Exercise Affects Not Only the Body, But Also the Brain

We all know that exercise help us change the shape of our body.  Lifting weights shapes muscles, running burns fat, and yoga increases flexibility.  Exercise has also been regarded as medicine for the mind.  With increased fitness levels comes an increase in oxygen, growth factors, hormones and nutrients to your brain.  This effect on the brain has even been shown to slow the cognitive decline that is associated with dementia, Parkinson’s disease and depression. 

Today, our understanding of the effects of exercise has grown significantly.  Researchers now know that various types of exercise (specifically, high-intensity intervals, aerobic exercise, weight training, yoga and sports drills) also affect the brain in various ways.   

This transition began in rodent studies in the early 2000’s.  Researchers then found that mice who used a running wheel experienced changes in the hippocampi, the area associated with memory.  They then studied older adults who participated in some type of aerobic exercise at least 3 times a week for a year.  Researchers found that they too experienced growth in their hippocampi and subsequently performed better on memory tests.  Additional studies have indicated that aerobic exercise may help Alzheimer’s disease and other forms of dementia.

Teresa Liu-Ambrose, a researcher at the University of British Columbia in Vancouver, Canada, considered whether other types of exercise would have similar or different results.  Since individuals with mild cognitive impairment (MCI), are known to be at increased risk of developing dementia, she selected 86 women already diagnosed with MCI. 

The memory and executive function (complex thought processes, including reasoning, planning, problem-solving and multitasking) of each participant was evaluated.  They were divided into 3 groups and spent an hour, twice a week doing specified exercises.  One group lifted weights, one took brisk walks and the last simply stretched for the time allotment.  After 6 months, both the walking and weight lifting groups showed improvement in spatial memory.  Additionally, the weight lifting group showed significant improvement in executive function and associative memory (for example connecting a person’s name and face together).   At the same time, the aerobic group displayed improvements in verbal memory (the ability to remember a word “on the tip of the tongue”).   The group that simply stretched had no change in either memory or executive function. 

Willem Bossers of the University of Groningen in the Netherlands continued with this line of thinking.  Would a combination of exercise types make a larger impact?  He divided 109 dementia patients into 3 groups.  After getting base line evaluations, 1 group walked briskly 4 times a week for 30 minutes.  A second group walked twice a week and did strength training twice a week.  The third group, the control group, did no exercise.  After 9 weeks of this regimen, the combination group showed more improvement in executive function than the other 2 groups.  He concluded: “It seems that, for older adults, walking only is not enough. They need to do some strength training.

Studies also show that healthy adults can reap some of the same benefits from exercise. Liu-Ambrose studied healthy older women and found that while balancing and toning exercises did not have significant effects, lifting weights led to marked improvements in executive function – even if the women only did the exercise once a week

Researchers propose that the combination of weight lifting and aerobic exercise is so effective is that they are affecting the body and brain in different ways giving individuals a type of neurobiological cocktail.  They have not yet extensively studied the longevity of results, but early indications are that individuals will benefit as long as they continue the physical activities.

What does this mean for young people?  Studies show that, like adults, children are affected differently by different types of exercise.  Some studies show that taking 20 minutes to walk, sprint or skip, has instant effects on attention, executive function and achievement in mathematics and reading tests.  There are also reports that state a brisk walk can help children with ADHD focus. 

One of the researchers looking at how exercise affects children is Charles Hillman at the University of Illinois at Urbana-Champaign.  He “agrees with current recommendations that children get at least an hour of exercise daily, but notes that it might be best spread over the course of the day. Because purely aerobic exercise keeps kids focused in the near term,” so “giving them breaks to walk or move around every 2 hours might be the best way to promote learning.”

Interestingly, researchers found that “highly structured” exercise that is “focused on specific skills, such as for a sport or to improve coordination” actually “hampers attention.”  So while a quick run around the playground might help them do better on a test, doing exercise with drills and rules may have the opposite effect.    However, these exercises do appear to help children develop longer attention spans over time. 

The portion of the brain known as the cerebellum is responsible for movement. Researchers now know that it plays a role in attention as well.   Since the cerebellum would be utilized in sports drills, this may improve attention span as well.

Hillman also says children’s fitness levels are related to differences in their brains.  His research revealed an association between children who are fit and larger hippocampi, basal ganglia, and higher scores on attention tests.  The hippocampi is a portion of the brain responsible for converting short term memory to long term memory as well as spatial memory.  Basal ganglia is a portion of the brain associated with motor movements, learning routine/habits and emotion. 

Because these areas continue to mature, making changes to fitness levels in children can have significant impact.  Hillman’s studies showed that improvements to the brain function actually occurred faster than improvements in fitness levels and weight loss. 

It’s not only at the ends of the age spectrum that the brain benefits from physical activity.  Researchers Tracy and Ross Alloway from the University of North Florida in Jacksonville realized working memory is improved by activities “of the type we often enjoy during childhood, such as climbing trees, crawling along a beam, or running barefoot”.  Tracy Alloway says working memory is the ability to prioritize and “process information, allowing us to ignore what is irrelevant and work with what is important.”  As such, it “influences nearly everything that you do, from the classroom to the boardroom.”  People of any age can positively impact working memory, according to their research, but the activity has to require the “need to balance and think at the same time.”

Researchers are also evaluating the possibilities of exercise affecting behavior.  One of the newer fitness trends involves high-intensity interval training (HIIT).  This type of exercise involves quick spurts of high intensity alternating with spurts of low to moderate intensity. 

Kym Guelfi at the University of Western Australia in Perth studied how this type of exercise affects appetite.  In her study, participants that exercised at the most intense intervals ate less immediately after the workout and into the next day and a half.  This may be due to the effects on ghrelin, the “hunger hormone”.  This hormone notifies the brain when the stomach is empty.  As the stomach fills, ghrelin decreases to let the brain know to stop eating.  The study participants who exercised at the higher intensity had lower levels of gherlin after their workout which may explain their lower food consumption. 

While we are still in the early stages of learning exactly how and why exercise affects our brain, there is enough evidence to say that the beneficial cognitive effects of exercise are numerous.  In youth, activity can help build up our brain and improve attention span.  As we age and the brain begins to deteriorate, exercise can slow and sometimes even reverse the effects of age.  Whatever exercise you do, your body, and likely your brain, will benefit. 

Statistics show that people tend to continue the exercise programs they enjoy.  There are so many options available that there is really no reason to stick with an activity you don’t like doing.  Experiment with types of exercise that sound interesting to you, making sure you adhere to trainer or class instructor guides for good form to stay injury free.  Talk to your doctor of chiropractic about what exercises might be best suited to your current health status. If you do not have a regular chiropractor, you can find a TCA member doctor here.


SOURCE: Burrell, Teal. New Finding: Different Types of Exercise Affect Different Parts of Your Brain. www.Prevent Disease.com, June 14, 2016.