How To Increase Blood Pressure

 

Written by Dr Katie Stephens, GP

Dr Katie graduated from the University of Manchester in 2007 (MBChB) and completed her GP training in the West Midlands in 2012 (MRCGP). 

 

Low blood pressure can be increased naturally with changes to diet and lifestyle, as well as with prescription medication. Most people in the UK who have a problem with their blood pressure suffer from hypertension, or high blood pressure. This is a very common condition and is a major cause of heart attacks and strokes. However, some people suffer from a blood pressure that is too low, or hypotension (hypo is Greek for ‘under’, hyper is Greek for ‘over’). Low blood pressure can cause symptoms such as dizziness and nausea and sometimes even fainting.

What is low blood pressure?

Low blood pressure is typically defined as a systolic blood pressure (top number, represents the pressure in the blood vessels when the heart muscle squeezes) of less than 90 mmHg, or a diastolic pressure (bottom number, represents the pressure in the blood vessels when the heart relaxes) below 60 mmHg.

However, some people (especially very fit athletes) may have a blood pressure that sits around or below this level naturally without ever having any symptoms or problems.

Others may have symptoms of low blood pressure at levels well above 90/60 mmHg. A common example of this is a condition called postural hypotension (or ‘orthostatic hypotension’). This is when the blood pressure falls quickly when someone stands up from being seated or lying down. To officially be diagnosed with postural hypotension, there should be a fall of at least 20 mmHg in the systolic reading, or at least 10 mmHg in the diastolic reading. The blood pressure itself may still be above 90/60 mmHg but usually the person gets symptoms due to the drop in pressure that occurs.

For example, if your sitting blood pressure is 125/82 mmHg and this drops to 100/75 mmHg when you stand, even though 100/75 mmHg is well above the cut off of 90/60 mmHg and so not officially ‘low’, this fall in blood pressure could still make you feel quite wobbly and would be enough of a drop to be classified as postural hypotension.

What causes low blood pressure?

There are many causes of low blood pressure. It might be easiest to think of them in terms of short-term causes and long-term causes. Short-term causes often involve a loss of fluid from the body (think tummy bugs, excessive bleeding, dehydration due to heat or exercise). Problems that tend to be more long term include:

• Problems with how well the heart can pump, e.g. heart failure
• Problems with the valves inside the heart, e.g. aortic stenosis, mitral valve prolapse
• Problems with the blood vessels and nerves, e.g. autonomic insufficiency (when the nerves don’t tell the right blood vessels to squeeze, leading to blood pooling in lower half of the body with gravity instead of being pumped to the brain). This can happen in Parkinson’s Disease and Diabetes, as well as with ageing.
• Problems with hormones, e.g. an underactive thyroid gland, Diabetes, Addison’s Disease
• Medications, e.g. over-treating high blood pressure, or side effects of other medications such as Viagra, opioid painkillers, water tablets or even drinking alcohol.

When should I worry about low blood pressure?

If you don’t usually have low blood pressure, but currently your blood pressure is either less than 90 mmHg on the top, or less than 60 mmHg on the bottom, OR it is a lot lower than normal AND you have any symptoms (including dizziness or feeling lightheaded, nausea, visual changes, or you just feel generally unwell), please get medical attention. Ring 111 if your symptoms are less severe, or attend A&E/ring 999 for life-threatening symptoms.

A blood pressure that has suddenly dropped low can be due to serious causes, such as sepsis. This is where an infection travels through the bloodstream, damaging multiple organs and making you feel very unwell. Usually there is a history of a fever and there may also be other symptoms such as confusion or shortness of breath. Other serious causes of a sudden low blood pressure include shock from heart problems like abnormal heart rhythms or even a heart attack.

It’s worth saying again: if you are feeling unwell and have a blood pressure that is newly low or suddenly dropped, please make sure you get the medical attention you need urgently, by ringing 111 or 999, depending on how bad your symptoms are. As long as it is safe to do so (ie a doctor hasn’t told you to limit how much you drink), having a good drink of fluids at the same time may help. Please read the NHS’ page on sepsis for further information.

How to raise blood pressure

For anyone else whose low blood pressure is not a sudden, new thing, it can still be helpful to speak to your GP, although if you are well, this is less urgent. Your GP can assess you for possible underlying causes of low blood pressure. If a cause is found, then treating this will often improve your blood pressure. For instance, if your low blood pressure is due to an underactive thyroid (hypothyroidism – there is that Greek ‘hypo’ again!), taking thyroid replacement medication (e.g. levothyroxine) should improve your blood pressure as well as boost your metabolism and help the rest of your body function more normally.

