You breathe without thinking because your body does it for you automatically. But things can change your breathing pattern and make you
feel short of breath, anxious, or ready to
faint. When this happens, it’s called hyperventilation, or overbreathing.
That’s when you inhale much deeper and take much faster breaths than
normal. This deep, quick breathing can change what’s in your blood. Normally, you breathe in
oxygen and breathe out carbon dioxide. But when you hyperventilate, the carbon dioxide levels in your bloodstream drop too low. You’ll notice it right away because you’ll start to feel sick.