Swollen feet of middle-aged people may be physiological factors caused by standing for a long time, but also disease factors, such as varicose veins of the lower extremities, chronic nephritis, and so on. 1. Physiological factors: such as standing for a long time, walking too much, resulting in poor blood flow in the lower extremities, thus causing swelling of the feet of middle-aged people, pay attention to rest can effectively alleviate the symptoms. 2. Varicose veins of the lower limbs: If it is simple superficial varicose veins of the lower limbs, the clinical symptoms are generally light and slow, but if it is deep vein valve insufficiency, or even deep vein reflux obstruction, then swelling and swelling pain of the lower limbs will occur, causing swelling of the feet of middle-aged people. 3. Chronic nephritis: Chronic nephritis is a kidney dysfunction, the body fluid can not be discharged in a timely manner, which causes swelling symptoms such as swollen legs, swollen feet, resulting in swollen feet in middle-aged people. There may be other causes of swollen feet in middle-aged people, when middle-aged people have swollen feet and delayed improvement, it is recommended to consult a doctor to find out the cause of the disease, according to the cause of the targeted treatment.