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Unexplained blackout


New Member
Apr 5, 2021
Apologies for posting this in multiple sub-forums but I want to get as much exposure to help as possible.

TL;DR - I blacked out during a static hold and remained unconscious for ~10 mins. The black out occurred at the 3 min mark which is not even 50% of my max hold of 7:05. Doctors did not identify any underlying heart or lung issues and diagnosed a vasovagal syncope (fainting). I am very hesitant to return to free diving until I can understand what caused this. Has anyone had or know of a similar experience?

For the month leading up to to the event, I been training ~4 times a week (O2 and CO2 tables) focused on static apnea as I was singed up to my first competition. The sessions to be completed during the week of the blackout were max attempts with a warm up. One of these attempts I reached 6:45 with no signs of anything abnormal. For this month I had not been drinking / taking any drugs. I was eating in a 8 hour window every day and consumed very little meat but not in a massive caloric deficit. I had not eaten anything on the day of the blackout. I was supplementing with fish oil and centrum multivit. I had slept well, was not feeling dehydrated and felt mentally and physically ready for the hold.

There was no warm up hold as the pool made me shiver in the last training session. I did my stretching and packing as normal and felt comfortable - no strange sensations.
Breath up: 4 mins of static breathing (5 seconds in - 5 seconds out), no major hyperventilation. Final breath and normal amount of packing all done routinely.

~2:00 stomach cramps start as a mild tingle and tightness in the general abdominal area (below lungs). This tingle is a sensation that has been present during static attempts before and has subsided. Until this point, I chalked it up to spleen squeeze / vasoconstriction.
~ 2:45 Thinking it would pass, the cramps have built in pain and tightness. At this point I get hands up to the edge as I am 90% certain I will not continue due to discomfort.
~ 2:50 Clean Surface Protocol
~ 3:00 Loss of consciousness

After (from my training partner / safety):
"Blow, tap, talk does not result in regained consciousness. We pull him out of the pool and lie him down on his back - face is very pale, lips are very blue. Pulse is strong and at +60BPM but breathing had stopped. A few forced assisted breaths through the nose brings back independant breathing. Legs are tensed and cannot be put into the recovery position. He spasms and his larynx locks up. More assisted breaths through the nose, I can feel a strong resistance to my flow of air. Independant breathing returns. Surface + 8 mins: his eyes open and he tracks my movement but no other response. Surface + 10 mins: Start getting vocal responses from him but is still unable to move his body.

Shortly after this the ambulance arrived and took me to the hospital. I was able to talk fully after another 5 minutes and could move all of my body in 10 although remained very fatigued for the next hour. Important findings from the hospital were:
Screenshot 2021-12-29 at 12.33.15.png

I have uploaded all results from the hospital along with my recount of the experience here: https://drive.google.com/drive/folders/1NcNoUaSs4bkrZEsM_qbd9bDyLBg1OPXj?usp=sharing

Any advice or suggestions are welcome, I would love to start freediving again!


Apr 17, 2021
Very interesting. EKG and echo findings are strongly suggestive of an undiagnosed underlying cardiogenic etiology. Ashame they didn't do a troponin test or I missed it on the labs. Being blue at 3-4 min makes me think of some sort of hyperdynamic blood flow situation like what you see in liver cirrhosis. It would require acute splanchnic vaso dilation and maybe then pulmonary as well. It could be something as simple as too tight a wetsuit hood? Spair cervical rib or neck weight pressing on your carotids in the neck. Or perhaps a tumor in the abdomen or thorax that got pressed against a large vessle. The possibilities are endless!!! Thank you for sharing. And best of luck.


New Member
Apr 5, 2021
The wetsuit was tight but I had not had any issues with it in the past; there is also no hood so that rules that out. Thanks for the reply, it gives me plenty of stuff to look into!


Well-Known Member
Sep 14, 2010
Hi, and thank you for sharing the details of your experience. Questions that come to mind: you say that you hadn't been drinking or using any drugs leading up to this training; what drugs if any were you using before? and how much drinking. Also, have you had a Covid vaccine? There are many cases of cardiac problems after some of these vaccines. For sure, a small percentage, but a possibility. There seem to have been athletes who have never had cardiac problems, who died or almost died during a ball game, for example. Also, I have seen people have a seizure that looks like this. Not freediving, all the ones I have seen were people with Lyme disease infections in my clinic and relating their at-home seizures. It's not a typical seizure for sure, but perhaps a possibility?
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