eSOM
The Road to D, or the Story of Singularity High School (SHS) and Cowa
2025.07.16
eSOM: The Road to D (34) Stress, Flow’s Greatest Enemy Part 2
1
The brain is equipped with a “brake pedal” in the hippocampus and prefrontal cortex, which alleviates stress responses and prevents excitement and panic attacks.
In contrast, the amygdala can be seen as the brain’s “accelerator.”
Brake 1: Hippocampus
The hippocampus is well-known as the “center of memory,” but it also plays a role in reducing stress (pp. 68-69).
Q Coro, how does the hippocampus reduce stress responses?
A ”The hippocampus contains abundant receptors for cortisol (glucocorticoid receptors). When cortisol binds to these receptors in the hippocampus, the hippocampus sends negative feedback to the hypothalamus, suppressing the secretion of CRH (corticotropin-releasing hormone). This inhibits the excessive release of cortisol and calms the activity of the HPA axis.”
“Hippocampal cells die when exposed to excessive cortisol” (p. 70).
“If the amygdala continues to trigger stress responses over a long period, the hippocampus’s brake wears out. Then, the amygdala, which is the accelerator, runs wild when the hippocampus shrinks and its brake becomes ineffective. This leads to a vicious cycle where stress generates more stress” (p. 71).
“This is the mechanism by which stress prolongs and becomes chronic. The damage to the brain from long-term stress is due to this vicious cycle” (p. 71).
Brake 2: Frontal Lobe
“…the anterior part of the frontal lobe, called the prefrontal cortex, controls higher cognitive functions. For example, it is literally a ‘noble place’ that suppresses impulses and performs abstract and analytical thinking. When feeling stressed, the frontal lobe works to prevent emotions from running wild and to prevent irrational behavior” (p. 76).
“The anterior part of the frontal lobe, the ‘prefrontal cortex,’ is the ‘brain’s command center’ as a source of Computational Thinking (CT).”
Like the hippocampus, the frontal lobe, which acts as a “brake,” also atrophies (shrinks) due to stress (p. 77).
Q. Coro, similar to the hippocampus, what is the mechanism by which the frontal lobe also shrinks due to stress?
A This is also due to an increase in cortisol secretion, similar to the hippocampus. More specifically, in the case of the frontal lobe, as with the hippocampus, the glucocorticoid receptors (GR) within it work to suppress cortisol in the HPA axis (negative feedback). However, if GRs continue to be overly active, it leads to the death of the cells that make up the frontal lobe, similar to the case of the hippocampus.
2
Just like with a car, the brakes (hippocampus, frontal lobe) wear out (shrink) with use.
Exercise (running/walking) minimizes this wear (shrinkage) and can even upgrade them to more sophisticated brakes.
Let’s look at the hippocampus first.
Exercise and the Hippocampus Relationship 1: Suppression of Cortisol Secretion
“If you are exercising regularly, your cortisol secretion will only slightly increase even when you are stressed by things other than exercise,” (p. 73).
“In other words, exercise trains the body not to overreact to stress” (p. 73).
“By actively moving the body, resistance to stress increases” (p. 73).
Exercise and the Hippocampus Relationship 2: Activation of Anti-Stress Neurons
When you exercise, new nerve cells (neurons) are born in the brain. (We will learn more about this in Chapter 5, “Maximizing Memory Power.”)
New neurons, like infants, are very active, stimulating brain activity and consequently amplifying stress. However, among the new neurons built through exercise are anti-stress neurons called “GABAergic neurons” (the “neuron nannies”), which suppress the excessive activity of other new neurons.
GABA = Gamma-aminobutyric acid, an amino acid (p. 55)
“GABA plays a ‘brake’ role, suppressing brain activity and preventing changes” (p. 55).
“Neuron nannies” release GABA.
“Neuron nannies” are mainly produced in the hippocampus (the area responsible for controlling emotions and calming anxiety).
Exercise leads to the building of “neuron nannies” in the hippocampus.
The GABA released by these neurons assists the hippocampus’s function as a “brake against the amygdala (accelerator)” by reducing the secretion of cortisol (stress substance).
