A few months ago, while I was on my computer preparing an outline for an upcoming magazine article, the inbox on my email account began to explode with an incessant stream of pings.
After clicking on the link embedded in a few of the emails, I was presented with an article that was comprised of a list of 100 benefits of exercise. After perusing the list, I discovered that none of the identified items was particularly compelling, at least to me.
A few weeks later, I came across a study that struck a nerve. Here it was, data that that yielded results showing a relationship between exercise and intelligence. Could exercise actually make a person smarter?
This research presented a concept that was absent from the aforementioned list of 100. Exercise, particularly aerobic exercise such as walking, was shown to improve intelligence. Really?
What Research Tells Us
For many years, neuroscientists and other health professionals have been analyzing data to show the relationship between exercise and intelligence. The latest findings appear to validate the idea that not only does exercise build a brain that resists physical shrinkage, but that cognitive ability can actually be improved through exercise.
Previous research has shown that when lab mice are placed in stimulating environments, such as those filled with toys and other engaging paraphernalia as well as a running wheel, improvements in brainpower result. But little research had been conducted that isolated the impact individual activities had on the development of cognitive ability.
Did the ability to play certain ways with toys cause the increase in mental capabilities? Was it the physical activity that was the variable?
Group 1 was provided with a sensual environment. Mice dined on fruits and cheeses, ate food dusted with cinnamon and drank flavored water. Color was rampant throughout their cages with, for example, neon colored balls that were surrounded by mirrored walls. Group 2 had all of the aforementioned plus an exercise wheel. Group 3 had only standard dull food and no exercise wheel. Group 4 had only an exercise wheel, but no toys or treats.
Before the study, all of the mice were tested on cognitive ability. Chemicals were injected in the mice enabling scientists to identify changes in their brain cells. The mice in each group were followed for a period of months.
After this period of time, the brain tissue of the mice was analyzed again. The scientists were amazed at what they uncovered. Exercise, regardless of the kinds of stimulating environments in which the mice lived, was the one variable that improved cognitive ability. Mice that did not run, regardless of the stimuli in their environment, showed no improvement in cognitive ability.
Why Does Exercise Improve Intelligence?
Just why does exercise appear to slow or reverse deterioration of brain cells? It wasn’t until the 1990s that scientists conducting autopsies discovered some human brains contained new neurons, and they were not sure why. Unlike the previous lab studies conducted on mice, research to determine the relationship between exercise and changes in human brain tissue was lacking.
When the scientists examined the mice that ran for a few weeks, they discovered these mice had twice as many neurons in the part of the brain that affected memory than did the mice that were sedentary. They found that neurogenesis, the creation of new brain cells, increased with exercise.
It appears that when people exercise, something called BDNF – brain-derived neurotrophic factor – strengthens the connections among neurons, thereby initiating neurogenesis. Scientists have shown that after people work out, their BDNF is elevated.
In a 2011 study, scientists followed a group of 120 men and women. Some of the subjects were assigned stretching exercises while other subjects were assigned to walk. After a one-year period, the walkers had a larger segment of the brain related to memory than did those who were assigned to stretching. The walkers also had higher levels of BDNF.
The researchers concluded that those 65-year-olds who walked had brains exhibiting physical characteristics of a 63-year-old.
The results of these experiments certainly indicate that mental ability need not decline at a steady pace throughout the aging process. In fact, intelligence may improve through a lifestyle that incorporates a walking program.
As for me, I continue to increase my mileage. Perhaps research will one day show that my regimen of walking 40-50 miles per week will provide a much-needed boost to my smarts. According to my rationale, if the mileage I log now can improve my cognitive ability, imagine how smart I might become if I chose to double the distance I cover.
Dr. Phil Heit is Professor Emeritus of Physical Activity and Educational Services at The Ohio State University.
