See Anxiety Fear serves a protective purpose by making a person cautious. For a child, a frightening situation may easily become associated with a harmless situation so that conditioning results and afterward the harmless situation alone will provoke a fear reaction. Regarding such persistent and unreasonable fears, see under Anxiety; Phobia.

(See Coma:  Fainting as a Cause of Coma; Shock.) Fainting-What to do Fainting usually results from reduction in the supply of blood to the brain. It may be caused, however, by anything that interferes with the vital functions of the brain cells, such as deprivation of oxygen or glucose. The usual kind of fainting is triggered by an emotional shock, such as the receiving of bad news, fear, or the sight...

We sometimes say the human body is like a machine. The body uses fuel and produces heat and energy. But there are many differences, and one of these is the effect of activity. Use of a machine wears it out; a machine used constantly will wear out sooner than one used only occasionally. In contrast, the serviceability and life expectancy of the human organism is improved by activity. Other factors being equal,...