The Power of Running - The mind and biological processes that actually occur when you run.

Most of us know that running is a powerful tool for the mind and body, we understand that aerobic exercises are anti-depressive and can decrease levels of anxiety, most of us know also know that aerobic exercise, such as running, increases our level of fitness, but unfortunately, that is the cap to most peoples knowledge of aerobic exercises, most people get their information from short form videos such as TikTok or Youtube Reels, and I believe that these videos do not delve deep enough into the benefits and drawbacks of aerobic exercise, and so in this article, I will attempt to succinctly answer the questions that often come to my mind when I think about what aerobic exercise actually does to the body and mind. To do this, I am going to use running as my example aerobic exercise. I will do so using scientific language, but I will try to make sure that is understandable to every reader, scientific background or not. This article is for the curious people out there that dare to understand more.

What actually occurs biologically in the brain when we run?

when we run, a plethora of ubiquitously known things happen, such as the release of endorphins in the brain, the increased heart rate which pumps more oxygen to every blood vessel in the body and increased energy production. All of these things lead to the numerous health benefits of running that we know, such as increased mood and higher levels of aerobic fitness. So, now we know what happens when we run. Let's see if we can find out why these things happen when we run. Endorphins are endogenous opioids (endogenous means that they are produced within the body) that are released from the pituitary gland in the brain. Endorphins, just like other opioids that one gets exogenously, such as morphine or heroin, bind to opioid receptors such as the Mu - opiate receptor (a large opiate receptor in the brain) and produce feelings of euphoria and pain relief. (These feelings are known as analgesia). This is because when these endorphins bind to the opiate receptors in the brain such as Mu, it triggers a conformational change in the opiate - receptor structure. A change in structure triggers an intracellular cascade of reactions that eventually produce one key effect. The inhibition of the neurotransmitters that signal pain in the body such as substance P. Imagine dominoes, where one falling domino causes the next domino to fall and so on and on, the intracellular cascade of reactions is very similar to that. Substance P has its benefits for detecting when we are in pain, however, when we are running, feeling this pain is negative. Evolutionary speaking, early primates that could not inhibit the production of substance P, stopped running at earlier times and potentially lost out on opportunities to find food, thus increasing their chance of death before reproduction. Potentially an example of natural selection. This also explains why, depending on the length of the run, and once your body has become used to running. We tend to feel the pain of the run after we stop running. So we know how endorphins mediate pain relief, but how to they produce feelings of Euphoria? Well, so far, what we have looked at (substance P) occurs in the peripheral nervous system of the body. However, we have not looked at the central nervous system of the body. When we run, the neurotransmitter that is inhibited by endorphins binding to their opiate receptors such as Mu, is a called gamma - aminobutyric acid (GABA), and the supression GABA results in production of dopamine, a neurotransmitter that is associated with pleasure, reward and motivation. On top of of this when we run, tryptophan, which is an amino acid that is needed for the synthesis of serotonin "the happy hormone" has a much higher availability for uptake into the brain. on top of this tryptophan persists after exercise. Essentially, the euphoria or "runners high" that we feel is all of that dopamine and serotonin mixed together in the brain. Despite this there is a lot of information out there, and the increase of dopamine and serotonin in brain from exercise is very complex, there have been some skeptics that doubt that serotonin is directly increased by exercise and unfortunately, scientists still have much to discover about euphoria, and how endorphins create dopamine and serotonin.

So, does cognition increase after consistent running? Can consistent running make us smarter?

The straight answer to this question "we don't know". Despite the fact that most people think they know that exercise increases cognition, when we look at the data from scientists and researchers, the story is a lot less clear cut than most of us might like to believe. A study done in 1987 evaluated the effects of aerobic exercise on runners short term memory. In the experiment, 24 college students of average cardiovascular fitness ran on a treadmill at a speed that corresponded to 80% of their VO2 max for 50 min. The participants completed a series of paired-associate memory tests immediately following exercise. Memory performances of the exercisers did not differ from those of a non-exercise control group. In another experiment done in 1995 young men were assessed and classified as having high or low fitness levels. Participants performed a 50-min cycling exercise regimen designed to be progressively more difficult every 10 minutes. A choice-reaction-time test and a test of concentration were administered during and following exercise and the exercise protocol turned out to have no effect on either measure and there were no substantial differences between the test performances of high and low fitness individuals. Conversely, there is evidence out there that suggests, with high levels of confidence, that exercise increases cognition. One of the main ideas that we can take away from running is that it increases neuroplasticity. Neuroplasticity refers to the brains ability to re-organize its structure and build new connections that are helpful for learning and memory. When we are children our brain is most plastic, thus we can pick things up extremely quickly and learn very fast. As adults, Our brain starts to become more structured, it becomes harder to re-organize our mind and harder to build new bonds and connections, thus making learning harder. That is where one of the main benefits or running, or any aerobic exercise comes in. When we run we trigger the release of various neurotrophic factors, such as brain-derived neurotrophic factor (BDNF). BDNF supports the growth and survival of neurons, creating an environment that allows for neuroplasticity.