Dehydration During Freediving


  • 3 free divers diving from a charter vessel. 
  • Divers were participating in an introductory level freediving course. 
  • After the first dive to 8 meters /24 feet, one diver began to cramp, feel flushed, and fatigued. 

Reported Incident

Diver A, a middle aged (45-54 y/o) healthy and fit diver participated as a student in an introductory level freediving course when he began to experience flushing and muscle cramps. Diver B, the instructor, and Diver C, an assisting diver, instructed Diver A to rest on the float while calling for assistance from their boat. 

The captain and divemaster helped get Diver A onto the vessel, out of their wetsuit, rinsed the diver with fresh water, and provided drinking water. The captain assured that they would take charge over the distressed diver, so Diver B and C returned to teaching other students. 

Upon surfacing from the second dive, Divers B and C saw that Diver A had been placed on emergency oxygen provided by the crew out of caution. EMS was alerted and took Diver A to a local hospital for further care. 

Diver A was later discharged with no complications or residual symptoms. 


Dehydration is caused when our bodies use more fluid than we take in, resulting in our bodies not having enough water to perform normal functions. Anyone may become dehydrated, especially if they are not drinking enough water during hot weather or while exercising. When diving in hot and humid climates, it is paramount to ensure to have proper hydration especially when wearing exposure protection like wetsuits or drysuits. 


The symptoms of dehydration include fatigue, dizziness, extreme thirst, confusion as well flushed skin and muscle cramps. Treatment for dehydration includes consuming clear liquids to replenish the body’s water supply, though more serious interventions may be needed. It is always best to seek medical attention if the symptoms worsen. Proper hydration begins days prior to diving, as it takes time for water to be absorbed. Water and electrolyte containing liquids should be made readily available to divers, and divers are encouraged to carry their own reusable water bottles for frequent hydration throughout the day.