In practicing yoga, we need to have an undogmatic openness, and a questioning, examining attitude to make progress. Yoga is rather a science (vidya), than a religion. The process of yoga is the pursuit of knowledge and its aim is the attainment thereof. Firstly, we gain knowledge of external objects and our own body, mind, egoity and intellect and only once that is faultless, do we progress to knowledge of the self.

The wide range of yogic breathing exercises is collectively referred to as pranayama. Pranayama is a compound noun, consisting of prana and ayama. The Sanskrit term prana denotes life force. Since life force is thought to have an air-like quality it is sometimes translated as inner or subtle breath. In some contexts prana simply means breath or even air. The full term pranayama means extension of prana. Extension of prana stands for life extension in a qualitative and quantitative sense. It is thought to not only increase the life span but also increase vitality.

The reason why breathing exercises are given such importance in yoga is that it is thought that the pulsating or oscillating of prana happens simultaneously with the movements of the mind (chitta vrtti). The practice of pranayama therefore is the study and exercise of one's breath to a point where it is appeased and does not agitate the mind.

The basic yogic breathing exercise is ujjayi pranayama (victorious extending of the breath). It is practiced by producing a gentle hissing sound through slightly contracting/closing the epiglottis as one breathes. The epiglottis is believed to function as a valve and by half-closing it the body is pumped up with prana (life force). The various asanas (postures) are used to become aware of all areas of the body. Where awareness goes-according to the traditional teaching-there goes life force. Chronic diseases are believed to develop where awareness is permanently lacking. The yogi learns to breathe into all parts of the body, an act that is equivalent to evenly spreading the prana throughout the body.

Yoga uses actively both the abdomen and the thorax to breathe. To describe this method of breathing D. Coulter has suggested the term 'thoraco-diaphragmatic breathing.' The intercostals are here exercised through actively exhaling. The air is literally pumped out of the lungs until all that remains is the respiratory rest volume, the amount of air left after a full exhalation. The aim is to breathe more deeply so as to increase vitality. The way to achieve this is not by inhaling as much as possible but by first exhaling completely in order to create space for the new inhalation.

Yogic tradition gives two vital reasons for wanting to increase breath volume. Firstly, by increasing our inhalation we increase the amount of oxygen supplied. Secondly, by increasing our exhalation we more efficiently exhale toxins, including mental, emotional, physical toxins, and environmental toxins.

Yoga sees these toxins to be held and stored in the body in 'stale' areas where there is only a small amount of oxygen, often around the joints or in adipose tissue. The build-up of these toxins-a literal energetic dying of certain body areas long before the death of the entire organism-is thought to eventually lead to chronic disease. By breathing deeply, exhaling accumulated toxins and inhaling oxygen, the yogi attempts to return the body to its original state of health.

Gregor Maehle has studied yoga for twenty-five years, focusing on his study of ashtanga yoga for the last seventeen years. In 1997, Shri K. Pattabhi Jois authorized him to teach ashtanga yoga. He is a passionate student of Sanskrit and formally studied anatomy and physiology in his native Germany. He is the cofounder and director of 8 Limbs Ashtanga Yoga studio in Perth, Australia. His website is www.8limbs.com