Low blood pressure, also called hypotension, does not necessarily indicate a serious problem. A sudden drop in blood pressure may happen when someone stands up too quickly and the body cannot bring the pressure back to normal fast enough. The normal blood pressure pulse is 120/80, or systolic over diastolic pressures. Doctors consider blood pressure lower than 90/60 as hypotension, according to the National Heart, Lung and Blood Institute. Some people have low blood pressure all of the time. Concerns come into play when symptoms occur.
Fatigue
The fatigue brought on from low blood pressure can lead to dizziness, light-headedness and fainting. Physical symptoms may also include blurred vision, rapid or shallow breathing, nausea, or cold, clammy and pale skin. Such symptoms as dizziness or light-headedness may not indicate serious problems with low blood pressure, since people can have varying levels. For some people, it may not be how low blood pressure is, but how fast it has dropped, MayoClinic.com notes.
Dehydration
Dehydration may cause blood pressure to drop significantly. Symptoms also include unusual thirst. Dehydration occurs from a loss of more water than the body takes in, sometimes resulting from strenuous exercise, fever, vomiting, severe diarrhea or an overuse of diuretics. Dehydration does not necessarily mean low blood pressure. However, replacing fluids in the body helps relieve such symptoms as dizziness and weakness.
Shock
Continued low blood pressure may cause a dramatic decrease in oxygen that affects the heart rate and can cause shock. Severe infection can cause shock when bacteria leave the initial site of an infection, often in the lungs, abdomen or urinary tract, according to the American Heart Association. The bacteria produce toxins that enter blood vessels and lead to a rapid and life-threatening drop in blood pressure. Anaphylactic shock can cause sudden and dangerously low blood pressure. The shock stems from an allergic reaction some people have to bee or wasp stings, certain medications or some foods. Itching, hives and swollen throat may also occur, calling for immediate emergency help.
Decreased Blood Flow
Insufficient blood flow to the brain from low blood pressure can cause oxygen deprivation. When blood flow to the heart decreases, a heart attack can result. Reduced blood flow to the kidneys can build up waste in the blood. Blood loss from severe trauma, dehydration or injury can cause a dramatic drop in blood pressure. Heart problems also interfere with blood flow to cause dramatically low blood pressure. Heart disease, heart failure and heart attack damage heart vessels and valves so not enough blood can circulate throughout the body.
Health Disorders
Certain disorders may eventually lead to low blood pressure. Deficiencies of vitamins B-12 and folic acid can result in anemia and low blood pressure. Low blood sugar, adrenal insufficiencies and an under active thyroid can interfere with hormone production and cause low blood pressure.
