How you can control stress and improve your brain

By: Extract from Stop Talking and Start Influencing by Jared Cooney Horvath PhD

People often use the terms 'emotions' and 'feelings' interchangeably. But believe it or not, these two words refer to two very different things. Emotions are the physical sensations that occur throughout the body in response to a particular moment or event. Driven by internal chemicals, emotions are things like butterflies in the stomach, tingling of the skin, shortness of breath, etc. Feelings, on the other hand, are the psychological interpretation of these bodily sensations.

Driven by subjective perception, feelings are the mental experience of physical emotions. Because this can be somewhat confusing, let's dig a bit deeper. Emotions are mediated by two small structures located deep within the brain: the amygdala and the hypothalamus. The amygdala receives signals from each of our seventeen senses (!) and uses these to select an emotion relevant to each situation. The hypothalamus, in turn, triggers the release of chemicals into the body to manifest that emotion. For instance, if you were surrounded by snarling wolves, your amygdala would subconsciously analyze the situation and might select the emotion 'fear'. Your hypothalamus would then release chemicals into your body to speed up your heart rate, dilate your pupils, shorten your breathing, etc. These physical sensations are the emotion of fear.

Interestingly, there are only so many chemicals our bodies can produce. For this reason, many researchers believe that the amygdala/ hypothalamus combination can really only generate six basic emotions. Once you recognize that we have a rather limited set of fundamental emotions (joy, fear, anger, surprise, sadness, and disgust), a question arises: where does everything else come from? Humility, nostalgia, embarrassment, jealousy … how do these manifest?

This is where feelings come into play.

Although the body may be restricted in how it can respond to the world, there is no limit to the ways in which we can mentally interpret these physical sensations. Returning to the example above, depending upon your prior wolf knowledge and experiences, you might interpret your racing heart negatively (leading you to feel scared, anxious, foreboding), positively (excited, exhilarated, intrigued), actively (enraged, furious, frenzied), passively (resigned, abandoned, powerless) or any combination of these.

Put simply, thanks to mental interpretations, the six basic emotions can give rise to a nearly infinite array of feelings.

Here's the most important part: the relationship between emotions and feelings is a two-way street. In other words, psychological interpretations can feedback to and alter physical sensations. For instance, if you interpret the wolves as threatening, this mental label can cause the release of additional chemicals that further speed up your heart rate. Conversely, if you interpret the wolves as funny, this mental label can cause the release of different chemicals that slow down your heart rate. In other words, feelings can exacerbate or diminish emotions.

So what?
This is all well and good, but what does any of this have to do with stress?

Simply put, stress is a feeling - not an emotion. For an event to be stressful, it must be psychologically interpreted as such.

Some people parachute out of an airplane, get a rush of chemicals (adrenaline, endorphins, etc.) and interpret this as 'excitement'. This feeling will feedback, alter the chemical flow and generate specific physical and mental changes. Other people parachute out of an airplane, get exactly the same rush of chemicals (adrenaline, endorphins, etc.), and interpret this as 'stress'. This feeling will feedback, alter the flow of chemicals in a different way and generate different physical and mental changes. Same situation, same chemicals, same physical sensations - but the interpretation changes everything.

To understand the impacts of stress there are several key players we must become acquainted with.

Hippocampus: The gateway to memory. Composed of billions of specialized cells called neurons that process new information and lead to the formation of new memories.

Amygdala: The selector of emotions. Heavily connected to and in constant communication with the hippocampus.

Cortisol: The primary stress hormone. In the body, it elevates blood sugar and regulates blood pressure. In the brain, it kills neurons within the hippocampus.

Norepinephrine: A secondary stress hormone. In the body, it increases heart rate and respiration. In the brain, it alerts the amygdala that cortisol is present.

ARC-proteins: Activity-regulated cytoskeleton-associated proteins. Developed in the amygdala, they have two jobs: to combat cortisol and to strengthen neurons.

FGF2: Fibroblast growth factor 2. These proteins lead to the growth of brand new neurons.

