Mathemetical Definition of Stress is Force per unit Area (F/A), Strain is caused by Stress. Simillar response is created my human being when unnecessary force (overloading) is applied to human being. Thus
"Stress is the Physical and Emotional strain caused by human response to pressure/force from the outside world."
Common stress reactions include tension, irritability, inability to concentrate, and a variety of physical symptoms that include headache and a fast heartbeat also lack of confidence.
In present scenario, it is almost impossible to live without some stress where everything related to life is moving very fast without having a occasion to think about the situation. And also most of us would not want to live completely without stress , because it gives life some spice and excitement, without that life is having no meaning. But if stress gets out of control, it may harm ones health, our relationships, and your enjoyment of life.
Examples of over load situation which are main causes of stress in todays life:-
1. Both husband and wife work full time while we are raising our family. At the same time, our parents are retired, in ill health, and are dependent on our help with shopping and running errands. That problem has no solution, ultimately leads to unwanted situation of stress.
2. Someone is a single person living alone, and whose salary isn't rising as fast as the rate of inflation. It's getting harder each month to pay the bills. And no one to share feelings of one.
3. The expectations and competition at ones workplace is becoming fierce. You find yourself coming in early, staying late, and taking on more work than you can handle. It is very difficult to survive oneself of average skill man.