Hypotension is the medical term for low blood pressure (less than 90/60). Many people worry about low blood pressure, but probably don't need to.
Some people have a blood pressure level that is lower than normal. In general this may be good news - because the lower your blood pressure is, the lower your risk of stroke or heart disease. However, if your blood pressure drops too low, it can restrict the amount of blood flowing to your brain and other vital organs, which can cause unsteadiness, dizziness or fainting, so you might need to speak to your doctor or nurse.
Is Low Blood Pressure Dangerous?
Usually, having low blood pressure is not a cause for concern. However, sometimes your blood pressure can drop to a point where you may feel faint or dizzy.
If you find that your blood pressure is suddenly much lower than usual, there may be a reason for this. Speak to your doctor or nurse.
Symptoms of Low Blood Pressure
While high blood pressure is known as the "silent killer," because it is associated with few acute symptoms, hypotension may be normal for a patient if it is without symptoms, but can be of great importance if it is associated with abnormal body function.
Unlike high blood pressure, low blood pressure is defined primarily by signs and symptoms of low blood flow and not by a specific blood pressure number. Some individuals routinely may have blood pressure numbers of 90/50 with no symptoms and therefore do not have low blood pressure. However, others who normally have higher blood pressures may develop symptoms of low blood pressure if their blood pressure drops to 100/60.
Dizziness or lightheadedness
Lack of concentration
Confusion, especially in older people
Cold, clammy, pale skin
Rapid, shallow breathing
Weak and rapid pulse
It is important to see your doctor if you have signs or symptoms of hypotension because they can point to more-serious problems. It can be helpful to keep a record of your symptoms, when they occur and what you're doing at the time.
What to do if you have symptoms
If you think you may be experiencing an episode of low blood pressure, you should:
stop what you're doing
sit or lie down
drink some water
The symptoms will usually pass after a few seconds or minutes.
Causes of Low Blood Pressure
Some people have a blood pressure level that is naturally low. That is, there is no specific cause or reason why.
However, some health conditions or medicines can cause you to develop low blood pressure.
Conditions that can cause low blood pressure include:
Pregnancy. During the first 24 weeks of pregnancy, it’s common for blood pressure to drop. Because the circulatory system expands rapidly during pregnancy, blood pressure is likely to drop. This is normal, and blood pressure usually returns to your pre-pregnancy level after you've given birth.
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.
Endocrine problems. Thyroid conditions such as parathyroid disease, adrenal insufficiency (Addison's disease), low blood sugar (hypoglycemia) and, in some cases, diabetes can trigger low blood pressure.
Dehydration. When your body loses more water than it takes in, it can cause weakness, dizziness and fatigue. Fever, vomiting, severe diarrhoea, overuse of diuretics and strenuous exercise can lead to dehydration.
Blood loss. Losing a lot of blood, such as from a major injury or internal bleeding, reduces the amount of blood in your body, leading to a severe drop in blood pressure.
Severe infection (septicemia). When an infection in the body enters the bloodstream, it can lead to a life-threatening drop in blood pressure called septic shock.
Severe allergic reaction (anaphylaxis). Common triggers of this severe and potentially life-threatening reaction include foods, certain medications, insect venoms and latex. Anaphylaxis can cause breathing problems, hives, itching, a swollen throat and a dangerous drop in blood pressure.
Lack of nutrients in your diet. A lack of the vitamins B-12 and folate can keep your body from producing enough red blood cells (anemia), causing low blood pressure.
Certain medications. A number of drugs can cause low blood pressure, including diuretics and other drugs that treat hypertension; heart medications such as beta blockers; drugs for Parkinson’s disease; tricyclic antidepressants; erectile dysfunction drugs, particularly in combination with nitroglycerine; narcotics and alcohol. Other prescription and over-the-counter drugs may cause low blood pressure when taken in combination with high blood pressure medications.
Orthostatic hypotension. Sudden drops in blood pressure most commonly occur in someone who's rising from a lying down or sitting position to standing. This kind of low blood pressure is known as postural hypotension or orthostatic hypotension.
