why would a person feel faintness, pins-and needles with stiffness and
cramp in the hands and fingers when asked to hyperventilate in a
recumbent position for several minutes?

Hello, nzuzi-ga!

 Hyperventilation, or rapid breathing, leads to a lowering of carbon
dioxide in the blood, and consequently, less oxygen available to the
tissues and organs.


 There are many symptoms associated with hyperventilation, including
faintness, and numbness and tingling in the extremities. This can
occur even if one is in a recumbant position.


 "Carbon dioxide plays a vital role in the body's oxygenation process
through its role of facilitating the release of oxygen from the red
blood cells and into the tissues. Therefore lowering of the body's
carbon dioxide level equates directly to less oxygen reaching the
organs of the body, including the brain. This is why hyperventilation
affects all systems of the body leading to a puzzling array of
symptoms."

From "The Symptoms of Hyperventilation." Buteyko Asthma Management.
http://www.buteyko.co.nz/buteyko/work/hypervent.cfm
(See the list of symptoms as well)


===


 "Rapid breathing results in abnormal balance of carbon dioxide and
oxygen in the bloodstream. Hyperventilation, by decreasing the amount
of carbon dioxide in the blood, causes the blood to become basic. In
other words, this shifts the balance of calcium and potassium across
cell membranes. The imbalance of ions causes abnormal nerve and muscle
function (numbness and tingling, spasm of certain muscles)."

From "Hyperventilation," by Scott H. Plantz. emedicine (9/1/2001)
http://www.emedicine.com/wild/topic31.htm 


==


 "When you hyperventilate you overbreathe. This removes carbon dioxide
(CO2) too rapidly from your blood and alters the balance of your blood
gases. "

From "Hyperventilation Symptoms."
http://www.healthcaremanual.com/firstaid/hyperventilation/hyperventilation-symptoms.htm


===

 I hope this very basic explanation answers your question!

umiat-ga

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