Its average depth is about 3,688 meters (12,100 ft), and its maximum depth is 10,994 meters (6.831 mi) at the Mariana Trench. Nearly half of the world's marine waters are over 3,000 meters (9,800 ft) deep. The vast expanses of deep ocean (anything below 200 meters or 660 feet) cover about 66% of Earth's surface.
hyperventilation. 1. increase of air in the lungs above the normal amount. 2. abnormally prolonged and deep breathing, usually associated with acute anxiety or emotional tension. A transient, respiratory alkalosis commonly results from hyperventilation. More prolonged hyperventilation may be caused by disorders of the central nervous system, or by drugs.
Medical Definition of Hyperventilation Hyperventilation: Overbreathing. Hyperventilation causes dizziness, lightheadedness, a sense of unsteadiness, and tingling around the mouth and fingertips. Hyperventilation can be severe enough to mimic the early warning symptoms of a heart attack, and is therefore a common cause of emergency room visits in the US.