Deep Breathing.
The Greeks are quoted as saying, "A healthy soul can only live in a healthy body." People are beginning to see that to a great extent, intellectual vigor depends upon physical vigor.
Man is an air breathing animal.
Air is life. One may go without food and water for days but not many minutes without air.
Air is the most important factor in generating vital force and it is the best tonic in the world.
A large, deep, chest indicates Health, Strength and Vitality. The size of the chest indicates the size of the lungs. A narrow chest indicates cramped lungs, heart, digestive organs and a small diaphragm.
The diaphragm is the dome shaped breathing muscle which serves as a partition between the chest and abdominal organs. Its contraction causes development of the lungs and heart and at the same time the internal massage of the abdominal organs.
The lungs have been called the scavengers of the body for they take off poison which would kill us.
As the blood stores oxygen especially at night, windows should be kept open to prepare the body for the next day's duties.