Many scuba diving purists agree that you should not consume caffeine at least 12 hours before a dive. Why? The hypothesis is based on the fact that caffeine is a diuretic which dehydrates you. If you dive when you are dehydrated, it increases your chances of succumbing to decompression sickness. When diving, experts suggest diving only when you are hydrated and to bring a bottle of water along. Air in the diving tank is in dehumidified form, which makes every breath you take hard on your body.
Although the caffeine hypothesis makes sense, many divers give anecdotal evidence that indulging in a cup or two of coffee before a dive does not drastically increase your chances of getting decompression sickness. In fact, many point out that the caffeine hypothesis has never been studied and no research exists that has established a high correlation between consuming caffeine and an increased likelihood of suffering from decompression sickness. Most likely, you will have to consume an exorbitant amount of coffee in order for it to make you more vulnerable to decompression sickness. So you can use your trusty coffee maker but just don’t go crazy, some of the best coffee makers like those aren’t going to cause you any issues.
Decompression sickness, also known as the bends or caisson disease, occurs when you decompress too quickly from exposure to increased pressure. When you dive, the amount of nitrogen absorbed by your body’s tissues from the breathing gas is based on the pressure surrounding your body. When the surrounding pressure is reduced too quickly (ie: surfacing too quickly), the nitrogen forms bubbles in your body’s tissues and bloodstream and causes a host of problems including numbness, paralysis, and other cerebral issues. If the bubbles enter your venous bloodstream, you may suffer congestive symptoms in your lungs and circulatory shock.
Symptoms that you might be suffering from decompression sickness include, unusual fatigue, itchy skin, pain in joints, pain in extremities and torso, dizziness, vertigo, ringing in your ears, numbness, tingling sensations, paralysis, and shortness of breath.
Signs of decompression sickness include blotchy rash, paralysis, muscle weakness, difficulty urinating, confusion, personality changes, bizarre behavior, amnesia, tremors, staggering, coughing blood, frothy sputum, collapse, and unconsciousness.
Symptoms and signs appear between 15 minutes to 12 hours after surfacing. Immediate recognition of symptoms and treatment will give you a greater chance for a full recovery.