freediving blackout; hypoxic blackout
Medical term for loss of consciousness caused by hypoxia during breath-hold diving, often without warning signs.
ノーパニック症候群は、フリーダイビング中の低酸素によって起こる意識消失です。
No-panic syndrome is a loss of consciousness caused by hypoxia during freediving.
From English 'no panic' + 症候群 (syndrome). The term describes the absence of panic or warning before a freediving blackout.