During the Oscar Pistorius trial an individual’s reaction when faced with perceived danger formed part of the defence team’s legal argument. The “fight or flight” response to danger created much public interest at the time. But what really happens in the body when faced with a “fight or flight” situation?
Thousands of years ago, our ancestors were hunter-gatherers who lived on plants and berries, and occasionally feasted on lean meat. Their main aim in life was to find food every day and to remain safe. It is estimated that in order to do this, they walked between 10 and 16 kilometres a day. This is essentially what the human body was designed for. Built into this ‘design’ was an emergency mechanism for when they could not find food or were not safe. This is what is known as the ‘fight or flight’ response and what we often refer to as stress today.
This mechanism was of course very well designed for those days, but in the modern world that we live in, we very seldom experience situations where we actually have to fight or flee. The problem now is that although it was so essential in those days, the flight-or-fight reaction hasn’t actually evolved and still functions in the same way as it did in our ancestors. That being said, the fact that the “threats” we face today often take more benign forms compared to those they faced, they can be equally taxing on our bodies.
Some stress, can of course be beneficial and the pressure it exerts can be an incentive to accomplish necessary goals. Often, however, stress reaches chronic, harmful levels, which has an undesirable effect on our bodies. This effect can include anything from a compromised immune system to weight gain. In short, brief periods of stress can work to our advantage, but chronic, long-lasting stress is much more harmful. Proper stress management takes on great importance given the wide range of bodily systems impacted by stress hormones.
A Canadian physiologist in 1936, Dr Hans Selye, did some ground breaking research on rats where he found that when he exposed them to different stimuli, which included anything from prolonged food deprivation to an exhaustive muscular workout, there was always a generalised response. Dr Selye called this the General Adaptation Syndrome (GAS), which is sometimes also referred to as the stress syndrome, during which, as Selye explained , the body passes through three phases of coping.
First there is an ‘alarm reaction’, in which the body prepares itself for “fight or flight” and the sympathetic nervous system in the body is highly activated – in addition, the adrenal glands secrete a large amount of adrenalin from the adrenal medulla into the blood stream in support of the sympathetic nervous system. This is a very short and acute phase and is essential to the survival of the person. No person can sustain this condition of excitement for very long however, and provided the person survives the first stage, a second phase of resistance ensues. In this second stage, certain re-adjustments occur in the body to ensure the survival of the organism. This takes place over a much longer period. Finally, because the re-adjustments made by the body in the previous phase are not able to restore homeostasis in the body, when the duration of the stress is sufficiently long, the body may eventually enter a stage of exhaustion.
When we dig a bit deeper into each of these phases to understand what exactly happens inside the body during each of them, we see that the alarm reaction is actually a massive activation of the sympathetic nervous system that takes place when a threat is perceived. This action results in the ‘fight or flight’ response, which is manifested by an increase in heart rate, dilation of bronchial airways to enhance the lungs’ capacity for oxygen, and enhancement of the metabolic rate so more of the stored energy in the body can be used to ensure survival. Most physiologists agree that this phase rarely lasts longer than around 20 minutes.
In the resistance phase the body secretes further hormones, in particular the chronic stress hormone, cortisol, that increase blood sugar levels to sustain energy and raise blood pressure. Although the body begins to try to adapt to the strains or demands of the environment, it cannot keep this up indefinitely and its resources are gradually depleted until the body enters the exhaustion phase where it basically suffers from ‘adrenal exhaustion’. At this stage the blood sugar levels decrease as the adrenals become depleted, leading to decreased stress tolerance, progressive mental and physical exhaustion, illness and eventually collapse.
It is interesting to note, that whether the stress is physical or emotional, the response is exactly the same. Chronic stress, such as that experienced by many people in our modern lifestyles, keeps us in the resistance phase, with the hypothalamus continuing to signal the adrenals to produce cortisol. This increased cortisol production keeps the body in “crisis” mode, which can lead to weight gain, poor memory, fatigue and depression. Cortisol also interferes with serotonin activity, which can further the depressive effect. It can also lead to sleep deprivation, which is in itself a powerful stressor for the body. Continually high cortisol levels also leads to suppression of the immune system and makes the body more susceptible to everything from colds and flu to cancer.
Fortunately, we can reduce the Cortisol levels in our bodies by making some relatively simple adjustments to our lifestyles.
The most effective way to reduce Cortisol levels in our bodies is exercise. A daily exercise routine that gets your heart pumping, such as running, brisk walking or cycling, increases the body’s production of endorphins and makes you feel happy and content. Eating three balanced meals a day that includes healthy carbohydrates, fats and proteins together, further assists in this regard. If you combine this with enough sleep (at least 7-8 hours per night), you should be well on your way to coping better with the stress in your life.