Low blood pressure (hypotension)

What is low blood pressure (hypotension)

Blood pressure is the force that is exerted against the walls of the arteries by the blood when is pumped though by the heart. Blood pressure is at its highest when the heart pumps the blood and is at its lowest when the heart rests between beats.

Low blood pressure is defined as the heart pumping out blood to the arteries in a weaker manner than normal. This means that the vital organs (such as the brain) may receive less of the nutrients they require because less blood is being pumped out than normal. If blood pressure is really low, it can cause health problems.

Some people have lower than normal blood pressure with no adverse effects (more women than men seem to be affected).

Low blood pressure is defined when blood pressure is lower than the following:

• Systolic – heart beat pressure
  • Normal is between 90-120mmHg
• Diastolic – resting rate between heart beats
  • Normal is between 60-80mmHg

Facts about hypotension

• Some people have low blood pressure without having any adverse effects
• Some medications can lower blood pressure
• People with hypertension (high blood pressure) can have low blood pressure if they are prescribed high doses of medication and do not have any follow-up to adjust medication to blood pressure status
• Any type of lowered blood pressure should be checked to ensure it does not have any underlying (serious) causes

Symptoms of low blood pressure (hypotension)

General symptoms of low blood pressure (hypotension) are:

• Cold skin
• Dizziness
• Fainting
• Fatigue
• Feeling cold
• Feeling light-headed
• Feeling low or downhearted
• Inability to concentrate

Severe symptoms

More severe symptoms of low blood pressure (hypotension) that indicate a need for immediate emergency treatment, include:

• Cold clammy skin
• Coma
• Loss of consciousness
• Major injury to the body, due to an accident
• Severe blood loss that is not able to be stopped
• Shock

Causes of low blood pressure (hypotension)

Low blood pressure can be due to many factors (although in some people no underlying cause can be found):

• Acute and severe infection – fluid loss from fever and the actual infection can cause blood pressure to become lower than normal
• Adrenal gland dysfunction – the adrenal glands regulate sodium levels in the body, which if too low can cause cause blood pressure to lower
• Age – ageing causes blood pressure (and heart rate) to be lower due to stiffening of the arteries and less blood going through properly the blood vessels
• Alcohol – can sometimes cause lowering of blood pressure due to the dehydration it causes
• Anaemia – low levels of the red blood cells or haemoglobin in people who have anaemia, can cause blood pressure to lower
• Blood pressure lowering medications – these medications may lower blood pressure too effectively in some people who may not go for regular check-ups to ensure correct dosage is taken and blood pressure is not lowered too much
• Dehydration – this condition cause lowered levels of the electrolytes due to fever, vomiting or diarrhoea and this can cause low blood pressure
• Diabetes – causes low blood pressure in advanced diabetes in some people
• Disease of the nervous system – rare diseases of the nerves which control the reflexes in the arms and legs can also cause blood pressure to lower
• Heart attack – as a heart attack is usually caused by a lack of blood flow due to artery restriction, it lowers blood pressure to dangerous (and sometimes fatal) levels
• Heart disease – certain types of heart disease can cause the blood pressure to lower
• Hypoglycaemia – low blood glucose levels can cause lowered blood pressure
• Medications – many types of medications can lower blood pressure; diuretics lower electrolytes, beta blockers, narcotics
• Menstruation – some women who bleed heavily during menstruation (especially the first 3 days) feel light-headed and dizzy due to their menstrual blood loss that can cause lowered blood pressure
• Pregnancy – (slightly) lowered blood pressure in women who are pregnant is quite normal for some women in the first half of pregnancy term
• Severe blood loss – either from an accident or injury prevents enough blood to be pumped to the organs and tissues due to a decreasing amount of blood in the body; this can lead to shock and death if blood loss is life-threatening and not quickly replaced
• Shock – this medical condition happens when there is too little blood in the body to enable correct blood pressure and this can cause damage to the organs
• Standing up suddenly – if someone stands up suddenly after lying down it can cause a temporary lowering in blood pressure as the body takes time to adjust to the new position (which happened to quickly)

Prevention of hypotension (low blood pressure)

Non-preventable risk factors

Hypotension (low blood pressure) may be unpreventable in certain circumstances:

