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dluring the slow exhalation. The baseline resting heart rate was about 70 bpm and blood pressure about 105/50 mmHg.
It has also been observed that the experience of enhanced energy, mental and physical balance, calmness and mental clarity associated with the pranayama practices increases greatly after several years of practice. The beginners following I he same techniques do not show such strong physiological changes.
Research has also been conducted on health threats of kumbhaka on people with abnormalities. It has been found that breath retention can induce a variety of cardiac arrhythmias?, but these appear to be a health threat only for people with significant pre-existing heart abnormalities22. Thus, the yogic precaution that kumbhaka techniques should be introduced gradually and only with proper guidance appear to be scientifically valid, particularly in the absence of a thorough heart examination. The techniques appear to pose no threat when done properly and introduced gradually for normal subjects.
Research on kumbhaka with bandhas When kumbhaka is performed with bandhas the heart rate for relatively inexperienced subjects increases only slightly or shows no change. In one experiment it was noted that the average heart rate increased about 8 percent during full inhalation kumbhaka with jalandhara bandha compared to the average baseline rate. The six subjects had about seven weeks of experience with the bandha. The average heart rate showed no change from the baseline rate during uddiyana bandha in a study with 39 subjects with less than eight months training24
In another study, which included moola bandha, the average heart rate increased by about 10 percent with 28 subjects25. Similar heart rate responses were found in subjects with no previous experience and in subjects with at least six months training. However, certain individuals may show a striking heart rate decrease during kumbhaka. The heart
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