It's a common misconception in pool management that the precepts of water safety mainly apply to small children, the elderly, and non-swimmers. This is a significant mistake. Even strong swimmers in the 15 - 26 year old age group are at risk for shallow water blackouts when they participate in aquatic activity.
Since shallow water blackouts are a recently understood phenomenon, you've probably never heard of them. However, regardless of their notoriety, they present a very real danger to every swimmer--particularly in unsupervised and mismanaged swimming environments.
What Is A Shallow Water Blackout?
A shallow water blackout is a loss of consciousness that occurs when a swimmer is holding their breath. Because it is linked to the rise in carbon dioxide levels caused by physical activity, divers and people who are capable of raising their heart rate are primarily at risk. This is a major reason that lifeguards and supervisory staff must be aware of the issue--shallow water blackouts happen primarily to accomplished swimmers.
Stages of a Shallow Water Blackout
The typical shallow water blackout happens in four phases. They are:
- Overbreathing--Before the event, victims engage in overbreathing. This elevated breathing can be the result of breath-holding prior to the incident, or simply due to physical exertion and an elevated heart rate. This causes carbon dioxide levels to drop in the victim's system.
- Carbon Dioxide Spike--As the swimmer holds their breath, oxygen is used--causing more carbon dioxide to be held in the swimmer's system. This imbalance causes the body to react differently to being oxygen-starved than under typical circumstances.
- Loss of Consciousness--The imbalance in oxygen and carbon dioxide causes the swimmer to lose consciousness much more quickly than expected. This can happen within seconds of the start of a dive--often while the swimmer is still multiple feet below the surface.
- Death--The cause of death from a shallow water blackout is drowning. However, upon losing consciousness, the victim's body will force a breath--causing their lungs to quickly fill with water. As a result, death can often occur in under 3 minutes instead of the typical 6-8 minute time frame.
Risks For Lifeguards and Pool Staff
Since shallow water blackouts are drowning incidents, effective supervision and lifeguarding can prevent a catastrophe in almost every circumstance. That said, because of their unique nature, shallow water blackouts pose specific issues that can catch the untrained lifeguard unaware.
Victim's Profile--The typical person who suffers from shallow water blackouts is a physically fit swimmer. That's because adept swimmers are more likely to elevate their heart rate from aquatic activity--and are also more likely to engage in diving and other activities where breath holding is required. Untrained lifeguards often inadvertently neglect these swimmers in their scans.
Incident Identification--Many people are capable of holding their breath for multiple minutes. A person who goes under and experiences an immediate blackout is in danger long before a casual observer will notice their situation. Only a lifeguard with experience in setting observation protocol and a disciplined application of this protocol will catch the incident in time.
Response Time--The elapsed time from beginning of blackout to death for victims of shallow water blackouts is under 3 minutes. That means the lifeguard must understand the situation, retrieve the victim, and begin rescue protocol in a short time frame. Only sharp, well rested and frequently rotated lifeguards will likely succeed under these circumstances.
Shallow water blackouts are a serious incident that present severe logistical issues for lifeguards and major liability issues for pool owners. Unfortunately, due to their unique circumstances, shallow water blackouts cannot be completely prevented. Only the response from a highly-trained and well-managed lifeguard crew can prevent a catastrophe from happening in your pool.