What is a low blood pressure numbers?

We all know that high blood pressure can be dangerous. But what about low blood pressure

Also called hypotension, low blood pressure is not a problem if you’re healthy and show no signs or symptoms of the condition. However, abnormally low blood pressure can cause problems such as dizziness and fainting and can be a sign that other serious conditions, such as heart disease, are present.

Blood pressure is the force of blood pushing on the artery walls as it is pumped out of the heart. Blood pressure is measured in two kinds of pressures. Systolic pressure is when the heart beats while pumping blood. Diastolic pressure is when the heart is at rest between beats.

Blood pressure is measured in millimeters of mercury (mmHg). Systolic pressure is listed first (or the “top” number), then diastolic pressure (or the “bottom” number).

Normal blood pressure in adults is less than 120/80 mmHg. Low blood pressure is a reading below 90/60 mmHg.

Most forms of hypotension happen because your body can't bring blood pressure back to normal or can't do it fast enough.

For some people, low blood pressure is normal. They have it all the time, with no symptoms or negative side effects.

In other people, abnormally low blood pressure is caused by certain medical conditions or factors. When this happens, less blood and oxygen flow to the body's organs.

Many different conditions and situations can cause low blood pressure, from standing up too fast to being pregnant. Sometimes, low blood pressure is linked to an underlying problem. That’s why it’s important to see your doctor right away if you experience the signs of low blood pressure.

Symptoms of low blood pressure can include:

Low blood pressure can be a sign of serious heart, endocrine or neurological conditions. If left untreated, the brain and other vital organs do not get the oxygen and nutrients they need. In extreme cases, this can cause shock, a life-threatening condition.

If you show signs of low blood pressure, your doctor will conduct an exam and may perform tests to determine what’s causing the condition. Low blood pressure can occur with many other conditions.

Some causes of low blood pressure are:

Medicines and lifestyle changes can help you live safely with chronic low blood pressure. Your doctor can recommend steps you can take to manage your low blood pressure. These actions can help control the condition:

Drink more water. This can help avoid dehydration.

Avoid alcohol. Alcoholic beverages are dehydrating, and alcohol changes how medicines work in your body.

Slow down. Take your time when standing up. If lying down, sit up first. Then wiggle your feet and move your legs. This will increase circulation and get your heart rate up so that you don’t feel lightheaded when you stand up.

If your medicine and lifestyle changes do not reduce your low blood pressure symptoms, talk with your doctor about other changes you can make.

Source: National Heart, Lung and Blood Institute; American Heart Association

• Blurry vision.
• Confusion.
• Dizziness.
• Fainting (syncope)
• Lightheadedness.
• Nausea or vomiting.
• Sleepiness.
• Weakness.

Each time that you have your blood pressure measured, it is important that the test is carried out under similar conditions to ensure that the results are consistent. If you have a low blood pressure reading, your GP will first consider the everyday causes that might have affected it, before considering the possible underlying causes.

Many factors have a daily, or sometimes even hourly, effect on your heart and circulation. Below are things that could affect your blood pressure and, in some cases, may cause low blood pressure.

If your blood pressure is still considered low after taking into account everyday factors such as those listed above, there may be another cause. Some possibilities are explained below.

Some medication may cause hypotension as a side effect. This tends to be orthostatic, or postural hypotension (low blood pressure when you stand up or change position). Examples of medication that can cause hypotension include:

Your GP will discuss any possible side effects with you when prescribing medication. While you are taking medication, your blood pressure will be carefully monitored if you are considered to be at risk of hypotension.

If you have an acute (short-term) illness, your blood pressure will be measured regularly because it is a good indicator of the severity of your illness. A heart condition, such as heart failure or a heart attack, can also cause low blood pressure, as your heart may not be able to pump blood around your body.

Autonomic disorders affect your autonomic nervous system and they can cause hypotension. Your autonomic nervous system is part of your nervous system (the network of cells that carry information around your body). It controls the bodily functions that you do not actively think about, such as sweating, digestion and the beating of your heart.

