Long hours in a car, the lower limbs can appear swollen, medically known as “traveler’s edema”. Therefore, when riding in a car, do not always sit, should always change the position, or stand for a while or elevate the lower limbs to sit for a while, also can be used to massage the lower limbs from top to bottom to help blood flow back. Edema is often one of the important manifestations of certain diseases and can be caused by as many as 30 different causes, most commonly caused by heart, liver and kidney diseases. However, there are some patients with edema who have no abnormal findings by multifaceted examination and laboratory tests, and after long-term observation, the health of these people is not significantly affected. Given that the causes and nature of this type of edema are not well understood, it is medically called benign edema also known as functional edema. Traveler’s edema is mostly seen in people over 40 years of age and fat people, and is more common in women, and it is a kind of benign edema. It manifests as numbness, swelling and heaviness in the hands and feet, and edema is more common in the two lower limbs and is looser, and the hands are often involved; it is mostly mild edema and has little relationship with water intake; it can disappear completely after rest and position change, and often disappears in the morning and appears in the afternoon. Prevention of edema in travelers: Don’t always sit in the car, change your position often, or stand for a while or sit with your lower limbs elevated for a while, or massage your lower limbs from top to bottom with your hands to help blood flow back. If the edema is strong, the salt intake can be appropriately limited, and the water does not necessarily need to be strictly controlled.