Sudden and short-lived stress
Sometimes stress can be sudden, acute and short-lived. For instance, those ten minutes before you step on stage to deliver a presentation. During these periods of short-term stress, here's what happens:

1. When stress begins, cortisol floods into the hippocampus and begins attacking neurons.

2. This attack triggers the release of norepinephrine which flows into the amygdala, signaling the need for back-up.

3. The amygdala releases ARC-proteins into the hippocampus. These proteins begin to combat cortisol.

4. The battle between ARC-proteins and cortisol triggers the release of FGF2.This protein embeds itself throughout the hippocampus.

5. As the stressful situation draws to a close, cortisol flees the hippocampus and ARC-proteins begin repairing the damaged neurons, making each thicker and stronger than before the battle.

6. Approximately two weeks later, FGF2 comes to fruition and new neurons sprout throughout the hippocampus. These neurons immediately take up the task of processing new information (learning).

First, during short-lived stress, ARC-proteins strengthen neurons within the hippocampus leading to the formation of deeper memories for that moment. It's as if ARC-proteins tell the hippocampus, 'Whatever caused that cortisol release must be important; please remember it.'
In addition, moderate stress triggers the release of FGF2 which leads to the formation of new neurons in the hippocampus.

Unfortunately, these neurons take about two weeks to sprout.

So how does this improve learning?

In the short-term, it doesn't. If you experience moderate stress today, this might improve your learning two weeks from now but will do nothing for the present moment. However, in the long-term, this process begins to make sense.

If you experience moderate stress every day (triggered by errors, failed predictions and unexpected events) you will have new neurons sprouting all the time. Since these new neurons are dedicated to processing new information, general learning will be greatly enhanced.

Prolonged Stress
Sometimes stress lasts for a prolonged period. For instance, if you've got 30 days to complete an important project, you might spend weeks worrying about the impending deadline. During these periods of long-term stress, here's what happens:

When stress begins, cortisol floods into the hippocampus and begins attacking neurons.

1. This attack triggers the release of norepinephrine which flows into the amygdala, signalling the need for back-up.

2.The amygdala releases ARC-proteins into the hippocampus. These proteins begin to combat cortisol.

3. The battle between ARC-proteins and cortisol triggers the release of FGF2. This protein embeds itself throughout the hippocampus.

4. As the stressful situation continues, more cortisol is pumped into the hippocampus. Eventually, stores of ARC-proteins run dry and cortisol begins killing neurons once and for all.

5. As neurons die, stores of FGF2 run dry and no new seeds are planted. Cortisol continues killing neurons and, since no new ones sprout to take their place, the hippocampus begins to wither away.

Here's why high stress can impair learning.
As ARC-proteins and FGF2 die away, cortisol has free reign to damage and destroy our gateway to memory. To make matters worse, as the hippocampus withers away our ability to access previously formed long-term memories becomes impaired. This means that prolonged stress not only makes it difficult to learn new information, but also cuts us off from old information learnt in the past.

Although this process might seem illogical, it actually serves an important purpose. Imagine you're trapped in a very bad situation and have no way to escape - say, stuck in a bear-trap deep in the woods and help won't arrive for three days. In this instance, you don't really want to make deep, vivid memories. Rather, seeing as you're helpless and there's no continuous lesson to learn, it makes far more sense to block out as much negativity as possible and simply survive until the ordeal is over. This is what the long-term stress response does: it helps prevent memories from forming during helpless situations.

However, rarely in the modern world do we get stuck in bear traps. More often than not, we experience prolonged stress within our jobs, families and responsibilities. In these instances, the long- term stress response can prove a dangerous liability leading to lost jobs, conflicting families and shirked responsibilities.

One last thing
We've learnt why high stress can be bad and why moderate stress can be good, but how could no stress be just as bad as excess stress?
In the absence of stress, cortisol does not flood into the hippocampus. In the absence of ARC-proteins, FGF2 is not released and new neurons do not form. In other words, without stress, all those chemicals that bolster memory and facilitate learning simply lay dormant. This means that in a perfect world without errors, failed predictions or unexpected events, the hippocampus slips into pause mode.

Although this might not sound horrible, it's important to remember that everything degrades with time. As such, the longer the hippocampus remains on 'pause', the more susceptible it becomes to the natural ravages of time. Without ARC-proteins, neurons within the hippocampus will naturally deteriorate and die away.

Similarly, without FGF2 no new neurons will be formed to replace the old. As neurons fade away, so too does our ability to remember and learn.