Or, if your blood pressure is the side effect of a medication, your GP may be able to reduce the dose safely or swap it out for an alternative that suits you better.

If you have seen your GP and there is no underlying cause to be found, and no medications to amend, then the main options for boosting blood pressure are through diet, exercises, lifestyle modifications and medication. It is also important to check that your blood pressure when lying down isn’t too high, as this can sometimes be linked with a blood pressure that drops when you stand, and affect which treatment options are best for you.

How to naturally raise blood pressure

Please be aware that if you don’t have symptoms with your low blood pressure, and your doctor doesn’t think you need treatment, there is absolutely no need to change things just to improve your blood pressure numbers. Having a naturally low blood pressure can be a sign of being very physically fit, and doesn’t necessarily need treating if it isn’t causing problems. This could just be what is normal for you.

However, if you ARE getting symptoms, and your GP has advised that you aren’t at the stage of needing to start medication to treat your symptoms, then please speak to them to see if they would recommend any of the following methods to raise your blood pressure at home:

• Drink more fluids. In particular, drinking two 500 mL glasses of cold water has scientific evidence of boosting the systolic blood pressure (top number) by more than 20 mmHg for about 2 hours. Staying well hydrated throughout the day is also sensible. One way to see if you are drinking enough is to check the colour of your urine when you next go for a wee. If it is fairly see-through, you are probably well hydrated. If it is quite yellow or dark, then it’s time to get a drink. Generally aiming for 1 ¼ to 2 ½ litres of fluids per day is helpful, unless you have been advised otherwise by your doctor (some people have to limit how much they drink due to medical conditions like heart or kidney failure).
• Leg exercises. Sometimes blood can pool with gravity in our legs. Doing leg exercises can help pump this back to our heart and get it circulating more, improving blood pressure. Muscles should be squeezed for 30 seconds at a time to be effective. Try flexing at the ankles to bring your toes towards you, then pointing them away, standing on tiptoes, crossing your legs, squeezing the thigh muscles, marching in place, and squeezing the gluteal (buttock) muscles.
• General exercise. Staying fit and active generally keeps the blood vessels and heart in better shape and can reduce symptoms linked to low blood pressure. If you aren’t used to much activity, start gentle and gradually work your way up to longer periods of staying active. Picking an activity where you are sat to start with may help (e.g. rowing). Avoid starting with heavy weight lifting as this may worsen symptoms. Light weights and gentle aerobic exercise is recommended.
• Salt intake. Please check with your GP that this is a safe option for you. As mentioned above, some people with low blood pressure while standing can actually have quite high blood pressure while lying, which could be made even worse with increasing salt. Other people may have to limit salt intake due to medical conditions such as kidney disease. If it is safe for you to do so, then increasing your salt intake to between 150 to 250 mmol of sodium (10 to 20 g of salt) per day may help raise your blood pressure and improve your symptoms.
• Compression garments. While compression stockings are widely used, there may be even more benefit from using abdominal (tummy) compression garments when needed.
• Prop your feet up when sat. Having your feet on the floor can increase the amount of blood pooling down by the ankles. If you are able to raise them up on a stool to the level of your heart, this can reduce the pooling. (If this isn’t an option, do at least try some of the leg exercises mentioned above while your feet are on the floor.)
• Avoid alcohol. We know that alcohol has a short term impact of lowering blood pressure. For people who suffer from low blood pressure, alcohol can make symptoms worse. Alcohol also is a diuretic and can make you wee out more fluids, which can also lower blood pressure if you are not well hydrated.

How to increase blood pressure with medication

If needed, your GP or specialist doctor may wish to start medication to raise your blood pressure. One commonly used drug is fludrocortisone. This works by increasing the sodium (salt) levels in the blood, which has a knock-on effect of boosting blood pressure. One possible side effect of fludrocortisone is lower potassium levels so usually careful monitoring with blood tests is done by whoever is prescribing this, to ensure all of the salt and potassium levels stay within a safe range.

In summary, low blood pressure can cause symptoms if it is less than 90/60 mmHg or at levels above this if it has dropped lower than normal. Symptoms include feeling faint and lightheaded. There are multiple causes including serious conditions but, in some cases, no underlying cause is ever found. Treatment isn’t always needed, but options include dietary changes, specific and general exercises, lifestyle modifications and medication.

If you think your blood pressure might be low, you can check it at home with a blood pressure monitor or speak to a chemist. If it is low and you are otherwise well with just occasional symptoms, please book a routine appointment with your practice nurse or doctor to discuss next steps. If it has suddenly dropped and you feel very unwell, please seek urgent medical attention, as discussed above.