Use the following reading passage to answer the question below:
Causes of Low Blood Circulation
Poor blood circulation may be caused by several underlying conditions, of which the most common one is atherosclerosis. Other potential causes should also be taken into consideration when you are suffering from low blood circulation.
Atherosclerosis
Atherosclerosis is the hardening of the blood vessels, which makes it difficult to pump blood throughout the body, most notably in the hands and legs. This is caused by plaque deposits forming along the artery walls due to high blood pressure, high cholesterol or diabetes. Conditions like smoking or aging can also cause the blood vessels to harden.
In addition to causing atherosclerosis, diabetes or high cholesterol also contribute to the level of plaque formed and deposited in your body. This plaque sticks to the walls of your arteries which narrows the area in which blood can move through. The harder it is to pump blood throughout your body, the lower your blood circulation levels will be. This condition can be increased by poor eating habits that both contribute to the severity of these conditions and deprive your body of the necessary nutrients to keep up your circulatory system.
In some cases, foreign particles can also get trapped in the tissues and cells, which are then deposited into the bloodstream when the cells deposit them as waste. If these tissues become lodged on the walls of your veins and arteries, they can cause atherosclerosis which will lead to poor blood circulation.
Venous thrombosis
Some people with poor circulation may be suffering from venous thrombosis or deep vein thrombosis. These conditions are caused by veins becoming inflamed, often as a result of blood clots becoming lodged in the veins. This can lead to tenderness, skin discoloration and swelling in the area where the vein is being affected. Some people also report fluids becoming collected in nearby cells which contributes to the discomfort of the patient. Patients suffering from these symptoms not only have to worry about their circulation becoming damaged, but also the blood clot breaking loose and causing further damage throughout the body.
Inadequate exercise
Not exercising frequently can also lead to poor blood circulation. When you spend a great deal of time in a neutral position blood in the pelvis and legs can become stagnant which can lead to poor circulation and blood pooling. Combining a lack of exercise with poor diet and smoking can also increase your risk of developing a dangerous condition.
Tight fitting clothing
In some cases, tight fitting clothing can decrease blood circulation, most notably in the pelvic region. Control-top pantyhose, tight shirts or skinny jeans are just a few examples of clothing that can contribute to this issue.
Stress
Stress can also lead to poor circulation, most notably in the hands. Stress leads to knots in the muscles in the shoulders and neck which can restrict blood flow to the heart and other major organs.
What is the meaning of this underlined word: “Stress leads to knots in the muscles in the shoulders and neck which can restrict blood flow to the heart and other major organs.”?