40m to 100m
A failure to do so can rupture the eardrum, causing painful and possibly permanent damage, and create something called sinus squeeze, which can lead to skull defects. The top 200m of the ocean is known as the euphotic zone. This i s the depth to which sunlight generally penetrates and where the bulk of the world’s commercial fish species live.
Because Dean’s Blue Hole is, well, a hole, natural light does not penetrate as far ( though because this is a made- for- TV event, there are powerful lamps that enable us to witness his descent).
Still, it is dark. With darkness and discomfort can come, surely, dark thoughts?
“Do you feel anxiety? Yes and no,” says Trubridge. “It’s not caused by the sensation of danger and risk. If you want to call freediving an extreme sport, well it’s at the safer end of those sports because of the systems in place.
“You can black out under water and you’ll be brought to the top and no harm will come to you.”
Still, athletes die doing this sport — most famously Audrey Mestre, girlfriend of Ferreras, who couldn’t be resuscitated after the air bag, that was meant to propel her back to the surface after a weighted sled had taken her to 171m in an attempt at a no- limits world record, failed to inflate.
Yet Trubridge says he never worries that the breath he just drew on the surface, the one that took longer than half a minute to draw, will be his last.
“Any anxiety I feel is more to do with success and failure.”
Although the heart is a relatively small muscle and doesn’t consume an enormous amount of precious oxygen, an elevated heart rate is the enemy of a diver. Trubridge has a relatively high resting rate ( about 55 beats per minute), but when he dives it will be about 30.
“If it’s higher than that it usually means there’s something else going on, and that can be hard to stop.”
In that respect, diving can be the ultimate mind trick: success, which you desperately want, i s easier to achieve by putting all thoughts of success to one side.
Autopilot is a phrase Trubridge likes to use, and at this point of the dive, with negative buoyancy and the pressure acting like an underwater vice, it is the only state he can be in. called narcosis. Sometimes known by the more dramatic term “rapture of the deep”, narcosis affects all divers. Because it is an anaesthetic feeling, similar to drunkenness, some even find it pleasant. All anxiety is erased and they feel like they have become masters of all they survey.
“It can have a soporific effect. You feel woozy. You may even have hallucinations,” Trubridge says.
The tags are in reach. Trubridge will reach down and pull one free.