
Anxiety and the Fight-or-Flight System
January 12, 2025
What is the fight-or-flight system?
The fight-or-flight system is part of our nervous system that has been around for a long time, it is a very primal part of us. It is part of many nerves that are known as the sympathetic nervous system. It was essential for our ancestors when they were faced with a physical threat, for example, a bear. It was responsible for priming the body ready to fight or to run away.
When this system is activated, it floods our body with a hormone called adrenalin. This results in physiological changes to our body that make us physically ready to fight or flee.
Symptoms include:
- An increased heart rate: This is so that we can pump more blood to our muscles so they are ready to be activated
- Increased breathing rate: This is so we can get more oxygen into our blood and then to our muscles for energy
- Feeling sick or nauseous: This is because our focus of the body is to be running away or fighting, so all the energy we have needs to go to that rather than digesting and the blood is diverted away.
- Needing to go to the loo: As we need to be lighter sometimes our body can flush us out to reduce weight and because the focus is no longer on digestion.
- Chest pain: This is because the chest muscles are working hard to increase the breathing rate.
- Pins and needles: This is because the blood is diverted around our body to where it is needed the most.
- Feeling dizzy/lightheaded: This is because of the suddenness of the rush of adrenalin.
How does it impact me when I am feeling anxious?
Although many years ago this system was activated by physical threats, as society has changed so have the triggers of this system. We used to have quite short-term and physically threatening triggers such as animals. Nowadays, numerous things can trigger this system as it is anything that you believe is a threat, for example, this could be speaking in a class or the build-up to exams. Also, the triggers can be more long-term for example a divorce of our parents or a difficult time at school.
When we feel high levels of anxiety due to these different triggers it can cause this response to be activated.
For example:
You are speaking in a social situation and you start to worry about how you are coming across. You start to think that you are coming across badly and that this person will not like you.
Or
You have just been told about an exam that is coming up. You don’t think you are going to be able to pass it and you start to worry about upsetting your parents.
In both these situations, your fight-or-flight response will notice that you are feeling uneasy and anxious and may activate. This is because there is something that is making you feel not right and your nervous system has decided it is a threat and you need to deal with it.
How does this maintain my anxiety?
Whilst the fight-or-flight system is a protective response, it can cause anxiety to be worsened. This is because the physical symptoms it causes are very unpleasant due to your body being in crisis mode whilst not having any use for the extra energy it is creating.
This can cause catastrophic misinterpretations which is where you may interpret these symptoms are a sign that something bad is about to happen. For example, I am experiencing a racing heart so I am going to die or I am feeling dizzy so I am going to faint.
Or it may be because you find the symptoms embarrassing. For example, I am so sweaty because my heart is racing I am sure that everyone can see and will think I am strange.
Due to this, there is now a new threat to your body and the symptom of the fight-or-flight system is going to activate the fight-or-flight system further.

Two myths about the fight-or-flight system
“I am going to have a heart attack”
As mentioned earlier it is very scary when the fight-or-flight system becomes activated. Symptoms such as chest pain can sometimes make people think they are having a heart attack. The group most likely to experience panic attacks (young women) are unlikely to have heart disease. This shows how it is doubtful that there is a connection between the two. If you are concerned you
can always go to your GP and if your GP has ruled out heart problems, it is unlikely you are having a heart attack.
“I am going to faint”
Due to how quickly your body releases adrenalin it can make you feel like you are going to faint. When people faint, this is usually because of a drop in blood pressure in the head. The fight-or-flight system causes an increase in blood pressure so it is the opposite of what occurs when you faint so it is highly unlikely to occur. The only exception to this is if you are scared of blood and have a blood-injury phobia.
How can I slow down the fight-or-flight system?
We don’t want to get rid of our fight or flight system, it is a crucial part of keeping us alive. It is a lot like a smoke alarm. It is annoying when it goes off when the toast is burnt but we would never get rid of it and need it in case there is an actual fire.
The best way to slow down the sympathetic nervous system is to activate the parasympathetic nervous system which is responsible for relaxing our body. If we think of the sympathetic nervous system as the accelerator pedal for our fight-or-flight system, the parasympathetic nervous system would be the brake pedal.
But we cannot just tell our body to active the break and we cannot just tell our heart rate to slow down or our blood to stop diverting around so what do we do?
The thing that we can control is our breathing rate. When we breathe out for longer than we are breathing in this activates our break pedal on the fight-or-flight system.
One great technique to do this is called rectangular breathing. This is where you find a rectangular-shaped object e.g. a door or window. You follow the edges of the shape breathing in as you go along the short edge and breathing out as you go along the long edge.

Another way is by using counting; count for 4 seconds as you breathe in and 7 seconds as you breathe out.
Grounding techniques are really good as well such as identifying:
- Five things you can see
- Four things you can hear
- Three things you can touch
- Two things you can smell
- One thing you can taste