Swimmers can fall victim to Shallow Water Blackouts - AmericaNowNews.com


Strong, capable swimmers can fall victim to Shallow Water Blackouts

Rhonda Milner's 25-year-old son, Whitner, was swimming with friends and practicing holding his breath in his backyard pool when he died of a condition known as Shallow Water Blackout (SWB).

He had been practicing for a special spearfishing trip to the Bahamas in which the swimmers were required to hold their breath for three minutes.

"When everyone decided to get out of the pool, he stayed in and did one more last breath hold," Milner said. "It was dark and late, and no one noticed Whitner still on the bottom."

When Rhonda went to turn off the pool lights the next evening, she saw Whitner laying on the bottom of the pool. Initially, she thought he was just practicing his breathing exercises. 

"I sort of splashed at the water and he didn't move," Milner said.

Then she attempted to rescue him.

"That's when I jumped in to try to pull him up out of the water," she recalled.

He was so waterlogged, she was unable to move him.

Most victims of SWB have two things in common: they are healthy and strong swimmers.

John Kirk is the co-owner of the Little Otter Swim School, a children's swim school located in Charlotte, NC. He is also a member of the U.S. Swim School Association.  

"This may be the leading cause of death among strong swimmers," Kirk pointed out to America Now's Casey Roman.  

Without providing any warning of distress to anyone who might be around, a swimmer can die in less than two minutes.

There are numerous ways SWB can occur. It could result from children or adults playing breath-holding games under the water, swimmers competing by swimming underwater side to side, or more commonly, intentionally hyperventilating in order to take in more air to stay under the water longer.

The problem is that you can't quickly store all that extra oxygen in your blood.  

All you have actually done is blown off large amounts of Carbon Dioxide (CO2).

Carbon Dioxide gas is critical to your survival because the increase in CO2 levels, not oxygen, is what triggers your brain to know its time to come up for air.

Because all that exhaling has lowered the CO2 level while the body's oxygen drops, the swimmer passes out and the urgent need to breathe never happens.  

"Eventually, you're just running on an empty tank and the body just checks out," Kirk said.

Life guards may be unlikely to spot the distressed swimmer under water because of surface glares and ripples. Meanwhile, the unconscious swimmer instinctively takes a breath.

"But it's going to be a lung full of water, and you're going to drown almost immediately," Kirk said.

SWB is never listed on an autopsy. If someone didn't see exactly what happened, the cause of death is usually labeled drowning.

Experts say the message here is clear and non-negotiable.

"Breath-holding games should never be practiced, it is very dangerous," Rhonda Milner warned.

That goes for poolside hyperventilating, and long underwater swims as well.

For swimmers who are training for deep water or free divers, Milner advised, "The only safe way to do that is if you're just continuously monitored by someone."

The challenge of trying to spend just a little more time underwater, can lead to a heartbreaking legacy of dying for air.

Copyright 2013 America Now. All rights reserved.

Additional Information:

The following information is from Shallow Water Blackout Prevention (Source: http://shallowwaterblackoutprevention.org/).

  • Shallow Water Blackout can be caused by repetitive, competitive or continuous breath holding or by taking several very deep breaths, or hyperventilating, just before diving underwater.                
  • Swimmers pass out due to the lack of oxygen (O2) and lower than normal carbon dioxide (CO2) levels of which the CO2 levels do not increase high enough to trigger the urgent need to breathe, resulting in unconsciousness/blackout.
  • After this occurs the delayed trigger to breathe results in water quickly filling their lungs while unconscious.
  • Death or brain damage occurs much sooner than the usual form of drowning.

The following information is from the Aquatic Safety Group (Source: http://www.aquaticsafetygroup.com/ShallowWaterBlackout.html).

  • Shallow Water Blackouts result from insufficient amounts of carbon dioxide to active at the body's natural impulse to breathe.
  • Practicing prolonged underwater breath-holding puts swimmers at risk.
  • Swimmers often attempt voluntary hyperventilation (rapid in and out breathing) in an attempt to take in more oxygen. However, carbon dioxide is being blown off.
  • Involuntary hyperventilation occurs during strenuous exercise, excitement or anxiety.
  • When blood oxygen runs low before the carbon dioxide levels rise to the point that triggers a breathing reflex, the swimmer loses consciousness, never feeling that a breath is needed.
  • Once submerged the swimmer is often hidden from view by surface glares and ripples
  • Water is inhaled, possible convulsions and ultimately cardiac arrest and death.
  • Past victims include healthy, athletic males, ages 15-26 who were strong swimmers.

The following information is from AthleticBusiness.com (Source: http://www.athleticbusiness.com/editors/blog/default.aspx?id=608).

  • By hyperventilating prior to submersion, an individual blows off an excessive amount of carbon dioxide thereby suspending his or her breathing reflex.
  • When the oxygen level in the blood runs low enough, that person loses consciousness without feeling the need to breathe.
  • Sometimes they feel euphoria.
  • Unlike regular drowning, which can take six to eight minutes before brain damage and death occur, SWB can kill within two and a half minutes.
  • Medical examiners typically state the cause of death as "drowning" -based on the fact that water is in the victim's lungs.
  • Official statistics on shallow water blackout fatalities don't exist.

The following information is from the CultureOfSafety.com (Source: http://www.cultureofsafety.com/aquatics/shallow-water-blackout/).

  • An individual simply loses consciousness and can drown without any sign of a struggle.
  • In some cases, an individual experiencing a shallow water blackout will appear to be making coordinated movements because their body may continue to function temporarily.
  • Victims typically have no prior medical problems, are physically fit, and give no warning.
  • Lifeguards should be trained to stop ALL breath holding activities, regardless of the swimmers physical fitness or expertise.

The following information is from the U.S. Navy (Source: http://www.public.navy.mil/navsafecen/Documents/media/seashore/seasonal/SeaShoreWinter09-10.pdf).

  • Few statistics exist on shallow water blackout but the Navy became concerned enough about SWB that commanders were directed to tell their people about the dangers and post warnings.
  • Victims usually lose consciousness within 15 feet of the surface, where expanding, oxygen-hungry lungs literally suck oxygen from the blood.
  • Swimmers fool observes because they appear to make coordinated movements although physiological brain damage, cardiac arrest or death is only minutes away.
  • Even if they are saved, the brain damage is often irreversible.
  • Don't hyperventilate.
  • Recognize that any strenuous exercise you do under water will drastically limit the time you can stay under water. Head for the surface sooner.
  • Explain in simple terms to children at a young age what SWB is and why they should never practice breath-holding.
  • The national average victim of shallow-water blackout is 15-40 year old male who is experienced at freediving and who regularly practices hyperventilation at the surface to extend his dive time.
  • Use a buddy. Chose someone with strong swimming skills who you can trust to watch you closely.
  • Take time to recover at the surface.
  • Don't overexert. Your dive time is decreased by exercise.
  • Know CPR and what to do in an emergency.
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