In order to have good blood, we must breathe well. Full, deep inspirations of pure air, which fill the lungs with oxygen, purify the blood. They impart to it a bright color and send it, a life-giving current, to every part of the body. Good respiration soothes the nerves, stimulates the appetite, and aids digestion. And it induces sound, refreshing sleep. MHH 151.4
The lungs should be allowed the greatest freedom possible. Their capacity is developed by free action; it diminishes if they are cramped and compressed. Ill effects follow the practice so common, especially in sedentary pursuits, of stooping at one’s work. In this position it is impossible to breathe deeply. Superficial breathing soon becomes a habit, and the lungs lose their power to expand. MHH 152.1
A similar effect is produced by tight clothing around the waist. Sufficient room is not given to the lower part of the chest. The abdominal muscles, which were designed to aid in breathing, do not have full play, hence the lungs do not take in a sufficient supply of oxygen. The blood moves sluggishly. The waste, poisonous matter, which should be thrown off in the exhalations from the lungs, is retained, and the blood becomes impure. MHH 152.2
Not only the lungs, but the stomach, liver, and brain are affected. The skin becomes sallow. Digestion is retarded. The heart is depressed. The brain is clouded. The thoughts are confused. Gloom settles over the spirits. The whole system becomes depressed and inactive, and peculiarly susceptible to disease. MHH 152.3
The lungs are constantly throwing off impurities, and they need to be constantly supplied with fresh air. Impure air does not afford the necessary supply of oxygen, and the blood passes to the brain and other organs without being vitalized. Hence the necessity of thorough ventilation. To live in close, ill-ventilated rooms, where the air is dead and unhealthful, weakens the entire system. It becomes peculiarly sensitive to the influence of cold, and a slight exposure induces disease. Close confinement indoors makes many men and women pale and feeble. They breathe the same air over and over until it becomes laden with poisonous matter thrown off through the lungs and pores, and impurities are thus conveyed back to the blood. MHH 152.4