When blood doesn\u2019t flow properly and slows too much, clots can form. Your body\u2019s ability to clot is lifesaving and involves many complex interactions.\nBlood clots that get too large in veins or form abnormally can cause problems. Your body naturally dissolves blood clots on its own without any treatment or intervention; however, sometimes you can have complications when a blood clot breaks apart and travels to other areas of the body or when veins become blocked and painful.\nHere's what you should know about blood clots. Click To Tweet\nWhat Are Blood Clots?\nBlood clots can partially or completely block the blood flow in a blood vessel. A blocked vein leads to fluid buildup and swelling, such as that associated with deep vein thrombosis (DVT).\nBlood clots can occur in different parts of the body. DVT often occurs in the large veins of the lower leg, while renal vein thrombosis develops in the vein that drains blood from the kidneys.\nA blood clot can also get caught in an artery, blocking off the blood flow. This is called an arterial embolism. These often happen in the legs or feet.\nBlood thinners are the most common treatment for blood clots and are used to prevent them for people at high risk.\nRELATED:\u00a0What is a \u201cBlood Thinner?\u201d\nVein Problems\nWhat are spider veins?\nSpider veins are small, twisty veins in the legs, calf, and thighs. When the blood vessels just under the skin expand, you get visible spider veins. Although we don\u2019t like the look of them, these are generally harmless and easily treatable.\nWhat are varicose veins?\nVaricose veins are twisted, enlarged, swollen blood vessels. They happen when the blood is unable to flow back up through the legs and to the heart, causing the blood to pool.\nIn addition to being painful, varicose veins that cause circulation or blood flow problems can lead to blood clots or deep vein thrombosis.\nSpider and varicose vein treatment\nTreatment for spider veins and varicose veins is relatively easy, ranging from compression stockings to minor outpatient procedures.\nSclerotherapy is the most common treatment for spider veins. In this procedure, a physician injects a saline solution into the damaged vein, causing it to harden and disappear.\nLaser treatment or ablation, a procedure that uses intense heat, are commonly used to remove or destroy varicose veins.\nRELATED:\u00a0Frequently Asked Questions: Varicose Veins\nKeep Your Blood Flowing\nRisk factors are similar for vein problems and blood clots. Smoking greatly increases your risk, as does obesity, estrogens and birth control, and sitting or standing for long periods.\nSmoking and sitting or standing for long periods of time increase your risk for blood clots. Click To Tweet\nStaying active, quitting smoking, and managing your blood pressure are all important ways to prevent problems with clotting or blood flow.\nWant to stay heart smart? Visit the UPMC Heart and Vascular Institute online to learn more about blood clots and how they can affect your long-term health.