The way our body responds to stress stems from how our ancestors adapted to threats. When encountering threats like predators in the wild, the body has adapted to mobilise all energy resources to either "fight" or "flight" to survive. Even though we are unlikely to have to fight or run for our lives nowadays, the way we respond to threats remains the same.
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Jetzt kostenlos anmeldenThe way our body responds to stress stems from how our ancestors adapted to threats. When encountering threats like predators in the wild, the body has adapted to mobilise all energy resources to either "fight" or "flight" to survive. Even though we are unlikely to have to fight or run for our lives nowadays, the way we respond to threats remains the same.
You might have experienced trembling, increased heart rate, and breathing when under stress; these are all parts of the fight-or-flight response.
Stress activates the fight-or-flight response, freepik.com
The flight or fight response is a way for the body to respond to threats that can be real or imaginary. Anxiety over an upcoming deadline can activate this response the same way as being attacked by a bear might.
After a threat is detected, the brain communicates with the autonomic nervous system, changing its activation from parasympathetic to sympathetic.
The fight-or-flight response can be defined as a stress response that involves activation of the sympathetic nervous system and release of stress hormones (adrenaline) to increase our chances of survival in threat situations.
In the absence of stressors or threats, the parasympathetic division of the autonomic nervous system (ANS) is activated. When threats are detected, the activity of the autonomic nervous system switches to the sympathetic branch of the ANS.
The autonomic nervous system controls involuntary actions like breathing, heart rate, digestion or blood pressure.
The autonomic nervous system consists of two divisions: sympathetic and parasympathetic.
In the following text, find out more about the processes involved in the fight-or-flight response.
The fight-or-flight response starts with the activation of the amygdala, a brain region that responds to emotions like fear, which triggers the activation of the hypothalamus.
The hypothalamus communicates with the autonomic nervous system and activates the sympathetic division. The sympathetic nervous system communicates with the adrenal glands (above the kidneys) that release a hormone called adrenaline (epinephrine). The release of adrenaline causes the liver to release stored energy in the form of glucose into the bloodstream, increases heart rate, blood pressure breathing rate and stops digestion.
Hypothalamus communicates that a threat was detected to the autonomic nervous system, StudySmarter Originals
This process might seem lengthy, but it occurs instantaneously. The fight-or-flight response in our body can occur before we consciously become aware of the threat.
If someone throws an object at you, the fight-or-flight response allows you to respond quickly. Due to the instantaneous release of energy into the bloodstream, your muscles quickly react, and you can dodge the object or even catch it.
When you realise you have an important deadline the next day, the fight-or-flight response can also be triggered; you might experience increased heart-beat, increased focus and determination to finish the work before the deadline, as your body enters the state of full alertness.
Adrenaline is a hormone that is secreted in times of stress or excitation. These can include bungee jumping, public speaking, taking an important test, or running away from predators. Upon secretion, adrenaline releases large amounts of energy into the bloodstream, allowing muscles to quickly use this energy to survive the threat by rapidly running away or fighting.
After the sympathetic nervous system triggers the adrenaline release, it causes the liver to release glucose that can be quickly used for energy by the muscles. Readily available glucose allows muscles to quickly use it to fight or flight.
Effects of adrenaline on the body, StudySmarter Originals
The HPA axis response involves the hypothalamus, pituitary gland and adrenal glands. This response takes longer (minutes or hours) than the instantaneous adrenaline response and involves the sympathomedullary response.
Similarly to adrenaline, cortisol also raises the blood glucose level. It suppresses the immune system function and other "non-essential" processes in times of threat (e.g. digestion), which can have significant, negative long term effects on health.
Stress is normal and sometimes good for us; it helps us get things done (although we don't need to run away from bears that often anymore). However, if the stress remains and the body is put into a constant state of 'fight-or-flight', it can severely affect our health.
In the short term, the fight-or-flight response is beneficial for us; it allows us to focus more intensely, fight or flight in dangerous situations, and perform better when under pressure. However, in the long-term, if we chronically experience the physiological consequences of stress, it can negatively impact the body.
Doctors often have to make rapid life or death decisions under pressure. In this case, the fight-or-flight response can be beneficial; the release of adrenaline can affect doctors' motivation and focus so they can quickly make a decision.
Chronic stress can cause headaches, cardiovascular problems, digestive problems, and increased chances of heart attack or stroke. Stress can even decrease the immune system function making people under stress more prone to catching colds or other infectious diseases.
Chronic stress can also have negative effects on one's mental health. Prolonged exposure to adrenaline and cortisol can be associated with problems like anxiety and depression, impair the ability to focus or even be a risk factor for addictions.
After the perception of the threat passes, the autonomic nervous system activates the parasympathetic division to help the body relax and restore normal functioning of the immune system and digestion.
The body returns to the "rest and digest state", and the parasympathetic nervous system slows down the breathing and heart rate. Blood vessels dilate, lowering blood pressure. Glucose is again stored, and digestion activity comes back to normal.
The fight-or-flight response can be defined as a stress response that involves activation of the sympathetic nervous system and release of stress hormones (like adrenaline) to increase our chances of survival in situations of threat.
The fight-or-flight response is caused by the activation of the amygdala in response to a threat or a stressor. The amygdala is a brain region that processes emotions related to fear. Once the amygdala is activated, it communicates with the hypothalamus, which activates the fight or flight response.
The hypothalamus controls the fight-or-flight response.
What is the purpose of the fight or flight response?
When encountering threats like predators in the wild our ancestors adapted to mobilise all energy resources to either "fight" or "flight" to survive. The response allows us to instantaneously take action and survive threats.
What triggers the fight or flight response?
The fight or flight response is triggered by threats which can include stressful events.
What is the function of the autonomic nervous system?
The autonomic nervous system controls involuntary actions like breathing, heart rate, digestion or blood pressure.
What divisions does the autonomic nervous system consist of?
The autonomic nervous system consists of the sympathetic and parasympathetic divisions.
What is the function of the parasympathetic division of the autonomic nervous system?
The parasympathetic division acts as a "brake" it is responsible for the "rest and digest" activity, it involves digestion of food, storing energy, slowing down the heart rate and breathing.
What is the function of the sympathetic division of the autonomic nervous system?
The sympathetic division acts as an "accelerator" it is responsible for activating the "fight or flight" response, it involves rapidly releasing energy to muscles, dilating the pupils, accelerating heart rate, blood pressure and inhibiting digestion.
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