Neurally mediated hypotension. Unlike orthostatic hypotension, this disorder causes blood pressure to drop after standing for long periods, leading to symptoms such as dizziness, nausea and fainting. This condition primarily affects young people and occurs because of a miscommunication between the heart and the brain. When it leads to passing out, it is called vasovagal syncope.
And prolonged bed rest.
How is Blood Pressure Measured?
Blood pressure is often measured using a sphygmomanometer, a device that consists of a stethoscope, arm cuff, dial, pump and valve.
The cuff is placed around your arm and pumped up to restrict the blood flow. The pressure is then slowly released as your pulse is checked using the stethoscope.
A measurement is taken on the mercury scale, giving an accurate reading of your blood pressure.
Many health care providers now use digital sphygmomanometers, which measure your pulse using electrical sensors.
Before having your blood pressure taken, you should rest for at least five minutes and empty your bladder.
To get an accurate blood pressure reading, you should be sitting down and not talking when the reading is taken.
Diagnosing Low Blood Pressure
The key to diagnosis is a good history and physical examination. If low blood pressure is found incidentally and no other symptoms exist, then documenting the lower readings will help remind the healthcare provider during future visits.
If the patient is symptomatic, documenting risk factors and exploring potential causes requires a detailed history of the situation; for example:
when symptoms occur,
associated complaints, and
a thorough review of past illnesses and medications.
Physical examination may include postural vital signs. The patient has the blood pressure and pulse rate taken when laying flat and again when standing (some may add a third set of measurements when sitting). If the blood pressure drops or the pulse rate increases, it may be an indicator of decreased intravascular volume from dehydration or bleeding. The rest of the examination will likely be directed by clues from the history, but may include palpation of the thyroid gland in the neck, listening to the heart and lungs, and examination of the abdomen and the extremities.
Blood tests may be done, again directed by findings in the history and physical examination.
An electrocardiogram (EKG or ECG) may be performed if the low blood pressure is thought to originate in the heart or if there is chest pain or shortness of breath associated with the low pressure.
Consideration for further testing will depend upon the potential underlying cause of low blood pressure.
Low blood pressure that either doesn't cause signs or symptoms or causes only mild symptoms rarely requires treatment.
If you have symptoms, treatment depends on the underlying cause. For instance, when low blood pressure is caused by medications, treatment usually involves changing or stopping the medication or lowering the dose.
If it's not clear what's causing low blood pressure or no treatment exists, the goal is to raise your blood pressure and reduce signs and symptoms. Depending on your age, health and the type of low blood pressure you have, you can do this in several ways:
Use more salt. Experts usually recommend limiting salt in your diet because sodium can raise blood pressure, sometimes dramatically. For people with low blood pressure, that can be a good thing.But because excess sodium can lead to heart failure, especially in older adults, it's important to check with your doctor before increasing the salt in your diet.
Drink more water. Fluids increase blood volume and help prevent dehydration, both of which are important in treating hypotension.
Wear compression stockings. The elastic stockings commonly used to relieve the pain and swelling of varicose veins can help reduce the pooling of blood in your legs.
Medications. Several medications can be used to treat low blood pressure that occurs when you stand up (orthostatic hypotension). For example, the drug fludrocortisone, which boosts your blood volume, is often used to treat this form of low blood pressure.Doctors often use the drug midodrine (Orvaten) to raise standing blood pressure levels in people with chronic orthostatic hypotension. It works by restricting the ability of your blood vessels to expand, which raises blood pressure.
Lifestyle and home remedies
Depending on the reason for your low blood pressure, you might be able to reduce or prevent symptoms.
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.
Eat 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 using more salt but you don't like a lot of salt on your food, try using natural soy sauce or adding dry soup mixes to dips and dressings.
Pay attention to your body positions. Gently move from a prone or squatting to a standing position. Don't sit with your legs crossed.Before arising 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.If you begin to get symptoms while standing, cross your thighs in a scissors fashion and squeeze, or put one foot on a ledge or chair and lean as far forward as possible. These maneuvers encourage blood flow from your legs to your heart.
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.
Your doctor also might recommend drinking caffeinated coffee or tea with meals to temporarily raise blood pressure. But because caffeine can cause other problems, check with your doctor before drinking more caffeinated beverages.