3
So, how does exercise improve the “effectiveness” of the “other brake (frontal lobe)” (i.e., control the runaway amygdala/accelerator)?
Exercise and the Frontal Lobe Relationship 1: Activation of Blood Flow and Building of New Blood Vessels by Exercise
“Actively moving your body increases blood flow to the brain. A large amount of blood immediately flows to the frontal lobe, promoting its function. Furthermore, continuing exercise over the long term eventually creates new blood vessels in the frontal lobe, increasing the supply of blood and oxygen, and thereby effectively removing waste products” (p. 79).
Exercise and the Frontal Lobe Relationship 2: Strengthening the Link Between the Frontal Lobe and Amygdala
Exercise strengthens the cooperation between the frontal lobe and the amygdala, allowing the frontal lobe to control the amygdala more efficiently (p. 79).
Exercise and the Frontal Lobe Relationship 3: Growth of the Frontal Lobe Through Exercise
“If you continue to exercise regularly, the frontal lobe will even physically grow, although it takes a long time” (p. 79).
Thus, the brain originally has “brakes” (hippocampus, frontal lobe) to alleviate stress, and running/walking enhances their “effectiveness” while reducing their “wear” (“the brain has a pre-programmed mechanism to calm stress”) (p. 81).
Beyond this, “brakes” exist outside the human body that alleviate stress.
These are “anxiety medications (diazepam, oxazepam, rohypnol, Xanax, etc.)” and alcohol.
These two “external brakes” alleviate stress in the same way.
Through GABA, which assists “Brake 1 (hippocampus)” by reducing the secretion of cortisol (stress substance).
Both anti-anxiety medications and alcohol strengthen the action of GABA (a neurotransmitter, gamma-aminobutyric acid), indirectly reducing the secretion of cortisol (stress hormone) and thus alleviating stress.
GABA, which appeared in “Exercise and the Hippocampus Relationship 2: Activation of Anti-Stress Neurons” above, is described in The Real Happy Pill as “a paradoxical entity in terms of exercise’s effects on the brain.”
Why is it a “paradoxical entity”?
Because while GABA alleviates stress by suppressing cortisol secretion and preventing brain shrinkage due to stress, it is also “a nuisance that inhibits brain growth” (p. 82).
As stated, “GABA plays a ‘brake’ role, suppressing brain activity and preventing changes” (p. 55), meaning it also acts as a “brake on brain growth.”
However, unlike running/walking, which is almost entirely beneficial for the brain, anti-anxiety medications and alcohol can cause serious damage to the brain and body.
While we’ll learn more about this in “Health” class, let’s keep the following in mind here:
“…if you try anti-anxiety medication even once, there’s a risk that your brain will crave it. Moreover, the brain quickly adapts to the drug, and even if the period of medication is short, the amount that initially provided relief will no longer be enough. To achieve the same effect, the dosage must be increased, which can lead to drug dependence.
…In addition to medication, there is another substance that has an astonishing effect in eliminating stress and anxiety and carries a very high risk of addiction: ‘alcohol'” (p. 81).
4
Just as GABA has both good and bad aspects in brain construction, stress itself also has good aspects, not just bad ones, in brain construction.
First, stress plays a role in sharpening nerves and increasing concentration (p. 66).
However, when that stress becomes excessive, “instead of increasing concentration, thinking becomes confused” (p. 66).
Stress also has the benefit of avoiding danger in the form of fight or flight (pp. 91-99). However, if it goes too far, “amygdala hijack” occurs (pp. 99-100).
The Real Happy Pill‘s conclusion is that to minimize these negative aspects of stress and maximize its positive aspects, one should activate the functions of various brain regions through exercise and increase the brain’s resilience to stress (pp. 100-109).
Finally, The Real Happy Pill makes a very interesting point about the benefit of controlling cortisol (anxiety-inducing substance) through exercise.
Cortisol is said to have the “effect of hindering the burning of body fat.”
In other words, optimizing cortisol secretion through exercise not only directly contributes to brain construction but also greatly contributes to the construction of the entire body, which is essential for brain construction.
(To be continued)
