What is Hyperventilation?
Hyperventilation is often brought about through a response to an intense or exciting situation. When a person is hyperventilating, they are breathing much deeper and faster than they normally would and will often feel dizziness or tingling. It is not uncommon for a person to feel as if they will faint while hyperventilating, though they rarely do.
How Does This Affect the Body?
Because of the breathing patterns when hyperventilating, the air is moving in and out of the body too rapidly which, in turn, brings the level of carbon dioxide in the blood below normal. Low carbon dioxide levels cause the calcium levels in the body's fluids to also go below normal, which affects the nerves (hence the tingling and dizziness).
What Does a Paper Sack Do?
When breathing into a paper bag (more calmly and slowly, if possible) will increase the carbon dioxide level in the bag. Then, as you rebreathe the air you just exhaled, the increased level of carbon dioxide in the air you're intaking will increase the level of CO2 in your bloodstream and restore your calcium levels.