Hyperventilation is a condition in which you start to breathe very fast. Healthy breathing occurs with a healthy balance between breathing in oxygen and breathing out carbon dioxide. You upset this balance when you hyperventilate by exhaling more... Read More. Hyperventilation is a condition in which you start to breathe very fast. Healthy breathing occurs with a healthy balance between breathing in oxygen and breathing out carbon dioxide. You upset this balance when you hyperventilate by exhaling more than you inhale.