Stress and your Body and Brain

Search for anything on my site

Chronic stress is likely to lead to depression anxiety and health problems such as high blood pressure, chronic illnesses, heart disease, weight problems and more. In order to understand why, lets look at how our brain perceives chronic stress. 

In modern days, we rarely face a threat from a predator, but our brain is still wired to perceive all stress as life threatening. When something distressing happens in our environment, such as conflict  at work with a coworker, a traffic jam, financial stress, or a more serious one such as dealing with a divorce, our mind body can mistakenly perceive this as a life or death situation. 

Stress and Anxiety and Depression

When we first experience stress in the environment a part of our brain called the amygdala, trips the switch that initiates the pattern of fight or flight, setting off a chain reaction. Part of that reaction is the creation of physical sensations which are perceived by our brain as fear and anger. Fear can be perceived as anxiety. If these states are experienced long enough, and the stress is chronic, they can often transform into depression.

The good news is we can circumvent this response with skills. But more on this later. Let's look at this response in more detail.  

 The Brain and the Stress Response

There are four main parts of the brain involved in the stress response.

Amygdala- The amygdala senses threats and initiates the entire stress response by alerting the other parts of the brain. 

Hypothalamus- The hypothalamus coordinates the response of stress hormones which start the fight or flight cycle

Hippocampus- The hippocampus stores and retrieves memories about the situation you are in. It allows you to learn from the past and apply that information to the current situation

Prefrontal Cortex- The prefrontal cortex creates a plan and motivates you to respond. It coordinates information between the amygdala and the hypothalamus. Your prefrontal cortex is your biggest aly when working with the other parts of your brain. These  parts are more geared for your survival and will trick you into overreacting. The prefrontal cortex can be wise and logical and used to gain new skills. 

Often, the stress response is unconscious. When learning new skills, we deliberately make this response conscious and override it. 


Organs, glands, muscles, and the immune system

It's interesting to me that many of my clients are baffled by their body's response to stress ( or anxiety which is really often a stress response gone wrong). When they learn about how their brain and body is wired to respond to stress it can sometimes help. 

Below are some of the parts and how they are involved in stress.

Adrenal glands

When the amygdala triggers the hypothalamus, it signals to your adrenal glands to secrete adrenaline and epinephrine to begin the fight or flight response.

These chemicals will:

  • Increase your heart rate and send blood to your muscles
  • Stimulate a hormone called ACTH that causes cortisol to be released and stimulate your liver to produce glucose. This will ensure you have extra energy to fight
  • Increase your blood pressure by causing a constricting of the vessels
  • Open your lungs to you can take in oxygen to increase your level of alertness

Your adrenal glands do all of these things to prepare your body to be in the best shape to fight. Remember, you don't really need to fight. 

Cortisol

Cortisol suppresses non emergency functions because it is meant to prepare your body by rallying it to withstand the great stress necessary to just " survive". This makes sense if you are going into battle. However, as explained earlier, most of our daily and chronic stress in modern times are inaccurately perceived as life threatening. Too much cortisol caused by chronic stress leads to illness, depression, anxiety, heart disease, and a number of other ailments. 

Think about some of your physical symptoms of anxiety specifically in relation to a panic attack. This is why you are having them!

Nervous System

Our nervous system helps distribute our stress response. It is composed of the parasympathetic nervous system and sympathetic nervous system.  

The sympathetic nervous system helps rev up the process of fighting. It helps the adrenal glands release adrenaline. 

The parasympathetic nervous system helps down regulate and calm your body. 

The interaction between these two parts helps your body return to homeostasis.

Chronic stress causes your nervous system to malfunction and the impact of it is your brain and body stay in a high arousal state. 

The Vagus Nerve

The Vagus nerve controls our freeze response. Similar to a deer that freezes in the face of a car coming down the road, we also have the ability to freeze when faced with overwhelming and paralyzing fear. We may do this when we feel overwhelmed instead of fighting. Feeling frozen, immobilized, and unable to act in the face of non threatening current day stressors can also play out to have catastrophic responses. 


How Does Stress Impact Our Body?

  • Stress damages our heart. 

Repeated surges of adrenaline damage our blood vessels and that can increase the risk of stroke and heart attack. Also, remember that stress, which increases the likelihood of the perception of anger and fear, is more likely to lead to anxiety and depression

  • Stress can increase weight

Cortisol will increase your appetite because in fight situations your body and brain will encourage you to eat. Fluctuating blood sugar levels make it hard to shed fat, and also disrupt sleep and appetite cycles. Additionally, all of this fluctuating blood sugar will make you more likely to stress eat. 

  • Stress can suppress your immune system

Specifically the production of cortisol is meant to suppress the immune system, and when it is functioning properly due to the impact of chronic stress we get sick. 

The Good News! Our Brain is Plastic. 

Too much stress causes all parts of your brain to become more sensitive and more reactive. The great news is we know that we can change the way we process stress. Neural pathways that we use become stronger, and neural pathways that we don't use become weaker. We prune them, like a tree. Although we once believed that our brain was relatively fixed at a certain age, we know now that our brain can continue to change as we grow into adulthood and old age. We understand more about brain plasticity, which essentially means that our brain can rewire itself. We can learn new skills and habits to help our brain unlearn habits of stress. Continue to visit this website and learn more about things you can do to become resisting to stress. 

mindfulness meditation

stress management 

self compassion

components of mindfulness

mindfulness in psychotherapy

stress in the workplace

stress and hives

weightloss and stress

corporate speedup



Greenberg, M. (2018). The stress-proof brain: Master your emotional response to stress using mindfulness & neuroplasticity. Strawberry Hills, NSW: ReadHowYouWant.



Thanks for visiting! Feel free to email me at kristenlynnmcclure@gmail.com

Follow me on pinterest to keep up with valuable mental health resources I am interested in

Follow me on twitter to keep up with valuable mental health resources I am interested in