shallow water blackout

• shallow water blackout is caused by low oxygen levels
• shallow water blackout can be caused by repetitive, competitive or continuous breath holding by taking several very deep breaths, or hyperventilating before diving underwater
• swimmers pass out from shallow water blackout due to lack of oxygen and lower than normal carbon dioxide levels of which the carbon dioxide levels do not increase high enough to trigger the urgent need to breath
• shallow water blackout results in unconsciousness / blackout