Drink more, consistently
Mild dehydration is the commonest everyday reason a reading sits low, and the climate here makes it easy to fall behind. Spread it through the day rather than catching up in the evening.
Medically Reviewed By: Dr Paul Lim – MBBS, M.Med (Int Med), MRCP (UK), FAMS (Cardiology)
Hypotension
Dr Paul Lim Chun Yih
Senior Consultant Cardiologist & Electrophysiologist
Low Blood Pressure Symptoms, Causes & When It Matters
A reading under 90/60 is the figure usually quoted, though low blood pressure is judged by symptoms rather than by a number. Many healthy people sit below it and feel perfectly well. Light-headed when you stand? Share your concerns with our friendly Dr Paul Lim and get peace of mind.
Dr Paul Lim Chun Yih
Senior Consultant Cardiologist & Electrophysiologist
Start Here
How Low Is Too Low?
There is no diagnostic threshold for low blood pressure. Whether a reading matters depends on symptoms, and on whether it has changed.
Singapore clinical guidance draws a line for high blood pressure: 140/90 at a clinic, and above it is a diagnosis. There is no equivalent line for low. The figure quoted almost everywhere is less than 90/60 mmHg, a useful rule of thumb rather than a threshold anyone is diagnosed against.
A low reading is common in people who are perfectly well. Younger, slimmer and fitter adults often run in the 90s over 50s and feel nothing at all. For them the number is normal, which is why low blood pressure is a problem only when it causes symptoms.
So a low reading raises two questions, and neither is “is it under 90/60?” Does it cause symptoms? And has it changed? Speak to your cardiologist if you are unsure.
The one measurement that does have a definition
It is what your blood pressure does in the first three minutes after you stand up.
The moment you get to your feet, gravity drags about half a litre of blood down into your legs. To push it back up, your heart has to beat faster and your blood vessels have to squeeze tighter, and it has to happen within a second or two. When that is too slow, your blood pressure drops and your brain is briefly short of blood. That is the moment the room tilts.
Formally, orthostatic hypotension is a sustained fall of at least 20 mmHg systolic or 10 mmHg diastolic within three minutes of standing, measured after lying down for at least five minutes. That is the whole test, and it takes a few minutes in a consulting room. It is a change rather than a value: you can meet the definition while your standing reading still looks respectable.
Is the dangerous level different for women?
No. The figures are the same, and there is no separate female threshold to measure against. Women do report symptoms more often, and there are real reasons for that: average blood volume is lower, iron deficiency and anaemia are more common, and blood pressure normally falls in pregnancy, at its lowest around the middle. Those explain why symptoms turn up more frequently. They do not create a different number.
Does it change with age?
The figure does not, but its significance does. A reading of 95/60 in a healthy 25-year-old is unremarkable. The same reading in an 80-year-old on three blood pressure medications is worth a proper look, because the consequences differ. Older adults are both more likely to have a blunted response to standing and more likely to be hurt by the fall that follows.
Red Flags
Is Low Blood Pressure Dangerous? When to Worry
Most low blood pressure is harmless, and the difference is usually in how quickly it arrived and what it is doing to you rather than in the reading itself.
Emergency — call 995 or go to A&E
A blood pressure that has dropped suddenly needs emergency care if there is:
- Confusion, drowsiness, or difficulty staying awake
- Cold, clammy, pale or mottled skin
- Rapid, shallow breathing, or a racing pulse
- Chest pain or severe breathlessness
- Bleeding, black or bloodstained stools, or vomiting blood
- Fever with shivering, or another sign of serious infection
- Swelling of the lips or tongue, a rash, or wheeze after a sting, a food or a new medicine
- Very little urine passed over many hours
Book a specialist appointment
Arrange a review promptly if your low blood pressure:
- Has caused a faint or a blackout
- Has caused a fall, or near-falls you have been getting away with
- Started or worsened after a medication change
- Comes with palpitations, chest tightness on exertion or breathlessness
- Is new, and your readings used to be normal or high
- Occurs alongside a slow pulse, a known heart murmur or an abnormal ECG
- Comes with persistent tiredness, weight loss or a poor appetite
Less likely to be a problem
These features point towards a reading that is simply your normal:
- It has read low for years, and you feel well
- You are young, slim or physically active
- Any light-headedness is brief, occasional, and follows getting up quickly
- It turned up on a routine screening rather than because of a symptom
- There is a clear one-off explanation, such as a hot day with too little to drink
Not sure which category you fall into? Speak to a cardiologist for a proper evaluation and peace of mind.
