What should you do if you notice a person swimming full lengths of the pool underwater?

The correct action is to immediately stop and explain the dangers of swimming underwater for prolonged periods. Swimming underwater can pose serious risks, including the potential for shallow water blackout, where a swimmer loses consciousness due to hypoxia, or the risk of drowning if they become disoriented or incapacitated due to the lack of oxygen.

By addressing the individual directly, you can communicate the hazards associated with this behavior and promote safer swimming practices. It’s crucial to intervene before any potential incident occurs rather than waiting to respond after an incident has taken place. This proactive approach is key in lifeguarding, ensuring the safety and well-being of all patrons in the swimming facility.

In contrast, ignoring the activity could lead to a dangerous situation where the swimmer may become unconscious or disoriented and need immediate assistance. Alerting other patrons or calling emergency services would also be an inadequate response unless the situation has already escalated to such an emergency, which could have been avoided with timely intervention.