________________
maximal aerobic capacity and an over 200-fold increase in respiratory work. likewise, the high heart rates observed 3 during bhastrika are consistent with moderate rather than mild work loads. The YRF (2004) study observed that when external retention was practised after the rapid breathing of bhastrika, oxygen saturation decreased. When external retention was combined with maha bandha, the effect was profound and oxygen saturation decreased up to 54 percent (maximum).
These practices can prove to be useful for persons with chronic obstructive lung disease when performed under expert guidance, because their activities can be limited by respiratory muscle endurance. However, they should use caution with rapid breathing, as it has been found that indiscriminate practice can exacerbate a condition. The YRF study, when it used a pulse oxymeter in the fourth week of the experiment, found that the changes in the pulse rate and oxygen saturation of blood during the various phases of bhastrika (including external kumbhaka and maha bandha) were very rapid. This confirms the repeated advice to practise caution, for such fluctuations will tax a weak heart, and an individual with heart, circulatory, respiratory and brain disorders may not be able to tolerate them. Similarly, when an organ is damaged, the fall in oxygen supply can further deteriorate its function.
It has also been recorded that while practising kapalbhati, bhastrika, surya bheda and moorchha pranayamas, there is awakening of extra electrical impulses in the central autonomous system, resulting in extra activity in the brain. The electrical voltage becomes at least 20 times higher than normal. In yogic terms, this indicates the awakening of sushumna. This is supported by the YRF (2004) study, which showed a change of swara to sushumna in most cases after the practice.
Research on kumbhaka Breath retention can initiate powerful parasympathetic and sympathetic reflexes. The net psycho-physiological effects depend gready on various physical and psychological parameters
145
