduce the risk of dementia.  Exercise improves blood flow to the brain and reduces the incidence of hypertension and stroke, both of which have been shown to worsen cognitive function. In addition, exercise increases neurogenesis, which is the creation of new brain cells in a mature brain. Many studies have now confirmed that exercise reduces dementia and age related decline. Two interesting studies looked at older adults and assessed their cognitive function and the amount of gray matter in the brain. Gray matter processes information in the brain and is involved in muscle control, memory, speech and decision-making. More gray matter means better overall brain health. In one study, older adults who walked three times per week for six months were found to have a significant increase in gray matter, memory recall and quicker responses.  In the Cardiovascular Health Study, 900 older adults were followed for ten years. The most active of those participants had substantially more gray matter and also had 50 percent less risk of developing dementia. It is unknown what types of exercise and how much exercise is needed to prevent dementia. In the Cardiovascular Health Study, positive effects were seen with walking, cycling, swimming, ballroom dancing and gardening and even the most active participants only exercised a few times per week.

It seems that a daily dose of exercise may be beneficial for brain function across the entire age spectrum; from students who want to improve their test scores to older adults who want to slow or reverse age related decline. So be like the great historical thinkers by put on your walking shoes, head outdoors and hike up your IQ.