Smoking and Diving – A Bad Combination

When I was a medical student at Duke University, we all observed the wards full of heavy smokers with lung cancer, heart problems and...

When I was a medical student at Duke University, we all observed the wards full of heavy smokers with lung cancer, heart problems and peripheral vascular disease, and it was fairly well-known that their nicotine habit was a big contributor. However, none of us said very much, because Durham was a tobacco town, and many of the doctors smoked. As a new doctor in the early 1980s, I became pretty vocal about the hazards of smoking, but that wasn’t cool at a time when everyone was into personal choice and tolerating the behavior of others, so I had to learn to keep my opinions to myself.

Across the current decade, the medical evidence has become too compelling to allow silence. There is simply no obvious reason why anyone should ever put a cigarette, cigar, pipe, chew or any other form of tobacco in his or her mouth. When the nicotine and carcinogens from tobacco lay into you, the misery becomes extreme and expensive.

The Physical Effects

Smoking causes medical problems related to the effects of nicotine and carcinogens (cancer-causing substances). Divers need to be physically fit, have healthy lungs, be able to tolerate environmental stress (such as cold) and rely upon finely tuned nervous systems. Assuming that a diver wants to be in the best physical condition and maintain the lowest risk for a serious disease or disorder, the ill effects of smoking work against the diver’s interests. Furthermore, the effects of smoking on a human can be so severe as to become disabling, both in the short and long term. Quite frankly, you can easily smoke yourself to death.

Smoking is likely the major cause of preventable disease, disability and premature death in the United States. Half of all regular cigarette smokers die because of smoking.

Let’s begin with the smoke itself. Cigarette smoke is an aerosol that contains multiple components created during the incomplete combustion of tobacco leaf. The smoke is a gaseous dispersal of particulate matter, which also contains volatile substances that have been distilled directly into the smoke. In the heat of burning, unstable chemicals found in the tobacco recombine to create new harmful substances in a process known as “pyrosynthesis.” What enters your mouth and lungs is frightening.

Although 85 percent of cigarette smoke is composed of nitrogen, oxygen and carbon dioxide, the remainder is laden with nicotine, tar, polynuclear aromatic hydrocarbons, phenol, cresol, trace metals, and other carcinogens and lung irritants like hydrocyanic acid, ammonia, formaldehyde and vinyl chloride.

In addition, there is an unhealthy dose of carbon monoxide, the odorless and colorless product of incomplete combustion that inhibits the transport of oxygen in the blood and the utilization of oxygen by the body’s tissues. On average, the amount of hemoglobin to which carbon monoxide is bound in a chronic smoker is 5 percent. Immediately after smoking, the amount can exceed 15 percent, which is unquestionably detrimental. If a person is a regular smoker, the carbon monoxide can cause a slight increase in the number of red blood cells found in the bloodstream, as well as a noticeable deterioration of nervous system activity, both of which might be detrimental for a diver.

When cigarette smoke travels through your nose and throat into the lungs, it first inhibits the movement of cilia, the microscopic “hairs” attached to cells which line the airway and create the “carpet” that carries tiny foreign particles and mucus out of the airway. Thus, you are not able to clear dirt, bacteria, and other debris as effectively, the effect of which is to promote infection and perhaps increase the risk of cancer. The smoke also inhibits the function of specialized cells in the bloodstream that capture and remove bacteria and other invaders from the human host.

Furthermore, smoke leads to increased and nonbeneficial production of mucus, which thickens and causes increasing and less fluid secretions, once again contributing to ineffective clearance of foreign material and increased potential for mucous “plugs,” which block tiny air passages.

Another insidious effect of smoke is to diminish the effect of chemicals that control the undesirable release of protein-destroying enzymes, such that there is degradation of essential components of the body’s barrier to invasion by infectious agents. All of these effects decrease the ease of airflow through the passages leading to and within the lungs. Smokers are more likely than nonsmokers to die from pneumonia or influenza.

One doesn’t need to directly inhale a cigarette to suffer ill effects. It has been shown that passive exposure to cigarette smoke in sufficient quantity can cause coughing, wheezing (harsh, labored breathing typical of asthmatics) and increased mucous production.

For strong epidemiological reasons, smoking and chewing tobacco have become synonymous with acquiring cancer. The combination of alcohol and tobacco use creates the most common risk factor for head and neck cancer. Smokeless tobacco is strongly linked to oral cancer. Lung cancer is the most common form of cancer in men and women in the United States, and the most common causative agent for lung cancer is smoking cigarettes.

Indeed, the most common cause of acquired lung disease of any type is inhalation of cigarette smoke. This includes chronic bronchitis and the dreaded irreversible lung damage known as emphysema. Numerous forms of cancer have been linked to smoking, including cancer of the kidney, pancreas, stomach, uterus, liver, skin, genitals, mouth, throat, esophagus and bladder, as well as leukemia.

The havoc wrought by tobacco extends far beyond cancer. Smoking increases the risk for angina, heart attacks and strokes, probably because it severely affects microscopic blood vessels. This promotes vascular disease of all types manifested by diminished blood supply to body tissues. Smokers have impaired maximum exercise performance. Furthermore, it has been noted that the ratio of high-density lipoproteins to low-density lipoproteins is reduced (the opposite of what is desirable).

