How does your brain look and behave when it is stressed? Neuroscientists have taught us how chronic stress exacts a heavy toll on body and brain. The amygdala is very good at what it does. It’s like the Work Health & Safety officer of the brain. If we take the smoke alarm analogy, we know that when the amygdala detects threat it sounds an alarm bell – a really loud one. You know when your smoke alarm goes off at home when you’re making toast? Everyone jumps when the alarm goes off, we clap our hands over our ears, we run around like headless chooks, someone gets a hammer and step ladder to smash the thing and a wiser someone flaps at the detector with a tea towel and then that incessant, maddening, deafening noise goes silent.
So when that amygdala is screaming its head off “Danger! Danger! Evacuate!” the hippocampus can’t do its job – data management, processing new information, retrieving old information. So our stress response is now powered on and dialled way up. A heap of stress hormones enter our bodies and the rapidly increased glucose levels, speeding heart rate, and increased blood flow to the muscles in our arms and legs allows us to respond to a threat – by either fleeing or fighting or freezing (hence headless chook running and wanting to smash things).
After the danger has passed, the system works to return hormone levels to normal. We relax, breathe a sigh of relief and we say “It’s only the toaster. Why doesn’t it know we’re only making toast?”
The flight-fight-freeze response
The response to short-term stress is critical for survival. It powers the “fight-or-flight” response that allows animals to respond quickly to danger signs. However, this ancient response enabled our ancestors to survive sabre-tooth tiger attacks, or stampedes of woolly mammoths when they had to quickly decide to fight the threat, run away from it, or freeze and pretend to be dead. Once the stampede had disappeared and the mammoths were far, far, away or the tiger had been speared and killed, the threat diminished. Our ancestors’ hormone levels returned to normal, stress hormones receded, heart rate and blood pressure returned to baseline and they got on with whatever they were doing before the threat arrived.
Stress is the body’s reaction to any change that requires an adjustment or a response, and can be a good thing if it motivates you. Some things are stressful, but predictable – think of a time before you had an exam – most likely you were a bit anxious and stressed about the exam, heart beat faster than usual, maybe you had a dry mouth and muscle tension. However, once the exam stress was over you no doubt felt relieved and less anxious and your body returned to normal. This is a normal, healthy stress response. Overwhelming, chronic, persistent stress needs attention as it can have a serious effects on your physical, emotional and psychological well-being.