Free divers find love and death in Netflix's 'Deepest Breath'

Early in "The Deepest Breath," an underwater drone follows free diver Alessia Zecchini as she plunges 100 meters down into the ocean's dark depths, and back up, all on a single breath.

The heart-pounding, claustrophobic three-and-a-half-minute sequence is as difficult to watch as it is mesmerizing.

As she ascends to the shallows, Zecchini's body begins to twitch. Rescue divers seize her and drag her up to the surface, her unconscious eyes rolling grotesquely backward as she is resuscitated.

It may seem shocking, but "blacking out" from lack of oxygen is a common occurrence in free diving, an extreme sport in which athletes compete to go as deep as they can without any breathing apparatus.

"You can watch all the videos in the world. It doesn't really prepare you for seeing a human being just pass out like that," said director Laura McGann, director of the Netflix documentary, out Wednesday.

"It's scary to see."

Through archive footage, interviews and a handful of re-enactments, McGann's film explores what drives these men and women to repeatedly risk their lives and push the limits of human endurance in pursuit of new competitive records.

"Seeing a human being behave more like a seal or a dolphin in the water, with no tanks, was kind of like learning that there was a group of people in part of the world that knew how to fly," she told AFP.

Specifically, the film focusses on the relationship between record-breaking diver Zecchini and Stephen Keenan, a nomadic young Irishman who becomes one of the sport's top safety experts.

Free divers, if not actively courting death, do not appear to fear it. Indeed, Zecchini airily claims in the movie's opening scene that she does not even think about death.

Yet...