Get screened today and know your heart risk. Basic Heart Check-Up, S$368 (NETT, incl. GST). Consultation and results review included.
What It Feels Like
Symptoms of Low Blood Pressure
Every symptom here comes from the same thing: not quite enough blood reaching the brain. That is why so many of them involve the head, and why nearly all of them ease on sitting or lying down.
The common ones
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Light-headedness and giddiness Usually the first thing people notice, and typically within seconds of standing. More on giddiness and its other causes.
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Vision that greys or blurs For a moment only, sometimes narrowing to a tunnel before it clears.
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Unsteadiness A sense of having to grab something until the moment passes.
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Tiredness and weakness Tiredness that does not lift with rest, and a general feeling of having no reserve.
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Difficulty concentrating Often described as thinking through fog.
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Nausea Occasionally with sweating and a clammy feeling.
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Aching neck and shoulders Comes on after standing a while and eases as soon as you sit. Easily put down to posture, and worth mentioning when it travels with light-headedness.
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Fainting The far end of the same spectrum. See fainting and syncope for what to do about it.
The timing matters more than the symptom
Within seconds of standing points to a postural drop. Half an hour to two hours after a meal points to a drop that follows eating. During exercise rather than after it is the one to act on promptly, because exertion is when the heart itself is most likely to be the reason.
Many people with a low reading feel none of this.
Recognise these symptoms? Dr Paul Lim will take your lying and standing readings, review your medications, and tell you whether the heart is involved.
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Your Cardiologist
Reviewed by Dr Paul Lim
Senior Consultant Cardiologist & Cardiac Electrophysiologist
Dr Paul Lim is a Senior Consultant Cardiologist whose subspecialty is heart rhythm disorders, which puts him on familiar ground with low blood pressure that causes fainting: the first job is separating a blood pressure problem from a rhythm that is running too slow, and the two can look identical from the outside. He completed advanced fellowship training at Barts Heart Centre, London under Singapore’s HMDP award.
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Why It Happens
What Causes Low Blood Pressure
Most of the time the cause turns out to be ordinary and fixable. Medication is the first thing to check, and the commonest thing to find.
Medication, which is where we look first
This is the commonest reversible cause, and the one most likely to be fixable in a single appointment. Several widely used medicines lower blood pressure by design, and a dose that suited you three years ago can be too much today, because blood pressure often drifts down with age, weight loss or a change in kidney function.
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Blood pressure medicines Every class, and particularly two or three taken together.
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Diuretics Water tablets, which reduce circulating volume.
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Alpha-blockers Prescribed for the prostate, such as tamsulosin. A frequent culprit in older men.
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Nitrates Taken for angina.
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Some antidepressants Especially the older tricyclics.
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Parkinson’s disease medications Levodopa and dopamine agonists both lower blood pressure on standing.
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Alcohol Adds to all of the above.
Never stop or adjust a prescribed medicine on your own. Bring the full list, including anything bought over the counter and any supplements, so the timing and doses can be reviewed together.
Everyday and situational causes
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Dehydration Singapore’s heat and humidity make this easy to slip into, and it is the single most common everyday explanation.
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Heat itself Widens blood vessels. A hot shower, a sauna or a long spell outdoors all lower pressure temporarily.
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Standing still for a long stretch Blood pools in the legs with no muscle pump to move it.
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A large meal Diverts blood to the gut. Covered in more detail below.
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Prolonged bed rest Or a period of illness, after which the reflexes that manage standing become sluggish.
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Pregnancy Blood vessels relax in early pregnancy and pressure normally falls to its lowest around mid-pregnancy, then climbs back towards baseline by term.
Medical causes worth finding
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Anaemia or slow blood loss Reduces what is available to circulate. Worth a blood test in anyone newly tired and light-headed.
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Heart problems A heart rate that is too slow, heart failure, or a valve that restricts outflow. These matter most when symptoms come on with exertion.
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Nerve damage affecting the automatic controls Most often from long-standing diabetes, and also from Parkinson’s disease. The usual reason a postural drop resists simple measures.
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Hormone disorders Adrenal insufficiency is the one that classically lowers blood pressure, and it usually shows as a postural drop. An underactive thyroid is often assumed to do the same; it more often raises the lower number and slows the pulse, and lowers the pressure only when it is severe.
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Severe infection, a major allergic reaction or significant bleeding These cause abrupt, dangerous falls in pressure and belong in the emergency category rather than this one.
