• Dr Stuart Associates

Anxiety: The Fight and Flight Response.

Updated: Sep 18, 2019

Demystifying the physical symptoms of anxiety.

The ‘fight and flight’ response is a mechanism that has evolved in our brain to help us to survive. The main evolution of the ‘fight and flight’ response occurred in hunter-gatherer times when human beings lived in more dangerous circumstances. The ‘fight and flight’ response enables humans to become, in a split second, much stronger, and was useful, for example when a human needed to either fight off a wild animal or be able to run away. You may have heard of stories where someone was able to suddenly show super human strength, when, for example, their child was in danger of being harmed – that is the ‘fight and flight’ response at work.


The Brain mechanism:

In the brain there is something called the amygdala, the amygdala controls our fear response or what has become known as the ‘fight and flight’ response. The amygdala is a central part of the limbic system, the limbic system is the most ancient part of the brain and this area of the brain reacts before any other part. The limbic system reacts to the danger without thinking about whether it is actually dangerous or not.


What happens in our body?

When the ‘fight and flight’ response is triggered we take in more oxygen, which means that we breathe more shallowly, we expel less carbon dioxide so our breaths are faster and shallower. Our heart beats much faster than normal and this allows the blood to be pumped around the body quicker - carrying the oxygen to the muscles to make them stronger. Adrenalin and cortisol are released and these are stress hormones.


The parts of the body that are not needed if we are just about to be attacked by a lion, stop working or work less well. For example, we stop digesting food and this sometimes gives the sensation of ‘butterflies’ in the stomach. We don’t need to digest food we just need to be able to fight or to run away. We also stop sending so much oxygen to the brain, this gives the sensation to some people that they feel light-headed or dizzy and that they have inability to be able to use their conscious mind in the same way that they would be able to normally. Some people feel faint when they are feeling anxious, but in fact because our blood pressure has gone up, rather than down, it is impossible for us to faint in these circumstances.


Although the Fight and Flight response can be a very useful survival mechanism, in our day and age it is triggered in situations where it would be more useful for it to not occur. For example it appears that the ‘fight and flight’ response is not only triggered in situations where we are in immediate physical danger, it also appears to be triggered in situations where we perceive ourselves to be in what we term ‘social danger’.


There has been research to suggest that individuals fear public speaking more than they fear death. It is common to feel intense anxiety symptoms when, for example, public speaking. However we are not in any immediate danger, so it seems counterproductive for our ‘fight and flight’ response to be triggered in these situations. The Fight and Flight response is triggered in these ‘social danger’ situations because we hypothesise that if we make a fool of ourselves than we may be rejected by others, if we are rejected by others we are more likely to live alone, if we live alone we are less likely to survive. So the Fight and Flight response is not only triggered by immediate physical danger, but it also seems to be triggered by cultural understandings of shame and rejection.


The ‘fight and flight’ response is also triggered in other situations, such as when we are worried about our health or the health of others. Again, a strong body is not really what is needed in those situations. What a shame it works in this way because we all experience anxiety in situations where it would be much more useful if we did not.




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