Low Blood Pressure Hypotension

Overview

Blood pressure is the force of your blood pushing against the walls of your arteries as your heart pumps. It is measured with two numbers — the top number (systolic) is the pressure when your heart squeezes, and the bottom number (diastolic) is the pressure when it relaxes between beats. Low blood pressure, also called hypotension, is usually said to be a reading below about 90/60 mmHg. But the numbers alone don't tell the whole story. For many healthy people, low blood pressure is normal and causes no problems at all. It only becomes a concern when it drops low enough to make you feel dizzy, faint, or unwell, or when it means your body's organs are not getting enough blood.

Yes, low blood pressure is common. Lots of people — especially young, slim, and very fit people — have blood pressure that sits naturally in the low range and never causes any trouble. Symptoms from low blood pressure are also fairly common, particularly in older adults and in pregnant women.

Anyone can have low blood pressure. It is often seen in healthy young adults and athletes, in pregnant women (especially in the first half of pregnancy), and in older adults — partly because blood pressure control gets less precise with age and partly because of medicines many older people take. People who are dehydrated, on long bed rest, or living with certain heart, hormone, or nerve conditions are also more likely to be affected.

Symptoms

Common symptoms

• Feeling dizzy or light-headed, especially when you stand up
• Blurred or fuzzy vision for a moment
• Feeling faint or actually fainting
• Feeling weak or unusually tired
• Trouble concentrating or a 'brain fog' feeling
• Feeling sick (nausea)
• Cold, pale, clammy skin
• A fast or shaky heartbeat
• Feeling thirsty

Symptoms in children

• Looking pale or grey, especially around the lips
• Being floppy, unusually sleepy, or hard to wake
• Feeling dizzy or faint when standing up quickly
• Refusing to drink or feed, or fewer wet nappies than usual
• Fast breathing or a fast heartbeat
• In babies and young children, low blood pressure can be a sign of dehydration or serious illness — get medical help quickly

Symptoms in older adults

• Falls or unsteadiness, often without feeling dizzy first
• Dizziness or fainting when standing up from a chair or bed (this is very common and often linked to medicines)
• Confusion or memory problems that seem worse than usual
• Feeling faint after meals
• Feeling weak or more tired than usual
• Blurred vision when changing position

Causes

Main causes

• Dehydration — not drinking enough, or losing fluid through sweating, vomiting, diarrhoea, or a fever
• Standing up quickly (the medical word is orthostatic or postural hypotension) — blood pools in the legs and pressure drops for a moment
• Eating a large meal, especially one high in starchy carbohydrates (postprandial hypotension) — blood flows to the gut and pressure dips
• Some medicines, including water tablets, some blood pressure medicines, some medicines for mood or Parkinson's disease, and some prostate treatments
• Long periods of bed rest or being less active
• Pregnancy, especially in the first 24 weeks
• Heart problems such as a slow heartbeat, heart valve problems, or heart failure
• Hormone (endocrine) problems such as an underactive thyroid or adrenal glands, or low blood sugar
• Nerve damage (for example from diabetes) that affects the nerves controlling blood pressure
• Heavy bleeding, severe infection (sepsis), or a severe allergic reaction — these are serious causes of a sudden drop
• Hot weather, hot baths, standing for a long time, or drinking alcohol
• Some vitamin deficiencies and, rarely, certain long-term conditions

Risk factors

• Age — blood pressure control becomes less fine-tuned as we get older
• Taking several medicines, especially medicine for high blood pressure
• Being pregnant
• Long-term bed rest or reduced mobility
• Diabetes or other conditions that can damage nerves
• A heart condition or a history of fainting
• Being dehydrated, or drinking a lot of alcohol
• Eating large, heavy meals
• Very warm weather or hot baths and showers
• Being naturally slim and very fit (this is usually harmless)

When to see a doctor

See a doctor urgently if:

• You have fainted, or you keep feeling as though you might
• Dizziness or light-headedness is affecting your daily life or making you unsafe on your feet
• You have had a fall or a near-fall
• Your home blood pressure readings are consistently low and you feel unwell
• You have a fever, vomiting, or diarrhoea and cannot keep fluids down
• You are taking medicines and your blood pressure has changed

Book a routine appointment if:

• You have occasional mild dizziness and want to understand why
• You have naturally low readings but no symptoms — a check-up can be reassuring
• You want to review whether any of your medicines could be affecting your blood pressure
• You have questions about how to manage dizziness when standing up

Diagnosis

A doctor or nurse will start by asking about your symptoms — when they happen, what you were doing, and how long they last — and about any medicines you take. They will check your blood pressure, usually more than once, and often while you are lying down or sitting and then again after you stand up. This shows whether your pressure drops when you change position. Your pulse and heart rhythm will be checked, and you may be asked to keep a diary of symptoms and home readings. Your doctor will then decide whether any tests are needed to find the cause.

Tests that may be done

• Blood pressure readings taken sitting, lying, and standing
• Home or 24-hour blood pressure monitoring
• A heart tracing (ECG) to check your heart's rhythm
• A longer heart rhythm monitor worn for a day or more if an irregular heartbeat is suspected
• Blood tests to check for dehydration, anaemia, blood sugar problems, thyroid or adrenal hormone levels, and vitamin levels
• A urine test
• A heart ultrasound scan (echocardiogram) if a heart problem is suspected
• A tilt-table test — a special test where you lie on a table that tilts upright, used if the cause is still unclear after other tests
• A check of your blood pressure after eating a meal, if you feel faint after meals

What to expect at your appointment

Most of this is quick and painless. The main step is simply having your blood pressure measured a few times in different positions. Blood tests involve a small needle prick. A heart monitor or a tilt-table test may mean a longer appointment, and your doctor will explain what is involved. If your readings are low but you feel well and the basic checks are normal, you may not need further tests at all.

Treatment

Treatment depends on the cause and on whether you have symptoms. If your blood pressure is naturally low and you feel fine, no treatment is needed — the 'treatment' is simply knowing your normal and looking after yourself. If symptoms are caused by something specific, such as dehydration or a medicine, fixing that usually solves the problem. If no clear cause is found and symptoms continue, there are several approaches — starting with everyday changes — that your healthcare team can help you put together.

Self-care at home

• Drink enough fluid, especially in hot weather or when you are active — and more if you are sweating, vomiting, or have diarrhoea
• Stand up slowly. Sit on the edge of the bed for a moment and clench your calf muscles before you get up
• Avoid standing still for long periods; if you must, cross your legs and squeeze your thigh and buttock muscles, or shift weight from foot to foot
• Eat smaller, more frequent meals rather than one large heavy meal, and go easy on very starchy food if meals make you dizzy
• Limit alcohol, which can lower blood pressure
• Avoid very hot baths, showers, and saunas, and be careful getting out of a hot bath
• Raise the head of your bed slightly if you have been advised to — ask your doctor first
• Wear compression stockings if your healthcare team recommends them
• Keep a note of when symptoms happen and your home readings, so you can share them at appointments
• Tell your doctor before starting any new medicine, supplement, or herbal remedy

Medical treatments

Your doctor will first look at whether any of your current medicines could be lowering your blood pressure, and may adjust or change them — never stop or change a medicine on your own. Beyond that, depending on the cause, options can include treating an underlying condition (such as an infection, hormone problem, or heart issue), advice on fluid and salt intake tailored to you, compression stockings, and — for some people with ongoing symptoms — medicines that help raise blood pressure or hold fluid in the body. These are only used when lifestyle measures are not enough, and they need to be balanced carefully against any other conditions you have. Your healthcare team will explain the choices and follow you up to check they are working.

When is surgery considered?