Think a medication might be behind it? Bring your full list, including anything bought over the counter, and have the timing and doses reviewed properly.
The Commonest Type
Orthostatic Hypotension: Low Blood Pressure on Standing
Also called postural hypotension. It is the type most people arrive with, and the type most likely to have a fixable cause.
The mechanism is described above, along with the 20/10 definition. It behaves quite differently from a simply low resting reading. Your pressure can be entirely respectable sitting in a chair and still fall through the floor eight seconds after you get out of it, which is why a single seated reading at a clinic can miss it completely.
What makes it more likely
- Age. The reflexes that manage standing become less brisk, and it becomes markedly more common past 65.
- Medication, which contributes more often than anything else at every age.
- Diabetes of long duration, through damage to the autonomic nerves.
- Dehydration, which turns an otherwise borderline response into a symptomatic one.
- Getting up first thing, when you are at your most fluid-depleted. Morning is when symptoms cluster.
When it is more than the occasional wobble
A quick moment of grey vision after jumping up from a chair happens to almost everyone, and on its own it is nothing to worry about. Get it checked if:
- It happens nearly every time you stand up
- It is getting worse
- You have had a fall because of it
- You have blacked out
The check itself is simple. Your blood pressure is taken lying down, then again after you stand up, and the difference between the two is the answer.
If you have blacked out, do not drive until you have been checked and told it is safe.
Other Patterns
Other Types of Low Blood Pressure
Postprandial hypotension: after eating
Digestion diverts a substantial volume of blood to the gut. In most people the circulation compensates without any of it being noticed. Where it does not, pressure falls in the half hour to two hours after a meal, bringing light-headedness, drowsiness or unsteadiness. Large meals and those heavy in refined carbohydrate provoke it most, and alcohol with the meal makes it worse.
It is far more common after 65, and it is a recognised cause of falls and fainting in older adults that often goes unidentified because the meal is not thought of as the trigger. Smaller, more frequent meals with less refined carbohydrate usually help, as does sitting for a while after eating rather than getting straight up.
Neurally mediated hypotension and the common faint
Here the pressure drops through a reflex misfire rather than through a shortage of fluid or a failing pump. Standing for a long time, heat, pain, the sight of a needle or emotional distress can trigger it, and the result is the ordinary faint that most people have either had or witnessed. Because it is a fainting problem more than a blood pressure problem, it is covered in full on the fainting and syncope page, including how to tell it apart from a faint caused by the heart.
Severe hypotension and shock
This is a different clinical event rather than a milder one. Pressure falls far enough that organs stop receiving what they need, and the cause is usually major bleeding, overwhelming infection, a severe allergic reaction or a heart that has suddenly stopped pumping adequately. It develops over minutes to hours rather than months, and the person looks unwell. The features are listed under emergency care, and it is treated in hospital.
Finding Out
How Low Blood Pressure Is Diagnosed
The aim is rarely to confirm the reading, which you usually already have. It is to establish what is producing it and whether the heart is involved.
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1
Lying and standing blood pressure
The most useful measurement, and the quickest. Blood pressure and pulse are taken after lying down for at least five minutes, then again at one and three minutes after standing. A fall of 20 mmHg systolic or 10 mmHg diastolic confirms orthostatic hypotension. Watching the pulse at the same time matters: a heart rate that fails to rise as the pressure falls suggests the automatic nervous system rather than simple dehydration.
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2
The history and a medication review
When symptoms occur, how long they last, what you were doing, and what changed before they started. Alongside that, a line-by-line review of everything you take, prescribed or otherwise. This pair identifies the cause more often than any test, which is why the full medicine list is worth bringing rather than reciting from memory.
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3
An ECG, and an echocardiogram where indicated
An ECG records the rhythm and looks for conduction problems, a slow rate or evidence of previous damage. Where a structural cause is suspected, particularly with breathlessness or symptoms on exertion, a 2D echocardiogram assesses the valves and the pumping function directly.
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4
Blood tests
Full blood count for anaemia, kidney function and salts, thyroid function, and blood sugar. These pick up the systemic causes that a heart trace cannot, and they are inexpensive. Most are bundled into a heart screening package if a broader risk assessment is wanted at the same time.
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5
Rhythm monitoring, where episodes are intermittent
Symptoms that come and go are the hardest to catch, because the clinic visit is rarely the moment it happens. A Holter monitor records continuously for 24 hours to 14 days. Where episodes are infrequent but the suspicion of a heart cause is real, an implantable loop recorder can watch for far longer.