'Wait … is stress the secret to keeping my brain healthy and active?'

In a manner of speaking, yes.

Novelty is one of the primary ingredients for keeping the brain agile and responsive. Each time you undertake a new activity, learn a new skill or dive into a new situation, this leads to moderate levels of stress. As we learnt earlier, moderate stress experienced every day can lead to a steady flow of FGF2 and the continual growth of new neurons within the hippocampus. Since these new neurons process new information, they (in essence) are what keep us learning and growing.

Don't worry about brain training games (they will only make you better at chunking information within each game). Instead, try new and scary things. Take up an instrument. Learn a new language. Try cooking a new dish. Continually jumping into novel, unpredictable situations will increase your chances of keeping your mind flexible and your memories active.
Just remember not to take any new activity too seriously. Once you begin feeling excess anxiety or undue pressure, it's time to move on. When playing with stress, there is a fine line between helping and harming your brain.

Employ physical and mental de-stressing techniques

Seeing as emotions are physical, many primary de-stressing techniques directly target the body. The concept is simple: if you can change the chemicals, you can change the emotion.
Arguably the best (and easiest) example of this is deep breathing. As you inhale, receptors in your lungs trigger the release of a chemical that slows the release of cortisol and norepinephrine. As you exhale, different chemicals are released that slow heart rate and reduce blood pressure. After a short time, those physical sensations commonly interpreted as 'stress' are gone and a new interpretation (feeling) can emerge.

Another example is called progressive muscle relaxation. In a nutshell, this technique is the systematic tensing, holding and releasing of different muscle groups. As each muscle group is tensed, that physical effort burns off excess cortisol within the body. As each muscle group is relaxed, blood pressure drops and heart rate slows. To experience this sensation, simply make a really tight first with your right hand, hold it for five seconds, then release and relax it.

Again, after a short time, the physical sensations of stress will disappear and a new interpretation can emerge.

Importantly, as we learnt earlier, feelings can feedback on and influence emotions. As such, there are many secondary de-stressing techniques that directly target the mind. Meditation; mindfulness; exposure therapy.

The main goal of these mental de-stressing techniques
is not to stop the physical sensations of stress from occurring; it's to re-frame and re-build interpretations. The idea is that if you can re- label stressful emotions as exciting, intriguing or funny (or if you can remove every label full-stop), this will shift the chemical response of your body.


Moderate stress can boost memories and general learning (though high stress and no stress can be detrimental).

  • Emotions are physical sensations within the body.
  • Feelings are mental interpretations of these physical sensations.
  • Stress is a feeling, not an emotion.
  • During moderate stress, ARC-proteins support neurons in the hippocampus (boosting memory) and FGF2 grows new neurons (boosting learning).
  • During high stress, cortisol kills neurons and the hippocampus withers.
  • During no stress, neurons naturally degrade and the hippocampus withers.

  • Leverage emotional shifts to boost memory.
  • Mix up activities to maintain moderate stress.
  • Novelty is one of the best tools to maintain brain health and flexibility.
  • Beware of emotional state dependency.
  • Safety first.
  • Employ physical and mental de-stressing techniques.

    Stop Talking, Start Influencing is available from
    and wherever good books are sold.

    Jared Cooney Horvath PhD, MEd is a neuroscientist and educator with expertise in human learning, memory, and brain stimulation. He has conducted research and lectured at Harvard University, Harvard Medical School, the University of Melbourne and over 50 international schools. Jared currently serves as director of the Science of Learning Group and NeuroEducation: two teams dedicated to bringing the latest in brain and behavioural research to education and business alike. His work has been featured in numerous popular publications (including the New Yorker, the Economist, the Atlantic, the New York Times, Scientific American, New Scientist, WIRED, VICE, and Men's Journal) as well as television and radio programs (including NOVA: Science Now and Catalyst).


    Mar 10 2019 8:46AM
    This is very interesting. I need to stress myself a bit to digest it all :) Thanks for your newsletters Judy. They are always read. I have been receiving them since the workshop you ran in the Southern Highlands at Werai on how to use your food scraps. Life enhancing.
    Comment by: Athalie
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    Athalie on How you can control stress and improve your brain :
    This is very interesting. I need to stress myself a bi... »
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