Sleep and blood pressure: what the research says

Short answer: yes, research links the two. People who sleep less are somewhat more likely to develop high blood pressure over the years.¹ But it's a link, not proof that short sleep causes it, and the effect in the numbers is modest. One sleep problem, sleep apnoea, is a different story: the European guideline treats it as one of the common underlying causes of high blood pressure.³

Here's what the research found, what it can't tell you, and what's worth writing down.

What a large review found

In 2024, researchers pulled together 16 long-term studies with just over a million people, followed for between 2.4 and 18 years.¹ They compared how long people said they slept with who went on to develop high blood pressure.

Against people who slept 7 to 8 hours a night:¹

1. Under 7 hours went with a 7% higher chance of developing high blood pressure.
2. Under 5 hours went with an 11% higher chance.
3. Between 5 and 7 hours went with a 5% higher chance, a borderline result.
4. Over 8 hours showed no clear link either way.

So the link was stronger under 5 hours, and sleeping long didn't show the same pattern.

What those numbers don't tell you

These are percentages on top of an existing chance, not a percentage of people. A 7% higher chance is a small shift, not a sure thing.

The studies were observational: they watched what happened to people, rather than changing anyone's sleep and measuring the result. The authors point out that the data come from non-randomised studies, and in every study people reported their own sleep in questionnaires. They also note that things the studies didn't measure may have affected the results.¹

That's why we won't tell you that sleeping more will change your blood pressure. The research doesn't show that. If you'd like your doctor to see your sleep alongside your readings, write it down next to them for a while and take the diary with you. They're the one to tell you what your readings mean.

Sleep apnoea: the one the guideline names

Here the European guideline is clear. It says sleep apnoea is common in people with high blood pressure, and particularly in those whose blood pressure is hard to bring down.² It treats it as one of the common underlying causes of high blood pressure that GPs should help look for.³

Two more points from the guideline are worth knowing. Doctors should suspect it when there are signs that point to it, but having no obvious signs doesn't rule it out.² And it's confirmed with a sleep study.²

If you're worried about your sleep, or someone you share a bedroom with is worried about it, talk to your doctor.

Is there a "right" number of hours?

Not from the guideline. The European guideline's chapter on lifestyle covers salt and potassium, physical activity, weight and diet, alcohol, coffee and soft drinks, and smoking.⁴ Sleep isn't one of its topics, so there's no guideline number of hours we can give you.

The 2024 review used 7 to 8 hours as its comparison point.¹ That's a research choice, not a recommendation, so read it that way.

Writing your sleep down

There's one place where the guideline asks for sleep to be recorded. When a doctor arranges 24-hour blood pressure monitoring, it says a diary should record activities, like meals and exercise, and sleep time, to help make sense of the readings.⁵

For readings you take yourself at home, a sleep note is simply useful context. Next to each morning reading, you could jot down:

• roughly what time you went to bed and got up
• about how long you slept
• anything unusual, like a broken night or taking ages to drop off

Time in bed isn't the same as sleep: falling asleep and waking in the night take time too. So it's worth writing the two down separately. A few days on paper might look like this:

Day	Bed	Up	In bed	About how long asleep	Note
Mon	23:15	6:45	7 h 30 min	7 h	dropped off quickly
Tue	00:40	6:45	6 h 5 min	5½ h	late film, slow to drop off
Wed	22:50	6:30	7 h 40 min	6½ h	woke at 3, awake for an hour

Rough times are fine. You don't need your sleep to the minute: "about six hours" is better than a blank.

In BePal you can keep all of this on your phone: when you went to bed and got up, with your morning readings next to it, all on one timeline you can show your doctor. If a smartwatch or another app tracks your sleep and saves it to Apple Health, BePal brings it in automatically, so you don't have to type it.

Take your readings the same careful way each time (here's the step-by-step), so your notes sit next to readings you can trust. Your doctor is the one to tell you what your readings mean.

In short

• Large studies link short sleep, especially under 5 hours, to a somewhat higher chance of developing high blood pressure.¹
• It's a link from observational research, not proof that short sleep causes it.¹
• The European guideline names sleep apnoea as common in people with high blood pressure.² If you're worried about your sleep, talk to your doctor.
• The guideline doesn't set a number of hours for blood pressure.⁴
• Writing your sleep down next to your readings can give your doctor useful context.