STRESS AND THE HUMAN BODY

Stress is not only a state of mind; it has very palpable effects on the human body. Stress can come in various forms: it may be external, eg.cold, heat, lack of oxygen, internal, eg.low blood glucose level, or psychological, eg. work demands. However, our body is a finely-tuned machine whose aim is to maintain the status-quo despite continuous "stressors". This state is called "homeostasis" and it is fundamental to life as stable conditions are essential for our body cells to function effectively and thus ensure the body's survival.

Let's take an example. When you exercise your body produces heat as well as lactic acid. Heat can inactivate the body's proteins if not dissipated quickly; as for lactic acid it can destroy body cells in too high a concentration. Through various mechanisms involving changes in blood chemistry and signals from the nervous system to organs, muscles, blood vessels, etc... the body will dissipate the heat (increased sweating for example) and reduce the amount of lactic acid in body fluids.

A major aspect of the homeostasis process is called "the fight-or-flight response". Since prehistoric times our body has been programmed to react rapidly and efficiently to threats. Hormones and signals from the nervous system play a major part in this process. For example, the hormone adrenalin will be released in order to increase the heart rate, pumping blood and therefore oxygen in the body so that it can react to an attack. At the same time they will inhibit "nonessential" functions such as digestion. Numerous other changes in the body will occur, all tending to ensure maximum efficiency of the musculo-skeletal system.

However, chronic and severe stress may cause this "state of alarm" to unduly persist. If for some reason this mechanism is no longer able to cope or, on the contrary, goes into overdrive due to strenuous exercise, fatigue or extreme psychological stress such as bereavement, you may experience a variety of problems. This could be painful muscle contraction due to loss of water and salt following excessive sweating or a build-up of lactic acid in the tissues, leading eventually to chronic muscle fatigue. Stress may even lead to some conditions such as gastritis, irritable bowel syndrome, hypertension, asthma or even depression and to a greater vulnerability, to chronic disease (*) as the stress response will affect the immune system through changes in blood chemistry and may impair wound healing.

Unfortunately reaction to stress is also a catch-22 situation. As you are feeling poorly you feel more miserable; this can lead to bad posture with shoulders bearing all the weight of the world, neck bent, rounded back. Muscles start to contract constantly leading to poor blood irrigation to the various tissues, lack of oxygen and eventually aches and pains as a result. So you are even more miserable and "stressed" and the circle goes on. In the process your rib cage does not expand properly because of your posture, your diaphragm is overworked and tight, thus compressing the nerve partly responsible for the good irrigation of the gut and the secretion of digestive fluids. You develop stomach problems such as heartburns, ulcers etc. As this particular nerve also controls swallowing and the vocal cords, you find your throat tightening and have difficulty in expressing yourself. So you feel even more stressed and this can go on and on...

Obviously this is a very schematised outlook of what is a very complex process involving multiple physiological aspects. But it shows that stress is not all in the mind. It has very concrete effects on our bodies leading to physical pains and discomforts and sometimes even serious disease. We cannot always change our life's circumstances. However we can try to ensure that our body is functioning at optimum level even under adverse circumstances.

* Tortora G.J. and Reynolds Grabowski S. (1996). Principles of Anatomy & Physiology (8th ed.)