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Stress and the Brain

X-ray image of head in hands

X-ray image of head in hands (posteriori, iStockphoto)

X-ray image of head in hands

X-ray image of head in hands (posteriori, iStockphoto)


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Stress is more than a feeling. Understanding the importance of stress can help you to manage it. It can even lead to an improvement in your mood and how you think!

What is stress?

Studying for a big test, preparing for a job interview, or applying to postsecondary school are all stressful situations. But what does it actually mean to be stressed? Stress is more than a feeling. It plays an important biological role for many living organisms. Understanding the importance of stress can help you to manage it. It can even lead to an improvement in your mood and how you think!


The Upside of Stress (2019) Braincraft (4:36 min.).

What is the difference between stress and anxiety?

To understand stress as a biological process, it is important to know the difference between stress and anxiety.

Stress is a physical change that takes place in the body. It occurs because of different stress factors. Examples of stress factors include meeting new people or being physically threatened. Stress can be measured by measuring changes in the levels of stress-related hormones in the body. These hormones control human behaviour in response to a specific stress factor. 

For example, imagine you are playing laser tag. The game simulates a predator-prey relationship or fighting. You are trying to “tag” somebody while trying to avoid being tagged yourself. This triggers your "fight or flight" response. When playing the game, you will naturally become stressed. Your stress hormone levels will go up, causing you to be more alert and active. In this case, stress is beneficial. But having a constant increase in stress levels can actually lead to depression and mental health issues. That’s why it is important to know the different types of stress.

Anxiety is a feeling of unease, or of being overwhelmed. It usually results from being afraid of something. For example, it is common to feel anxious about an upcoming test because you are afraid of failing or doing poorly. Anxiety is a negative feeling in response to stress.

What are the different types of stress?

There are two main types of stress. Eustress, which is positive stress and distress, which is negative stress.

Types of stress
The main types of stress (©2020 Let’s Talk Science).


Eustress is the most common form of stress. You may feel it before performing in front of people or taking a test or after having an argument with someone. The factors that lead to eustress only result in short-lived changes in stress hormone levels in the body. Normally, this type of stress does not last long and will not have long-term negative health effects.

Eustress is actually thought to be necessary for healthy development. This is because it teaches the brain how to respond to stress in a healthy way. However, being exposed to any type of stress for a long period of time can lead to serious health problems.

Distress may be acute (short term) or chronic (long term).

Acute stress (or episodic stress) is caused by events like the loss of a friend or family member or the breakup of a relationship. These events have a greater impact on the body than everyday stress. If not managed properly, the stress from these events can lead to negative brain changes. However, this stress can be managed if you are in a supportive environment and have positive interactions with others that help to decrease stress levels.

Chronic stress (or toxic stress) is often the most long-lasting and damaging form of stress. It is caused by stress factors such as physical or emotional abuse, bullying, neglect, and addiction. Toxic stress can lead to lifelong physical and mental health issues. These health issues occur because the stress changes the way that the brain communicates with itself and the rest of the body.

What is the biology behind stress?

Stress is a biological response to things that happen to you. If you perceive a situation as stressful, the hypothalamus region of your brain begins the stress response. It starts by sending a message to the pituitary gland. The pituitary gland then sends a message to the adrenal glands. The adrenal glands are found on top of your kidneys. These glands then release the stress hormone cortisol.

Diagram showing the pathway between the brain, the pituitary gland and the adrenal gland that is responsible for controlling stress-related reactions in the body
Diagram showing the pathway between the brain, the pituitary gland and the adrenal gland that is responsible for controlling stress-related reactions in the body (Let’s Talk Science using an image by VectorMine via iStockphoto).


During the stress response, your breathing and heart rate increase and your blood pressure goes up. With the help of cortisol, your liver will break down molecules and release more sugar (glucose) into the blood. An increase in blood sugar level provides more energy for the body. This is critical for the fight or flight response. The increase in energy helps you to escape from or deal with a stressful situation. It also helps the body to return to a normal state afterward. 

Did you know?

During the stress response, some of your other body systems are less active. This includes your immune system and your digestive system. This is why you don’t feel hungry during a stressful situation. 

It is possible for people to adapt to moderate levels of stress over time. If you experience a stressful event over and over, the prefrontal cortex, or the command centre of the brain, recognizes the stressor and tells your hypothalamus that stress response is meant to be short-lived. Experiencing repeated or long-term stress means that cortisol levels in the body stay high. 

But what happens if your body experiences high levels of stress hormones over an extended period of time? The stress eventually becomes unhealthy. Over time, high levels of cortisol actually start to wear down the brain and other body systems. This type of damage to the brain has been associated with a number of health problems, including depression and anxiety disorders as well as memory loss and dementia. 

So remember, although some stress is good for you, too much stress can be harmful over time!

Types and Causes of Stress (2013)

Video (5:18 min.) by John Kenworthy showing the two main types of stress, and the main cause of stress.

Understanding the Facts: Stress

Article by the Anxiety and Depression Association of America about what stress is, what stress can be caused by, and the potential health effects.

Why Some Stress is Good for You (2016)

Article by Melanie Greenberg for Psychology Today discussing how some stress can be beneficial, but too much can become overwhelming and toxic.

Stress Management

Article from the Mayo Clinic on the effects of chronic stress, and the damage it can do to both your mental and physical health.

What is Eustress And How is It Different than Stress? (2020)

Article by Juliette Tocino-Smith for Positive Psychology discusses 'eustress' or positive stress, the potential benefits, and how it can be used to combat 'distress' or negative stress.


Alberta Family Wellness Initiative. (n.d.). Positive, tolerable & toxic stress.

American Psychological Association. (n.d.). Stress: the different kinds of stress. Writers. (n.d.). Effect of stress on the brain. HowStuffWorks.

McLeod, S. (2010). What is the stress response?