How does physical exertion affect learning?

Many people aspire to be the next Elon Musk, Steve Jobs, Marie Curie, or Leonardo da Vinci. However unrealistic as it is to dream of becoming the next Jeff Bezos, what if there was a way to maximize the potential and efficiency of your brain functioning? To be able to learn what these history-makers learned? Would it be something you would try at a second's notice?

Although exercising cannot make you the next Isaac Newton, physical exertion is the answer to optimizing your brain to absorb new knowledge. Exercise does not improve learning directly - running a mile will not implant the cure for cancer in your brain. However, running that mile facilitates the neurochemical-rich environment for your brain to be equipped to discover the cure for cancer once you sit down.

Learning on the Neurochemical Level

Learning can be defined simply as the strengthening between neurons. The tighter the proximity between neurons, the smaller the synaptic gap. The smaller the synaptic gap, the faster the neuron fires. The more often the neuron fires, the healthier it is.

Looking at the mechanisms of action for learning, the synaptic gap is our home base. All of our ‘learning’ occurs as neurotransmitters are released into the synapse. The myelin sheath is our security system, it protects the axon of the neuron. The axon is our transportation system, if it is having an off day, our home base lacks efficiency because neurotransmitters cannot get where they need to go fast enough. If our axons do not get to fire neurotransmitters into the synapse, they die. The myelin sheath influences neuron firing rates greatly due to its envelope-like structure surrounding the axon like a sleeve. The thicker the myelin sheath, the faster the neurotransmitters move along the axon. Research has demonstrated that this ‘firing’ and ‘wiring’ of neurons is optimized when your neurotransmitters are balanced. To gain attraction between neurons to wire them closely together, the process of long-term potentiation (LTP) is triggered. LTP is the term used to describe the process of strengthening the infrastructure of the neurons through continuous stimulation.

Neurotransmitters are the most balanced and optimized during exercise due to the nature of physical exertion being a multifaceted experience involving many different moving pieces. Physical activity releases serotonin, norepinephrine, dopamine, 5-hydroxytryptamine, and others. Serotonin is broadly responsible for keeping brain activity under control (sleep, appetite, sex drive, pain perception). Norepinephrine is our mood regulator who also influences attention, perception, motivation, and arousal. Dopamine is considered the “learning, reward (satisfaction), attention, and movement transmitter” (Ratey, 2013). During physical activity, 5-hydroxytryptamine (5-HT) – which is vital in the chemical production of serotonin – increases significantly as an individual approaches their exertion threshold (Hu, 2015).

This is what a neuron looks like when it is active!

Protein Factors

At the neurochemical level, getting your heart rate up through exercise positively influences synaptic activity by releasing protein factors that help facilitate the optimal brain structuring to learn – IGF-1 (solidifies memory: fuel activation), VEGF (capillary building: fuel transport), FGF-2 (tissue growth: infrastructure) and most importantly, BDNF (synaptic plasticity: Miracle-Gro). A crucial benefit of exercise that typically is not understood well due to the lack of research in this specific area of the field, is how physical activity fosters our neuroplasticity.

Neuroplasticity, or synaptic plasticity, is our ability to form and reorganize synaptic connections that occur during learning. Through the work of these protein factors, the brain has the infrastructure in place to absorb information (create new memories) on a cellular level. Ratey described BDNF as the key to learning, “BDNF gives the synapses the tools they need to take in information, process it, associate it, remember it, and put it in context” (2013). Discovered in Carl Cotman's lab, BDNF levels in mice increased the farther that they ran. This discovery led to a cascade of new knowledge regarding exercise, BDNF levels, and how they tie together to impact learning. The brain flourishes with BDNF as a result of consistent exercise, which leads to a higher capability of efficiently learning.

