We just returned from the American Swimming Coaches Association’s annual World Clinic - What a fabulous way to gather information while being inspired to return with passion for our sport!
Bob Bowman who is perhaps best known for his work with Michael Phelps gave an even more important presentation titled “Shallow Water Black Out”. Unfortunately the inspiration for the session came from an all too real life experience for the staff at his pool several months ago. The lessons learned are painful but the information below is critical to the safety of all our swimmers.
SHALLOW WATER BLACK OUT occurs in 15 feet of water or less. The three most likely candidates are US Navy Seals, deep free divers and elite competitive swimmers.
The event happens when a swimmer hyperventilates forcefully several times in preparation for an underwater swim. In our case a long stretch of underwater dolphin kicks or breaststroke swims. A long stretch is relative but the consensus is 25 yards is fine, after that things get uncertain. 50 meters is definitely in the very dangerous/fatal zone.
When a swimmer hyperventilates in an effort to increase the amount of oxygen that can be stored in the lungs what happens is the amount of carbon dioxide in the bloodstream is reduced to dangerously low levels. Carbon dioxide is the ingredient that causes the urge to breathe. Without the urge the swimmer simply passes out, loses consciousness. The body’s natural response after this happens is to open the mouth and take a deep breath. But the swimmer gets water instead.
You have no more – often less – than 2.5 minutes to see that the event has occurred, get the swimmer out, empty the lungs of water, get oxygen to the brain or the swimmer dies…in shallow water regardless of the fact the she/he is in top physical condition.
You must have a safety plan for the operation of your practices and what happens in the event of a SHALLOW WATER BLACK OUT.
Obviously, the best plan is to limit the amount of distance under water to 25 yards and to avoid those competitive urges at the end of practice. Also, if you do not have multiple back to back underwaters and do not allow hyperventilation you greatly decrease the risk.
We will have some more information on this deadly situation as it becomes available.
This may have been the most important blog we have ever written. Bob Bowman is an intensely competitive person and coach. He made it very clear that this incident shook him to his core and sharing the information with us was more important than any discussion he has ever led in the world of swimming.