Visible blood vessels may be a normal physiological phenomenon, or they may be caused by varicose veins and other diseases. 1. Normal physiological phenomenon: If the skin is thin and the subcutaneous fat is less, the more superficial blood vessels will be more obvious. Or after exercise, the blood circulation of the body is accelerated and the blood vessels on the surface of the body are filled up, thus making the blood vessels visible. The above situations are normal physiological phenomena, no need to worry. 2. Varicose veins: Varicose veins can be caused by excessive pressure in the veins due to various reasons and the accumulation of blood flow in the veins, which can lead to twisted and enlarged veins. If this happens to the veins on the surface of the body, there is a possibility that the veins on the surface of the body may protrude from the surface, making the blood vessels visible. If the veins are protruding too much or if the protruding veins have a strange shape, it is recommended to go to the hospital for the appropriate examination to find out the cause and then treat it according to the doctor’s instructions.