Hi here is a physoilogical view.
If Pranayam is practiced as paying attention to the breathing
without changing its natural rhythm in any way, this part can hardly
have any adverse physiological effects.
But if the breathing is forced or reduced and so the natural self-
regulation of this very complicated and delicate process is
tampered with, the consequences can be rather knowledgeable.
The resting breath rate is about 15/min. securing a oxygen density
in the tissues at close to 100%
If breath rate is increased (Hyperventilation) it does not affect
the oxygen tension much, but it does markedly decrease the CO2
This causes an increase in free hydrogen ions and thus a lowering of
the pH of the blood and subsequently the body fluids. (Respiratory
acidosis) This has rather immediate and noticeable effects on the
body involved. Some symptoms are dizziness, confusion. (Even out of
body experiences and hallucinations)
As a result of the lowering pH of the blood, even a lowering of
calcium occurs, resulting in numbness and tingling in hands, arms
and in the face, spasms or cramps of hands and feet.
It has bees suggested here to breathe deeply at a rate of 60/min.
This will in a short time result in such a respiratory acidosis of
the body. Possibly with any number of the above mentioned symptoms
emerging. It is not a serious medical condition, as the person
affected if he does not stop, will finally pass out, thereby
automatically returning his breathing to normal and correcting the
offset blood chemistry.
Hyperventilation is an integral part of most panic disorders,
all of these symptoms giving the sufferer "proof" that something is
seriously wrong in the body.
The condition is treated with reassurance and if needed, placing a
plastic bag over the mouth and nose so the CO2 can reenter the body.
Magnesium deficiency is of rare clinical relevance.
Dietary or external applications has at best a very limited effect.