What is the primary reason for prohibiting breath holding contests in swimming?

The primary reason for prohibiting breath holding contests in swimming is to prevent sudden underwater blackout. This phenomenon occurs when a swimmer holds their breath for an extended period, leading to carbon dioxide levels dropping too low. When the body senses low carbon dioxide, it may trigger a loss of consciousness due to a lack of oxygen to the brain. This can be particularly dangerous in water, as it increases the risk of drowning and serious injury. Hence, safety guidelines emphasize protecting swimmers from engaging in practices that could lead to this critical condition, illustrating the importance of always maintaining safe swimming habits.