FREEDIVER BLACKOUT
Understanding
Freediver Blackout
Knowledge saves lives. Learn to recognize, prevent, and respond to shallow water blackout.
Often considered by divers to be one of the greatest dangers in freediving.
CRITICAL SAFETY EDUCATION
Understanding Freediver Blackout
Watch this essential safety video to learn how to recognize, prevent, and respond to shallow water blackout
DEFINITION
What is Shallow Water Blackout?
Shallow water blackout (also called syncope or hypoxic blackout) is a loss of consciousness caused by hypoxia (low oxygen) induced by breath-hold diving activities.
It’s the body’s protective response that shuts down non-essential functions to preserve oxygen for the brain and heart. However, this occurs well before complete oxygen depletion.
Depth is just one variable affecting oxygen depletion. One of the first symptoms of even mild hypoxia is confusion making it critical to have a trained buddy watching from the surface.
Critical Fact
Blackout can occur without any warning signs. The confusion caused by hypoxia prevents you from recognizing danger—this is why the buddy system is non-negotiable.
“Most blackouts occur during the final meters of ascent when oxygen levels drop rapidly”
WARNING SIGNS
Loss of Motor Control (LMC)
LMC is a “near blackout” state where divers lose physical control upon surfacing. It can be more dangerous than full blackout because protective reflexes are absent.
Signs of LMC
Shaking and unable to breathe properly
Delayed or no response to buddy signals
Uncoordinated movements at surface
Difficulty maintaining positive buoyancy
Confusion or disorientation
Inability to maintain airway above water
If You See These Signs
Support the diver, keep their airway clear of the water, encourage them to breathe, and maintain close supervision. Recovery typically occurs within seconds.
STAY SAFE
Prevention Techniques
Risk reduction, not elimination. These practices dramatically reduce your chances of blackout.
Never Dive Alone
Always dive with a knowledgeable buddy of similar ability who remains on the surface and is prepared to respond to a hypoxic incident.
Know Your Limits
Plan depth and duration conservatively and stick to your limits
Avoid Hyperventilation
Never hyperventilate before a dive—it delays the urge to breathe without increasing oxygen
Surface Monitoring
This is the single most effective safety rule. Diving is a team sport, rotate your dives and stay safe.
EMERGENCY PROTOCOL
What To Do When Blackout Occurs
Every second counts. Follow these steps immediately when your buddy blacks out.
1
Secure the Airway
Immediately bring the diver’s face above water and keep the airway open
2
Remove Mask
Quickly remove the dive mask to allow better airway access and stimulation
3
Stimulate Breathing
Blow across the face, gently tap cheeks, and speak calmly to encourage breathing response
4
Exit Water
Get to shore or boat immediately. If the diver is not breathing or breathing properly, call for help and start CPR immediately until a healthcare professional arrives.
5
SEEK MEDICAL ATTENTION
Even if the diver appears to have fully recovered, they should be evaluated by a healthcare professional.
6
STOP DIVING FOR THE DAY
After any LMC or BO event, the dive is over. No fish is worth your life.
MYTHS VS FACTS
Common Misconceptions
Myth
Blackout only happens to beginners
Truth
Experienced divers are also at risk, especially if they push limits or become complacent
Myth
You’ll feel warning signs before blacking out
Truth
Blackout often occurs with NO warning signs—hypoxia causes confusion before you realize danger
Myth
Hyperventilation increases oxygen
Truth
It only reduces CO2, delaying the urge to breathe while oxygen depletes dangerously
Myth
Shallow dives are always safe
Truth
Shallow water blackout occurs near the surface during ascent when oxygen drops rapidly
Get Proper Training
Reading about blackout is a start—but hands-on training with real scenarios saves lives. Request a free safety workshop for your community.
