There was a little piece in the Life section of The Guardian on Thursday about Tanya Streeter, who broke the world freediving record this week. I've had a passing interest in freediving since watching the Luc Besson film, 'The Big Blue', so I was curious to read more about Tanya. It seems that she has a slightly freaky physiology, which makes her ideally suited to freediving. Simon Donoghue — a physiologist at Oxford University — measured her blood oxygen level while she held her breath for five and a half minutes (five and a half minutes!), and watched the levels plummet:
"The [blood] oxygen levels she gets down to are something I've only seen in people who have had a cardiac arrest," he says. While most people have a blood oxygen level of about 98% and anything below 80% is considered dangerous, after five-and-a-half minutes without breathing Streeter's went much lower. The machine's measuring range goes down to 50%, which is itself "not really compatible with human life," Donoghue says. "Tanya went down off the scale."
To which I can only say...blimey. I hope she carries some kind of SOS tag explaining this. If she was actually in an accident and they were monitoring her blood oxygen levels, they might prematurely decide that she was dead.