Patients with simple varicose veins can run. The movement of muscles, especially during running when the calf muscles are active, can compress the deep veins, facilitating the emptying of these veins. This benefits the flow of blood in the superficial veins through the communicating veins back to the deep venous system, thus participating in the systemic circulation. Therefore, patients with varicose veins in the calves can still run in the majority of cases. However, there are exceptions. If a person experiences significant muscle pain, it is important to be cautious as there may be a thrombus in the muscle veins. If there is a thrombus in the muscle veins, and the return flow in the deep veins is obstructed, this may also cause varicose veins. In cases of fresh thrombosis, running might lead to the detachment of the thrombus. Thus, patients in such conditions are advised not to run until further evaluation is confirmed by an ultrasound examination.