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6
A tilt table test, occasionally
You are secured to a table and tilted upright while heart rate and blood pressure are watched continuously. It is reserved for cases where the diagnosis stays unclear after the steps above, and it can reproduce the drop under controlled conditions.
Costs for individual tests and consultations are listed on the cardiology fees page.
Not sure which of these you need? The lying and standing check takes a few minutes in the consulting room, and what follows depends on what it shows.
What Helps
How Low Blood Pressure Is Treated
Treatment follows the cause. Where no cause is found and there are no symptoms, the right answer is often to leave it alone.
First: the medication review
It resolves more cases than any other single measure. If a blood pressure tablet, a diuretic or a prostate medicine is contributing, the options are a lower dose, a different time of day, a switch, or stopping it. Moving a dose from morning to evening alone can lift the readings at the time of day symptoms occur.
It is a balance rather than a simple reversal. Someone treated for high blood pressure who now reads too low still needs their cardiovascular risk managed, so the target is adjusted rather than abandoned. That judgement belongs with the doctor who knows your full picture.
Measures you can start yourself
Stand up in stages
Sit on the edge of the bed for a moment, flex your ankles and calves a few times, then rise. Those seconds give the circulation the head start it is missing.
Compression stockings, worn high enough
Blood pools in the abdomen as well as the legs, and the abdomen is where compression makes the difference. Waist-high stockings or an abdominal binder are what to ask for; knee-high stockings on their own do little.
Smaller, more frequent meals
For symptoms that follow eating. Less refined carbohydrate at any one sitting, no alcohol with the meal, and a few minutes seated before you get up.
Respect the heat
Long hot showers, saunas and midday sun all widen blood vessels and drop the pressure further. Alcohol does the same, and does it while you are already dehydrated.
Raise the head of your bed
Around 10 to 20 degrees, by propping the bed head rather than adding pillows. It reduces the overnight fluid loss that makes mornings the worst time of day.
Salt is not the general answer it appears to be
Extra salt and fluid do raise blood pressure, and they are a recognised measure in orthostatic hypotension. The catch is that the advice is the reverse of what most adults are told, and for good reason: added salt can be actively harmful if you have heart failure, kidney disease or high blood pressure being treated with medication. Take it as something to discuss and be prescribed an amount of, rather than something to start on your own.
Medicines used to raise blood pressure
These are considered when the measures above have been given a fair run and symptoms are still limiting what you can do. They are prescription-only, they need monitoring, and neither is a first move.
| Medicine | How it works | Main considerations |
|---|---|---|
| Fludrocortisone | Prompts the kidneys to hold on to salt and water, expanding the circulating volume. | Used off-label, and avoided in heart failure. Needs monitoring of potassium and of swelling, and it can raise blood pressure while lying down. |
| Midodrine | Tightens the blood vessels, which raises standing blood pressure directly. | Improves standing pressure and symptom scores in trials. It can push blood pressure up while lying down, so it is timed to the day and avoided close to bedtime. |
Listed for recognition, not as a recommendation, and set out in more detail in a practical clinical review of how orthostatic hypotension is managed. Availability and licensing vary. Always speak to your own doctor before starting, stopping or changing a dose.
Why it is worth sorting out
Two reasons. The first is falls. In older adults the injury from the fall does far more damage than the reading ever would, and a fractured hip changes a life in a way a blood pressure of 92/58 does not. The second is that low blood pressure is often a messenger. Anaemia, a slow heart rhythm, an underactive thyroid and a medication that has outstayed its usefulness are all found this way, and all of them are treatable once identified.
Next Steps
When to See a Cardiologist for Low Blood Pressure
Plenty of low blood pressure needs no cardiologist at all. A cardiologist is worth seeing once the question is no longer just about the reading, but about whether the heart itself is behind it.
Book a review if:
- You have fainted or blacked out
- Symptoms come on during exercise rather than after it
- The pressure drops alongside palpitations or a slow pulse
- It started with no explanation, and your readings used to be normal
- You have known heart disease or an abnormal ECG
The same applies if you are concerned, or would simply like a second opinion on a reading you have already been given.
Get in Touch
Book a Low Blood Pressure Assessment
See Dr Paul Lim to have lying and standing readings taken properly, your medications reviewed, and the heart ruled in or out.
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Common Questions
Low Blood Pressure FAQ
The questions people most often arrive with about low readings, symptoms and treatment.
What is considered low blood pressure?