Gastric (stomach) and duodenal (intestinal) ulcers are more frequently noted in smokers than in nonsmokers, but cigarette smoke does not appear to cause increased secretion of stomach acid. Rather, smoke is theorized to exert its effects by inhibiting the ability of the pancreas to secrete bicarbonate (a base) necessary to neutralize acid in the intestine, by predisposing a human to infection by the bacterium Helicobacter pylori (which has been shown to cause ulcers) or by causing acid to be dumped more quickly from the stomach into the duodenum. A smoker’s immune system is diminished in effectiveness, which predisposes to infections.


Nicotine is the toxic alkaloid drug, transmitted via cigarette smoke, to which human smokers become addicted. Nicotine is rapidly absorbed through the lungs and moves into the brain within seconds of its appearance in the bloodstream.

At first, it causes a brief increase in blood pressure and heart rate, while causing microscopic blood vessels to constrict. Nearly simultaneously, it causes the release of compounds such as catecholamines, cortisol and beta- endorphins, each of which exerts its own physiological response. Some of the effects are to perpetuate blood vessel narrowing and elevated blood pressure.

Others are to cause central nervous system arousal, then relaxation, and to affect mood, attention and reaction times. In general, smoking inhibits appetite and increases a human’s metabolic rate. Nicotine can be present in the bloodstream for more than three hours, so that with repeated exposure, it accumulates.

What characterizes an addiction? Nicotine is an addictive drug by all measures, in that there is compulsive use that leads to psychoactive effects, reinforced by repeated exposure to the drug. People report a genuine urge to smoke, a compelling physical and emotional need to have a cigarette. When they do, they receive pleasure and often are rewarded with a better mood. They may appear to be more alert and attentive.

However, one mustn’t be misled by these personality changes to believe that smoking is a good thing. What is likely occurring is that the habitual smoker is treating the manifestations of nicotine withdrawal by inhaling a cigarette. When someone is addicted to nicotine and quits smoking, when the nicotine effect diminishes to a certain point, he begins to crave tobacco and suffer a depressed mood, irritability, insomnia, anxiety, difficulty concentrating, restlessness and increased appetite. (Remember, nicotine suppresses appetite.) So smoking a cigarette may make a person feel better for a brief moment in time, but that is deceiving.

Without any exposure to nicotine, the withdrawal syndrome peaks in 24 to 48 hours, then subsides. There are no withdrawal effects noted at three to four weeks.

Who’s Lighting Up?

For some reason, women appear to be losing ground. Each year, more than 1 million children and teenagers in America begin to smoke, and many epidemiologists suspect that the number of females exceeds the number of males. Death rates from lung cancer among women are rising rapidly. Lung cancer now kills more women each year in the United States than does breast cancer.

Some experts theorize that this may reflect the ways that a woman’s metabolism deals with the tar, nicotine and carcinogens in cigarette smoke, but this has not yet been proven.

Despite all attempts by the media to portray the contrary, smoking is not exciting, glamorous or sophisticated. It becomes an addiction, with the well- defined withdrawal syndrome described above, hardly anyone’s definition of glamour. It remains a personal choice, but one that is ill-advised. For a diver, it is physiologically irresponsible to smoke and dive, because essentially, smoking diminishes one’s tolerance for cold and lowers the capacity for exercise, which may have serious consequences in a situation where extra physical resources are necessary to complete a difficult dive or perform a rescue.

Cold Turkey

Quitting smoking may not be easy. Often a person will gain weight, in part because a smoker actually burns roughly 100 to 200 more calories a day than does a nonsmoker. In addition, smoking is a hand-mouth habit (a pack-a-day smoker inhales more than 70,000 times a year) for which a ready substitute is eating. The complex psychological and physical addictions combine into a rough habit to break, but it can be done.

If you are a diver, it should be done. The first thing to do is to decide that you want to quit. Then commit to the process. Pick a date and stick to it. If you go “cold turkey,” anticipate that you will have two days of withdrawal, which will be unpleasant. It may help to plan a reward for your success, like spending your cigarette money on new dive gear.

If you’re out of shape, you may want to initiate an exercise program at the same time to take your mind off smoking. (If you are a long-term smoker and have suffered any symptoms of heart disease, such as chest pain, be certain to have any new vigorous exercise program cleared by your physician.)

If you can’t give up smoking all at once, a rationing approach may work better. Gradually decrease the amount of smoking over a few weeks. But don’t plan to quit over a period longer than that, because you are likely to relapse. Nicotine patches and nicotine gum can be useful aids, but remember that eventually you must wean yourself from these as well. Nicotine is not good for you in any form.

When you have kicked the habit, you will feel better and, hopefully, live longer. Food will taste better, you will have more endurance for exercise, and you will save money. If you suffered from coughing, this will probably improve. You will be more resistant to infections and perhaps notice that the circulation in the skin of your hands, feet, nose and ears has improved.

Certainly, you will save money. Most important, you will have contributed in a significant way to your health and welfare, and taken a very responsible action toward improving your potential as a diver and a dive partner.

By Paul S. Auerbach, M.D.