1

The Biological Impact of Exercise on Cognition

Specific Aims:

Exercise is well known for its numerous physiological benefits such as improving sleep

patterns, lowering blood pressure, strengthening the heart and lungs, and preventing diseases.

Equally important, and often disregarded, are the benefits which exercise has on cognitive

functioning. Researchers discovered that there is a “mind-body” connection. There are specific

chemicals in the body that play a substantial role at improving cognition, and it is these

hormones and neurotransmitters that are released during exercise and movement. The effect of

these biological chemicals on the brain include quicker thinking, improved memory, and,

therefore, a higher GPA. Extended research continually demonstrates that those who perform

aerobic exercise regularly have greater cognition and score higher on tests. The aspect which

appears to be unclear, though, is the exercise frequency and duration that is necessary to gain the

cognitive benefits.

There is so much that is unknown about the human brain; why it does what it does and,

more complexly, how it goes about doing it. Being a Biology/Pre-Med major, I find it intriguing

that everything we consume and everything we do has an effect on our brain. My objective in

doing this research is to determine the effect that exercise has on cognitive functioning and how

it relates to students’ grades. There has been much more research completed regarding the effects

that exercise has on the brain over time. To date, however, there is not sufficient research on the

immediate effects of exercise, and I would like to explore that further.

Dr. Buckley is the professor of Exercise Physiology at Aurora University, and an expert

on analyzing body composition and exercise’s effect on the body. Collectively, we are the best

2

team to do this study because we are passionate about this topic, and each of us would bring our

own distinct knowledge to the table in order to complete this study appropriately. My hypothesis

is that Aurora University students who perform acute aerobic exercise for forty-five minutes

before taking their final will have greater growth than the sedentary group when comparing their

midterm exam grade to their final exam grade.

Specific Aim 1: To determine the effect acute aerobic exercise has on cognition after forty-five

minutes.

Hypothesis: I hypothesize that the individuals in the exercise group will demonstrate

improvement on the final exam and the individuals who do not exercise before the exam will

have a similar score to the midterm score.

Specific Aim 2: To determine whether or not there is a significant difference in scores between

those who exercise versus the sedentary group.

Hypothesis: The exercisers will demonstrate greater growth overall on the final exam.

Specific Aim 3: To provide information to school boards regarding the effect of exercise on

cognition so they can make appropriate improvements to the academic curriculum.

Hypothesis: I predict there to be a positive correlation between those who exercise before taking

a test versus those who remain sedentary.

Neuroscience has been greatly expanding, and researchers are constantly looking for

innovative breakthroughs. Being that many school boards are eliminating recess and gym class

from schools in an effort to improve students’ grades, it is crucial that solid evidence is found to

prove that recess and gym class is vital for students. This applies especially to pre-adolescents

3

whose brains are still developing and are very “plastic.” Academically, the United States is far

behind other countries. If more studies like this continue to demonstrate the importance of

exercise on improving cognition, this could have a huge impact on the academic curriculum.

This being said, I expect to see that those who perform acute aerobic activity before taking their

final exam will see improvement in the growth from their midterm to final exam letter grades.

Literature Review:

I have compiled extensive research regarding the correlation between exercise and

improved cognitive functioning. According to Ratey (2008), “In today’s technology-driven,

plasma-screened-in world, it’s easy to forget that we are born movers- animals, in fact- because

we’ve engineered movement right out of our lives” (P.3). Many individuals have become

accustomed to a sedentary lifestyle, and some forget the important role that exercise plays in

their lives. Exercise is so vital, in fact, that it is the way in which advanced brains developed;

they developed while we were moving. The ancestors of human beings did not have the lives of

luxury that many have today, and in order to survive they were forced to move, often twelve or

more miles per day, in search of food and shelter (Medina 2008). Exercise has many

physiological benefits and even aids in disease prevention. During aerobic exercise, oxygen

uptake into the bloodstream is elevated and carbon dioxide is expelled. This increased oxygen

intake speeds up cellular processes and improves mitochondrial functioning in active muscles

(Katch, McArdle, Katch 2001). The ease of blood circulation throughout the heart and its

accompanying arteries is increased when the arteries vasodilate during exercise, enabling the

person’s blood pressure to decline (Katch et al. 2001). This is what leads to the physiological

health benefits that most individuals are familiar with already. Nonetheless, when these

biological processes are taking place neuroplasticity is occurring in the brain.

