What is stress?
Everybody talks these days about how stressful life can be and this does seem to be the case for a lot of people. Stress is a word that is used to describe experiences that are challenging emotionally and physiologically. Everyone knows stress can have many negative effects on the body ranging from difficulty sleeping to comfort eating and excessive fatigue. But what is stress and how does it have such a significant impact upon our lives? The stress response is a very primitive response and is actually a safety response. By that I mean it developed as a result of evolution as a means of identifying danger and either dealing with it or fleeing to safety. This is part of the autonomic nervous system- the sympathetic (or fight-or-flight) component of the autonomic nervous system (see autonomic nervous system page). Therefore it is primarily a safety mechanism but that only works efficiently when the stress is fleeting. It was not designed to deal with ongoing stressors such as the type that people deal with in their everyday life.
The brain is the central organ in the stress response. It decides what is or is not stressful and it generates the stress response. When you begin to experience stress a signal is generated from the amygdala in your brain- this is the part of your brain that is designed to perceive fear- and this begins the activation of the sympathetic nervous system through sending signals to the hypothalamus of your brain to then generate the release of stress hormones to manage the stress and hopefully resolve it (by fighting or fleeing). Results of this activation would be physiological things such as an increase in the heart rate and blood pressure and increase in blood sugars to produce more energy- this allows more blood to get to your muscles, brain and lungs to allow you to deal with this acute stress. Then when the stress is gone these effects should fade away and the parasympathetic nervous system should take over as you are back to your resting state. These effects are primarily mediated through the sympathetic nervous system by the release of several hormones primarily cortisol and adrenaline.
Stress in acute situations can be helpful- for example if you are under pressure to reach a deadline the stress response that comes with that can be helpful in terms of getting it completed.
So what happens when the stress is chronic? When stress becomes chronic this stress response or fight-or-flight response is always turned on. This means those hormones- cortisol and adrenaline- are constantly present and the over exposure to these hormones leads to the typical negative symptoms of stress- poor sleep, poor eating habits, fatigue, anxiety and then even more serious increased risk of high blood pressure and the consequences of having high blood pressure such as a heart attack.