The short answer: Blood pressure dips during sleep, then climbs as you wake, because stress hormones and the nervous system switch on to get you upright. Some rise is normal. A 2022 HOPE Asia consensus statement calls it morning hypertension when your average morning home reading is 135/85 mm Hg or higher.
What happens to blood pressure when you wake up?
Blood pressure follows a daily rhythm. It is lowest in deep sleep and rises in the first hours after waking. This rise is called the morning blood pressure surge.
A 2018 review in Integrated Blood Pressure Control describes what drives it. The sympathetic nervous system, which runs the body's "fight or flight" response, is the key player. At the moment of waking, the adrenal glands release more epinephrine (adrenaline). When you then stand up, the nerves release norepinephrine to keep blood flowing to your head.
Hormones add to the push. The same review lists the stress-hormone axis (ACTH and cortisol) and the renin-angiotensin system, which tightens blood vessels and holds on to salt. All of these follow a body-clock rhythm tied to the sleep and wake cycle.
So two things raise your pressure in the morning: the clock inside your brain, and the physical act of getting out of bed. That is why a reading at 7 a.m. is often higher than one at 9 p.m. If your readings swing for other reasons, our guide to why blood pressure varies between readings covers the general causes.
How much of a morning rise is normal?
There is no single agreed cutoff for a "normal" surge. Researchers usually measure it on a 24-hour ambulatory monitor. The standard method, from a 2003 Circulation study by Kario and colleagues, takes the average systolic pressure in the 2 hours after waking and subtracts the lowest pressure during sleep.
Studies then flag the top 10 percent of people as having an exaggerated surge:
- In that 2003 study of 519 older Japanese adults with hypertension, the top tenth had a surge of 55 mm Hg or more. Their stroke rate over about 41 months was 19 percent, against 7.3 percent in the others.
- In the IDACO study of 5,645 people from 8 populations, published in Hypertension in 2010, the top tenth had a sleep-through surge of 37 mm Hg or more. Over a median 11.4 years, their risk of death from any cause was 32 percent higher than average.
The two cutoffs differ because the groups differ in age, ethnicity, and baseline pressure. The takeaway is simple: a moderate morning rise is expected. A very steep one, in the top tenth, is linked to more strokes and deaths. You cannot measure the surge itself with a home cuff, because you would need readings while you sleep.
What is morning hypertension?
Morning hypertension is a home-reading idea, and you can check it yourself. The 2022 HOPE Asia consensus defines it as an average morning blood pressure of 135/85 mm Hg or higher, whatever your office readings show. It names two types:
- Morning surge type: pressure falls normally overnight, then jumps steeply after waking.
- Sustained nocturnal and morning type: pressure never falls much overnight, so it is already high when you wake.
If your office readings are normal (under 140/90 mm Hg) but your morning readings are high, the consensus calls this masked morning hypertension. The same group sets a morning target under 135/85 mm Hg for most people, and under 125/75 mm Hg for some high-risk patients.
US guidelines use slightly different numbers. Under the 2017 ACC/AHA guideline, a home average of 130/80 mm Hg matches stage 1 hypertension. A home average of 135/85 mm Hg matches an office reading of 140/90 mm Hg (stage 2), as a 2018 Hypertension analysis of two US cohorts explains. So a morning average of 130/80 or more is worth raising with your doctor in the US.
Why do heart attacks and strokes cluster in the morning?
The morning is the riskiest time of day for the heart. A 1985 New England Journal of Medicine study timed the onset of heart attacks in 2,999 patients. Onsets peaked between 6 a.m. and noon. In the 703 patients with lab-confirmed timing, heart attacks were about three times as frequent at 9 a.m. as at 11 p.m. The rhythm did not appear in people already taking beta-blockers, which blunt the adrenaline response.
The 2018 review notes the same morning peak for sudden death and stroke. One theory is that the surge puts sudden stress on fragile arteries. Researchers have not proven that link as cause and effect.
Home morning readings also predict risk. The J-HOP study, published in Hypertension in 2016, followed 4,310 Japanese adults with cardiovascular risk factors for about 4 years. Each person took home readings morning and evening for 14 days at the start. Morning systolic pressure predicted stroke better than office pressure did. Evening pressure added less. Neither predicted coronary artery disease, and the authors asked for confirmation in other ethnic groups.
What makes the morning rise worse?
The 2018 review lists factors linked to a larger morning surge. These include older age, high blood pressure, diabetes or prediabetes, alcohol, smoking, and psychological or physical stress. Several are worth a closer look:
- Medicine wearing off: if you take a short- or intermediate-acting pill in the morning, its effect may fade before the next dose. The review notes this can leave the hours before your morning dose poorly covered. Whether timing helps is a separate question, covered in whether to take blood pressure pills morning or night.
- Evening drinking: a 2020 Cochrane review found that a high dose of alcohol (more than 30 g, a little over two US standard drinks) lowers pressure at first. Thirteen or more hours later, systolic pressure was 3.7 mm Hg higher than with placebo.
- Sleep apnea: the HOPE Asia consensus lists sleep apnea among conditions likely to keep pressure high through the night. That feeds the sustained type of morning hypertension. Our sleep apnea and blood pressure guide covers testing and treatment.
- Cold: cold outdoor temperatures and winter are linked to a larger surge, because cold raises sympathetic activity.
Poor sleep in general is part of the same picture. If you lie awake at night, the resources at insomnia.md cover sleep problems in more depth.
How do you check your morning blood pressure at home?
This checklist combines the HOPE Asia morning protocol with the CDC home-measurement steps:
- Measure within 1 hour of getting out of bed.
- Empty your bladder first.
- Take the reading before your morning blood pressure pills.
- Take it before breakfast and coffee. The CDC advises no food or drink for 30 minutes before, and no smoking or exercise.
- Sit in a chair with your back supported for at least 5 minutes. Keep feet flat and legs uncrossed.
- Rest your arm on a table with the cuff on bare skin at chest height. Do not talk.
- Take two readings, 1 minute apart, and write both down.
- Repeat for more than 5 days, giving more than 10 morning readings, then average them.
- Take evening readings too, so your doctor can compare the two.
Use a validated upper-arm cuff. Bring the log, or the device, to your next visit.
The bottom line
Higher blood pressure in the morning is normal physiology: waking hormones and standing up push it up. What matters is how high it goes. An average morning home reading of 135/85 mm Hg or more meets the research definition of morning hypertension, and US guidelines flag home averages from 130/80. Measure the same way each morning for a week and share the average with your doctor.
Last updated: October 2026. This article is for informational purposes only and does not constitute medical advice. Talk to your doctor before changing when or how you take blood pressure medicine.