Habits are easily formed; but, when once formed, not so easily broken. They ought to be our servants; very commonly they become our masters.
In reference to eating and drinking, habits regular as to time and moderate as to quantity are especially important. The habit of eating hastily and masticating the food imperfectly, is certain, sooner or later, to produce disease. Over-eating, again, is a fertile source of disease, especially when the excess is in animal food. The amount of stimulation produced by a given dose of alcohol, gradually diminishes with its repetition; the consequence is, that in order to produce the amount of stimulation to which the system has become habituated, the stimulant requires to be gradually increased. The craving for stimulants is often a sign of ill-health, owing to disregard of hygienic laws or actual disease. Not infrequently it is due to badly-ventilated rooms or long hours of work without food, producing a sense of depression which food does not immediately allay. When the cause is unknown, recourse should be had to competent medical advice, and not to the brandy bottle.
Attention to the Action of the Bowels is a matter which is commonly neglected. The importance of a regular habit in this respect cannot be exaggerated; the bowels should always be relieved at a particular time each day. Where this does not occur the condition of constipation results. Owing to the retention of the fæces in the intestines beyond the normal period, the stomach and higher parts of the intestines do not perform their functions normally; indigestion and “dyspepsia,” accompanied by headache, flatulence, and other symptoms follow. Hæmorrhoids (piles) are another frequent consequence. At the junction of the small and large intestines is a dilated sac (in the cæcum). This becomes distended when constipation occurs; inflammation may be set up, and an operation required, or the condition is fatal. Powerful purgative medicines are injurious to the bowels, and they tend afterwards to increase constipation. It is better to take slow-acting aperient remedies, and better still not to take any at all, but relieve the condition by means of such articles of diet as stewed fruit, pears, figs, olive oil, or brown bread. As a rule more exercise is required in this condition, and always a prompt attention to the calls of nature.
[CHAPTER XXXVII.]
PERSONAL HYGIENE—EXERCISE.
Physiological Considerations.—In the strict sense of the word, exercise signifies the performance of its functions by any part of the body; thus, digestion is exercise of the stomach, respiration is exercise of the lungs, thinking is an exercise of the brain. But the term is usually applied chiefly to muscular contraction, and restricted to contraction of voluntary muscles. Involuntary muscles, which are concerned in the carrying on of the unconscious organic functions of life, are not directly controllable, and so their growth and state of nutrition cannot be regulated. There are two sets of involuntary muscle, which are of special importance—the heart and the muscles of respiration. The heart contracts at least sixty times per minute; the respiratory muscles contract about seventeen times per minute; and this amount of exercise goes on throughout the whole day. But although we cannot make our hearts beat quicker by a direct volition, and cannot breathe more rapidly than usual beyond a few seconds, yet a brisk walk will cause increased action of the heart and respiratory muscles, as well as a vigorous contraction of the muscles directly concerned in walking. Going uphill is a valuable exercise for the heart. The vermicular contractions of the intestines are to some extent also increased by voluntary exercise, through the indirect excitation of the whole system; thus, exercise is an important element in the treatment of constipation.
The muscles contain about a fourth of the whole blood of the body, and a very large share of the metabolism (page [4]) of the body occurs in them.
Hence the importance of keeping them in a healthy condition by exercise. The great danger is of not equilibrating the muscular and nervous functions. The ideal condition is where neither mental nor muscular culture is neglected, but both are co-ordinated to the production of a healthy man.
Effects of Healthy Exercise.—1. The Nutrition of the Muscles is improved. The volume, density, and energy of the muscles are increased.
2. The action of the lungs is increased. Dr. E. Smith found that if the air inspired while lying down be represented by unity, the amount inspired when erect is 1·33; when walking at the rate of one mile per hour, 1·9; at four miles per hour, 5; at six miles per hour, 7; riding on horseback, 4·05; swimming, 4·33. Or, putting it in another way, under ordinary circumstances a man inspires 480 cubic inches per minute; if he walks four miles per hour, he inspires 2,400 cubic inches; if six miles an hour, 3,260 cubic inches.