What do hookah and e-cigarettes do to the lungs?

Hookah is usually a social activity, and e-cigarettes usually seem pleasantly scented and smokeless. For this reason many people, from teenagers to adults, assume their harm does not match that of cigarettes. This article explains what reliable sources have found about this belief. Its aim is not to blame anyone; it is simply that you know what your lungs are taking in.

What is in hookah smoke?

The CDC writes that a hookah is a water-based device for smoking specially prepared tobacco. According to the CDC, its smoke contains “many of the same harmful components as cigarette smoke”: nicotine, tar and heavy metals. Because the tobacco is heated with hot charcoal, carbon monoxide, metals and cancer-causing substances are added as well. The CDC describes hookah tobacco smoke as “at least as toxic as cigarette smoke”.

Some comparisons from the CDC:

• In one hookah session, a person can take in about 9 times the carbon monoxide of one cigarette and 1.7 times the nicotine.
• In a one-hour session, about 90,000 millilitres of smoke is inhaled. One cigarette is about 500 to 600 millilitres. The CDC calls this “100 to 200 times” more smoke.

The water in a hookah does not clean the smoke. The CDC says that even after passing through water, the smoke contains high levels of toxic substances. According to the CDC, “herbal” or fruit hookah without tobacco has also been found in studies to contain carbon monoxide and toxic substances. Secondhand hookah smoke (tobacco and charcoal smoke) can also be harmful to people who don’t smoke hookah.

The CDC states plainly that hookah is not a “safe alternative to cigarettes”. It links hookah with cancers such as lung, bladder and mouth cancer, heart disease and reduced lung function, and on lung cancer it says a direct association has been seen in some studies. On electronic hookahs (vape pens or steam stones), the CDC says information is limited.

What is in e-cigarette vapour?

The WHO writes that an e-cigarette turns a liquid into an aerosol that the user inhales. The WHO calls these devices “harmful to health and unsafe”. The CDC (January 2025) says:

• Tiny aerosol particles reach deep into the lungs.
• Some flavourings, such as diacetyl, are linked to a serious lung disease.
• Using e-cigarettes and regular cigarettes together may bring more toxic substances and worse breathing outcomes than either alone.
• Most of these devices contain nicotine, which is highly addictive.
• The aerosol can contain heavy metals (nickel, tin, lead), volatile organic compounds, fine particles and cancer-causing substances.
• The aerosol usually contains fewer harmful substances than cigarette smoke (about 7,000 substances), but the CDC says this does not mean it is safe, and the long-term consequences are still being studied.

The ATS also lists e-cigarette vapour among asthma triggers, and counts cigarettes, marijuana or vapour among the causes of chronic cough. The ALA writes that a person with COPD must give up smoking and all tobacco products, including e-cigarettes and vapes.

What signs does the lung give?

Most lung damage builds up slowly and silently. Symptoms that should not be ignored: a persistent cough or a cough with phlegm, wheezing, shortness of breath sooner than others your age, chest tightness and frequent infections. The NHS writes that many people call the phlegmy cough of smokers a “smoker’s cough” and take it lightly. GOLD has a five-question questionnaire; if you answer “yes” to three or more, ask your doctor about COPD: Do you cough several times on most days? Do you have phlegm on most days? Do you get breathless sooner than others your age? Are you over forty? Do you smoke or have you smoked? A simple spirometry test can show lung function (see the guide “Lung tests”).

Quitting: what helps?

Nicotine is addictive, and quitting does not succeed on willpower alone. The ATS says most people make several attempts before quitting for good, and that one unsuccessful attempt does not mean failure. The WHO writes that counselling and medication more than double the chance of quitting, and that in the WHO’s global survey more than sixty percent of smokers said they intend to quit. The ATS says nicotine replacement (patches, gum, lozenges) more than doubles the chance of success, and that combining medication with counselling, such as a quitline, raises the chance further. The ATS also says nicotine on its own does not cause cancer, and that it is the addiction to it that keeps a person smoking.

One important point: the ATS writes that there is not enough evidence for using e-cigarettes as a quitting aid. It considers nicotine replacement and prescription medicines effective and safe for quitting. So if you want to quit, ask your doctor which method suits you. The type and dose of medicine are decided by the doctor.

What can be done?

• If you use hookah or e-cigarettes and have a cough, wheeze or shortness of breath, tell your doctor. The questions are not about judging you.
• If you aren’t ready to quit yet, talking to your doctor about it is itself a first step. Make the decision and choose the method together.
• Stay away from secondhand hookah and cigarette smoke, especially for children, older people and people with lung disease, asthma and COPD.
• If you have asthma or COPD, smoke and vapour are among the main triggers of attacks.
• Pregnancy: the CDC says nicotine is toxic to the fetus and that daily hookah use has been linked to low birth weight. If you are pregnant or planning to become pregnant, talk to your doctor.

When is it urgent?

If you are gasping and cannot speak a sentence, your lips have turned blue, you are coughing up more than a few spots or streaks of blood or you have severe chest pain, call 115 (Iran’s emergency number). The full list is in the guide “When should I call urgently?”.