How shall be determined the proper amount of exercise for any individual? The human body is constructed for use, and will suffer from want of use, rust out, as it were; and it will suffer from over-use if any one set of muscles or any one supply of nerve power is overtaxed.

Exercise, in some form, is necessary for every one; work is necessary; recreation is necessary. Rest is to recreate, to renew. The food that we eat is digested and made into blood; the blood flows through the system of tissues, depositing building material and taking up waste matter. The arterial system, physiologists tell us, supplies the new material; the venous system takes up the waste material, returning the blood to the heart, after which the fresh air comes in contact with the blood in the lungs, and is aerated and oxygenated, and waste material given off. The heart pumps the blood through the arterial and venous systems. When we move or work, more blood is needed, and the heart pumps harder. When little or no exercise is taken, the heart loses its vigor from want of use; and it may be strained if overtaxed.

Brain power and nerve power depend on the blood supply for renewal of their tissue. Any organ or any combination of organs and muscles, when exercised, give off their accumulated material, and then, after a limit of assimilation is reached, the products are reabsorbed. The materials properly accumulate only when needed.

These facts bring to our notice three conditions—a condition of atrophy, or too little use; a perfect condition of equilibrium of forces; and a condition of strain from over-work. In the condition of equilibrium or perfect health, the brain is active and the muscular tissue under perfect control. The mind can receive impressions, and can convey them at will; and the muscles obey without difficulty and without fatigue, because of the great existing power of resistance. On the power to resist fatigue depends the power of prolonging exertion.

In exercising we exert our powers, and if from lack of use or other cause our amount of stored energy is small, exercise for even a very short period will produce a condition which makes rest absolutely necessary. Muscles must be gradually accustomed to work; and if work is prolonged beyond the point where exercise is beneficial, a state of tension and exhaustion ensues which can be remedied only by rest prolonged enough to allow the system to recuperate. Where the tissues, from disuse, have come to have little resistance value, a very gradual and persistent course of exercise must be determined upon, for unaccustomed muscles are quickly fatigued, and the subsequent rest they require may seem out of proportion to the work done. This condition of affairs is discouraging when not understood; yet there can be no different result except in degree; and in degree must the condition be changed and the tissues gradually renewed. If there is but little power stored, only little may be used until the power of assimilation is established.

The thin woman is benefited by bicycling; the liver works better, the food digests better. The stout woman is benefited, for the exercise hardens and condenses the flesh. The average healthy woman is kept in the best of health by the exercise and plenty of pure, fresh air. For the sedentary, the undeveloped, and the insufficiently nourished, the bicycle seems to work wonders. All the powers are accelerated and a general renewing of tissues takes place. The organs of digestion are stimulated and do better work, the appetite improves, the complexion brightens, and the mind responds readily. But people of either of these classes should be careful not to prolong exercise until loss of appetite is brought about; for the exercise should tend to increase, not to decrease, the desire for food and power of assimilation.

Baths should be taken in moderation, the skin being kept in free, healthy condition by dry rubs and tepid baths until the system is brought to the state where the cold bath can be used beneficially. The diet should be generous and wholesome, and care should be taken to avoid food that does not digest easily. Sufficient clothing should be worn but not too much, and all exercise should be avoided that might produce very copious perspiration. Only a healthy activity of the skin should be induced, and plenty of water drunk.

Do not work nervously. Go to work gently, and save your energies to make the wheels go around. A thin person can remain thin and a fat person remain fat while exercising assiduously if the exercise is not properly directed.

To overcome fat, persistent, systematic, and regular exercise is needed, and attention to diet must be considered essential. For the food consumed produces certain results; and if the system selects and digests most readily the fat-producing elements, their amount should be curtailed, and a diet of good working quality chosen. Fat is burned in producing heat; but if the same amount of fat-producing elements are again taken into the system, the same amount of fat results. The fat-producing tendency must be overcome, and the fat already accumulated consumed, until a good healthy average of tissue is produced and maintained.

Tea and coffee are not foods; they retard the assimilation of tissue, and must be eliminated from the diet of the weight-reducer. Sugar and starch—the latter when eaten is converted into sugar—are heat-producing foods, first forming fats which are used as energy-producing material. Persons wishing to reduce weight, therefore, must manufacture, not so much fat, but bone and sinew. To produce these, nitrogenous foods must be eaten. Fat consists largely of water; and heavy work, like hill-climbing, which induces free perspiration, is desirable. But any one wishing to seriously undertake weight-reduction should learn to enjoy bicycling for itself before attempting this application of the exercise.

Excess of fat produces physical laziness, which is hard to overcome; and stout persons, after exercise, crave fat-producing elements of food to reduce the tissue consumed. A taste seems to develop for sweet stuff and mild stimulants, and it is difficult to refrain from indulging it. Stout people are apt to believe, also, that they cannot endure exercise. They cannot comfortably, and must work with care until they are in a fair state of balance, where exercise ceases to fatigue, before attempting anything like scientific weight-reducing. Sufficient exercise regularly taken, proper diet persistently selected, will finally have the desired effect.

Exercise sufficiently to produce good, thorough perspiration; take a bath and rub down, and put on fresh clothing; avoid tea and coffee, sugar and ice cream, dessert and pastry.

For those in health and in the habit of exercising regularly, there are only the dangers of the sport to avoid while enjoying its pleasures and benefits.