Some people have fine blood vessels, others are weak, for example, if the amount of blood circulating is low. A good number of female patients have thin blood vessels, while male patients have fuller blood vessels. When a female patient has menstruation, there is less blood volume in her body and her blood vessels are correspondingly thin. Some female patients have slow blood flow, even though there is no diagnosed disease, and some of this is physiologic and not pathologic. When the feeling of arterial blood thin, the lower extremity foot may be cool, cold feeling, there will be fear of cold, then may need to go to the hospital to check the lower extremity arterial ultrasound, to observe whether it is a slow flow of blood vessels, blood vessels fine and so on, while some people have a small body size blood vessels will be thinner.