"Stress" is the body's natural response to particular triggers - it is not, in itself, a bad thing.
However, in today's modern society it can become very dangerous.
This blog post sets out the biological background to stress.
The two types of stress
"Stress" was first coined as a scientific term in 1936, by a Hungarian medical researcher called Hans Selye.
There are in fact two types of stress.
The first is the acute type, which is also called the "fight-or-flight" response.
This is where the body reacts strongly to a particular trigger - a bit like we would if a sabre-toothed tiger was creeping up on us.
The second is the chronic type, which is what happens when our body is put into that "fight-or-flight" state too frequently, and not given a chance to recover in between.
(This is what Hans Selye was researching.)
So in and of itself, "fight-or-flight" is not an negative response - in fact, it is responsible for keeping homo sapiens alive.
However, in modern society, too many things (that don't warrant it) trigger this "fight-or-flight" response in us.
And what's worse, we are not able to recover sufficiently in between each episode - to "re-set" our system to calm.
This is what then results in the chronic stress response that is so common - and so dangerous to our health.
The biology of stress
The body has two managing systems: the sympathetic nervous system, and the parasympathetic nervous system.
They work in counterbalance to each other: the first one excites you; the second calms you down.
Chronic stress occurs when the sympathetic nervous system is overactive, and the parasympathetic nervous system is under-active.
In a situation of "fight-or-flight", the sympathetic nervous system is triggered, so that you are ready either to run away from the threat, or fight it:
your adrenal glands secrete stress hormones (including cortisol); your heart rate and breathing increases
blood goes from the surface of your skin to your brain and muscles your pupils dilate to let in more light and aid perception of the threat
Once the threat has gone away, the parasympathetic nervous system takes over to calm the body down.
What happens after the stress trigger is removed
It can take 20-60 minutes for the body to return to a neutral state.
And if it's never given this chance (because another trigger occurs), it means the body get exhausted from the overactive sympathetic nervous system.
And what makes this worse is the brain's capacity for "neuroplasticity".
What this means is that the brain's wiring (its synapses and neural pathways) adapt to the thoughts and feelings that are experienced most often, making those pathways stronger and more likely to be used again in the future.
So if you repeatedly experience stress, your brain physically changes so you are even more likely to get stressed in the future.
Studies have shown that the pre- frontal cortex (your logical brain) is smaller in people who are chronically stressed, and the amygdala (the emotional brain) gets bigger.
This makes your stress response more intense, and more prolonged.
The impact of chronic stress
Once your body is suffering from chronic stress, this can result in increased blood pressure, obesity, insulin resistance, and heart disease.
And you are likely to experience a number of symptoms, from difficulty sleeping, to headaches, jaw clenching, changes in weight, an impact on your digestion, general aches and pains, a racing heart, tiredness, or anxiety and panic attacks.
But stress is a part of life!
So it is very important to learn how to deal with it healthily.
On Monday 18th November, I am launching my new online stress buster programme.
This will be 30 days of emails, videos, audios, tasks and inspiration to help you transform your approach to stress.
Just in time for Christmas!
Normal price will be £29.99 (less than £1 per day), but there will be a special half-price launch offer of £14.99.
Keep your eyes open for more details, or to get on the waiting list email me on firstname.lastname@example.org!