Why is considered low blood pressure

Blood pressure also declines with age, and some people have naturally low blood pressure due to genetic factors. Some temporary causes, such as pregnancy, resolve on their own. Others may require dietary changes and other care or management strategies. Some potentially more severe health issues can also cause low blood pressure, including :. Low blood pressure may sometimes result from alcohol use or the use of certain medications, such as :.

To address low blood pressure, a doctor may adjust the dosage of an existing drug or recommend medications to increase blood pressure. Medications that they may prescribe include fludrocortisone and midodrine. Learn about the low blood pressure diet here. Low blood pressure symptoms can disrupt daily life, and they generally become more serious with age. It is important to contact a doctor if any of these symptoms, such as dizziness and fatigue, occur.

A doctor can identify the cause and recommend the best treatment approach. People experiencing any specific signs of anaphylactic or septic shock require emergency care. Signs of anaphylactic shock include:. Low blood pressure refers to the blood circulating with a low level of force. It can cause a range of symptoms, including dizziness and nausea.

This can then cause symptoms. Throughout the day, your blood pressure can vary by between mmHg both systolic and diastolic depending on what you are doing. Having a stressful week at work, the temperature outside, and even what you had for lunch could affect your blood pressure reading. 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. 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. 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.

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. A blood pressure reading is taken using two measurements. The first measurement is known as systolic, which is the pressure in your arteries when your heart contracts and pushes the blood around your body. The second measurement is known as diastolic, which is the pressure in your arteries when your heart refills with blood in between heartbeats.

Both systolic and diastolic blood pressures are measured in millimetres of mercury mmHg. Your GP, or practice nurse, will use a device known as a sphygmomanometer to measure your blood pressure. This device has an inflatable cuff and a scale of mercury, like a thermometer, as a pressure gauge. The cuff is placed around your upper arm and inflated to restrict the flow of blood in your arm.

The air is then slowly released from the cuff. Your GP or practice nurse will watch the mercury pressure gauge and listen to your blood flow in the main artery of your arm using a stethoscope. It may be low because you're fit and healthy, or you may have inherited it from your parents. Page last reviewed: 09 September Next review due: 09 September Low blood pressure hypotension. Symptoms of low blood pressure Get your blood pressure checked if you keep getting symptoms like: lightheadedness or dizziness feeling sick blurred vision generally feeling weak confusion fainting This might mean your blood pressure is too low.

Some adults regularly have blood pressure in the hypotensive range but have no symptoms and do not require treatment. In serious cases, though, hypotension can result in a decreased supply of oxygen and nutrients to your brain and other essential organs, which can eventually lead to life-threatening shock.

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.

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.