• Adrenal glands problems – malfunctioning of the adrenal glands can cause blood pressure to lower. This is because the adrenal glands control many hormones which regulate the levels of sodium in the body and as sodium is linked to blood pressure levels, when it is too low, it can cause blood pressure to lower too much
• Age – just being older predisposes people to developing lowered blood pressure, especially if their arteries and blood vessels are not as elastic and healthy as they should be
• Certain illnesses – certain illnesses will predispose people to having lowered blood pressure. The most common conditions to cause lowered blood pressure are: anaemia, diabetes, serious bacterial or viral infection that causes fever, diarrhoea and/or vomiting and heart disease
• Certain medications – people taking certain medications, especially high blood pressure lowering medications (diuretics, beta blockers and others) can be at a higher risk for experiencing low blood pressure, especially if their dosage is too high
• Dehydration – in more serious cases of dehydration, the levels of the electrolytes can become seriously depleted and this increases the risk of experiencing lowered blood pressure
• Heart attack – in the event of a heart attack, the blood flow to the heart is seriously hampered and this will lower blood pressure to dangerous levels and requires immediate and urgent medical assistance
• Infection – sometimes a bacterial or viral infection may lower blood pressure, especially when high fever and even diarrhoea and vomiting has been present for a number of days and there has been a subsequent loss of electrolytes (which includes sodium)
• Pregnancy – some women who are pregnant are at a higher risk for experiencing slightly lowered blood pressure in the first half of their pregnancy. This is not usually very serious
• Serious accident or injury – people who are involved in a serious accident or injury that also experience heavy blood loss are at a much higher risk for experiencing very low blood pressure due to the blood loss
• Severe blood loss – if there is an accidental injury to the body which causes a great deal of blood loss, low blood pressure is the result as the amount of blood in the body is not at adequate level. This will usually cause shock too and is a medical emergency
• Shock – this occurs when there is a serious and sudden drop of blood flow in the body and results in seriously low blood pressure. Shock can occur after a serious injury to the body and is a medical emergency

Preventable risk factors

There are ways to prevent hypotension (low blood pressure) from occurring:

• Anaemia – some types of anaemia are due to a deficiency of certain nutrients (iron, folic acid) and these types are normally preventable by ensuring the diet is rich in foods high in these nutrients
• Excessive alcohol intake – drinking excessively can cause dehydration (especially the next day) which can lower blood pressure, as well as cause a number of other adverse health effects
• Heavy menstruation – some women have very heavy bleeding each month, especially in the first 1-3 days of their menstrual cycle. The heavier than normal blood loss can cause blood pressure to lower more than normal and they may experience symptoms. While it may be difficult to prevent the heavy blood loss (especially if it is part of their normal menstrual cycle), foods high in iron and folic acid should be part of the diet prior to and during the first few days of the menstrual cycle to counter the heavy blood loss and prevent lowered blood pressure. Alternatively, supplements may be used, but only after they have received professional advice that it is safe to do so (as they may not be deficient)
• Hypoglycaemia – when food intake is not regular and not adequate, it can cause temporary lowered blood sugar levels (hypoglycaemia) and this is easily preventable by eating at least three meals a day with some healthy snacks in between
• Standing up too quickly – sometimes when people stand up very quickly after sitting or especially lying down, they can experience the symptoms of low blood pressure

Complications of low blood pressure (hypotension)

The main complications of low blood pressure (hypotension) occur due mainly (but not always) from shock caused by severe injury or illness and include:

Loss of consciousness

In the case of anaemia, it can cause temporary loss of consciousness. If the condition is severe and there is a great deficiency of iron (or haemoglobin) in the blood. In the case of injury or accident, the shock of this major trauma can cause the body to shut down and lose consciousness, either from the pain of the injury or due to the shock that ensues after the injury (or severe blood loss). If the blood loss is not remedied (transfusion) or if the injuries are not treated immediately with emergency treatment, it can result in coma or death.

Coma

In the case of very severe injury that results in shock, where there has been severe blood loss can result in coma, due to the major blood loss or damage to the organs, in particular to the brain.

Death

In the case of very severe injury that results in shock, where there has been severe blood loss. This can result in death, from the loss of blood and subsequent irreversible damage to the organs. If there is multiple organ failure, due to a major injury or illness and subsequent shock, this will cause death.

When to see a doctor about low blood pressure (hypotension)

Anyone who has symptoms of low blood pressure (hypotension), which is not associated with any serious accident or injury (as they will have emergency medical treatment should it occur) should make an appointment to see their doctor to diagnose their condition and advise treatment options.

People with existing low blood pressure (hypotension) need to ensure they are following their doctor’s recommendations on treatment.

People with existing low blood pressure (hypotension) need to ensure they consult with their doctor if their symptoms become worse or if they start to experience a different set of symptoms.

