We had just finished a training session on Gili T (Gili Trawangan), Indonesia, relaxing over coffee, when a young woman ran into the dive shop asking for a freediving instructor. Within minutes, my training partner and I were on bikes, then a horse and cart, doing everything we could to keep a diver alive. This is that rescue, and what it taught me about safety no course can fully prepare you for.
What is a freediving blackout?
A freediving blackout is a loss of consciousness caused by low oxygen levels in the brain during a breath-hold dive, most often as a diver nears the surface. Left unrescued, a blackout can quickly turn into a drowning. This is the story of a rescue on Gili T where we found a diver right on that edge, and what it taught me about safety.
The moment everything changed
We arrived to find the diver already strapped to a spinal board, surrounded by people from a nearby scuba operation. He was still in his spearfishing suit, moaning, gargling, and thrashing his arms as though he was fighting his way to the surface. His face was deeply discoloured and purple. His hands and feet were stark white.
It was immediately clear he didn’t need CPR. What he needed was oxygen, and fast. We called for the scuba team’s oxygen tank, turned it on, and fitted the mask to his face. He fought it the entire time, pulling at the mask and wrestling anyone who came near him.
A few signs told us exactly what we were dealing with:
- Discolouration and white extremities, a sign of severe oxygen deprivation
- Gargling sounds, meaning his airway was full of fluid
- Thrashing and attempts to swim, as though he still believed he was underwater
- No response to voice or touch, despite being conscious enough to fight
We had seen this pattern before, in a diver who had suffered hypothermic shock and kept trying to swim to the surface even after being pulled from the water. It told us this wasn’t a straightforward blackout. It was tipping into a drowning in front of us.
Recognising a blackout that could turn into a drowning
His dive watch later showed a total dive time of 5 minutes and 47 seconds, an extreme breath-hold by any measure. He had been pulled from around 20 metres and didn’t start breathing again for another minute, meaning close to 7 minutes had passed since his last proper breath.
Once we got a reading, his oxygen saturation was sitting at 55%. A normal reading sits between 95% and 100%, so this was a genuinely life-threatening number, made worse by the fact it was still that low over an hour after the incident. He couldn’t see properly, couldn’t follow a finger, couldn’t speak, and was still hallucinating. We aren’t doctors, but the signs were consistent with serious oxygen deprivation to the brain.
Get the training that makes the difference
Recognising the difference between a blackout and a drowning, and knowing how to respond to both, is exactly what we train for in our freediving courses in Sydney. If you want the skills and confidence to handle a real emergency, book a course with us today.
An evacuation with everything against us
Getting him to help was its own battle. We strapped him to a flatbed horse and cart, the only transport available, and set off for the nearest medical centre with a language barrier the whole way. One of the scuba divers who’d helped us carried the weight of the board for most of the ride so it wouldn’t drag on the ground.
The medical centre wasn’t equipped for an emergency like this. My training partner and I ended up stepping in ourselves, because we could see he was drowning in the fluid sitting on his lungs. Staff didn’t have enough sedation on hand, so we had to physically hold him upright and force oxygen into him while he fought us.
Eventually we found his phone, and it turned out to be the only way we could reach anyone who knew him. Face recognition wouldn’t unlock it, and his hands were too cold and wet for a fingerprint to register. The only reason we got in at all was because his emergency contacts were saved right on the lock screen.
That let us reach his partner, which mattered for more than comfort. We needed his next of kin present before any evacuation decision could be made on his behalf. It also turned out the operator running his trip hadn’t collected his emergency contacts at all. That’s such a basic piece of information to have on hand, and without it saved on his phone, we would have had no way to reach anyone.
We carried him across a wharf, onto a boat, and across to a hospital in Lombok with a neurologist on staff, insisting the whole way that he stay upright and awake rather than laid flat, which would have put him at serious risk of secondary drowning.
Why we couldn’t let him fall asleep
Any time someone blacks out underwater, we treat it as though there’s water sitting on the lungs, because there usually is. Secondary drowning is a real risk in the hours afterwards, especially if the person is allowed to fall asleep before their lungs have properly cleared. This is why we always recommend a proper medical check after any underwater blackout, even if the person seems to have bounced back.
Every time hospital staff laid him flat, he started gargling again, his oxygen saturation dropped, and the colour drained from his face. He was also so exhausted that he kept passing out. We had to keep him upright and wake him the moment his eyes closed, for hours on end. We believe that’s what kept him alive through the night.
