The Movement Paradox:
5 Ways Exercise Unexpectedly Moves Us
Paradox is a pervading and inescapable fact of life: “the more I learn, the less I know”, “The only constant is change”, “more options make it harder to choose”. When we see past the surface of these apparent contradictions and penetrate to the core of their meaning, we access a deep well of knowledge and understanding. Metabolic processes that happen when we exercise, seem to be one of life’s paradoxes. How does using up energy give us more? How does imposing stress on our bodies make us more adaptable? How does a changing brain create rigidity?
Mechanisms of action, both innate and acquired, work constantly within us whether we are aware of them or not. Electrical, chemical, physical and responsive. What happens when we move our bodies, especially for long periods of time or at higher intensities, plays a huge role in how we respond and adapt to stressors, concrete or percieved. In this article, we will take a look at 5 ways movement of our physical form changes our biochemistry and electrical wiring. Later blog posts will further investigate each point individually.
1) More stress hormone=less stress
Cortisol is a hormone released by the adrenal glands when there is a threat, or stressor. Its main job is to create fast fuel by breaking down proteins into glucose and mobilizing fatty acids from fat cells. Considering our body’s “fight or flight” response to stress, this adaptation makes sense. We need immediate energy to be able to react to the impending danger. When we exercise, we impose a stressor upon the body therefore increasing cortisol levels.
Here, we have our first apparent paradox. More cortisol leads to less stress. Here’s how:
The release of cortisol when we exercise actually triggers the adrenal glands to, over time, stop releasing the hormone through something called a “negative feedback loop”. The hypothalamus, a structure in our brain, is the powerhouse behind this whole operation by starting or ending the chain of reactions necessary for cortisol release. When the hypothalamus senses stress, it releases a hormone that triggers a chain of events leading the release of cortisol. When levels are high, like when we are training intensely, the process is reversed and the hypothalamus triggers a chain of events that stops cortisol production and release. By exercising and allowing this piece of our stress response to run its course, we not only metabolize our excess cortisol but make our bodies better at responding to high levels of cortisol, in and out of the training room.
2) The Plastic Paradox
Synaptic plasticity is a term that refers to the changes that can occur to a nerve cell or at a junction between nerve cells. It can occur by neuron literally changing shape to better fit a stimulus (like the presence of a certain hormone), or by the improving the timing of impulses between nerve cells. Plasticity controls how effective cells are at reacting and communicating with each other (ever heard the term “cells that fire together wire together”?). Physical activity effects plasticity in several ways.
One way we increase the plasticity of our neurons is by the increased sophistication of movement. By training sophistication, we challenge our nerve cells to do their job more efficiently by creating new motor pathways and communicating with greater efficiency, therefore increasing plasticity.
Another way movement changes how our brain cells communicate is through the activity that occurs in the hippocampus, an area of the brain responsible for memory consolidation, response inhibition and spatial processing. When our bodies are moving, especially for longer bouts of time, the circuitry of the hippocampus shifts to longer, slower electrical waves, a phenomenon known as “hippocampal theta” in which several plasticity-related events occur. I will explore this process in more depth in a later post, but for now, just know that in a state of hipoccampal theta, the deep layer of your brain becomes better at doing its jobs and better at communicating with other part of the brain.
This leads us to something called “the plastic paradox”, in which the flexibility and changeableness of our neurons actually lead to more rigid behaviors. When cells that “fire together wire together”, neural pathways are created which subsequently get used again and again, like a river taking the path of least resistance down a mountainside. When we input novel stimulus (ie, sophistication of movement or a state of hippocampal theta), we suggest the possibility of new pathways that, when used often, become ingrained and routine. Our cell’s changing nature leads to stronger pathways-plasticity providing rigidity.
3) Transient Hypofrontality: Shutting down the brain helps it function better
Transient hypofrontality is a fancy term that basically means that your prefrontal cortex, the front part of your brain responsible for higher cognitive function like decision making and problem solving, literally shuts off, or at least decreases its electric activity. Shutting down that forebrain dampens nerve responses corresponding to anxiety and hyper-productivity and actually leads to more activity and connection in other parts of the brain. When we enter this state of transient hypofrontality (what we call “flowstate”, which I’ll get more into in later blog post) we enter a state of effortless action, losing our ego and sense of time, and become completely immersed in the task at hand. This not only gives our overloaded prefrontal cortex a break, but also allows access to other networks of our brain (network=different brain areas working at the same time). Sustaining transient hypofrontality during a bout of physical activity, we are paving the way for more creative problem solving, accessing the WHOLE of our brain, rather than just our “control panel”, or prefrontal cortex. The paradox of “off” creating “more on”.
