How to Check Your Blood Pressure at Night
Quick Answer
You cannot reliably measure your sleeping blood pressure with a standard home monitor, because the act of waking up to take a reading raises the number for a few minutes on its own. An occasional manual night reading can help you spot a rough pattern, but repeated checking through the night mostly costs you sleep and pushes the number higher through anxiety. If you want a real answer about your blood pressure during sleep, the tools are a 24-hour ambulatory monitor (the standard, ordered by a doctor) or a dedicated nocturnal home monitor that inflates automatically overnight. If you do take a manual reading, sit up, empty your bladder, rest five minutes, take one or two readings, and write down the number and the time. A nighttime average of 120/70 mmHg or higher on proper monitoring is the threshold for nocturnal hypertension.
Should you check at all?
The honest answer for most people is: not the way you are probably picturing it. Setting an alarm to wake up and check, or checking every time you happen to wake, has three problems.
- Waking raises the number. Coming out of sleep activates the nervous system for several minutes. A reading taken in the first minute or two after you wake is often 10 to 20 points high purely for that reason, so it is not your sleeping blood pressure at all.
- Watching the number pushes it up. The anxiety of taking a reading you are worried about is itself a pressor. People who re-check repeatedly usually watch the number climb, not settle.
- You lose sleep, and short or broken sleep is itself linked to higher blood pressure, so the measuring can worsen the thing you are measuring.
An occasional single reading on a night you are already awake, done calmly, can be useful for spotting whether there is a pattern worth mentioning to a doctor. Beyond that, the value drops off fast.
If you take a manual reading: how to do it right
If you are going to do it, do it in a way that gives a number worth writing down. This follows the same standard technique the American Heart Association recommends for any home reading:
- Sit up on the edge of the bed with your feet flat on the floor. Do not measure lying down.
- Empty your bladder if you need to. A full bladder raises blood pressure measurably.
- Rest quietly for five minutes before the first reading. Do not check your phone.
- Rest your arm on a surface so the cuff sits at heart level. Use an upper-arm cuff, not a wrist device, if you have the choice.
- Do not talk during the reading. Take one or two readings a minute apart.
- Write down the number, the time, and what woke you (bathroom, noise, a dream, nothing in particular).
- Then stop. Do not re-check in 10 minutes. Re-check in the morning under normal conditions.
The tools that actually measure sleeping blood pressure
Because a reading you operate yourself needs you to be awake, the reliable options are automated:
| Method | How it works | Where it fits |
|---|---|---|
| 24-hour ambulatory monitor (ABPM) | A cuff worn for a full day and night that inflates automatically every 15 to 30 minutes, including during sleep | The standard for diagnosing nocturnal hypertension and non-dipping. Ordered by a doctor, usually worn once |
| Dedicated nocturnal home monitor | A home device programmed to take several readings during sleep with minimal disturbance | An emerging option. Research suggests at least six readings over two nights agree reasonably well with ABPM |
| Standard home monitor, used manually | You wake and take the reading yourself | Only useful for an occasional pattern check, not for measuring true sleeping pressure |
| Smartwatch or ring | Cuffless estimate from sensors | Not accurate enough for diagnosis; useful mainly for flagging disrupted sleep or low overnight oxygen |
A 2019 review in the Journal of Hypertension on nocturnal blood pressure measured by home devices concluded that modern automated home monitors can capture nighttime blood pressure with results clinically similar to ambulatory monitoring, and that they detect non-dippers about as well, provided enough readings are taken across more than one night.
What a night reading does and doesn't tell you
Blood pressure normally falls 10 to 20 percent during sleep. On proper overnight monitoring, a nighttime average below 120/70 mmHg is considered normal, and 120/70 or higher is the threshold for nocturnal hypertension, per the 2023 European Society of Hypertension guidelines.
A single home number cannot be judged against that average. What it can do is flag a rough pattern: if your calmly taken night readings, and your first-thing-morning readings, consistently run as high as or higher than your daytime numbers, that is worth showing a doctor, because it may point to non-dipping or nocturnal hypertension that a proper monitor should confirm. Our explainer on blood pressure that reads higher at night than during the day covers that pattern.
When to ask your doctor for overnight monitoring
Raise the question of ambulatory monitoring if any of these apply:
- Your evening and morning readings run high with little or no drop between them.
- You have signs of sleep apnea: loud snoring, witnessed pauses, gasping awake, unrefreshing sleep, daytime sleepiness.
- You have diabetes, chronic kidney disease, or blood pressure that stays high on three or more medications.
- Your office and home readings disagree and you are not sure which to trust.
- You have had a cardiovascular event, or there is a family history of early stroke or heart failure.
For the bigger picture on why nighttime numbers matter, see our explainer on whether nocturnal hypertension is dangerous and the full guide to nocturnal hypertension.
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Read Our Independent ReviewFrequently asked questions
Should I check my blood pressure at night?
Occasionally, to understand a pattern, is reasonable. Getting up repeatedly through the night to check is not, because the act of waking raises blood pressure for a few minutes and the anxiety of watching the number keeps it up, while you lose sleep. If you are worried about your blood pressure during sleep, the better route is to ask your doctor about 24-hour monitoring.
How do I measure my blood pressure at night correctly?
Sit up on the edge of the bed, empty your bladder if needed, then rest quietly for five minutes. Take one or two readings a minute apart with your back supported, feet flat, and the cuff at heart level, and do not talk during the reading. Write down the number, the time, and what woke you. Do not re-check repeatedly.
Is a nighttime home blood pressure reading accurate?
A single reading you get up to take reflects being awake, not your pressure during sleep, so it is of limited value on its own. Dedicated nocturnal home monitors that inflate automatically during sleep are more useful: research shows that at least six readings across two nights give results that agree reasonably well with ambulatory monitoring.
What is a normal blood pressure at night?
Blood pressure normally falls 10 to 20 percent during sleep. On a 24-hour monitor, a nighttime average below 120/70 mmHg is considered normal, and 120/70 or higher counts as nocturnal hypertension, according to the 2023 European Society of Hypertension guidelines. A single home reading cannot be judged against that average.
Can a special monitor measure my blood pressure while I sleep?
Yes. A 24-hour ambulatory blood pressure monitor is the standard: a cuff worn for a full day and night that inflates automatically, including during sleep. There are also dedicated nocturnal home blood pressure monitors designed to take several readings overnight with minimal disturbance. Both are more reliable for sleep readings than a standard monitor you operate yourself.
How often should I check my blood pressure during the night?
If you are taking manual readings to spot a pattern, once on a given night is enough, repeated over a few nights. Checking several times in one night usually pushes the number up through anxiety and broken sleep, and it does not add useful information. Automated overnight monitoring, ordered by a doctor, is the way to get multiple valid readings.