SWBShallow Water Blackout

SWBShallow Water Blackout

By Michelle Brislen

What is SWB?What is SWB?

Loss of Consciousness while in water Usually caused by hyperventilation

while freediving or breath-holding Often happens to freedivers,

athletes, and good swimmers. Can happen in the ocean, pools,

lakes, rivers, etc.

Loss of Consciousness while in water Usually caused by hyperventilation

while freediving or breath-holding Often happens to freedivers,

athletes, and good swimmers. Can happen in the ocean, pools,

lakes, rivers, etc.

“Hero Worship”“Hero Worship”

Image from NY Times

Energy ProcessesEnergy Processes

QuickTime™ and a decompressor

are needed to see this picture.

Cellular Respiration C6H12O6 + 6O2 6CO2 + 6H2O + Energy

€

→Sugar Oxygen Carbon Dioxide

Water

How does it happen?How does it happen?

Release of CO2 (Carbon Dioxide) through hyperventilation or deep exhales

When under water O2 (Oxygen) is used up and turned in to CO2

CO2 is lower than normal because of hyperventilation thus decrease urge to breathe

Stay down/under water longer and O2 continues to be used and deprives brain

Blackout occurs

Release of CO2 (Carbon Dioxide) through hyperventilation or deep exhales

When under water O2 (Oxygen) is used up and turned in to CO2

CO2 is lower than normal because of hyperventilation thus decrease urge to breathe

Stay down/under water longer and O2 continues to be used and deprives brain

Blackout occurs

Normal Dive

SWB Dive

Diagrams from Wikipedia

€

→Problem

Diagram from Aquatics International

Shallow Water BlackoutShallow Water Blackout

How to Prevent SWBHow to Prevent SWB Do not hyperventilate Do not have breath-hold competitions

under water Do not perform underwater laps When you feel the urge to breathe, begin

your ascent “Leave something in the tank!”

Dive with a Buddy!!!! Maintain watch for 30 seconds after surfacing

Be weighted correctly and willing to release your belt if you’ve pushed it too far.

Tell your friends! Adults too!

Do not hyperventilate Do not have breath-hold competitions

under water Do not perform underwater laps When you feel the urge to breathe, begin

your ascent “Leave something in the tank!”

Dive with a Buddy!!!! Maintain watch for 30 seconds after surfacing

Be weighted correctly and willing to release your belt if you’ve pushed it too far.

Tell your friends! Adults too!

ReferencesReferences

shallowwaterblackoutprevention.org “Confessions of a Freediving Spearo” by

Sheri Daye; Hawaii Skin Diver Magazine 2010

www.aquaticsafetygroup.com/PDF/DyingforAirAquaticsInternationalFebruary2005.PDF

www.aquaticsafetygroup.com/PDF/ShallowWaterDeathTheCombatEdge2003.pdf

www.wikipedia.com

shallowwaterblackoutprevention.org “Confessions of a Freediving Spearo” by

Sheri Daye; Hawaii Skin Diver Magazine 2010

www.aquaticsafetygroup.com/PDF/DyingforAirAquaticsInternationalFebruary2005.PDF

www.aquaticsafetygroup.com/PDF/ShallowWaterDeathTheCombatEdge2003.pdf

www.wikipedia.com