Blood Pressure - How Low Can You Go?

We spend a lot of time talking about avoiding high blood pressure, but is there a number that’s too low? For most adults, anything lower than 90/60 mm Hg is considered low blood pressure. Symptoms include dizziness, blurred vision or even fainting, as your brain isn’t getting enough blood. There are three common instances of low blood pressure:

• Sudden drop when going from sitting to standing, or standing to lying down (called postural hypotension): This could be related to dehydration, pregnancy, long-term bed rest, certain conditions or medications, or your age, as it’s common in those over age 65.

• After meals (postprandial hypotension): Also more likely to affect older adults, this type occurs when there’s a drop in pressure 1-2 hours after eating. This is caused by failure of the blood pressure sensors in the arteries or stretch receptors in the stomach.

• After standing for a long time (neurally mediated hypotension): Also known as the fainting reflex, this usually affects young adults and children. Extended periods of standing causes blood to pool in the legs and ankles, meaning there’s not as much flowing to the heart and brain.

Some people may experience low blood pressure related to known conditions or medications they’re taking, including:

• Pregnancy, especially within first 24 weeks
• Heart issues, like heart valve disease and heart failure
• Endocrine disorders
• Lack of vitamin B-12, folate and iron
• Diuretics
• Alpha and Beta blockers
• Pramipexole/levodopa for Parkinson’s disease
• Some antidepressants
• Some erectile dysfunction drugs

But other unexpected health issues can cause low blood pressure like dehydration, blood loss from an injury or internal bleeding, a severe infection or anaphylaxis (severe allergic reaction).

While a one-time low reading is usually not cause for alarm if you don’t have noticeable symptoms and feel fine otherwise, your provider may opt to monitor your pressure more regularly. But an extreme drop in pressure can lead to shock, so seek emergency care right away.