low blood pressure symptoms at night

What happens to low blood pressure at night, 20% rule

Did you know that blood pressure has a daily pattern and that it is not unusual to have low blood pressure at night?

But how would you know that? You sleep at night.

Most people are under the impression that blood pressure keeps steady throughout day and night and does not deviate from 120/80 (when in good health).

But that’s not true. Not only blood pressure fluctuates minute to minute,  varies depending on what you do, but also has a natural twenty-four hour cycle.

When low blood pressure at night is normal

The heart has its own rhythm and blood pressure has its own diurnal fluctuations. The rhythm is quite simple. Blood pressure goes up during the day and keeps low during the night. That sounds easy enough, but when you look closer, you can see that a healthy heart behaves differently than a compromised heart .

An interesting observation was made by researchers who tested blood pressure at night. Apparently, blood pressure rests at night as well. When you retire it goes down by about 10-20%.1

This pattern is seen in healthy adults and it means that the normal daily reading of 120/80 morphs into 100/65 at night and yet continues being considered as normal (not low blood pressure or hypotension).


When low blood pressure at night isn’t normal

It would be prudent to check what your blood pressure does at night, because you want to know how low it goes in your case. Not all dips are normal or healthy and you don’t want to have a hidden risk.

Waking up in the middle of a night to check  blood pressure is neither convenient, nor normal. Besides, interrupted sleep won’t lead you to great health. However, you can get yourself a home unit that automatically measure blood pressure at night. This way you can get your numbers neatly lined up in the morning for your inspection.

Once you have your numbers in front of you, calculate the percentage the top and the bottom they go down by. You should be concerned if either one of the numbers nose-dives more than 20%.

Your number * 20% = Your number’s maximum dip

If either of them does, you may be an “extra dipper”. Extra dipper is a name given to people whose blood pressure dips below normal values at night. Some extra dippers can see their numbers sliding down by 50%, but that’s not good. Not good at all.

The effects of low blood pressure at night

Being an extra dipper isn’t anything you should aspire to. Extreme blood pressure lows aren’t good for the body. They can damage organs, including the heart and the brain. This is due to extremely low blood pressure causing insufficient blood flow. For that reason extra dippers are more likely to suffer silent strokes.

The lows aren’t good for the eyes either. Lack of oxygen overnight can damage optical nerves and lead to vision loss.

Who are the extra dippers?

There are two types of people who are more likely to be extra dippers: diabetics and people with sleep apnea.  Extreme dipping and lack of oxygen may explain way diabetics are chronically tired, prone to nerve damage, and have higher incidence of vision loss. Extreme dipping is also frequent among people with arterial plague.

What if blood pressure doesn’t go down at night?

While extreme dipping is a sign of compromised health, a complete lack of dipping isn’t healthy either. Studies correlated lack of blood pressure fluctuations at night with poorer sleep, night waking, and sleep apnea.

Revived low blood pressureNon-dipping was also associated with enhanced risk of cardiovascular events such as strokes and heart attacks as well as endocrine and nervous system dysfunctions including hyperthyroid and various neuropathies (nerve damage).  Non-dippers reported experiencing more stress, and have stronger family history of hypertension.

Low blood pressure – a hidden problem

Low blood pressure (regardless of the dipping status) is a concern. It causes poor blood flow, low oxygenation, and tissue damage. Many effects of low blood pressure aren’t discovered on time to prevent permanent organ damage.

That’s because the stress caused by seeing a health practitioner artificially increases blood pressure numbers, making hypotension practically undetectable.

Don’t wait. If you find your numbers low all day long, follow instructions given in Revived!. If you find your numbers going erratically up and down, you want to get The Ultimate Guide to Low and Fluctuating Blood Pressure instead. Enjoy the read and get healthier soon!

Health troubles are seldom random
Do your beliefs support your health goals?


  1. Diana Chacon September 26, 2018
  2. Dorothy Adamiak January 1, 2019

Leave a Comment