Shallow Water Blackout

- the silent killer

In simple terms Shallow Water Blackout (SWB) is when a swimmer suddenly faints underwater. No exact figures are available but some sources attribute over 50% of all drownings to SWB, which makes it the single most common cause of death amongst children

  • Swimming ability is no protection against Shallow Water Blackout; it can and does happen to the most experienced of swimmers, regardless of their health or age, in pools and/or in open water
  • SWB occurs when low levels of Carbon Dioxide (CO²) in the body, combined with low levels of Oxygen, causes a swimmer to faint
  • If the swimmer is not rescued immediately they will drown
  • SWB can be caused by taking several deep breaths (Hyperventilation) before, for example, swimming a length underwater or 'trying to beat-your-own-record' for distance swum underwater
  • Hyperventilation artificially lowers the body's CO² levels
  • It is HIGH levels of CO² in the body that triggers the need to breathe; not LOW levels of Oxygen
  • With artificially low levels of CO² the 'BREATHE NOW!' reflex is suppressed and unconsciousness occurs instantly when the swimmer's Oxygen level falls below a certain point
  • SWB can occur without warning, to any swimmer, regardless of their ability or level of experience
  • Many victims are strong, fit swimmers who have not previously experienced this problem before
  • Therefore; educate everyone who uses your pool, especially kids, about the dangers of Hyperventilating
  • Don't let them compete at holding their breath, or seeing who can swim furthest underwater


We supply all plant and equipment featured on this website. All our work is Guaranteed; Parts and Labour

For free and unbiased advice, a site visit or no-obligation Quotation*, please make initial enquiries by email. Tell us a little about your pool problem and include a daytime phone number. Thanks, we look forward to meeting you soon

Note: - Please contact our recommended pool professionals for supply and installation of all pool-related services: - 


Andalusia and the Costa del Sol - Pool Safety SpainPool Safety Spain

Nerja area - This email address is being protected from spambots. You need JavaScript enabled to view it.

*We only offer Quotations: - a fixed, agreed price that cannot, and will not, be increased. We do not give 'estimates', as an estimate offers the client no guarantee of final price

Share this website with other Pool Owners and Users,  encourage them to read about Pool Safety, learn CPR and help them to save lives, time and money. Please help us to make every pool a safer place - by sharing this information we can cut the number of pool accidents and deaths.  Please also see our FacebookFacebook page

Ken Walker - MyPoolGuru©