Blood clots, also known as thrombi, are formed inside major blood vessels and are the major cause of many heart attacks, strokes, and other cardiovascular disorders.
Symptoms of blood clots are usually not apparent, which is why diagnostic screening on a regular (yearly) basis is recommended.
Blood solidification, or clotting, usually occurs as a healthy response within minutes after the skin is cut or there is trauma that causes bleeding. A clot helps seal the damage. However, blood clotting can be dangerous when it occurs inside healthy blood vessels. Unhealthy clotting can occur from platelets that get "activated" to clump together. This occurs when platelets come in contact with damaged arterial walls, or due to nutrient deficiencies, poor dietary habits, or genetic predisposition. Once platelets get sticky, their shape changes and they easily mesh or clump together, causing a clot.
Another factor that can cause unhealthy blood clots is the production of fibrin, which helps bind the clump of platelets together. Fibrin is the end product of a cascade of coagulation (clumping) factors that occur with the activation of just one molecule. This, in turn, can lead to the explosion of up to 30,000 molecules of fibrin at the site of injury on the arterial wall.
Factors that can cause a buildup of platelet stickiness and fibrin include: the use of birth control pills, late stages of pregnancy, nutrient deficiencies, smoking, free radicals (inadequate antioxidant nutrients), a high-cholesterol diet, low essential fatty acids, a diet high in saturated fat and low in vegetables and fish, and liver disease. Prolonged sitting on long airline flights, especially in cramped conditions, can also increase the risk of developing pulmonary thrombosis. Blood clots forming in the legs or another part of the body break loose and then block one of the arteries to the lungs. Some practical preventive measures during long flights include getting up and walking the aisle every hour, wearing loose, comfortable clothing, periodically stretching the legs and tightening and loosening the muscles of the abdomen and buttocks, and taking some slow, deep breaths.