Smokers may have bad breath, stained teeth, and clothes and hair that smell like cigarette smoke, but because of a decreased sense of smell, often don't realize it. If you smoke, you may have a dulled sense of taste and require more salt or other seasonings to flavor your food. Smokers can be a risk to others because of secondhand smoke and the increased risk of fire from an unattended cigarette or from falling asleep with a lit cigarette. Smokers also run the risk of serious diseases such as a heart attack, stroke, high blood pressure, asthma, pneumonia, stomach ulcers, recurrent colds or chronic obstructive pulmonary disease such as emphysema. There is also an increase in upper respiratory infections in infants whose mothers smoke.
Smoking is the single major cause of lung cancer.
When you inhale cigarette smoke, you are inhaling nicotine, carbon monoxide, tar and other possible cancer-causing compounds. These chemicals go directly into the lungs and then into your bloodstream. Nicotine causes the blood vessels in your hands and feet to constrict, and it also increases the likelihood of blood clots. Adrenaline in your bloodstream increases your heart rate and your heart's demand for oxygen. Carbon monoxide is another substance that, when entering the body, displaces valuable oxygen.