4

According to Knaepen et al. (2010), neuroplasticity is the brain and CNS’ ability to

change to an environment and form different connections (P.766). Neuroplasticity takes place

during both aerobic and anaerobic activities, such as weight lifting and running. The most

cognitive gains, namely memory and quicker thinking, have been observed during aerobic

activity. Along with this, experiments with various groups of people, ranging from athletes to

people with mental disabilities, demonstrated higher Brain-Derived Neurotrophic Factor (BDNF)

concentrations in their blood serum. BDNF is one of the key neurotransmitters in the body which

leads to improved cognition (Gligoroska and Manchevska 2012). The people with disabilities

who did not work out often had the highest concentrations in their blood, while athletes had the

least. The theory here is that athletes are accustomed to exercising and the BDNF is taken up and

processed so rapidly and efficiently that it does not linger in the bloodstream (Knaepen et al.

2010), P.793).

How much exercise is enough though to gain improved cognition? This is the real topic

in question. As it turns out, sometimes less is more. Many people have the misconception that to

gain the cognitive and physiological benefits, they must do strenuous types of exercises for long

periods of time. According to Ploughman (2008), however, acute aerobic exercise leads to

greater cognitive gains (P.238). Additionally, Ploughman’s (2008) study demonstrated that after

one week of voluntary exercise, the increase in BDNF in rats’ brains enabled them to have

improved spatial memory and better remember the location of a platform while traveling through

a maze (P.237). There is not specific data regarding a set amount of exercise, the frequency, and

the precise types of exercise one must carry out to gain the cognitive benefits as of this time.

According to many of the authors, “this area needs to be further researched.”

5

Through correlational studies of middle school students who had above average scores

for physical activities such as sit and reach, long jump, push ups, sit ups, and jumping jacks, also

had better academic achievements than those students who were not physically fit. Aerobic

fitness was directly linked to better reading and math test scores (Tomporowski et al. 2008). This

is not surprising, considering that increased oxygen uptake, movement of muscles producing

Insulin-Like Growth Factor (IGF-1) and Vascular Endothelial Growth Factor (VEGF) proteins,

and the mass production of various hormones and neurotransmitters throughout the body

improve cognition. Castelli et al. (2007) performed an experiment examining 259 students in

third and fifth grade to determine if there was a positive correlation between physical activity

and higher academic achievement. The Fitnessgram was utilized to carry out the experiment.

Fitnessgram is an exercise program consisting of different types of exercises, such as The

Progressive Aerobic Cardiovascular Endurance Run (PACER), as well as analysis of body

composition and BMI. The end result showed that low BMI and plenty of aerobic activity were

associated with greater academic achievement (P.245).

In the United States, 65% of adults are obese and 10% of the population suffers from

diabetes (Ratey 2008). The United States is also behind academically when compared to other

countries. This being said, it is astonishing that most school districts are removing physical

education from the curriculum (Ratey 2008). Unfortunately, neuroscientists and members on the

school boards do not collaborate on this issue, and board members think they are going to see an

improvement in students grades by removing recess and physical education in order to focus

more on core classes. However, if they had been informed about the research that proves there is

a “mind-body” connection between exercise and improved cognition, it is likely that this would

not be the case.

6

There are numerous physiological benefits of exercise which are directly linked to brain

functioning. Specifically, the endocrine system is responsible for positive changes that occur in

the brain during and after exercise. Some of the hormones that are increased during exercise are

serotonin, norepinephrine, dopamine, glutamate, and gammaaminobutyric acid (GABA). These

neurotransmitters are responsible for the responses and signals within the brain (Ratey 2008).