4) Using up energy gives you more energy
Exercise can help you rest in more ways than wanting to jello-leg it to the couch after a run. The chemical cocktail released when we move our bodies for long periods of time or with increased intensity is highly related to healthy sleeping patterns.
First let’s look at seratonin, a neurotransmitter produced mainly by the small intestine but also partly in a section of our brain stem. Seratonin is most widely known as a “happy hormone”, due to its link to depression, but its actual functions range much farther than simply boosting mood. It aids in digestion, blood clotting, memory, behavior modulation, appetite, sexual function and….you guessed it! SLEEP! Seratonin is actually a precursor for melatonin--a hormone that calms the body and prepares it for sleep as levels rise when it gets dark outside. Through various chemical processes, seratonin is a step in the melatonin-making process. Exercise induces production and release of seratonin into the blood stream, which in turn helps us with our melatonin production, regulation, and thus our sleep patterns.
Another chemical component of sleep induction is cortisol. In a healthy individual, cortisol levels in the blood stream are highest in the morning and decrease throughout the day. In modern life, many people have irregular levels of cortisol because our bodies are under constant perceived stress. As discussed in point number one, physical activity helps our bodies metabolize that cortisol and get our systems better at regulating cortisol levels. In doing so, we return to our natural rhythm and become more capable of metabolizing the cortisol in the blood stream when it does spike and generally less responsive to stressful triggers, so there is less cortisol release to begin with when those stimuli occur.
Beyond making us tired by expending excess energy in the form of calories, exercise also helps our sleep by regulating our hormone cycles related to it. While expending more energy, we feed mechanisms that lead to more restful nights, including melatonin production and natural cortisol rhythms.
5) “Feeling the Burn” Relieves Pain
Runner’s high is more than just a clever euphemism, it’s a real state in which physical activity effects the brain’s opiod receptors. Endorphins, and similar hormones, are endogenous opiods, or morphine-like substances that the body produces itself. The brain is your own personal natural in-home pharmacy (completely free of charge, might I add). Like cortisol, these hormones are released in response to stress. The effects of these endogenous opiods latching onto their corresponding receptors are pain relief, reduced anxiety, increased mood and enhanced pleasure. So by inducing a temporary state of “pain”, or physical stress (ie, exercise), we help create the hormones that help us feel less pain.
Through physical activity, we modify our internal environment to work more efficiently, with us and for us. The mechanisms at play behind these modifications seem, at first, paradoxical--events that seemingly detract from capability, in turn make us stronger and more capable of adaptation. Modulating our stress response, increasing plasticity, rewiring the brain, helping us sleep and relieving our pain are all ways that exercise makes us better at being human. It is within paradox that we find a middle path in life, a way of being that takes the “bad” and “good” out and observe the process of what is. We are what we repeatedly do, and by repeatedly allowing the systems of our body to run their course we fortify our innate capacity to respond, regulate and recover.
Thanks for reading,
“The Effects of Acute Exercise on Cognition, Neurophysiology, and Neurochemical Pathways”. Basso, J.C., Suzuki, W.A. https://static1.squarespace.com/static/5651cdc8e4b03de1aca6c145/t/5a944ee9f9619a83af8d6385/1519668971239/Basso_Suzuki_2017.pdf
“How to Measure the Psychological ‘Flow’? A Neuroscience Perspective. Cheron, G. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5138413/
“The Neuroscience of Flow”Cheruvu, R. https://www.researchgate.net/publication/325273409_The_Neuroscience_of_Flow
“Neurocognitive Mechanisms of the Flow State” Harris, D.J., Vine, S.M., Wilson, M.R. https://www.researchgate.net/publication/318665014_Neurocognitive_mechanisms_of_the_flow_state
“The Mystery of Serotonin: Can it Really Make you Happy? Major, C. https://www.developinghumanbrain.org/serotonin-mystery/
“What is the Function of Hippocampal Theta Rhythm? Linking Behavioral Data to Phasic Properties of Field Potential Unit Recording Data” Hasselmo, M.E. https://www.ncbi.nlm.nih.gov/pubmed/16158423
“What are Endorphins?” Scheve, T. https://science.howstuffworks.com/life/inside-the-mind/emotions/endorphins2.htm