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. Causes of traveler’s edema: 1, due to long-distance travel by train or on foot, due to gravity, the lower limbs and sagging upper limb venous reflux is restricted, increasing the hydrostatic pressure in the capillaries, resulting in fluid seepage in the subcutaneous tissue gap. 2, due to increased secretion of aldosterone during uprightness, resulting in an increase in renal tubular reabsorption of water and sodium related. It is more common in women and may be related to endocrine disorders; it is more common in obese people because they need to rely on peripheral vasodilatation to distribute body heat, prompting an increase in venous pressure in the lower limbs and an increase in capillary filtration pressure. Travelers edema as long as you stop traveling, 2-3 days to recover, no need to treat with drugs. Sometimes the salt intake can be appropriately restricted, water does not necessarily need to be strictly controlled, when edema is significant, a small amount of dihydrocotrimoxazole can be used, each time 25mg (1 tablet) twice a day, and the edema can subside after a series of days.