Gligoroska and Manchevska (2012) state that the various hormones and neurotransmitters, along

with necessary nutrients, are carried throughout the body and to the brain when blood flow is

increased during exercise (P.199). According to Ratey (2008), the neurotransmitter most

involved in learning is glutamate. Glutamate and GABA are responsible for “fine tuning” the

flow of signals in the brain which aids in learning and enables individuals to focus better.

Another molecule, BDNF, is equally important in the functioning of the neural system. It

functions as the infrastructure of the neurons and is the “miracle grow” in this scenario (Ratey

2008). BDNF enables the dendritic branches to expand and grow while forming new

connections, which allows for quicker thinking. These hormones and neurotransmitters work

synergistically, all completing similar tasks, and ensuring that the neurons are functioning

properly. Higher levels of these chemicals in the brain and body are desirable, because they help

to improve cognition and ensure more efficient firing of neurons (Gligoroska and Manchevska

2012). Similarly, Gligoroska and Manchevska (2012) noted an increase in axons in the cortical

region of the frontal lobe, which is the region associated with higher level thinking (P.200).

Muscles also play a role in the chemicals and proteins used to increase brain functioning

by releasing certain proteins, known as IGF-1 and VEGF proteins, into the bloodstream and they

travel up to the brain to aid in the growth and proper brain functioning (Ratey 2008). Recently it

has been demonstrated through research of these hormones and proteins that the brain is rather

7

“plastic.” This means that it is able to be molded every time it processes new information (Ratey

2008). It is very similar to the way muscles use amino acids and peptide proteins to rebuild

themselves after a workout. When comparing a sedentary individual’s brain to someone who

exercises on a regular basis, it is evident that the active individual’s brain has more BDNF and

higher concentrations of neurotransmitters responsible for improved cognition. In contrast, the

sedentary individual’s neurons have actually begun to be depleted due to lack of use. The athlete

also has improved blood flow, due to increased nitric oxide, which is a flow-regulating molecule

that enables blood flow to expand throughout the body; particularly the dentate gyrus region of

the brain, creating a rich environment for the growth of new neurons and blood vessels (Medina

2008). In the brain, the hippocampus contains the dentate gyrus region which is responsible for

memory. During and after exercise, the increased blood flow in this region allows for the growth

of new neurons and capillaries; it literally increases the brain’s volume and blood volume in the

memory areas of the brain. This further supports improved cognition and memory, along with all

of the increased hormone and protein secretions during exercise that play a role in cognitive

growth (Medina 2008).

Numerous studies have been completed on students in an effort to determine if there is, in

fact, a direct correlation between exercise, test scores, and GPA. According to Cressy (2011), it

was noted that college students who utilized the campus recreation center had not only a higher

GPA, but also more of a desire to learn and higher retention rates. Additionally, it was

discovered that college males who were active in sports or worked out on a regular basis were

4% more likely to graduate than non-athletes (Cressy 2011). A study involving middle and high

school boys and girls showed similar results. According to Fox, Barr-Anderson, Neumark-

Sztainer, and Wall (2010), it was demonstrated that middle school boys, high school boys, and

8

high school girls had significantly higher GPA than non-athletes. Middle school girls had no

significant data. This study was based on student athletes only and not students who chose to

exercise on their own time, so there has been some debate about whether it is the sports team

participation itself or the actual physical activity that is correlated with the improved GPA in this

case (Fox et al. 2010).

Although, Hillman, Castelli, and Buck’s (2005) experiment demonstrated that more fit

individuals had greater neurocognition. Twenty-four children and twenty-seven adults were

asked to push a button once they were subjected to various stimuli, such as a picture of a dog.

