Smoking and scuba diving

I’m ashamed to admit it, but I used to be a smoker. When I realised just how seriously it was damaging my body and impacting on both my free diving and scuba diving I quit: cold turkey.

Since that day my outlook and opinions about smoking have drastically altered. I would now describe myself as very much anti-smoking and remorseful that I ever smoked at all.

Other than the fact smoking can be fatal, and you’re essentially paying for something that will eventually kill you or seriously deteriorate your health, I don’t smoke because I’m a scuba diver. Of all the recreational activities scuba diving is probably the least compatible with smoking.

DAN researchers reviewed 4,350 cases of decompression sickness that were reported over an eight-year period, comparing the severity of symptoms among non-smokers, light smokers and heavy smokers. They found that heavy smokers were more likely to have severe symptoms compared to non-smokers, and both heavy and light smokers were more likely to have severe and moderate symptoms than non-smokers, who tended to have milder cases of DCS. In short, if you're a smoker and you get bent, you're more likely to have a serious neurological event than a mild case of joint pain or skin mottling.

Cigarette smoking causes both a temporary narrowing of the blood vessels, and permanent vessel stiffening and narrowing, which sends your blood pressure soaring. It also causes blood clotting, making it even harder for circulation to flow through your constricted vessels. Finally, cigarette smoke contains carbon monoxide, which binds to your red blood cells 200 times faster than oxygen, filling the space that should be occupied by the oxygen your body desperately needs and is already struggling to get through your bottlenecked arteries. Submerge this overburdened heart into cold, deep water and you've set the stage for a heart attack.

“The science of scuba diving is built around gas exchange, and smoking greatly interferes with this exchange," says Caruso. Most notably, cigarette smoke contains carbon monoxide, which as mentioned earlier, binds to your red blood cells so they're less effective at carrying oxygen to your body's tissues. The carbon monoxide levels of heavy smokers can be as high as 10 percent, meaning 10 percent of your oxygen is displaced by carbon monoxide, compared to just 2 percent among non-smokers. Without healthy gas exchange, you're at increased risk for narcosis, decompression problems and a throbbing diver's headache.

If these cold hard facts aren’t enough to make you reconsider smoking and diving, it may interest you to know that since I quit smoking my free diving static breath hold nearly doubled and my air consumption scuba diving also greatly improved.

However, if you do smoke, and can't wait until you're off the boat to light up, I'll spare you the medical lecture. But please be considerate and follow the basic rules of etiquette. According to the Ocean Conservancy, cigarette butts top the Dirty Dozen list of the most common forms of marine debris. During the 2006 International Coastal Cleanup, volunteers collected 1,901,519 of them. It isn’t just yourself you’re damaging, but the ocean we all love so much. 

You wouldn't drink and drive. Don't smoke and dive.