Before beginning any practical breathing exercises, it is useful to familiarize yourself with the three elements that make up a single breath and their relative importance in your breathing practice. These are inhalation, exhalation and the transition between these two actions, known as retention. Exhalation is the focus of most breathing exercises.
As your lungs take in air, oxygen passes into your body, providing it with one of the essential ingredients of life. The inward flow of air into your lungs is more or less automatic, since once you exhale, inhalation effortlessly follows. For this reason, the in-breath is not emphasized in many of the exercises in this book.
The outward flow of air from your lungs expels gaseous waste products, such as carbon dioxide, from your body – your lungs therefore act as an organ of excretion. Yogis believe that exhalation also eliminates impurities from the mind, and that if you suffer from shortness of breath or cannot exhale completely, toxins will accumulate in your body which can negatively affect your mind. Exhaling also helps your mind and body adjust to change. For example, if you jump into a shower that is much colder than expected, you are likely to exhale sharply.
Smoking tobacco harms every organ in the body, but is particularly deadly for the organs of respiration – the lungs – and increases your risk of dying from lung disease ten-fold. The breathing exercises in this book will not make you stop smoking. However, if you would like to stop, they can offer some powerful assistance. Breathing exercises cleanse your respiratory system to make you feel revitalized. They can also strengthen your willpower by showing you that rather than giving something up, you are in fact giving yourself a gift – the joy that comes from breathing deeply again.
The following elements affect the outcome, or the physical and emotional effects, of any breathing exercise:
• The length of the inhalation.
• The length of the exhalation (usually twice as long as the inhalation).
• How long you retain your breath after inhaling.
• The volume of air you inhale or exhale.
• The ratio of each part of your breath – the inhalation, exhalation and retention – to the other parts.
• Where in your body you focus your thoughts – for example, your heart or your navel.
• The number of times you repeat an exercise or a cycle of breaths.
The absence of either inhalation or exhalation is known as retention, the transition between the two actions. When you inhale and hold your breath, the rate of gaseous exchange in your lungs goes up as a result of the increase in pressure (see pages 20–21). This means that more oxygen passes from your lungs into your bloodstream. At the same time, more carbon dioxide and other gaseous waste products pass from your blood into your lungs, ready to be eliminated with your exhalation. The pause made by your out-breath as it stops for a moment en route to becoming your in-breath is technically also a retention. This portion of your breath is rarely noticed, but is actually deeply calming and is employed in some of the breathing exercises in this book.