Their cognitive processing speed and latency was recorded. Physically fit adults had greater P3

amplitude than their peers, while physically fit children had greater P3 amplitude than other kids

who did not exercise (P.1971). P3 is an endogenous element of event related potential (ERP) that

occurs 300-800ms after the stimuli is initiated. The potential is produced when an individual

attempts to differentiate between the given stimuli. The P3 is measured in microvolts, and is

basically the brain electrical response to the stimuli. In addition to the P3 being evaluated, the

latency was also determined in this study. The latency is measured in milliseconds and reflects

the response time to a given stimuli. Therefore, the shorter latency indicates faster cognitive

processing speed. In this particular study, adults that participated in regular aerobic exercise had

greater P3 amplitude and faster latency.

It is apparent that there is a definite correlation between exercise and students having

higher test scores and GPA. There are various biological components that play a significant role

during and after exercise that aid in the development and growth of neurons in the brain. This

allows for better cognitive function, therefore resulting in students having better grades overall.

Students on sports teams are not the only ones to benefit from improved cognition. Individuals

9

who exercise regularly on their own time also have been shown to have improved cognitive

functioning. Although the social aspect of participating on a sports’ team may be motivating, the

extensive research demonstrates that the biological components aid in improved cognitive

functioning. Studies have been done at various universities on many students across the country,

and the results show that there is, in fact, a correlation between exercise and students having

better grades as a result. The factors that need to be further researched are the duration,

frequency, and specific types of exercise that need to be done in order to gain the cognitive

benefits.

Experimental Design:

In knowing the positive effects exercise has on the brain overall, I felt that it would be

beneficial to go further and analyze the effects that acute aerobic exercise has on the brain. In

order to do this, eight Aurora University students were selected on a voluntary basis from Dr.

Buckley’s Fitness and Health Promotion class. After the experimental design was approved by

the Institutional Review Board, students were informed by an informational consent form

acknowledging that there is minimal risk in participating in the experiment. The possible risks

included any form of injury that could occur by running on a treadmill, such as, pulling a muscle

or rolling an ankle. The students were also informed that they may quit participating in the

experiment at any time without penalty. Each student received his or her own copy to keep, and I

collected the additional copy to have on file.

The study took place in the Wellness Center at Aurora University. Four volunteers were

asked to remain sedentary and complete absolutely no physical activity the morning of their final

exam. The other four volunteers were asked to either ride a bike or run on the treadmill while

10

remaining in their target heart rate zone (65-80% of the max.) for forty-five minutes. Before they

began, they were asked to complete a demographics sheet stating their gender, age, BMI, target

heart rate zone, how many hours a week they perform aerobic and weight training exercise, as

well as some qualitative questions regarding exercise’s impact on cognition. Once everyone,

including the four sedentary individuals, completed the demographics sheets they were turned in

and no names were attached them for privacy. The four exercisers completed the physical

activity while the four people in the sedentary group did not perform any exercise before their

final exam. Everyone had thirty minutes to complete the cumulative final exam, and growth was

compared for each student from their individual midterm exams and final exam letter grades. See

data in Table 1 below.

Group Type Age Gender hrs/wk ex. hrs/wk wgt. BMI Targ. HR Athlete Midterm FinalExe. tread. 21 m 3 7 to 10 27.33 119-159 no A- Aexe. tread. 22 m 5 to 7 5 to 7 26 119-198 no C C-exe. bike 22 f 6 to 10 6 23.96 118-158 yes,CC B+ B-exe. bike 22 f 5 2 26.2 119-158 no A- B+non sed. 21 f 4.5 2.5 23.5 119.4-159.2 yes, soc A- Bnon sed, 21 m 3 3 25.5 119-159 yes,lacr. B- Bnon sed. 23 f 2 to 3 0 17.5 118.2-157.6 no C- D+

Table 1: Results demonstrating growth by one individual in the exercising category and one individual in the non-exercising category.

