A shallow water blackout occurs when a person loses consciousness while swimming or diving in shallow water. This can happen due to hyperventilation before holding their breath, which lowers carbon dioxide levels in the blood. When the body’s oxygen supply becomes critically low, the person may faint, often leading to drowning if not rescued quickly. This phenomenon is particularly dangerous because it can happen in just a few feet of water, making it easy for swimmers to underestimate the risks. Awareness of breath-holding techniques and the importance of supervision can help prevent these incidents and ensure safety while enjoying water activities.