Diagnosis of low blood pressure (hypotension)

Initially, when diagnosing low blood pressure, the following tests are done:

• Medical history – the doctor will take a full medical history about the duration and severity of symptoms and also when they started. The doctor will ask many questions about any related symptoms too
• Blood pressure measurement – this is a routine test that either involves a manual or electronic measurement of the blood pressure. If it is low, then further tests may be done if it is warranted
• Blood test – a blood test can determine if conditions such as anaemia or hypoglycaemia are present, both of which can lower blood pressure more than normal through either low iron (or haemoglobin) levels or due to low blood glucose levels. This is one of the most common tests that are performed in order to diagnose (or rule out) low blood pressure (hypotension)

Further tests

Further tests can be done to diagnose the reason for the low blood pressure to determine if there are any other underlying (serious) reasons for the lowered blood pressure:

• Heart tests – various tests can be used to test the functioning of the heart to determine if that is the reason underlying the low blood pressure – some common heart test include echocardiogram, stress test
  • Electrocardiogram – this is a a machine which, when hooked up with electronic cords and wires to specific parts of the body tests the electrical activity of the heart. This test is ordered if an underlying heart problem is suspected
  • Stress test – this test involves being hooked up with electronic wires while on a treadmill. The test involves walking on the treadmill at a flat level and then it is inclined and the pace is increased. This test is used to determine if any exercise puts stress on the heart, is an underlying heart problem is suspected
• Tilt test – this involves being strapped to a table and being titled to determine if the low blood pressure is due to quickly standing up after lying or sitting down

Conventional treatment of low blood pressure (hypotension)

Emergency treatment

• If a person faints from low blood pressure, seek immediate medical attention (call an ambulance on 000, if they do not respond or awaken)
• If a person is seriously injured and bleeding, call an ambulance on 000
• If a person passes out and stops breathing, immediately start CPR (cardiopulmonary resuscitation) and call an ambulance on 000

Treatment of serious causes of low blood pressure:

Severe blood loss

Severe blood loss, which normally happens after a serious accident or injury is a serious condition and needs immediate and urgent medical intervention to prevent death.

Treatment involves the following:

• Intravenous fluids – to rehydrate the body fluids back to normal levels and usually includes all the electrolytes and glucose
• Blood transfusion – to replace the blood that has been lost through the trauma

Shock

Shock is a serious condition which can be life threatening. Shock usually happens when the body has undergone a serious trauma through accident or injury and needs immediate and urgent medical intervention to prevent death.

Treatment involves the following:

• Intravenous fluids – to rehydrate the body fluids back to normal levels and usually includes all the electrolytes (chloride, potassium, sodium) in certain levels together with glucose to help rehydrate the body
• Medication – intravenous vasopressors will be given to increase blood pressure by increasing the diameter of the blood vessels to allow more blood to flow through and reduce the effects of the shock from injury
• Treatment of injury – the injury will be treated either with surgery, medications or a combination of both, depending on the nature of the injury

Other than an emergency situation, the treatment of low blood pressure depends on the underlying reason for the condition. Some causes of low blood pressure do not require any treatment, while others need medication and other treatments.

Main treatment for low blood pressure

The main types of treatment for low blood pressure are:

• Blood pressure medication – people who have hypertension (high blood pressure) and experience symptoms of low blood pressure need to have the dosage of their blood pressure medication adjusted by their doctor to get blood pressure back to normal
• Compression stockings – these can assist with better blood flow in the lower extremities and help with low blood pressure for people with general low blood pressure symptoms, especially older people or those with any underlying heart problems
• Diuretics – these medications, if prescribed by a doctor for a number of different medical conditions, can lower blood pressure through the dilution of sodium levels in the body. The usage of diuretics needs to be closely monitored by a doctor and should not be self-prescribed for any reason
• Electrolytes – this non-prescription powder contains the electrolyte minerals (chloride, sodium and potassium) and is purchased over the counter in pharmacies and redresses the issue of low blood pressure due to dehydration, usually caused by infection or fever
• Hormones – replacement of the hormones that have caused the low blood pressure may help reduce symptoms. The thyroid and adrenal gland hormones are the ones that are usually required
• Medication – other types of medication may be required for treating the underlying problem
• More salt intake – salt (sodium) increases blood pressure and may be recommended by a doctor for people with low blood pressure

Alternative / complementary treatment of low blood pressure (hypotension)

Emergency treatment

• If a person faints from low blood pressure, seek immediate medical attention (call an ambulance on 000, if they do not respond or awaken)
• If a person is seriously injured and bleeding, call an ambulance on 000
• If a person passes out and stops breathing, immediately start CPR (cardiopulmonary resuscitation) and call an ambulance on 000

Do not use alternative / complementary treatment for any serious injuries or illness, which require emergency treatment. Always discuss any alternative / complementary treatment for low blood pressure with your doctor before trying any of it.

