What Is Considered Low Blood Pressure? Numbers and Symptoms
Low blood pressure usually means a reading below 90/60 mmHg, but the number alone isn't the problem. Symptoms decide whether a low reading needs a doctor.
This article is educational content, not medical advice. Always talk to a healthcare professional about your blood pressure.
The thresholds on this page follow the ACC/AHA guideline used in the United States (set in 2017 and kept in the 2025 update), which sets high blood pressure at 130/80 mmHg. Other bodies differ: ESH in Europe and NICE in the UK still define it at 140/90 mmHg. Check the guideline your own clinician uses.
Low blood pressure, called hypotension, usually means a reading below 90/60 mmHg. That's the cutoff the US National Heart, Lung, and Blood Institute uses. But the number on its own isn't the problem: plenty of healthy people run that low every day. A low reading matters when it comes with symptoms like dizziness or fainting, or when it drops suddenly from your usual level.
The NHLBI defines low blood pressure as anything below 90 mmHg systolic (the top number) or 60 mmHg diastolic (the bottom number). For comparison, the ACC/AHA categories used by the American Heart Association call a reading below 120/80 normal. The AHA itself says there's no specific number at which day-to-day pressure is too low, as long as you have no symptoms. Mayo Clinic takes the same line: most clinicians only treat low blood pressure as a problem when it causes symptoms.
A separate pattern, orthostatic hypotension, is defined by a drop rather than a level. The NHLBI describes it as a fall of at least 20 mmHg systolic or 10 mmHg diastolic within three minutes of standing up.
What blood pressure is too low?
There isn't one number that's dangerous for everyone. What a low reading means depends on how you feel and on what's normal for you. This table sorts the common situations.
| What you see | What it usually means | What to do |
|---|---|---|
| Below 90/60 mmHg, you feel fine | Often just your normal level | Keep logging; mention it at your next checkup |
| Below 90/60 mmHg with dizziness, blurred vision, fatigue or nausea | Symptomatic low blood pressure | Book an appointment with your doctor |
| Systolic falls 20+ mmHg, or diastolic 10+, within 3 minutes of standing | Possible orthostatic hypotension | Tell your doctor, especially if you feel faint |
| Any fainting, even for a few seconds | Needs prompt assessment | See a doctor right away |
| Low reading with confusion, cold clammy skin, pale skin, rapid shallow breathing or a weak, fast pulse | Possible shock | Seek medical help immediately (call your local emergency number) |
The last row is the one that can't wait. Mayo Clinic lists those signs as warnings of shock, which can follow serious bleeding, a severe infection or a severe allergic reaction. Don't sit at home re-measuring if you or someone near you has them.
What does a low blood pressure reading mean?
On its own, not much. It needs context. A steady 88/58 mmHg in someone who has always read low and feels well is a very different thing from a reading that has fallen 25 points below that person's usual level. The NHLBI points out that a sudden drop is the bigger worry, because the brain, heart and other organs may briefly not get enough blood flow.
That's why a single number tells you so little. You need to know your own baseline, which comes from weeks of readings, not one. If you're new to reading the two numbers, our guide to understanding your blood pressure numbers explains which is which.
Why is my blood pressure low?
Some people simply run low. The NHLBI notes that for them, low pressure is their normal state and causes no trouble. When readings are lower than usual, or come with symptoms, Mayo Clinic lists common reasons:
- Dehydration, or being overheated
- Standing up quickly after sitting or lying down
- Pregnancy, when pressure often dips in the first 24 weeks
- Some medicines, including those for high blood pressure
- Heart problems, hormone conditions such as thyroid disease, or nutrient deficiencies
- Serious bleeding, infection or allergic reaction (the emergency causes above)
If you take blood pressure medicine and your home readings run low, don't change anything on your own. Whether a dose is right is your prescriber's decision. Your job is to bring them good data: the readings, the times, and how you felt.
Could the reading itself be wrong?
A low number is sometimes a setup problem, not a body problem. Before you worry, check that the measurement was sound. The American Heart Association's scientific statement on measurement lists setup errors that push readings in both directions, and a few of them read low.
A cuff that's too large for your arm tends to under-read. So does an arm held higher than your heart, for example propped on a stack of pillows or a high armrest. A cuff wrapped over a thick sleeve can also give an unreliable result. Our cuff size chart shows how to match the cuff to your arm, and the guide to positioning your arm covers heart height.
If a reading looks oddly low, fix the setup and measure again. One surprising number from a rushed check doesn't mean much on its own.
How to re-check and record a low reading
When a low number shows up and you feel fine, use a calm routine to see whether it holds:
- Sit with your back supported, feet flat, and arm resting at heart height.
- Rest quietly for five minutes.
- Take two readings one minute apart and note both.
- Write down any symptoms: lightheadedness, blurred vision, tiredness, nausea.
The AHA statement recommends this two-reading pattern in the morning and evening for about a week when you're building a home picture. That's 2 readings × 2 times a day × 7 days = 28 readings, enough to see your real average rather than one outlier. Our post on how many readings to average explains why.
If you get dizzy when you stand, sit or lie down straight away so you don't fall. Mention the pattern to your doctor, who can compare lying and standing readings properly.
Tracking low readings with BPlus
Low readings only make sense next to your usual ones, and that's hard to judge from memory. BPlus is a logging app that keeps those readings in one place. Enter systolic, diastolic and pulse by hand, or scan your own monitor's display with the camera, and the time, date and arm are stamped automatically. Add a note like "dizzy on standing" to any reading.
The app charts readings over time, sorts each into color-coded categories, and exports a PDF or CSV report you can hand to your doctor. Daily reminders help you keep a regular routine, and medication reminders sit in the same place.
Your data stays on your device, works offline, and needs no account. BPlus is a wellness and logging tool, not a medical device. It doesn't measure blood pressure, diagnose low blood pressure or tell you what to do about it, and it's no substitute for professional care.
Mini-FAQ
Is 90/60 too low? Not by itself. The NHLBI uses 90/60 mmHg as the edge of the low range, but many healthy people sit right around it with no symptoms. It becomes a concern if you feel dizzy, faint or unusually tired, or if it's well below your usual readings. Then it's worth a doctor's visit.
What blood pressure is dangerously low? There's no single number. Danger shows in how you feel: confusion, cold and clammy skin, rapid shallow breathing or a weak, fast pulse alongside a low reading can signal shock, which can follow heavy bleeding, a severe infection or an allergic reaction. If you see those signs, seek medical help immediately and don't wait to re-measure.
Can low blood pressure be a sign of good health? Often, yes. Some people run below 90/60 mmHg their whole lives and feel well, and the AHA says a low number without symptoms isn't usually a concern. The question to ask is whether your readings have changed, not just how low they are.
Should I skip my blood pressure pill if my reading is low? No. Never skip, stop or change a dose based on home readings. That decision belongs to your prescriber. Log the low readings with their times and any symptoms, and contact your doctor within a few days, or the same day if you feel faint or dizzy. Bring the log so they can see the pattern.
Sources
Keep your readings in one calm place
BPlus does the logging with you: record by hand or scan your monitor, watch your trends, and export a doctor-ready report when you need one.
Medical disclaimer. BPlus is a wellness and informational tool that helps you record, organize and understand your blood pressure readings. It is not a medical device and does not diagnose, treat, cure or prevent any disease. BPlus does not measure blood pressure on its own. Always consult a qualified healthcare professional. Readings are not a substitute for a clinically validated blood pressure monitor.
