Enervation is a state of lowered nerve force, a condition brought on by using up nerve force in excess. A state of mere temporary or partial exhaustion of power from too long continued or excessive action is quickly recuperated from, if sufficient rest and sleep are secured. Activity of all kinds use up energy; energy is recuperated during periods of relaxation and repose. Rest is Nature's great restorer. If stimulants are substituted for rest, recuperation lags and, finally, function falters.

For the body to maintain the state of good health it must be given light, heat, air, water, rest, exercise and given these elements in right amounts, proportions, qualities and combinations. Too much light overstimulates and brings on enervation; the same is true of heat. Not enough light also enervates, as does lack of heat. Deficient or impure air lowers the health standard, either by oxygen starvation or by poisoning. Food, even though suitable, may be taken in excessive or in deficient quantities, or it may be taken at the wrong time, or in wrong combinations. Water may be wholesome or taken in deficient quantities. Exercise may be carried to excess; or rest may be overdone and produce enervation. The mental state can be stimulated to the extent of producing mental or physical "disease."

The nervous system possesses two general powers--the motive and the sensorial. The motive power is employed in those important vital operations which are concerned in the growth and sustenance of the body, and in the actions,and functions of the various organs. The sensory power is employed in the functions of sensation, reflection, volition. These two powers of the nervous system, though somewhat different from each other, are yet so intimately related that for their highest and best condition, they both equally depend on the most healthy and perfect state of the nervous system. Whatever, in any measure, deteriorates the nervous structure, or impairs its functional powers, always necessarily diminishes both the motor and sensorial powers of the body. In the nervous structures excitement or exalted sensibility is followed by reduced function or enervation.

Since both these powers depend upon the integrity of the nervous system, all excessive exercise or expenditure of one always diminishes the functional energy of the other. All excessive exercise of the mind or the passions always necessarily diminishes the functional power of the stomach and all other organs concerned in the growth and sustenance of the body. On the other hand, everything that increases the demand for the concentration and expenditure of nervous power in the stomach and other organs, for the performance of their function beyond what is indispensibly necessary for the healthy operations of the body, always and necessarily diminishes the sensorial powers. In short, whether energy is Wasted in motor or in sensory activities or in both, the result is the same.

Excesses, mental or physical, use up nerve force and cause enervation. Anything that "acts" on the body and mind stimulates and causes a "reaction." We can "react" as long as we have nerve energy. When we have used up our surplus nerve energy we are fatigued, and require rest and sleep to recuperate. When we do not stop 'stimulating our nerve energy ebbs away, and the organs of the body lose power to function efficiently. The individual can dissipate his nervous energy, but he cannot add to it by any act of his own. Nature alone can build this up, and it is done during rest and sleep.

Work, worry, and the pleasure-seeking habit peculiar to civilization, or any influences that draw heavily on the capital stock of nerve energy, enervate. If nerve energy is used up in work or play, worry or grief, fear, anger; ill temper, or overworked emotions, passion, excessive joy and sorrow, overeating, eating improper food or wrong combinations of food, or eating putrescent food causing ptomaine poisoning, or the use of stimulants, or in intrigue, dishonesty, fault-finding, grouchiness, or complaining, or in sight-seeing, or if the body or mind is abused in any way, or if sufficient rest and sleep are not obtained, and if such habits are continued and become chronic, there is a gradual lessening of nervous energy producing enervation. Outside influences may reduce man's energy and cause faulty elimination. Enervation always causes a checking of elimination.

In the following presentation of the causes of enervation, no effort has been made to group the many enervating influences with reference to their importance; rather it has been sought to sum up the cumulative effects of the expenditures these occasion.