Decompression illness in breath-hold divers: insights from an online survey

Breath-hold divers can surface with neurological symptoms consistent with nitrogen buildup in tissues or gas entry into the arterial circulation, collectively termed decompression illness (DCI). While DCI has historically been attributed to diving with compressed air, breath-hold divers have reported similar syndromes. The causes, diagnosis, and management of DCI in breath-hold divers is poorly understood.

We developed an online survey that queried breath-hold divers on the symptoms they experienced during decompression illness events and the medical management of each event.

A total of 36 (31 M, 5 F) breath-hold divers filled out the survey. A majority identified as recreational freedivers, competitive freedivers, and/or spearfishers with an average age of 45 years and 18 years of breath-hold diving experience. Of those surveyed, 33 (92%) held a certification from an accredited training agency. A total of 18 (50%) reported experiencing DCI, with 21 DCI incidents reported by 13 individuals from 1999-2024. Sixteen (76%) of DCI incidents occurred during training, with an average depth of 83.4 m and average speed of 1.0 m∙s-1. Thirteen (62%) percent of DCI incidents occurred while diving to depths shallower than a previous personal best. The most common symptoms were weakness, numbness, slurred speech, and fatigue. The most common treatment modalities were surface oxygen, in-water recompression, and hyperbaric oxygen therapy. Sixteen divers (76%) had partial or complete resolution of their symptoms. The top cited contributors to the DCI incidents were depth, short surface interval between dives, and pulmonary barotrauma.

Breath-hold divers can experience DCI even when diving within their limits. The most cited contributors to DCI were depth, short surface interval between dives, and pulmonary barotrauma. Most divers' symptoms resolved after treatment with surface oxygen, in-water recompression, and/or hyperbaric oxygen therapy.