Hypotension

Introduction
Low blood pressure, also called hypotension, would seem to be something to strive for. After all, high blood pressure (hypertension) is a well-known risk factor for heart disease and other problems. In fact, in recent years there has been an ongoing downward revision of what is considered a normal blood pressure reading. A blood pressure less than 120/80 millimeters of mercury (mm Hg) is now considered normal and optimal for good health.

So, it's easy to understand why you might assume the lower the better when it comes to blood pressure. And it's true that for some people, those who exercise and are in top physical condition, low blood pressure is a sign of health and fitness. But that's not always the case.

For many people, low blood pressure can cause dizziness and fainting or indicate serious heart, endocrine or neurological disorders. Severely low blood pressure can deprive the brain and other vital organs of oxygen and nutrients, leading to a life-threatening condition called shock.

Signs and symptoms
Some people with low blood pressure are in peak physical condition with strong cardiovascular systems and a reduced risk of heart attack and stroke. But low blood pressure can also signal an underlying problem, especially when it drops suddenly or is accompanied by signs and symptoms such as:

  •  Dizziness or lightheadedness
  •  Fainting (syncope)
  •  Lack of concentration
  •  Blurred vision
  •  Nausea
  •  Cold, clammy, pale skin
  •  Rapid, shallow breathing
  •  Fatigue
  •  Depression
  •  Thirst

Causes of low blood pressure varyAthletes and people who exercise regularly tend to have lower blood pressure than do people who aren't as fit. So, in general, do nonsmokers and people who eat well and maintain a normal weight, but in some instances, low blood pressure can be a sign of serious, even life-threatening disorders.

The American Heart Association considers the following as possible causes of low blood pressure:

  • Pregnancy: Because a woman's circulatory system expands rapidly during pregnancy, blood pressure is likely to drop. In fact, during the first 24 weeks of pregnancy, systolic pressure commonly drops by five to 10 points and diastolic pressure by as much as 10 to 15 points.
  • Medications: Many drugs can cause low blood pressure, including diuretics and other drugs that treat high blood pressure; heart medications such as beta blockers; drugs for Parkinson's disease; tricyclic antidepressants; sildenafil (Viagra), particularly in combination with nitroglycerine; narcotics; and alcohol. Some over-the-counter medications can cause low blood pressure when taken in combination with medications used to treat high blood pressure.
  • Heart problems: Some heart conditions that can lead to low blood pressure include extremely low heart rate (bradycardia), heart valve problems, heart attack and heart failure. These conditions may cause low blood pressure because they prevent your body from being able to circulate enough blood.
  • Endocrine problems: An underactive thyroid (hypothyroidism) or overactive thyroid (hyperthyroidism) can cause low blood pressure. In addition, other conditions, such as adrenal insufficiency (Addison's disease), low blood sugar (hypoglycemia), and in some cases, diabetes, can trigger low blood pressure.
  • Dehydration: When you become dehydrated, your body loses more water than it takes in. Even mild dehydration can cause weakness, dizziness and fatigue. Fever, vomiting, severe diarrhea, overuse of diuretics and strenuous exercise can all lead to dehydration. Far more serious is hypovolemic shock, a life-threatening complication of dehydration. It occurs when low blood volume causes a sudden drop in blood pressure and a corresponding reduction in the amount of oxygen reaching your tissues. If untreated, severe hypovolemic shock can cause death within a few minutes or hours.
  • Blood loss: Losing a lot of blood from major injury or severe internal bleeding reduces the amount of blood in your body, leading to a severe drop in blood pressure.
  • Severe infection (septicemia): Septicemia can happen when an infection in the body enters the bloodstream. Lung, abdomen or urinary tract infections are usually the cause of septicemia. These conditions can lead to a life-threatening drop in blood pressure called septic shock.
  • Allergic reaction (anaphylaxis): Anaphylaxis is a severe and potentially life-threatening allergic reaction. Common triggers of anaphylaxis include foods, certain medications, insect venoms and latex. Anaphylaxis can cause breathing problems, hives, itching, a swollen throat and a drop in blood pressure.
  • Nutritional deficiencies: A lack of the vitamins B-12 and folate can cause anemia, a condition in which your body doesn't produce enough red blood cells. In addition to making you feel tired because you're not getting enough oxygen,
anemia can lead to low blood pressure.

Risk factors

Low blood pressure can happen to anyone, though certain types of low blood pressure are more common depending on your age or other factors.

Drops in blood pressure on standing or after eating occur primarily in older adults. Orthostatic hypotension happens after standing up, while postprandial hypotension happens after eating a meal. Neurally mediated hypotension happens as a result of a miscommunication between the brain and heart. It primarily affects children and younger adults.

People who take certain medications, such as high blood pressure medication, have a greater risk of low blood pressure.

Certain diseases. Parkinson's disease and some heart conditions put you at a greater risk of developing low blood pressure

Complications

Even moderate forms of low blood pressure can seriously affect quality of life, leading not only to dizziness and weakness but also to fainting and a risk of injury from falls. And severely low blood pressure from any cause can deprive your body of enough oxygen to carry out its normal functions, leading to damage to your heart and brain.

Self-care

Depending on the reason for your low blood pressure, you may be able to take certain steps to help reduce or even prevent symptoms. Some suggestions include:

  • Drink more water, less alcohol: Alcohol is dehydrating and can lower blood pressure, even if you drink in moderation. Water, on the other hand, combats dehydration and increases blood volume.
  • Follow a healthy diet: Get all the nutrients you need for good health by focusing on a variety of foods, including whole grains, fruits, vegetables, and lean chicken and fish. If your doctor suggests increasing your sodium intake but you don't like a lot of salt on your food, try using natural soy sauce — a whopping 1,200 milligrams of sodium per tablespoon — or adding dry soup mixes, also loaded with sodium, to dips and dressings.
  • Go slow: You may be able to reduce the dizziness and lightheadedness that occurs with low blood pressure on standing by taking it easy when you move from a prone to a standing position. Before getting out of bed in the morning, breathe deeply for a few minutes and then slowly sit up before standing. Sleeping with the head of your bed slightly elevated also can help fight the effects of gravity.
  • Eat small, low-carb meals: To help prevent blood pressure from dropping sharply after meals, eat small portions several times a day and limit high-carbohydrate foods such as potatoes, rice, pasta and bread. Drinking caffeinated coffee or tea with meals may temporarily raise blood pressure, in some cases by as much as 3 to 14 millimeters of mercury (mm Hg). But because caffeine can cause other problems, check with your doctor before increasing your caffeine intake.
 

When to seek medical advice

In many instances, low blood pressure isn't serious. If you have consistently low readings but feel fine, your doctor is likely to monitor you during routine exams. Even occasional dizziness or lightheadedness may be relatively minor — the result of mild dehydration, low blood sugar or too much time in the sun or a hot tub, for example. In these situations, it's not a matter so much of how far, but of how quickly, your blood pressure drops.

Still, it's important to see your doctor if you experience any signs or symptoms of hypotension because they sometimes can point to more serious problems.

It can be helpful to keep a record of your symptoms, when they occur and what you were doing at the time. If these occur at times that may endanger you or others, you should talk to your doctor.