It is inevitable that you are going to get scared, particularly in this month of all months. October will surely have you trembling. Whether you stumble upon a horror film on television or you scream because you are walking down the hallway to see a rubber hand oozing with blood coming out of someone’s locker (not that it has happened to me before), the reality of fear surrounds us. But have you ever thought about how your body processes this fear?
When your body perceives the emotional response that it is afraid, it stimulates the “fight or flight” response. The branch that initiates this response is the sympathetic nervous system, which conducts involuntary action. As a part of this process, your body releases acetylcholine via the preganglionic fibres of the nervous system. This neurotransmitter then goes on to release epinephrine and norepinephrine (also referred to as the adrenaline compounds) through the postganglionic fibres. These neurotransmitters are sent to various parts of the body, resulting in the common actions we associate with being afraid: your heart starts beating faster, the bronchioles in your lungs are dilated as well as your pupils, blood vessels leading to your digestive organs are constricted and so forth.
In addition, your long-term stress response is activated, releasing the steroid hormone, cortisol from the adrenal cortex. Cortisol lasts longer than the effects of epinephrine and norepinephrine. The hormone is also responsible for glucose metabolism from non-carbohydrates. Thus, providing more energy and fuel for the body. However, if the long-term stress system is stimulated for too long, it can lead to detriments. Non-carbohydrates are more difficult to access glucose and often increases acetone levels in the body. This causes an unbalanced pH in the bloodstream. Furthermore, a prolonged usage of cortisol can cause memory loss and damage to the cells in the hippocampus, the part in the brain responsible for converting short-term memories to long-term memories. Cortisol is also a anti-inflammatory, thus, deterring the function of your immune system.
So this Halloween, enjoy the scare, but try not to get too scared for too long. After all, it’s just science.