Stress is misunderstood and not always bad; it is the way our body has evolved to deal with life’s challenges. Unfortunately our physiology is stuck in the days when we were running across the African savannah chasing or being chased by predators and has not kept up with the world we live in now. Our stress response use to be life saving and kick into the “FLIGHT or FIGHT” response, to run away or fight that marauding lion in Africa. Usually our stressors are not that extreme these days – traffic jams, money worries, overwork – few of them are ‘real’ in that they are not immediately ‘life threatening’ in the sense of running away from the lion; but our response is often the same and can cause a lot of health problems.
To understand how prolonged stress is bad for our health, we need to look at what our body evolved to cope with being chased by a lion. In life-threatening situations, our Sympathetic Nervous System sets off a cascade of chemicals in our body to activate our flight or fight response to make us hyper-alert and pump energy into the body. We get an ‘adrenalin rush’, blood pressure increases and more blood is pumped by the heart to the muscles in readiness for either running or fighting. Our perception of pain is blunted, so that we can still fight or run away, our hearing and perception are heightened. Our thyroid and adrenal glands are activated to provide extra energy. Adrenaline floods the bloodstream and “steroid” hormones and insulin are released. Energy in the form of glucose is surging through the body to prepare for defense or fighting. To cope with this massive energy requirement the brain immediately shuts off expensive energy consuming projects: digestion, growth and reproduction. Also the immune system is inhibited. It takes a lot of energy to make those antibodies, fight off tumours and in the ‘flight or fight’ where you might die, looking for bacteria and tumours isn’t the best way to expend energy at that moment.
This response is our saviour in those acutely, life threatening situations. With prolonged stress, however, this response can become more damaging than the stressor itself, especially when the stress is purely psychological. We can even generate this stress response to the expectation of physical or psychological insult. Stress-related disease can emerge. Stress increases the risk of you getting diseases that make you sick.
If the body is constantly turning off long-term energy projects, nothing will get properly repaired, you’ll never have any surplus energy, you’ll feel fatigued, your low immune system means you are more likely to fall victim to a number of infectious diseases, cancers and less capable of combating them once you have them. All this unused glucose sloshing about the body has to be got rid of too, in a later article we will see how this links to diabetes and weight gain.
The Sympathetic Nervous System is essentially catabolic, which means it tears down the body. Energy is used to prepare for defense, rather than for nourishment. Unless the body has a chance to replenish itself and heal, the Sympathetic Nervous System domination will soon start breaking the body apart. Our “Fight-or-flight” response is hard-wired into our nervous system and represents a genetic wisdom designed to protect us from harm. This is an instinctive response to any potential danger, whether real or perceived and unfortunately our mind cannot distinguish stressors. It reacts the same way to a lion – or to a boss giving you “the look” or a bad news on TV. They are all DANGER –“Fight or Flight!” Yet you can’t really fight or flee… and how many stressors are we exposed to daily? From morning till late at night we are constantly keeping ourselves busy, over-stimulated, and in information overload. We multitask, solve problems, and resolve conflicts. We answer phones while eating and walking, reply to emails, and get scared watching news. Our acute stress response cannot handle this chronic stress.
If you want a more detailed biological explanation of the mechanism of stress on the body and related disease (it’s both fascinating and scary!) and where much of this information in this article has been sourced, I’d recommend reading Robert Sapolsky’s Why Zebra’s Don’t Get Ulcers.