Are you aware how easy a shallow water blackout can occur?

It can affect anyone that is breath-holding, even the physically fit swimmer. It is especially seen in competitive swimmers, Navy, snorkelers, spear fishermen or anyone who free-dives. SWB cuts across the spectrum of freediver training affecting all levels.

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.

Jack MacMillan was only 12 years old when he sadly lost his life after breath holding games in his pool on 29th January 2013.

Nic Fisher, from NSW, sadly also lost his life to breath holding games in his pool 16 years ago while celebrating Christmas.

He too was just 12 when he passed out and quickly and quietly drowned. A fit kid who was a fantastic swimmer and water skiier.

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 whilst unconscious. Death or brain damage occurs much sooner than the usual form of drowning.

People who hold their breath while swimming or practicing breath-holding underwater in pools are at risk of “passing out” due to lack of oxygen and no warning.

This phenomenon is commonly referred to as shallow water blackout (SWB) and Hypoxic Blackout in some countries and is the result of a SEVERE LACK OF OXYGEN TO THE BRAIN due to falsely lower than normal carbon dioxide levels which is our trigger to breathe at high levels as our oxygen levels become low. It is our bodies natural built in mechanism.

HOW TO BEST AVOID SWB FATALITY via shallowwaterblackoutprevention.org

  • Do not practice prolonged breath-holding. The ARC, YMCA and USA Swimming now ban hypoxic training and prolonged underwater swimming although far too many still practice it. (make sure your swimming coach is aware of the dangers and is fully qualified before participating in hypoxic drills. Shallow Water Blackout Australia does not condone hypoxic training and would like to see this practice banned in Australia)
  • Never swim alone.
  • Underwater breath-holding should never be encouraged, but if practiced the rule of thumb for safety is;
    One Breath-hold, One Time, Once Only, Rest (taking a 5 minute rest break to help your Co2 & O2 levels return to normal).
  • Never Hyperventilate.
  • Repetitive breath-holding Increases risk of SWB. If Breath-holding under water, a buddy must be next to you tapping you on your shoulder so you can signal that you are OK. Their total focus needs to be you and your safety.  They should never breath-hold with you. Do not rely on lifeguards. SWB is difficult to detect above water.

Be aware and teach your kids how to swim safely.

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  • I have never come across this before. Seems like all parents should be aware of it. Dangers lurk where we least expect


  • Thanks l haven’t heard of this!


  • I remember reading about a Dad who drowned after diving back into the water before breathing naturally for long enough. His wife suddenly realised he hadn’t resurfaced. looked down and spotted him at the bottom of the pool. She yelled out for help as she ran inside with their young baby, put her in a safe place, grabbed the phone as she ran back out, then dived into the pool and dragged him to the surface, then got her breath back before getting him out of the water. Meanwhile neighbours who heard her yelling jumped the fence and started helping with CPR while she called the Ambulance. He had actually fainted in the water and inhaled water which filled his lungs completely. Unfortunately they were unable to save him.


  • An informative article that is good for pool and water safety awareness.


  • We used to do this as kids all the time ! But I won’t be encouraging my grandchildren to do it !


  • I too have heard about this but i am pleased the article reinforces the awareness of this activity, and lets other people who are not aware of the danger aware of the deadly risk.


  • I have heard about this before; thank you for the reminder.


  • I had no idea about shallow water blackouts. Very sad for those who have lost their lives in this way.


  • Who doesn’t do breath holding games and competitions whilst taking a dive and swim as long as possible under the water ? Especially for teens and preteens a popular swim activity I would think. Good to be aware of the dangers. I’ll let my older kids read this article, so they’re aware of the dangers too.


  • i had never heard of this before. it is good that awareness is being spread regardless. very scary


  • I’ve never even heard of this! Its quite sickening because we all used to play games like that in our pool. We were so lucky nothing went wrong.


  • never heard of this before, thanks for sharing!


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