Most cigarettes contain over 4,000 chemicals, including “human-friendly” ones like cyanide and formaldehyde. Sixty of these chemicals are known to cause cancer. The list of smoking-related cancers keeps growing and includes:

• Lung
• Lip, mouth, pharynx, larynx, and esophageal
• Cervical and uterine
• Bladder and kidney
• Stomach
• Pancreatic
• Acute myeloid leukemia

Blood carries cigarette poisons throughout the circulatory system. Among other effects, these poisons damage and narrow blood vessels, increasing the heart rate while decreasing the flow of oxygen to the rest of the body. These are a few of the cardiovascular conditions smoking contributes to:

• Atherosclerosis—a disease causing fatty deposits in arteries
• High blood pressure—increased pressure in the blood vessels
• Heart attack—damage or death of heart muscle from lack of blood flow
• Congestive heart failure—ineffective pumping by the heart
• Peripheral vascular disease—narrowing of vessels in the legs
• Abdominal aortic aneurysm—a bulge in the wall of the aorta

Chemicals in cigarettes irritate air passages and lungs. They slow—and eventually stop—the cleansing action in the lungs, so poisons can remain there. Lungs become vulnerable to problems like these:

• Coughing, colds, sore throats, and pneumonia
• Asthma—airways become inflamed
• Chronic bronchitis—airways produce extra mucus
• Emphysema—walls between air sacs break down, slowly destroying the ability to breathe
• Lung cancer—uncontrolled growth of lung cells that invade normal tissues

By reducing blood supply, smoking weakens both muscles and bones. It also slows the production of bone-forming cells and keeps your body from absorbing calcium. Here are some of the effects:

• Increased risk for bone fractures, which also take longer to heal
• Higher complication rate after surgeries
• Increased risk of overuse injuries, such as bursitis; greater chance of sprains
• Negative impact on sports performance—slower pace and shortness of breath
• Association with low back pain and rheumatoid arthritis—a progressive disease causing swelling in joints

Smoking hurts the digestive system, which means the body doesn’t get the nutrients it needs. Smoking does this by:

• Injuring the esophagus, allowing stomach acids to flow back (called heartburn) into the esophagus, and by making stomach acids more harmful
• Increasing acidity, increasing the risk for an infection that leads to open sores in the stomach or small intestine (called peptic ulcers)
• Leading to inflammation in the lining of the intestine (called Crohn’s disease)
• Changing the way the liver handles drugs and alcohol

Smokers notice the change in their brains almost the minute they light up. Smoking quickly changes brain chemistry, affecting mood and often leading to addiction. Brain chemistry changes, as well as decreased blood flow, increase the risk for:

• Stroke—double that of nonsmokers
• Dementia and Alzheimer’s disease
• Depression, especially in women

Need to hear more? Smokers are at increased risk of developing the most common type of diabetes. These are a few of smoking’s other effects:

• Reduced sense of smell and taste
• Premature skin aging from reduced blood flow and vitamins
• Increased risk for gum disease
• Increased risk for cloudy lens in the eye (called cataract)—a leading cause of blindness
• Increased risk for impotence, infertility, and problems during pregnancy and delivery
• In babies of smoking mothers—increased risk for low birth weight, reduced lung function, and sudden infant death syndrome (SIDS)
• Menopause at an earlier age; increased number of menopausal symptoms

The benefits of quitting begin almost immediately. Heart rate drops within minutes. Circulation and breathing improve within months. And, among other improvements, your risk of stroke much lower after five years of quitting. Although it’s best to quit when you’re younger, you can benefit at any age.