Exercise Facilitates Brain Chemistry to Learn

More commonly known benefits of exercise include the strengthening of the cardiovascular system, fuel regulation, obesity reduction, stress threshold elevation, lifting mood, and boosting the immune system and motivation. A wise man once stated, ‘physical activity is cognitive candy.’ The brain, although only accounting for 2% of our body mass, uses 20% of the energy we produce, “your brain burns more energy at rest than a human thigh while running” (Nunez, 2020). When our brain uses energy (glucose) there is a production of free radicals that are left floating around. Through circulation triggered by physical exertion, oxygen acts as an electron magnet that clears out these free radicals by converting them into something useful. One of the primary reasons that physical activity benefits us so great is this increase in oxygen circulation. Exercise is also beneficial to the brain in the way that it increases blood flow. There is an increase in the delivery capability of glucose and oxygen to the brain via the bloodstream when our heart is beating more often.

The most vital snippet of information to understand is that the optimal time to learn does not occur during exercise. If we know anything about the prefrontal cortex, we know that it’s the boss. Its purpose is executive functioning. During exercise, blood is being pulled away from the prefrontal cortex to fuel the muscles which diminish executive functioning capability. Immediately after physical activity is completed, however, the energy flow will shift back to the brain, and peak information absorption and retention will occur. Physical activity generates the chemical foundation to optimally learn.

Dr. Wendy Suzuki in her TED X presentation ‘The Brain Changing Effects of Exercise’ explains how exercise benefits the brain immediately. Exercising increases levels of neurotransmitters that boost our mood, allow our attentional span to focus and shift efficiently and result in a quickening of our reaction time. These results are not only felt immediately but also linger for up to two hours. Exercise has also been identified as a useful tool in alleviating depression and anxiety symptoms at rates greater than prescribed medication because "in the prefrontal cortex, exercise shifts our self-concept by adjusting all the chemicals" (Ratey, 2013). When a person decides to go outside for a walk, the mental and physical benefits are endless.

Training, Overreaching, and Overtraining

Exercise, by nature, demands attention and focus. The purpose of training is to improve performance. Without causing a deliberate disturbance in homeostasis, performance would not necessarily improve. Most physically active individuals understand this concept of training (typically toward a goal that wants to be achieved). Intensifying training routines to enhance performance is a concept that has proven valid and reliable over time.

Yet once we pass the threshold of training, we cross into what is considered overreaching (OR). OR is the middle ground of the ‘overtraining continuum,’ yet is a strong point of contention due to the differing views on if it is a “relatively normal and harmless stage of the training process” (Meeusen, 2007). Functional overreaching (FOR), using a short training camp as an example, is supported because there is a result of 1) improved performance, 2) a short-term performance decrement (vs. a long-term performance decrement), 3) and some psychological stress (vs. a debilitating amount). If an athlete is overreached in an unhealthy way (non-functional overreaching (NFOR)), the amount of time needed for performance restoration would be outside of the characteristic 2-week window (Halson & Jeukendrup, 2004). Characteristics of the NFOR state are, “symptoms of prolonged training distress such as performance decrements, psychological disturbance (decreased vigor, increased fatigue), and hormonal disturbances will occur, and the athletes will need weeks or months to recover. Several confounding factors such as inadequate nutrition (energy and (or) carbohydrate intake), illness (most commonly upper respiratory tract infections), psychosocial stressors (work-, team-, coach-, family-related), and sleep disorders may be present” (Meeusen, et. al., 2007). Non-functional overreaching is fascinating when looking through the lens of learning because this is the stage where it is clear that too much physical exertion can negatively impact the ability to learn.

There has not been enough research completed to understand what specific areas of the brain are affected by the harsh consequences of overtraining (OT). But we do know that physical activity releases a plethora of neurotransmitters – serotonin, norepinephrine, dopamine, 5-hydroxytryptamine, and others. If the brain releases these during exercise, and even more at higher intensity, we can deduce that when an individual is overtraining or overtrained, they are releasing an unstable level of endorphins during physical activity. This large continuous depletion of neurotransmitters leaves the brain wiped out. There is nothing left to perform mental tasks well.

When looking at the relationship between exhaustion and learning, “exhaustion reduces the level of energy that is needed to perform cognitive tasks associated with learning…fatigue makes it difficult for learners to focus their available cognitive resources on the most relevant aspects of focal tasks” (LePine, 2004). Looking at this statement through the lens of exercise, it is extremely challenging to engage mentally when physically exhausted. Pushing ourselves physically, beyond the benefits and into the overtraining/burnout realm, simply depletes potential energy that could be used to grasp new cognitive information.

