29 Jul

Fight-or-Flight, what does it really mean?

By: Marleen Filimon

You’ve most likely heard of the term “fight-or-flight” system when talking about anxiety and stress. Sometimes it’s referred to as the “fight-or-flight response” or the “fight-flight-freeze system”. But what does it really mean?

During a stressful situation such as preparing to write an exam, or bungy jumping for the first time, or speaking in front of an audience, the body reacts by firing the fight-or-flight response which results in a cascade of hormones that cause physiological changes in the body. This stress response starts in the brain when our eyes or ears detect a stressor and activates the limbic system.


This system sits on top of the brainstem and is made up of three main brain regions (the amygdala, the hippocampus, and the hypothalamus) and a couple of other nearby brain regions. It plays a role in emotional regulation, formation of memories and intuitive responses to our environment.

If the amygdala interprets the images and sounds as a threat, it immediately sends a distress signal to the hypothalamus (aka the command centre of the brain). The hypothalamus maintains homeostasis in the body and communicates through the autonomic nervous system with the rest of the body. It sends out signals to control involuntary body functions such as heart beat, pupil dilation, blood pressure, and digestive processes.

The autonomic nervous system can be subdivided into two further systems

  • The sympathetic nervous system, aka the activation system, that fires the body up to either fight or flee during a stressful event
  • The parasympathetic nervous system, aka the relaxation system, that helps the body to calm down after the stressor is no longer perceived as a threat.

After the hypothalamus receives the distress signal, it sends a signal through the sympathetic nervous system to the adrenal glands to release the hormone epinephrine (aka adrenaline) into the bloodstream. As this hormone makes it way through the body, some significant physiological changes occur that will help the body to either fight, flee, or freeze in response to the stressor. The heart rate increases to speed up the blood flow through the body, so the muscles get more oxygen to be ready for muscle movements. At the same time, the person breathes more rapidly, blood flows faster to the lungs, dilating the bronchioles, which in turn allows more oxygen to be sent to the brain to heighten alertness. A bunch of other physiological changes occur at the same time, making our body a perfectly functioning machine.

As the initial surge of epinephrine dwindles, the hypothalamus activates a second stress response that consists of the Hypothalamus-Pituitary Glands-Adrenal Glands Axis (HPA axis). The HPA axis makes sure that the sympathetic nervous system remains activated and involves the release of the stress hormone cortisol. With cortisol rushing through our bloodstream, the body stays on active mode and remains alert.


Another brain structure not yet mentioned but extremely important in understanding the fight-or-flight response is the Prefrontal Cortex which sits right behind our forehead and is important in

  • Personality expression
  • Decision making
  • Goal formation
  • Differentiate between conflicting thoughts
  • Differentiate between good vs bad, better vs best
  • Understand the implication of decisions on future consequences

During the fight-or-flight response, the prefrontal cortex receives less blood, resulting in a diminished ability for rational thoughts, cause-and-effect analysis, an inability to focus on small tasks, and incapability of engaging in meaningful relationships.


Once the ears and eyes realize that the threat is over, cortisol levels in the bloodstream decrease and the parasympathetic nervous system sends signals to start a body relaxation reaction. This part of the nervous system is regulated by the cranial, spinal and vagus nerves. The main neurotransmitter released by the parasympathetic nervous system is acetylcholine which helps to reduce the stress response. By reducing this response, the body flows back into homeostasis, meaning that the heart rate and breathing slow down, thus allowing the to body to return to a resting state.

When the parasympathetic nervous system is engaged, we regain access over our brain, including the prefrontal cortex. This reinstates the ability for planning, conscious thought, and socialization.

Works Cited

Boeree, C. G. (2009). The Emotional Nervous System. Retrieved from General Psychology: https://webspace.ship.edu/cgboer/limbicsystem.html

Bohren, A. (2018). Parasympathetic Nervous System: A complete guide. Retrieved from Cognifit’s Blog: https://blog.cognifit.com/parasympathetic-nervous-system/?amp

Greenberg, M. (2018). How PTSD and Trauma Affect Your Brain Functioning. Retrieved from Psychology Today: https://www.psychologytoday.com/ca/blog/the-mindful-self-express/201809/how-ptsd-and-trauma-affect-your-brain-functioning

HHP. (2018). Understanding the stress response. Retrieved from Harvard Health Publishing: https://www.health.harvard.edu/staying-healthy/understanding-the-stress-response

Hurley, T. (2018). Activating the Parasympathetic Nervous System to Decrease Stress and Anxiety. Retrieved from Canyon Vista: https://canyonvista.com/activating-parasympathetic-nervous-system/

NUROBODI. (2018). The Limbic System. Retrieved from NUROBODI: https://nurobodi.com/news/nurobodi-helping-the-limbic-system

SoP. (2017). Prefrontal Cortex. Retrieved from The Science of Psychotherapy: https://www.thescienceofpsychotherapy.com/prefrontal-cortex/

18 Feb

Why mindfulness can help relieve symptoms of PTSD

By: Marleen Filimon

PTSD, or Post Traumatic Stress Disorder, is a very normal reaction to a very abnormal situation. It is a way for our brains to protect the body, while still retaining the ability to somewhat function in everyday life.

Under non-trauma circumstances, a person’s stress hormone levels will temporary rise in reaction to a threat. When the threat has passed, these levels will return back to normal. What a great machine our body is!

For people with PTSD, the system still works the way it is meant to. The person encounters a threatening situation, stress levels rise and… take much longer to return back to their baseline. In addition, because now the fight-or-flight response is continuously operating in the background, the stress hormone levels spike in response to even very mildly stressful situations.

These constant elevated levels of stress hormones contribute to an array of different factors: memory and attention problems, difficulty concentrating, feeling irritable and easily agitated digestive issues and trouble sleeping. If you think about why this is happening; when your body is in a constant state of stress, your brain is more preoccupied with keeping you alive than having you solve mathematical equations or finish reading a Harry Potter book. Makes sense right?

Another indicator that your system is still working the way it is supposed to. Except now, in the case of PTSD, you are on high alert.

Being traumatized means that you are, subconsciously, organizing your life as if the trauma is still happening. Sights and sounds in daily life trigger you to have flashbacks about the trauma, your emotions are hypervigilant and in constant alertness to any kind of danger, and your energy is focused on silencing the inner chaos.

And this is exactly why practicing mindfulness is so important!

I’m not talking about meditating for hours on end. Mindfulness is so much more than just that. In case you are not too familiar with mindfulness, it is the practice of being in the here-and-now, without judgement towards yourself or others, and having a curiosity towards the things around you.

Visualization is a form of mindfulness. This teaches your brain to calm down, relax, and acts as a reset button. Day dreaming is a form of visualization. Picture yourself on your favourite vacation, whether that is on the beach in Cayos Coco, or on a trail walking across Europe. Use visualization to envision what happiness feels like, or what your perfect day looks like, or even what you will be cooking for dinner.

Five minutes, that is all it takes.

Practice makes perfect, you won’t expect your child to be an Olympic swimmer in one day?