What happens when a person hyperventilates?

When a person hyperventilates, they begin to breathe very rapidly and deeply, which can lead to a significant decrease in the carbon dioxide (CO2) levels in the blood. This condition, known as hypocapnia, causes the body to enter a state of respiratory alkalosis, where the blood becomes more alkaline. As the CO2 level drops, various physiological responses can occur, including dizziness, confusion, and ultimately loss of consciousness. This happens because the brain is sensitive to changes in CO2 levels; when they drop too low, it can impair cerebral blood flow and function.

Other options, while related to different aspects of physiology, do not accurately describe the direct consequences of hyperventilation. Feeling relaxed and calm is typically associated with slower breathing rates, not the rapid and uncontrolled breathing seen in hyperventilation. Similarly, an increase in body temperature is not a direct result of hyperventilation; rather, it usually relates to metabolic processes or exercise. Lastly, while hyperventilation might lead to feelings of lightheadedness that can be misinterpreted as muscle looseness, it does not actually lead to muscles becoming excessively loose. Thus, loss of consciousness is the most direct and significant risk associated with hyperventilation.