An 18-year-old girl woke up from a nap and found that her left thigh was much thicker than her right thigh, and it was accompanied by swelling and pain, and she could hardly walk when she got out of bed. When she went to the hospital for a checkup, the doctor said, “Thanks to the early arrival, otherwise I’m afraid it’s life-threatening. My God, how can it suddenly be so serious? It turns out that the woman is a waitress and works standing up every day. The weather is hot, and the girl did not have the habit of drinking water, came home to sleep overnight became so. The doctor told her that it was lucky to come early, otherwise it might be life-threatening. The doctor said, the vein is the return vessel, lower limb vein thrombosis, we can image understanding as the sewer is blocked. Once the thrombus is formed, it is afraid to fall off. Venous blood is to return to the heart, and then by the heart pump sent to the pulmonary artery. Once the thrombus is dislodged, it will flow back to the heart with the venous blood and then pump to the pulmonary artery, which is likely to block the pulmonary artery. When the patient will have difficulty breathing, hemoptysis, serious suffocation death, even too late to rescue. After listening to the doctor’s explanation, the girl was very afraid. For three consecutive days in the Internet cafe, the boy did not save because of thrombosis caused death is not sensational, the doctor told reporters that a few years ago a case still fresh in his mind. At that time, there was a young man in his 20s, stayed in the Internet cafe for three days, playing games even cared not to drink water. After leaving the Internet cafe, he felt pain in his stomach, and later came to the central hospital, where the doctor suspected that he might not simply have stomach pain. As a result, angiography found that he had mesenteric vein thrombosis, which caused intestinal edema due to venous thrombosis, followed by intestinal necrosis, and the patient was too late to be rescued. Doctors said that arterial thrombosis is generally more common, while necrosis caused by venous thrombosis is a little slower and often overlooked. Analyzing this case, the doctor said that it has a lot to do with him being sedentary and not drinking water, and the young man himself is fat and the fat on his stomach is too thick, which may also have pressure on the veins. All kinds of causative factors led to the evil consequences. Some people may think that the formation of blood clots is a very long process, while doctors say that some people can actually form them after standing and sitting for a day. Clinically, we have met people who played mahjong for an afternoon and got up to find that their legs would not move. There is also a disease called economy class syndrome, which is a series of clinical manifestations related to lower extremity deep vein thrombosis and/or pulmonary embolism that occur during or after travel by airplane. Cabin factors are mainly the long-distance flight and cramped seats leading to prolonged limb movement restriction, low air humidity, etc.; individual passenger factors are mainly the risk factors for venous thromboembolism present in passengers, including severe obesity, chronic heart disease, hormone therapy (including taking birth control pills), history of venous thromboembolism, malignancy, etc. In fact, prolonged travel by other means of transportation such as cars and trains can also increase the risk of lower extremity deep vein thromboembolism. In some people, a day of prolonged standing and sitting can result in venous thrombosis. While arterial thrombosis is more common, the necrosis caused by venous thrombosis is a little slower and is often overlooked. Doctors remind that in the summer, people are easily dehydrated, and if they are not hydrated in time, their blood will become sticky, which is also a trigger for the onset of the disease. Once you find your leg swollen and painful, go to the hospital in time, the sooner it comes, the better the treatment will be. Also doctors warn such a group of people who find their legs a little swollen when they sleep at night and get better after a good night’s sleep. Such people are likely to have poor venous reflux in the lower limbs, which may cause varicose veins in the lower limbs in the long run, and such people can elevate their legs when they sleep at night.