Blood Pressure 85 Over 40–84: Which Are OK?
With an upper value of 85, the answer depends on your lower number. Here are all readings, sorted by what they mean.
On its own, a systolic (upper) value of 85 mmHg is Low blood pressure by the international categories (2023 ESH guideline) and low under the 2025 AHA/ACC guideline. The worse of your two numbers decides the category, so a raised diastolic (lower) value moves a 85 reading up: from 85/80 it counts as normal.

Low blood pressure 85/40 to 85/75
What to do with a reading of 85 over …
Low. If you feel well, that is often harmless; with dizziness, light-headedness or fainting, talk to your doctor — especially after a change of medication. A lower number below 50 (from 85/49 down) is clearly low: measure again, and if it is confirmed or you feel dizzy, faint or confused, contact a doctor the same day. Keep your readings in a free blood pressure log and read how to measure correctly.
Sources: ESH 2023 guideline · AHA/ACC 2025 guideline.