Hypoxia has been a frightening term for doctors and medical students because of the possibility of damage to cells, tissues and organs. However, we now know that brief, episodic hypoxia gives rise to several adaptive responses. These responses in general prepare the body for better tolerating such hypoxic episodes, and also offer protection against several other types of insults. Indeed, scientists at the erstwhile U.S.S.R. have developed what is known as 'hypoxia therapy' and reaped the benefits of brief intermittent hypoxia for the last several decades. In India, yogic treatment of various diseases is common. A lesser known but important variety of Pranayama is 'nisshesha rechaka', which may be described as breath holding at residual volume. Studies done at our centre have demonstrated that Nisshesha rechaka is the easiest way to produce brief, intermittent hypoxia. There is therefore reason to believe that Nisshesha rechaka pranayama may offer benefits through this mechanism.
Keywords: Adult stem cell migration; breath holding; erythropoietin; expiration; intermittent hypoxia; vascular endothelial growth factor; yogic Pranayama.