The Recommended 'Dose' of Exercise

Exercise is singlehandedly the most powerful tool we possess that can optimize brain function. Nevertheless, exercising for an hour a day seems like too great of an ask for most of the population. ‘I don’t have the time’ or ‘I’m focusing on other things right now’ are very common responses when asking individuals about their exercise habits. It seems as if society does not know that they have the power to be brilliant through a minor behavioral implementation.

A shocking statistic recently reported states that, “physical inactivity is estimated to cause 3.2 million deaths a year globally, making it number four on the list of risk factors” (Kamerow, 2015). This lack of physical exertion is detrimental to the brain. If we want to remain cognitively and physically intact as we age, we must continue to exercise and challenge the mind to grow. According to Ratey (2013), the recommended exercise regimen is aerobic exercise six days a week, 45-60 minutes a day, which is correlated to 5% of wake time spent on moderate and intense exercise. The CDC recommends 4 hours a week of physical activity. ‘Experts’ say that children and teenagers should get about an hour a day of physical activity, and adults should try their best to exercise for 2 hours (30-minutes of high-intensity) at minimum per week (Park, 2010). So who is right?

We know that being physically active helps everyone, however, exercise is not a ‘one size fits all’ entity. When we get our body moving and our heart pumping, we are providing ourselves with the necessary ingredients to live a long and healthy life. Working out releases endorphins that raise our energy levels and allow our bodies to function more efficiently. A small research study implementing a 3-month exercise regimen reported that there was a 30% increase in capillary volume in the hippocampus from the initial measure. When we are physically active, the brain grows!

Boiled down to the core message – exercise as much as you can. Don't know where to start? Go on a walk with a friend. To maintain adherence to exercise and get your brain working better, there are a few simple steps that are discussed by Ratey. First, start with low intensity (being able to hold a conversation while walking with a friend for an hour). Once one feels capable of doing so, the natural progression would be to move on to moderate-intensity exercise. This is when your body begins to tear things down to build them up again. Once comfortable with the workload of moderate-intensity, then the individual should try and incorporate high-intensity workouts into their training schedules. Only at this high-intensity level, the brain emits high levels of endorphins, ANP, endocannabinoids, and neurotransmitters.

The better your fitness level, the better your brain functions, and the better your brain functions – the more you can learn.

Application

To gain optimal brain function as a person, and as an athlete, the responsibility falls to coaches, athletes, sports psychologists, athletic trainers, and athletic directors (to name a few). Starting with those in control of making the training schedule, coaches should design training sessions towards learning at the forefront of their minds. After physical exertion, as previously stated, the brain has had the chemical foundation laid to be able to learn efficiently. Therefore, if within the coach's power, morning workouts before school are not too bad of an idea… at least if you ask a coach who can give you an educated answer about why exercising before using your brain is important. In addition to understanding the best times to exercise to encourage efficient brain functioning, coaches should know what intensity of physical activity is going to spark the release of endorphins and in what environment. If athletes practice in groups, are consistently challenged, and have a training regimen that dips into functional overreaching minimally for brief periods, they are set up for success both physically and mentally.

A clinical psychologist working with athletes would have the tools and credibility to make recommendations in regards to the athletes' lifestyle and training schedule. Overreaching is the realm in which a majority of collegiate-athletes reside – yet have no clue. The societal normalization of athletes being non-functionally overreached as a 'standard' to 'compete with the best' is devastating. If athletes were trained with optimal brain performance in mind, and the goal was to learn the most about their sport, there is no doubt that this approach would foster healthier, smarter, more focused, and physically fitter athletes. Sports psychologists have a deep understanding of how to respond to burnout and unnecessary training, but it must start with the education and understanding of all those involved in sport why health and wellness are the essential focus.

If we can societally grasp the neurochemical benefits of exercise and how exercise unlocks the door of learning, we will be able to answer questions that have plagued us for centuries. Simply making the cognitive choice to take a walk around the block before an exam ignites a chain reaction of neural firing that will immediately boost brain benefits, but also preemptively begin the journey of taking care of our future selves.

Now, do you believe your brain can change the world?