The presence of calf swelling in the afternoon indicates a likely abnormality. There is unilateral calf swelling and bilateral calf swelling. In the case of unilateral calf swelling, it is likely that poor blood return to the lower extremities or the presence of certain blood clots due to atherosclerosis will require ultrasound of the appropriate area to determine the diagnosis. Bilateral swelling of the lower leg may be due to poor local blood flow in the lower limb or thrombosis caused by atherosclerosis, and the corresponding ultrasound needs to be done to make a differential diagnosis. Excluding local causes, it is caused by systemic diseases, such as heart disease and kidney disease, which can easily lead to edema of lower limbs, especially heart disease, which can easily lead to edema of lower limbs in the afternoon or after a day of exercise in the lower part of the body. Therefore, after excluding local causes, it is necessary to consider whether the edema is caused by heart disease.