The Dangers of Shallow Water Blackouts: Told by an Eye-Witness
November 21, 2016
Hang on for a minute...we're trying to find some more stories you might like.
Email This Story
Less than a week ago, I witnessed teammate have a shallow water blackout during swim practice. It was a very alarming and terrifying experience, but thanks to quick response by coaches, fellow swimmers, and first responders, the person who suffered the blackout survived without any permanent damage. However, this event did have the permanent impact of raising awareness about the dangers of shallow water blackouts for all of the members of the swim team, which is of utmost importance in our society that has a constantly growing number of swimmers, freedivers, and spearfishermen.
According to Shallow Water Blackout Prevention, shallow water blackout (SWB) is “an underwater ‘faint’ due to a lack of oxygen to the brain brought on by holding your breath for long periods of time”. If the person who blacks out is not quickly rescued, then he or she will drown.
The hypoxia, or lack of oxygen, that results in SWB can be caused by multiple factors.
Hyperventilating, the process of having short and rapid breaths, is used by many as a tool for holding breath for extended periods of time, but it can also lead to SWB. What makes swimmers feel the urge to breathe is not hypoxia, but hypercarbia, the excess of carbon dioxide (CO2) in the body. Hyperventilating prevents hypercarbia by lowering carbon dioxide levels inside the body, lowering the urge to breathe during a breath hold. However, hyperventilating does not raise oxygen levels, therefore not preventing hypoxia.
To put this in a more familiar situation, imagine the human body as a car, where oxygen is the fuel and carbon dioxide is the low fuel warning. Hyperventilating eliminates the low fuel warning, but it does not add more fuel to the car, making it much easier to run out of gas, or black out.
In addition hyperventilating, SWB can be caused by doing multiple dives and/or underwater swims without adequate rest in between, or it can be caused by playing breath-holding games. SWB affects people of all ages but is more common in physically fit swimmers and divers. In addition, SWB is instantaneous and can happen at any depth of water, from a bathtub to a 20 feet deep pool, so the swimmer can not sense the approach of a blackout.
Overall, it should not take a personal experience to be aware of the dangers of SWB. It is a life threatening condition that does not receive as much attention as it deserves. The next time you snorkel, freedive, or breathhold underwater, make sure you are taking the appropriate safety measures to prevent SWB from happening.