The outcome that I expected to see was that the individuals who exercised before their

final exam would demonstrate greater growth from their midterm to final exam grades. This was

not the case, and my hypothesis had been false. Some possible variables and factors that came

into play that could be improved is the small sample size, the amount of time the individuals

exercised for, lack of gender specificity, using two types of workout equipment, lack of

knowledge regarding students’ workout history, and lack of knowledge regarding what kind of

student the individuals were. The main variable was probably the small sample size. It is difficult

11

to gather significant data without having that much to examine. Also, with a larger sample size

statistical equations could have been utilized for more accurate data collection. Being that the

sample size was so small, qualitative data was also taken into consideration. Students were

asked, “After performing aerobic exercise, do you feel that there is a link between your own

exercise habits and the ability to complete tasks, such as writing papers or various homework

activities?” All eight students responded by saying that they feel aerobic exercise positively

impacts their exercise habits and their ability to perform on school work. Additionally, students

were asked, “Do you feel that aerobic exercise impacts your grades at all and benefits you

mentally and not just physically?” Seven out of eight students said “yes.” Putting quantitative

data aside and examining the qualitative data, it is evident that there is something to be said

about the physiological experience the students feel after exercise. There must be some sort of

correlation if they are all agreeing that aerobic exercise is beneficial to cognition and

productivity.

During exercise, there is a surge of neurotransmitters and hormones that positively

impact the brain, improving memory and reaction time. This has been demonstrated repeatedly

in lengthier studies, and the idea here is that these chemicals help to mold the brain and increase

dendritic expansion and interconnections, thus improving memory, attention, and reaction

capabilities. There is no solid evidence stating that it takes time, though, for these chemicals to

manipulate brain structure. In fact, it is very likely that these effects are immediate. Further

studies similar to this one have the potential to prove that acute exercise has a definite positive

effect on brain function, especially in regions involving memory and attention. If solid evidence

is demonstrated, it is very likely that there would be a great change in the academic curriculum in

12

school systems. This is the reason why this experiment is so significant, and I would thoroughly

enjoy continuing this type of research.

13

References

Castelli, D.M., Hillman, C.H., Buck, S.M., Erwin, H.E. (2007). Physical fitness and academic

achievement in third-and fifth-grade students. Jouirnal of Sport and Exercise Psychology.

29,239-252.

Cressy, J. (2011). The roles of physical activity and health in enhancing student engagement:

implications for leadership in post-secondary education. College Quarterly, 14(4).

Fox, C. K., Barr-Anderson, D., Neumark-Sztainer, D., & Wall, M. (2010). Physical activity and

sports team participation: associations with academic outcomes in middle school and

high school students. Journal Of School Health, 80(1), 31-37.

Gligoroska, J.P. and Manchevska, S. (2012). The effect of physical activity on cognition-

physiological mechanisms. Mat Soc Med. 24(3): 198-202.

Hillman, C., Castelli, D.M., Buck, S.M. Aerobic fitness and neurocognitive function in healthy

preadolescent children. (2005). Official Journal of The American College of Sports

Medicine.

Katch, V.L., McArdle, W.D., Katch F.I. (2001). Essentials of Exercise Physiology. Fourth

Edition. Baltimore: Lippincott Williams & Wilkins.

Knaepen, K., Goekint, M., Heyman, E.M., Meeusen, R. (2010). Neuroplasticity- Exercise-

induced response of peripheral brain-derived neurotrophic factor. Sports Med. 40(9), 765-

801.

Medina, J. (2008). Brain Rules. Seattle: Pear Press.

14

Ploughman, M. (2008). Exercise is brain food: The effects of physical activity on cognitive

function. Developmental Neurorehabilitation. 11(3), 236-240.

Ratey, J.J. (2008). Spark. New York: Little, Brown and Company.

Tomporowski, P. D., Davis, C. L., Miller, P. H., & Naglieri, J. A. (2008). Exercise and children’s

intelligence, cognition, and academic achievement. Educational Psychology Review,

20(2), 111-131.