These are some of the main strategies for dealing with low blood pressure, depending on the cause.

Herbs

There are a no herbs which are recommended to help to provide relief for symptoms.

Vitamins

There are a number of vitamins which may help to provide relief for symptoms:

• Folic acid – if there is a folic acid deficiency which is causing anaemia this vitamin will be required to be supplemented and/or foods rich in folic acid included in the diet to top up levels
• Vitamin B12 (cyanocobalamin) – if there is a vitamin B12 (cyanocobalamin) deficiency which is causing anaemia this vitamin will be required to be supplemented and/or foods rich in vitamin B12 (cyanocobalamin) included in the diet to top up levels

Minerals

There are a number of minerals which may help to provide relief for symptoms:

• Chloride – people who have been sweating too much (either through a hot environment, from exercising a lot or from an infection) need to have their electrolytes balanced by replacement with an electrolyte formula that includes chloride (as well as sodium and potassium)
• Iron – women who are pregnant need extra iron to nourish their growing baby and women who have heavy menstrual blood loss need extra iron to replace the iron lost each month and to prevent anaemia
• Potassium – people who have been sweating too much (either through a hot environment, from exercising a lot or from an infection) need to have their electrolytes balanced by replacement with an electrolyte formula that includes potassium (as well as sodium and chloride)
• Sodium – people who have been sweating too much (either through a hot environment, from exercising a lot or from an infection) need to have their electrolytes balanced by replacement with an electrolyte formula that includes sodium (as well as chloride and potassium). People with a condition that causes a sodium deficiency will require sodium supplements to help improve symptoms

Other nutrients

There are a no other nutrients recommended to provide relief of symptoms.

Dietary modifications

There are a number of dietary modification strategies which may help to provide relief for symptoms:

• Eat foods rich in folic acid – if a folic acid deficiency has been identified and which is causing anaemia, it may be advisable to eat foods rich in this nutrient to help the body absorb more into the blood. Supplements may also be recommended to increase folic acid levels and reduce the low blood pressure symptoms from the anaemia
• Eat foods rich in iron – if an iron deficiency has been identified and which is causing anaemia, it may be advisable to eat foods rich in this nutrient to help the body absorb more into the blood. Supplements may also be recommended to increase iron levels and reduce the low blood pressure symptoms from the anaemia
• Eat foods rich in vitamin B12 (cyanocobalamin) – if a vitamin B12 (cyanocobalamin) deficiency has been identified and which is causing anaemia, it may be advisable to eat foods rich in this nutrient to help the body absorb more into the blood. Intravenous injections or supplements may also be recommended to increase vitamin B12 (cyanocobalamin) levels and reduce the low blood pressure symptoms from the anaemia

Lifestyle modifications

There are a number of lifestyle modifications which may help to provide relief for symptoms:

• Manage anaemia effectively – people with anaemia must eat more foods rich in iron and/or take iron supplements, based on the doctor’s recommendation, if their anaemia is caused by an iron deficiency. If the anaemia is caused by other deficiency (folic acid, vitamin B12), take supplements as recommended and/or eat foods rich in these nutrients. If the anaemia is due to another cause, follow the doctor’s instructions for treatment
• Manage diabetes effectively – people with diabetes need to ensure they are following their doctor’s instructions to manage their condition properly, so that symptoms do not worsen and the condition does not progress to a more advanced stage. Use the medication prescribed, engage in exercise that is recommended, follow dietary recommendations and visit the doctor regularly to monitor the condition
• Manage heart disease effectively – people with heart disease (atherosclerosis, angina, high blood pressure, high blood triglycerides levels, high cholesterol) need to ensure they are following their doctor’s instructions to manage their condition properly, so that symptoms do not worsen and the condition does not progress to a more advanced stage. Use the medication prescribed, engage in exercise that is recommended, follow dietary recommendations and visit the doctor regularly to monitor the condition
• Pregnancy care – women who are pregnant must take care to ensure their diet is rich in all the nutrients at the higher level recommended for the healthy growth of their baby. Adequate iron intake is recommended and your doctor will recommend if supplements are necessary

Alternative treatments

There are a no other alternative treatments recommended to provide relief of symptoms.

Always ensure that you notify your medical practitioner of any supplements that you want to take – it may interfere with other medication or conditions you have. Confirm with your doctor it is safe to take before you try it.

