Stress is part of life, but it's turned into a catch-all expression to describe anything from minor frustrations and overwork to real distress and total crisis.

Stress as we understand it was termed the General Adaptation Syndrome (GAS) by endocrinologist Hans Selye in the mid-20th century. Stress is our physical and psychological reaction to problems and agression.

Stress is basically a normal reaction, but it becomes an issue when our efforts to adapt get out of proportion, we let it affect us psychologically or get run down (too much to do, too little time). Stress becomes chronic when it gets to the stage where it affects us even though there isn't a real stress factor behind it.
 
Physically, stress manifests itself in heart palpitations, accelerated breathing, sweating, stomach ache (the kind you get before an exam), and muscular tension. Psychologically, stress causes feelings of anxiety, sleeping problems, behavioural problems, irriatbility and, in its advanced stages, apathy. There are many symptoms, and most of us have experienced them at some point in our lives.