Smoking is bad for your health. Everyone knows it and has heard the messages about what smoking can do to your lungs and your health a thousand times or more throughout their lives. It is doubtful at this point that there is anyone alive and above the age of ten that doesn't know. However, what many people may not know is how smoking affects your body in relation to diving. Needless to say, smoking and diving do not mix at all, but you might be wondering why that is so let's take a look.
Smoking makes the symptoms of decompression sickness worse. The Divers Alert Network (DAN) has analyzed more than 4000 cases of decompression sickness and they have found that when they compared the symptoms experienced by non-smokers, light smokers, and heavy smokers, the light smokers and heavy smokers were more likely to experience moderate to severe symptoms than the non-smokers. Since the non-smokers tended to have milder symptoms of decompression sickness and light and heavy smokers tended to have moderate to severe symptoms, if you are a smoker, then you are more likely to experience symptoms such as serious neurological damage rather than something simple like joint pain.
Smoking is also dangerous for the diver in a number of other ways. Smoking causes a temporary restriction of the blood vessels, known as vasoconstriction, and permanent stiffening and narrowing of the blood vessels, known as atherosclerosis. If that isn't enough, smoking also causes a thickening of the blood, which makes it even harder for the blood to flow through the already narrowed blood vessels and this causes increased blood pressure. Finally, since cigarette smoke contains carbon monoxide, this carbon monoxide attaches itself to the red blood cells, taking up the space that oxygen should occupy. This in turn reduces the amount of oxygen getting to the important places in the body on someone who already has decreased blood flow. Once you put this person underwater with a breathing regulator and the stresses of diving, you have an accident waiting to happen.
Unfortunately, that is not all when it comes to the risks of smoking and diving. Smoking also increases the risk of damage to the lungs, which are already damaged from the smoking itself. The job of the lungs is to take oxygen from the air and expel carbon dioxide and other waste. The alveoli are the part of the lungs responsible for this gas exchange and smoking damages them, which eventually leads to the condition called emphysema. The early stages of emphysema may not be noticeable and divers who have damaged alveoli will not have as good gas exchange as a diver with healthy lungs. This means a greater risk of a ruptured lung, arterial gas embolism, nitrogen narcosis, decompression illness, and a diver’s headache.
Finally, smoking completely paralyses the cilia, which are the fine hairs that line the sinuses and whose job it is to clean the air of dirt and debris before it goes into your lungs. When these cannot work properly mucus build-up begins and there is an increased risk of developing a mucus plug in the lungs. A mucus plug is a blockage in one of the bronchial tubes and this can cause gas to be trapped behind the blockage upon ascent, increasing the risk of the diver rupturing a lung or developing an arterial gas embolism.
So what can you do if you are a smoker and you want to dive? The absolute best thing to do is to quit smoking. However, this can be very difficult to do and people generally have to try many times before they quit for good. There are things that can help, such as nicotine replacement therapy, which you can get as a patch, gum, nasal spray, lozenges, lollipops, and even inhalers. These can help you wean off your dependence on nicotine and help you beat the cravings without smoking a harmful cigarette. However, it is important to know that nicotine, even in the therapeutic form, will still increase your risk of heart attacks and other heart related problems as nicotine acts as a vasoconstrictor. Whatever you decide to do, you should consult your doctor to determine your level of risk. If you do quit cold turkey, then wait until after the worst of the withdrawal symptoms have passed before you dive.
Having said all the above, if you still choose to smoke and you are on a dive, then be respectful of the other divers and smoke well away from them, down-wind of them so that they do not have to share your smoke. When you are finished, dispose of your butts properly as they are one of the most common types of garbage found in marine environments. The rest of the paper and tobacco will decompose, but you will need to keep the plastic filter and throw it is the garbage can. Then you can enjoy your dive and stay as safe as possible.