Living with low blood pressure (hypotension)

There are a number of strategies which are recommended to help deal with low blood pressure (hypotension), depending on the cause:

• Adequate fluid intake – irrespective of the cause of the low blood pressure (hypotension), you must ensure you are drinking enough water each day, to keep your body well hydrated. Approximately eight glasses is the recommended amount, but increase this if you are exercising a lot or sweating a lot to replace the water you are losing
• Get up slowly – if you start to feel dizzy if you get up quickly, you need to make sure you get up slowly, a little at a time and lean on something solid to help you on your way up. This cause of low blood pressure (hypotension) tends to affect older people and those with an infection
• Increase iron intake – if you are pregnant or have heavy menstrual blood loss, you must increase your intake of foods rich in iron, to top up your iron levels. Pregnant women need more iron due to their developing baby and women with heavy periods lose more blood than normal and need to top up iron levels
• Monitor side effects from medications – if you are taking any blood pressure lowering medications and you start to experience symptoms of low blood pressure (hypotension), you need to consult with your doctor, as you may need to have your medication adjusted. If you are taking any other medication and start to experience symptoms of low blood pressure (hypotension), ensure to tell your doctor as this could be a side effect from your medication and your doctor may switch to a different type
• Monitor your diabetes – if you start to experience the symptoms of low blood pressure (hypotension) and you also have diabetes, you must inform your doctor, as this could mean your condition is worsening, or your medications are not working effectively to manage your condition
• Rest – no matter what the cause of the low blood pressure (hypotension), it is important to rest, to give your body more energy to more effectively deal with the underlying cause

Caring for someone with low blood pressure (hypotension)

Partner

There are a number of strategies you can use to help a partner with low blood pressure (hypotension):

• Emergency treatment – if your partner has gone into shock, due to injury or illness, make sure they are lying down comfortably, on their side in the recovery position and call an ambulance on 000. If you need to perform CPR, make sure you do while they are lying flat on the ground
• Encourage your partner to rest – as most causes of low blood pressure are due to infection or some other condition which requires rest to recover, encourage your partner to rest to enable quicker recovery
• Liquids – ensure your partner is drinking adequate liquids, in the form of water mostly, but also herbal tea and juices (use natural ones)
• Pregnancy – if your partner is pregnant and is feeling dizzy or has other symptoms of low blood pressure, ensure they rest and if it continues more than what is considered normal, make sure to take your partner to their doctor for investigation (it could be as simple as low iron levels – anaemia, which is common in pregnancy as the requirement for iron is higher during this period)
• Salt – if your partner has low blood pressure due to sodium loss, ensure they have an adequate intake of sea salt (as per their doctor’s instructions)

Friends

There are a number of strategies you can use to help a friend with low blood pressure (hypotension):

• Emergency treatment – if your friend has gone into shock, due to injury or illness, make sure they are lying down comfortably, on their side in the recovery position and call an ambulance on 000. If you need to perform CPR, make sure you do while they are lying flat on the ground
• Pregnancy – if your friend is pregnant and feeling dizzy, or has other symptoms of low blood pressure, ensure they rest, but if it continues and is bothersome, encourage your pregnant friend to visit the doctor for investigation. It could be as simple as low iron levels – anaemia, which is common in pregnancy as the requirement for iron is higher during this period
• Rest – as most causes of low blood pressure are due to infection or some other condition which requires rest to recover, encourage your friend to rest to enable quicker recovery

Parents

There are a number of strategies you can use to help a child with low blood pressure (hypotension):

• Emergency treatment – if your child has gone into shock, due to injury or illness, make sure they are lying down comfortably, on their side in the recovery position and call an ambulance on 000. If you need to perform CPR, make sure you do while they are lying flat on the ground
• Liquids – ensure your child is drinking adequate liquids, in the form of water mostly, but also herbal tea and diluted juices (use natural ones)
• Rest – as most causes of low blood pressure are due to infection or some other condition which requires rest to recover, encourage your child to rest to enable quicker recovery
• Salt – if your child has low blood pressure due to sodium loss, ensure they have an adequate intake of sea salt (as per their doctor’s instructions)

References

• Fisher C, PainterG. Materia Medica Of Western Herbs For The Southern Hemisphere
• Osiecki H. The Physicans Handbook of Clininical Nutrition, 6th Edition. Bioconcepts Publishing QLD, 2001
• Tratter R, Jones A. Better Health Through Natural Healing: How to Get Well Without Drugs or Surgery, 2nd Edition. McGraw Hill, 2001

Last reviewed and updated: 14 May 2024