Outer Banks season 4 is already chock-full of suspenseful adventure, but the show also introduced an all-new threat in the form of the terrifying “bends“. As season 3 concluded, the Outer Banks crew of JJ Maybank (Rudy Pankow), John B. Routledge (Chase Stokes), Sarah Cameron (Madelyn Cline), Pope Heyward (Jonathan Daviss), Kiara Carrera (Madison Bailey), and Cleo Anderson (Carlacia Grant) found themselves quickly thrust into their latest treasure hunt – for the storied pirate Blackbeard’s treasure from the real-life Outer Banks. As it turns out, this places JJ and Kiara in danger from a surprising source.

As viewers learn, Wes Genrette is only interested in retrieving a specific amulet from the highly protected shipwreck and not the entire treasure, believing the item to be associated with a curse that haunts his family. Due to the shipwreck’s proximity to the Coast Guard base, the group dive for the amulet at night, sending Kiara and JJ underwater. A mysterious villain then viciously attacks them over the treasure and destroys their diving gear. As a result, JJ and Kiara become severely ill with “the bends,” and are rushed to the hospital. “The bends” refers to decompression sickness – a potentially deadly real-life condition.

The Bends (AKA Decompression Sickness) Happen When Bubbles Form In The Blood & Tissues

JJ And Kiara Suffer The Bends When Their Gear Is Tampered With

Rudy Pankow as JJ and Madison Bailey as Kiara in Outer Banks season 4

Following the scuffle in the shipwreck, JJ and Kiara struggle to come up for air, and become extremely ill when they do reach the surface. The group rushes their friends to the hospital for their trouble breathing and brutal pains. “The bends” are slang for decompression sickness, a phenomenon in which dissolved gasses (usually, nitrogen) form bubbles in the bloodstream and tissues (via National Institute of Health).

The sickness occurs due to a rapid decrease in pressure in the surrounding area, making it most common for SCUBA divers. Divers dive with compressed nitrogen and oxygen, and if divers surface too abruptly, the nitrogen does not have time to dissolve properly, causing the bubbles (via Harvard Health Publishing). The condition gains its nickname because of the intense joint and bone pains that occur throughout this process.

How The Bends Are Cured (Is It Only With A Hyperbaric Chamber?)

There Are Several Treatment Options For The Bends

JJ and Kiara in the hyperbaric chamber in Outer Banks

In Outer Banks, Kiara and JJ are placed in a hyperbaric chamber in the hospital to treat their decompression sickness. This is the optimal treatment for the condition, but in emergency situations far from hospitals, there are several other on-the-spot measures to be taken. Maintaining blood pressure and administering fluids on the scene is imperative.

The hyperbaric chamber is a high-pressure unit that administers patients 100% oxygen to reverse the effects of decompression sickness.

The hyperbaric chamber is a high-pressure unit that administers patients 100% oxygen to reverse the effects of decompression sickness. The chamber also liquefies the nitrogen, allowing it to pass through the body over the course of several hours with fewer side effects (via Harvard Health Publishing). As viewers see in Outer Banks season 4, Kiara and JJ are told to remain in the chamber for 12 hours. This injury is likely only the first of many to come as the crew continues to dive headfirst into adventure in Outer Banks while also being a pertinent reminder of the real-life perils of SCUBA diving.