Low blood pressure might seem desirable, and for some people, it causes no problems. However, for many people, abnormally low blood pressure (hypotension) can cause dizziness and fainting. In severe cases, low blood pressure can be life-threatening.
A blood pressure reading lower than 90 millimeters of mercury (mm Hg) for the top number (systolic) or 60 mm Hg for the bottom number (diastolic) is generally considered low blood pressure.
The causes of low blood pressure can range from dehydration to serious medical disorders. It’s important to find out what’s causing your low blood pressure so that it can be treated.
Symptoms
For some people, low blood pressure signals an underlying problem, especially when it drops suddenly or is accompanied by signs and symptoms such as:
- Dizziness or lightheadedness
- Fainting
- Blurred or fading vision
- Nausea
- Fatigue
- Lack of concentration
Shock
Extreme hypotension can result in this life-threatening condition. Signs and symptoms include:
- Confusion, especially in older people
- Cold, clammy, pale skin
- Rapid, shallow breathing
- Weak and rapid pulse
When to see a doctor
If you have signs or symptoms of shock, seek emergency medical help.
If you have consistently low blood pressure readings but feel fine, your doctor will likely just monitor you during routine exams.
Even occasional dizziness or lightheadedness may be a relatively minor problem — the result of mild dehydration from too much time in the sun or a hot tub, for example. Still, it’s important to see your doctor if you have signs or symptoms of low blood pressure because they can point to more-serious problems. It can be helpful to keep a record of your symptoms, when they occur and what you’re doing at the time.