After a long trip or a sedentary period of time may cause obstruction of venous blood return to the lower extremities, the hydrostatic pressure in the veins of the lower extremities rises, and fluid and other components of the blood penetrate into the tissue interstices causing edema. After sitting for a period of time, moderate exercise can reduce the lower limb edema. After the occurrence of lower limb edema caused by sedentary conditions, it is still necessary to exercise moderately and elevate the lower limbs at night when resting to facilitate venous return, after such treatment most of the lower limb edema disappears within two or three days. If the lower limb edema does not improve or even worsens after the above treatment, it is necessary to apply low molecular heparin or go to the hospital for angiography and vascular ultrasound to clarify whether there is venous thrombosis.