Circulation problems are a common medical issue that can be caused by a variety of factors. One of the most common causes is a CLOT, which is a four-letter word in this crossword puzzle. Clots are formed when blood cells and proteins stick together and form a mass, blocking the flow of blood. This can lead to serious health issues, such as stroke, heart attack, and pulmonary embolism. Treatment for circulation problems often involves medications or surgery to remove the CLOT.