Examples of mental stress are high responsibility, long hours, perfectionism, anxiety, and worry. Present-day reasons for increased stress are: rapid and disturbing changes due to modern science and technology; education that creates a spirit of competition and rivalry; the great expansion of cities; the change in values and lifestyles; the break-up of family life and loss of faith and love in mutual relations. This stress or build-up of mental tension does not only result in a lack of peacefulness but causes many physical and mental diseases such as: high blood pressure, insomnia, indigestion, asthmatic ailments, peptic ulcers, heart attacks and even cancer. It lowers man's immunity to diseases and accelerates the process of ageing.
Academic researchers have shown direct evidence that prolonged exposure to stress can accelerate the aging of brain cells and lead to impairment of learning and memory. Abnormally high levels of stress hormones, such as adrenalin, damaged brain cells (of rats) and in humans may be linked to Alzheimer's disease by affecting the cells of the hippocampus region of the brain.
Although the problem of increased stress starts at the individual or group level, it acquires global dimensions. Wars, hot or cold, are an outcome of tension, as are communal riots or ethnic strife. Political tension may result in nuclear war which, in turn, could cause world catastrophe. Almost every individual suffers from tension and a man under tension often disturbs others and spreads waves of peacelessness. Sustained or frequent states of tension make a person physically and mentally weak so that he is unable to face even the slightest opposition or the smallest problem.
Stress causes the brain to lose the ability to think, and worry can make the hippocampus shrink by half, with the shrinkage increasing as the stress lasts longer.