What blood pressure is too low?
There’s no single cutoff for low, but under 90/60 is the usual definition. Low numbers with no symptoms are often harmless. If you get dizzy when you stand, faint, feel confused or see a sudden drop from your usual, call a doctor.
What to do
| What you notice | What to do |
|---|---|
| Under 90/60, you feel fine | Measure again another day. Mention it at your next visit. |
| Dizzy, lightheaded, blurry vision, unusually tired or nauseated | Call your doctor. |
| You faint, or a number falls well below your own usual | Call your doctor the same day. |
| Cold, sweaty skin, fast breathing, bluish skin, a weak and rapid pulse | Call emergency services. These are signs of shock. |
| Chest pain, shortness of breath, weakness, numbness or trouble speaking | Call emergency services, whatever the number. |
Common causes
The National Heart, Lung, and Blood Institute lists these:
- Dehydration
- Blood loss from an injury
- Medicines for high blood pressure, depression or Parkinson’s disease
- Heart rhythm problems
- Diabetes
- Pregnancy
- Problems with the nerves that control blood pressure
If you take medication and your numbers run low, call the clinician who prescribes it. Don’t change or skip a dose on your own. A log of your home numbers gives them something real to go on.
The dizzy-on-standing check
Some people have normal numbers when they sit, and their pressure drops when they stand. The standard definition of orthostatic hypotension is a fall of at least 20 in systolic pressure (the top number), or at least 10 in diastolic (the bottom number), within 3 minutes of standing.
To gather numbers for your doctor, sit or lie quietly and take a measurement. Stand, holding on to something stable if you need to, and measure again within 3 minutes. Sit down right away if you feel faint. Write down both pairs and how you felt. If you’ve fallen or fainted, ask your doctor to do this check in the office.
Is lower better?
It is, up to a point. Researchers pooled studies of about one million adults and found that vascular death rates kept falling as blood pressure went down to at least 115/75. Below that, they found little evidence either way. A number like 105/65 with no symptoms isn’t a reason to worry on its own. See what is a good blood pressure.
Your own usual counts
If you’ve run 100/60 for years and feel well, that’s not the same as someone who usually runs 135/85 and suddenly sees 100/60. To find your usual, measure at home for a week and work out the average. When a new number falls well below it and you can’t explain why, call your doctor. Bring the last week of numbers and a list of what you take.
3 sources
- National Heart, Lung, and Blood Institute, Low Blood Pressure, checked 2026nhlbi.nih.gov
- Ringer M, Hashmi MF, Lappin SL, Orthostatic Hypotension, StatPearls, 2025pubmed.ncbi.nlm.nih.gov
- Prospective Studies Collaboration (Lewington S et al.), Lancet, 2002pubmed.ncbi.nlm.nih.gov
