Short answer: Dizziness, dimming vision or near-fainting that appears after rising from bed or a chair can occur with orthostatic hypotension. Symptoms alone do not confirm it. Recurrent episodes or actual fainting warrant a review of lying and standing blood pressure and pulse, medicines, hydration, bleeding risk and other possible causes.
How is orthostatic hypotension assessed?
The American Heart Association defines orthostatic hypotension as a sustained fall of at least 20mmHg systolic or 10mmHg diastolic within three minutes of standing. The CDC measurement protocol has a person lie down for five minutes, records blood pressure and pulse, then repeats both after one and three minutes of standing. Lightheadedness or dizziness during the test is also important to report even when the numerical threshold is not met.
Because standing while dizzy creates a fall risk, do not attempt this alone. If a home check can be performed safely with someone present, treat it as information for a clinician—not a self-diagnosis.
What causes should be considered?
Possible contributors include dehydration or blood loss, medicines, diabetes, autonomic or neurologic disorders, and heart or kidney disease. Record recent vomiting, diarrhea, heavy sweating, symptoms after meals, and any medicine that was started or changed. Dizziness can also come from inner-ear disorders, anemia, an abnormal heart rhythm and other conditions, so the pattern needs clinical context.
What should you do when symptoms begin?
Sit or lie down promptly and move again only after symptoms have cleared. Avoid driving, stairs and other fall hazards. Do not stop blood-pressure, diuretic, prostate or other prescribed medicine on your own; document the timing and discuss it with the prescriber. Extra fluid or salt is not suitable for everyone. People with heart failure, kidney disease or a prescribed fluid or sodium limit should ask their clinical team first.
When is it an emergency?
Call the local emergency number if someone cannot be awakened within a minute, does not fully recover, or has chest pain, trouble breathing, a pounding or irregular heartbeat, new speech or movement difficulty, a seizure, or a serious injury. Fainting during exercise or while lying down also needs urgent assessment. Dizziness with vomiting blood, black tarry stool, major bleeding or a continuing fall in blood pressure may signal an emergency.
What should you record?
Note the position and time symptoms began; blood pressure and pulse after five minutes lying down and after one and three minutes standing; meals, exercise, heat, diarrhea or vomiting; medicine names and times; and any fainting or fall. Useful questions include: “Could a medicine or dehydration be contributing?” and “Do I need an ECG, blood tests or another evaluation?”
Related guides
- Blood pressure and lab results log
- Medication and supplement list
- Sudden palpitations and emergency warning signs
Sources and review date
- Korea Disease Control and Prevention Agency — Low blood pressure
- American Heart Association — Orthostatic Hypotension in Hypertensive Adults
- CDC STEADI — Measuring Orthostatic Blood Pressure
- NHS — Fainting
Reviewed October 13, 2026. Use 119 in South Korea, 999 in the UK, 911 in the US, or your local emergency number. This is general information and does not replace individual medical care.