*Heart conditions: Heart attack, angina, heart failure, severe heart disease, high blood pressure
*Blood clots: Suspected blood clots, deep vein thrombosis, thrombophlebitis
*Skin conditions: Burns, dermatitis, sores, purulent wounds, malignant tumors
*Surgery: Recent surgery, especially for varicose veins
*Pregnancy: Pregnant women
*Implantable devices: Pacemakers or other medical devices
*Infections: Infections in the legs or treatment areas
*Kidney or liver failure: Renal or liver failure
*Acute inflammation: Acute inflammation caused by bacteria, viruses, or poisons
*Acute injuries: Bone fractures or other acute injuries
*Cancer