Today's useless fact - Does breathing into a paper bag really stop a person from hyperventilating? If so, why?

Apparently so. The paper bag technique as a popular home treatment for hyperventilation. To find out why this cures most (but not all) cases, we consulted one of the links and learned that most instances of hyperventilation are relatively mild. Anxious or nervous people start to feel they can't get enough oxygen and breathe too quickly. This lowers the carbon dioxide level in the blood, which can cause "symptoms of numbness and tingling of the hands, and dizziness."

The paper bag works effectively because it forces the person to breathe in the carbon dioxide rather than "lose it into the atmosphere." After 5 to 15 minutes, the feeling of panic usually goes away. Just be careful not to overdo it and breathe in too much carbon dioxide.

Of course, when it comes to all things medical, it pays to err on the side of caution. If you're having trouble breathing and suspect something other than a mild case of hyperventilation, please seek medical assistance. And, for God's sake, never use a plastic bag. Check out the links in our Breathing category for more.