Surgery is not used to treat low blood pressure itself. Occasionally, low blood pressure is caused by a heart problem that needs a procedure — for example, a slow heart rhythm that may need a pacemaker. If that is the case, your specialist team will discuss it with you in detail.

Living with this condition

Most people with low blood pressure live completely normal lives. The key is learning your own patterns — when you are most likely to feel dizzy, and what helps. Many people find that a few small habits, like getting up slowly, keeping hydrated, and not skipping meals, make a big difference. Tell the people around you what to do if you feel faint: sit or lie down straight away and put your feet up, and drink some water.

Lifestyle tips

• Keep a water bottle with you and sip through the day
• Get up in stages rather than jumping out of bed or off the sofa
• Avoid long hot showers and standing in queues for a long time
• Be careful with alcohol, and with very large meals
• Stay active — regular movement helps your circulation adjust to changes in position
• Wear loose, comfortable clothing and consider compression stockings if advised
• Have something to hold on to if you feel dizzy, and sit or lie down rather than trying to 'push through'
• Keep your home safe: good lighting, clear walkways, and no loose rugs, to reduce the risk of falls

Diet and exercise

Eat regular meals and don't skip breakfast. If large meals make you light-headed, try smaller meals more often. Some people are advised to include a bit more salt in their diet, but this should only be done on your doctor's advice, because too much salt can be harmful for other conditions such as heart or kidney problems. Caffeine with breakfast can help some people, but check with your doctor if you have heart or sleep problems. For exercise, gentle regular activity — walking, swimming, cycling, or light strength work — helps your body control blood pressure better. Cool down slowly after exercise rather than stopping suddenly, and drink water before, during, and after. If you feel dizzy during exercise, stop, sit down, and rest.

Mental health and emotional wellbeing

Feeling dizzy or faint can be unsettling, and if you have fainted you may feel anxious about it happening again. That anxiety is very understandable, and it is worth talking about. Fear of falling can lead people to avoid going out or being active, which can make things worse over time. Tell your doctor if worry is affecting your sleep, mood, or daily life — there is support available, and sometimes simply understanding the cause and having a plan makes a big difference.

Prevention

You cannot always prevent low blood pressure, especially if it is simply how your body works. But many of the episodes that cause symptoms can be prevented: staying well hydrated, standing up slowly, avoiding long periods of standing still, not skipping meals, limiting alcohol, and having your medicines reviewed regularly all help. If you have a condition that affects your blood pressure, keeping it well managed is the best protection.

Vaccines

There is no vaccine for low blood pressure. Staying up to date with routine vaccinations is still worthwhile, because infections — especially ones that cause vomiting, diarrhoea, or fever — can lead to dehydration and low blood pressure.

Screening programmes

There is no screening programme for low blood pressure. Blood pressure is checked routinely at many appointments, for example when you see your doctor for another reason or as part of a long-term condition review. If you are over 40 or have a long-term condition, you may be offered regular blood pressure checks — these are a good chance to mention any dizziness you have noticed.

Complications

If left untreated

• Falls and injuries, including fractures and head injuries, especially in older adults
• Fainting at a risky moment, such as while driving, cooking, or on stairs
• Reduced confidence and less willingness to go out or stay active
• If the cause is serious — such as heavy bleeding, severe infection, or a heart problem — the underlying condition can become dangerous without treatment
• In some people, repeated low blood pressure can reduce blood flow to organs over time, which is why ongoing symptoms deserve a proper look

Long-term outlook

The outlook is good for most people. For many, low blood pressure is simply a normal personal characteristic and never causes a problem. For those with symptoms, the cause is often something straightforward — dehydration, a medicine, or standing up too quickly — that can be put right. Even when the cause is long-term, careful self-care and a plan agreed with your healthcare team usually keep symptoms manageable, and most people carry on with their normal lives. If you have new or worsening symptoms, speak to a qualified healthcare provider so they can look into it with you.

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