A reading below 90/60 mmHg is the figure usually quoted. It is a convention rather than a diagnostic line: Singapore clinical guidance sets thresholds for high blood pressure but publishes no equivalent cut-off for low blood pressure. Plenty of healthy people, particularly younger adults and those who are fit, sit below 90/60 and feel entirely well, and for them it is simply their normal. What turns a low reading into low blood pressure is symptoms, such as light-headedness, blurred vision, unusual tiredness or fainting, or a reading that has fallen well below your own usual level.
Is low blood pressure dangerous?
Usually not, when it is long-standing and causes no symptoms. It becomes a problem in three situations. The first is when it causes falls or blackouts, which is the main risk in older adults, and where the injury does more harm than the pressure itself. The second is when it appears suddenly, because a rapid fall can signal bleeding, severe infection, a heart problem or a severe allergic reaction, all of which need emergency care. The third is when it points to an underlying condition worth finding, such as a slow heart rhythm, a valve problem, anaemia or a hormone disorder. A low reading you have had for years and feel nothing from is a different situation from one that is new.
What are the symptoms of low blood pressure?
The commonest are light-headedness and dizziness, especially on standing, along with vision that blurs or greys briefly, unsteadiness, tiredness, nausea, difficulty concentrating and, at the far end, fainting. Some people notice an ache across the back of the neck and shoulders that eases on sitting down. The pattern is often more telling than the symptom itself: if it arrives within seconds of getting up and settles once you sit or lie down, that points strongly towards a postural drop rather than to a low reading in general. Many people with a low reading have no symptoms at all.
Is there a different dangerous low blood pressure level for women?
No. The figures are the same for men and women, and there is no separate female threshold. Women do report symptoms of low blood pressure more often, for reasons that include a lower average blood volume, iron deficiency and anaemia being more common, and the normal fall in blood pressure during pregnancy, which reaches its lowest around the middle. Those are explanations for why it happens more, rather than a different number to measure against. As with anyone, what matters is whether the reading causes symptoms and whether it has changed from your own usual level.
Why do I feel dizzy or light-headed when I stand up?
This is orthostatic hypotension, also called postural hypotension. Standing pulls roughly half a litre of blood down into the legs and abdomen. Normally the heart speeds up and the blood vessels tighten within seconds to compensate, but if that response is slow or blunted the pressure dips and the brain is briefly under-supplied. It is defined as a sustained fall of at least 20 mmHg systolic or 10 mmHg diastolic within three minutes of standing. An occasional wobble after jumping up quickly is common and usually harmless. Have it checked if it happens most times you stand, is getting worse, has followed a change in medication, or has caused a fall or a blackout.
How can I raise low blood pressure?
Start with fluid, because mild dehydration is the commonest everyday reason a reading sits low, and Singapore’s heat and humidity make it easy to fall behind. Beyond that: stand up in stages rather than all at once, use waist-high compression stockings or an abdominal binder if symptoms come on standing, eat smaller and more frequent meals if they follow a meal, go easy on alcohol and long hot showers, and raise the head of your bed slightly. Extra salt does raise blood pressure, but it is not right for everyone and should only be added on your doctor’s advice, since it can be harmful if you have heart failure, kidney disease or treated high blood pressure. If a medication is contributing, the fix is usually a dose or timing change made by the doctor who prescribed it. Prescription medicines to raise blood pressure exist and are used when these measures are not enough.
Can blood pressure medication make my blood pressure too low?
Yes, and it is the commonest reversible cause. Blood pressure tablets, diuretics, nitrates and alpha-blockers prescribed for the prostate all lower pressure by design, and the dose that suited you a few years ago may be too much now, because blood pressure often falls with age, weight loss or a change in kidney function. Some antidepressants and Parkinson’s medications have the same effect. Taking several of them together compounds it. Do not stop or adjust anything yourself. Bring the full list, including anything bought over the counter, to a consultation so the timing and doses can be reviewed properly.
Is low blood pressure normal in pregnancy?
A fall is expected. Blood vessels relax in early pregnancy and blood pressure typically drifts down from the first trimester to its lowest around the middle of pregnancy, then climbs back towards its usual level by term, which is why light-headedness on standing is commonest in the first half. It is not usually a cause for concern on its own. Lying flat on your back later in pregnancy can also drop the pressure, and turning onto your side relieves it. Anything more than mild light-headedness, and in particular fainting, bleeding, severe abdominal pain or breathlessness, should be raised with your obstetrician, who is the right person to manage blood pressure during pregnancy.