A weak pulse means there is difficulty feeling a person's pulse, or heartbeat, according to the New York Times. A weak or absent pulse is a medical emergency, and it usually indicates a serious problem, according to Health Line. Causes of a weak pulse include shock, which can also cause shallow breathing, rapid heartbeat and unconsciousness.
Peripheral artery disease can also cause a weak pulse, and it is characterized by the narrowing of the peripheral arteries of the legs and pelvis, according to the American Heart Association. It is similar to coronary artery disease as it is also caused by the narrowed and blocked arteries of various regions of the body, as noted by the American Heart Association. In addition to a weak pulse, symptoms of peripheral artery disease include painful cramping in the hip, thigh or calf muscles following certain activities such as climbing stairs or walking, leg numbness or weakness and coldness in the lower extremities, according to Mayo Clinic. Other symptoms of peripheral artery disease may include sores on the feet, legs or toes that do not heal, a loss of hair or slowed hair growth on the feet or legs, a change in leg color, shiny skin on the legs, slower growth of toenails and erectile dysfunction, notes the Mayo Clinic.