How he’s doing now
Since the rescue, we’ve stayed in touch and heard how his recovery is going. His vision has returned, which was one of our biggest concerns given how disorientated he was in the hours after the blackout.
He also has a burst eardrum. When someone blacks out underwater and starts sinking, they stop equalising their mask, ears, sinuses and lungs. As the pressure keeps building on the way down, those air spaces can’t adjust, and something eventually gives. In his case, that was his eardrum.
His brain function is believed to have returned, though that won’t be fully confirmed until he’s home and properly assessed. His lungs took on a significant amount of water and are expected to need around a month to recover. When we last heard from him, he was still in intensive care, being kept upright, recovering alongside his partner. He thanked us for the chance to keep living his life with the people he loves, which is about as good an outcome as we could have hoped for.
What likely caused this blackout
Spearfishing blackouts usually come down to one of two mechanisms, and neither works quite the way most people assume.
Blacking out from simply holding your breath too long is actually fairly uncommon. The urge to breathe is a strong reflex, and most divers surface well before it becomes dangerous. When it does happen, it’s usually because a diver hasn’t made it to the surface in time. Sometimes it happens just after they surface, when there isn’t yet enough oxygen circulating for normal motor control, known as a shallow water blackout.
There’s also a warning sign that often comes before a full blackout, known as loss of motor control, or LMC. It shows up as shaking, jerky movements, or a sudden loss of coordination, usually right at the surface, and it means the brain is dangerously short of oxygen. Any buddy who sees LMC in a diver should treat it as seriously as a full blackout and act immediately.
The second, and more common, cause is hyperventilation before the dive. Breathing harder and faster than your body needs lowers your carbon dioxide levels, and carbon dioxide, not a lack of oxygen, is what triggers your urge to breathe. With that warning system delayed, a diver can push on well past a safe point without ever feeling it.
Hyperventilating works against you a second way too, through something called the Bohr effect. Lower carbon dioxide makes your blood hang onto oxygen more tightly, so less of it actually reaches your brain and muscles, even when blood oxygen levels look fine on paper. You feel like you can keep going, right up until you can’t.
We later learned his speargun had been fired, which told us he was likely on his ascent when he took the shot, chasing a fish rather than watching his time. A few other factors probably stacked the odds against him:
- Goal fixation on a fish late in the dive, delaying his return to the surface
- Possible hyperventilation before he went down
- Fins that were too small for the depth he was diving
- Being overweighted, which meant more effort and oxygen used just to get back up
The safety lessons every freediver should take from this
You don’t need to be spearfishing at 20 metres for this to matter to you. The same lessons apply whether you’re training in a pool or diving on holiday. A few things we’d urge every freediver to take seriously:
- Dive with a buddy who watches you the entire time, not just occasionally
- Save your emergency contacts somewhere visible on your phone’s lock screen, in case face or fingerprint unlock isn’t an option
- Confirm your dive operator actually records and holds your emergency contacts before you get in the water
- Set a dive plan and stick to it, especially your depth and time limits
- Use fins and weighting suited to your experience, not just what’s cheapest
- Learn to recognise loss of motor control (LMC), often the last warning sign before a full blackout
- See a doctor after any underwater blackout, even if the person seems fine, since secondary drowning is a real risk
- Learn the difference between a blackout and a drowning, and how quickly one becomes the other
None of this replaces proper training. Reading about what to do in a freediving emergency is a good start, but a good freediving buddy who has actually practised rescues is what saves lives.
Why this story matters to me
I’ve spent more than 12 years teaching freediving and working as a safety diving consultant, including as National Geographic’s head safety consultant on the 2021 Disney+ series Secrets of the Whales. This wasn’t the first blackout I’ve rescued someone from, but it was the first time I’d been called to help with a diver completely outside our own operation, and by the time we reached him it was tipping into a drowning rather than a straightforward blackout.
What stayed with me most wasn’t the physical side of the rescue. It was how quickly a relaxed day of freediving turned into a fight for someone’s life, and how few people around us on that beach even noticed it was happening. If sharing this story helps even one diver take their safety more seriously, it’s worth telling.
Book a course with us
If this story has made you think twice about your own safety in the water, the best thing you can do is get proper training. Book a freediving course with us in Sydney and learn the skills that could one day save a life, maybe even your own. You can also get in touch with our team if you have any questions before you sign up.