When I first moved to the islands I kept hearing other staff members telling people the headache they were getting was from a CO2 hit. They also kept saying dehydration was the leading cause of DCS. The reality was the people were not getting headaches from a CO2 hit, rather they were dehydrated. After they drank a bottle of water, from my encouragement, their headache went away, much to their astonishment. Dehydration is common in the tropics with people who are not used to the heat and humidity as well as from drinking a fair amount the night (and day) before.
