Smoking leads to numerous health problems, most notably lung cancer and emphysema. Cigarette smoking also affects your vascular system, but these effects often go unrecognized in the early stages. The damage smoking causes in veins and arteries builds over time and may result in stroke or heart disease. Smoking also raises your risk for deep vein thrombosis, or DVT, a condition in which blood clots form in leg veins.
Deep Vein Thrombosis
DVT is the formation of blood clots in deep veins, usually in the legs, The Merck Manual says. Clots formed in deep veins may break off and travel to the lungs, heart or brain. DVT often has no symptoms until a blood clot has traveled to other parts of the body. Symptoms of DVT, if they occur, include a calf that is swollen, painful and warm to the touch. Your ankle, foot or thigh may also swell. Blood clots form less commonly in the arms.
Risk Factors
Bed rest or sitting for prolonged periods, for example, during a long airplane flight, increases your risk for DVT, The Merck Manual notes. As the calf muscles move, they squeeze the veins to move the blood up to the heart. Without the movement of the muscles, the blood flow slows. Medical conditions or medications that promote blood clotting or any factor that causes the veins to narrow may also lead to DVT. Smoking not only increases your risk of DVT, but it heightens the effect of other risk factors.
Effects of Smoking
Cigarette smoke contains chemicals that damage blood vessels, the American Medical Association explains. The carbon monoxide in smoke reduces the oxygen level in your body and causes your heart to beat faster. The nicotine constricts blood vessels, says eHealthMD, raising blood pressure as the blood pushes through narrowed arteries and veins. Additionally, smoking increases cholesterol levels in the blood while lowering the proportion of so-called "good" cholesterol. Higher cholesterol levels lead to fatty plaque buildup on the interior walls of the blood vessels, narrowing them further. The buildup of plaque increases the risk of blood clots, as pieces of the plaque can break off and block the blood vessel.
Prevention
DVT can be prevented by stretching and flexing your ankles 10 times a day if you are confined to bed for a prolonged time, The Merck Manual suggests. During a long airplane flight, stand and walk up and down the airplane aisle for several minutes every two hours. Compression stockings have little effect on preventing DVT. Pneumatic stockings, however, contain an electric pump that squeezes your legs to keep blood moving through the veins.
Quitting Smoking
Quitting smoking greatly reduces your risk of DVT and other vascular conditions, eHealthMD advises, although the effects are not immediate. Your circulation will improve within a year after you quit smoking. Quitting does not reverse the plaque buildup inside your blood vessels, but quitting will slow the progression.