The autonomic nervous system also controls the widening and narrowing of your blood vessels. If there is a problem with it, your blood vessels could remain too wide, causing low blood pressure. In particular, autonomic disorders tend to cause orthostatic hypotension.

Some examples of autonomic disorders are:

The adrenal glands are two small glands that are located just above your kidneys. They produce hormones that control your blood pressure and maintain the balance of salt and water in your body. One of the hormones they produce is called aldosterone, which is responsible for controlling the amount of salt in your body.

If your adrenal glands become damaged - for example through an infection or a tumour - the production of aldosterone may be reduced, resulting in a loss of salt from your body. This can cause dehydration which, in turn, leads to low blood pressure.

If a problem with your adrenal glands is diagnosed, it can be treated by increasing the amount of aldosterone in your body. This could also be a symptom of Addison’s disease (a condition in which the adrenal glands cannot produce enough of the hormones cortisol and aldosterone). Addison’s disease can also be treated with medication.

Low blood pressure can also be caused by serious injuries or burns, particularly if you have lost a lot of blood. This can mean that there is less blood being pumped around your body. Low blood pressure can also occur if you go into shock after having a serious injury.

Other kinds of shock are described below.

Septic shock and toxic shock syndrome are caused by bacterial infections. The bacteria attack the walls of the small blood vessels, causing them to leak fluid from the blood into the surrounding tissues. This causes a significant drop in blood pressure (severe hypotension).

Anaphylactic shock, or anaphylaxis, is caused by an allergic reaction to something - for example, a wasp sting or a peanut. During an allergic reaction, your body produces a large amount of a chemical called histamine, which causes your blood vessels to widen and leads to a sudden, severe drop in blood pressure.

Cardiogenic shock occurs when your heart cannot supply enough blood to your body, so your blood pressure drops. This can happen during a heart attack.

Low blood pressure is also known as hypotension. People with a reading of around 90/60, or less, are commonly regarded as having low blood pressure.

Most doctors do not consider hypotension a problem unless it is associated with certain signs and symptoms:

According to the AHA, there is no specific number at which day-to-day blood pressure is considered too low. However, when low blood pressure is accompanied by any of the above listed dangerous symptoms, it is time to seek medical care.

Some people have naturally low blood pressure, and they don't experience any symptoms. But for those who are used to having high blood pressure, a sudden decrease in blood pressure can signal a problem and can cause the symptoms listed above.

An episode of hypotension is more likely to occur under these conditions:

Low blood pressure can cause fatigue — that feeling of overwhelming tiredness and lack of energy. Research has found an association between low blood pressure and chronic fatigue syndrome, a condition characterized by profound fatigue, pain, and sleep abnormalities that are often made worse by exertion.

There is no cure for this type of fatigue, but doctors may suggest treating underlying causes, such as sleep disorders or mental health issues. Treating low blood pressure with dietary changes and proper physical activity can also help.

If your blood pressure is always on the low side and you do not have any of the dangerous symptoms, there is usually no cause for concern. Similarly, if you have a single at-home blood pressure reading that is abnormally low without any symptoms, you probably do not need to see your doctor. It is normal for your blood pressure to rise and fall over time, and your body is usually able to get your blood pressure back to normal.

But, says Dr. Lawrence, “when you sense there’s a recurrent problem, or there’s no clear explanation for what’s happened, you need to seek medical advice."

If your blood pressure drops suddenly and you are experiencing symptoms like dizziness, you should call your healthcare provider. They can assess your situation and rule out underlying problems, such as internal bleeding, serious infection, or an allergic reaction.

Treatment for hypotension will depend on the cause of the low blood pressure. Immediate steps might include the following:

After evaluation, a doctor may make these recommendations:

People who experience shock related to hypotension will need emergency treatment to restore blood flow to their organs and raise their blood pressure back to normal.

It’s important to determine whether your low blood pressure is “a primary problem or secondary problem,” notes Lawrence. A primary problem means that the body’s reflexes are not working as they should. Secondary causes mean that the low blood pressure is a result of things like dehydration or the effects of certain medications.