Controlled breathing

Controlled breathing is abnormal breathing consciously controlled.
During this activity, we control how many breaths we take per minute, how deep each breath is, how long we inhale and exhale and how we use the lungs.
There are literally hundreds of breathing techniques that are classified as controlled breathing.
Some are totally ineffective, but do no harm; some are potentially dangerous; some heal;
some produce visions, hallucinations, and out of body states.
Some produce states of relaxation conducive to the receipt of wisdom and inspiration,
and movement along the spiritual path.
Thus this is one activity where you need a teacher, who really knows what they are doing.