Hyperventilation is defined as

• A. An abnormal increase in the volume of air breathed in and out
• B. A decrease in breathing rate
• C. An increase in oxygen in the blood
• D. A symptom of dehydration

Answer: (A)

Hyperventilation means you are moving more air in and out than your body needs—a ventilation increase beyond metabolic requirements. This excessive air exchange lowers the carbon dioxide level in the blood, which can cause symptoms like lightheadedness, tingling, and chest discomfort. It’s not simply about breathing faster, and it’s not defined by a rise in oxygen in the blood or by dehydration. So the precise description is an abnormal increase in the volume of air breathed in and out.