Swollen feet of the elderly in their 80s are considered to be physiological factors, but may also be caused by pathological factors. 1. Physiological factors: prolonged sitting, prolonged standing or prolonged bed rest will lead to poor blood circulation in the lower limbs, so that venous return is blocked, thus resulting in swollen feet. 2. Pathologic factors. (1) malnutrition: the elderly in their 80s are affected by age, nutritional absorption obstacles, which can lead to insufficient protein intake, and the lack of protein in the body can lead to swollen feet. (2) Cardiogenic diseases: 80-year-olds with coronary heart disease, coronary heart disease and other causes of cardiac insufficiency, can lead to sodium retention in the body, resulting in swelling of the legs and feet. (3) Kidney disease: renal insufficiency in the 80s can lead to a decrease in plasma osmotic pressure, and the water in the blood vessels will seep into the tissue interstitial space, resulting in swollen feet. Swollen feet of the elderly in their 80s can be examined in the hospital to exclude pathologic factors and follow the doctor’s instructions to improve.