Does the time of day affect blood pressure?

Last reviewed:
30 Jan 2023,

Medically reviewed by:

Does the time of day affect blood pressure?

As people grow older, it’s normal for their blood pressure to increase. According to the study ‘Does Blood Pressure Inevitably Rise With Age?’, published originally in the journal Hypertension in May 2012, in Westerners over the age of 40 years old, blood pressure increases by around 7 mm/Hg per decade. Systolic blood pressure is also noted to increase, and by the eighth decade, is around 140 mm/Hg.

Caring for an older person or a child places a lot of responsibility on your shoulders, and it’s important to be aware of when they might be at risk of developing high blood pressure. One thing you might not understand is the natural fluctuation of blood pressure during the day. These fluctuations may trick you into believing your loved one is suffering from high blood pressure or cause you to fail to recognise they’re at risk of high blood pressure.

Below is a look at the nature of blood pressure fluctuation, how blood pressure fluctuations can be misleading, some of the questions around blood pressure medication, and how to care for someone in terms of their blood pressure and taking blood pressure readings.

The nature of blood pressure fluctuation

Over the course of a 24 hour day, several of the body’s functions vary. Blood pressure circadian rhythm is one of them.

Normally, blood pressure will rise a few hours before we wake and will then continue to rise until around midday, which is when it’s at its highest. Blood pressure tends to fall during the late afternoon and the evening. At night it tends to be lower. This is the typical pattern.

Examples of an irregular blood pressure pattern include:

  • high blood pressure during the night;
  • high blood pressure early in the morning;
  • a drop in blood pressure of less than 10% overnight (non-dipping blood pressure).

Irregular blood pressure patterns could mean the person you’re caring for has:

  • badly controlled high blood pressure;
  • obstructive sleep apnoea;
  • kidney disease;
  • diabetes;
  • thyroid disease;
  • a nervous system disorder.

Misleading fluctuations in blood pressure

It’s likely you already know the common factors that affect blood pressure, such as age, obesity, lack of exercise, poor diet and genetic history; however, there are other factors you may not be aware of, such as the circadian rhythms, which we’ve already touched upon and which create natural fluctuations in blood pressure. Here are some more:

Labile hypertension

Labile hypertension refers to blood pressure that fluctuates far more than normal. Blood pressure rises and falls various times during the day. It can even do so within minutes, but if their blood pressure changes excessively within minutes, this could be a sign your loved one is suffering from labile hypertension. Physical activity, emotion, body position, diet and sleep deprivation are all potential factors.

Whitecoat hypertension

Do you have to take your loved one to the doctor’s surgery or other medical facility? If they show high blood pressure readings in the doctor’s office but regular readings in nonmedical settings, they could be suffering from ‘whitecoat hypertension’. Some people find medical visits stressful, and the stress triggers a temporary increase in blood pressure. Research suggests untreated whitecoat hypertension carries an increased risk of heart problems.

Masked hypertension

Some people experience normal blood pressure readings at the doctor’s office but high ones at home, a phenomenon called masked hypertension and is estimated to occur in 10 to 30% of people. No one really knows how common this is because when a patient gives a normal blood pressure reading in the surgery, the doctor doesn’t tell them to monitor their blood pressure at home.

Understanding about medicines for blood pressure

If you’re caring for someone who is taking medication for their blood pressure, it’s important to know what this medication is and how it works. Be sure to keep a diary of the brand names and generic names, and the dosages.

Your loved one should take the medicines as scheduled, at the same time every day. If either you or they think they need a change in medication, speak to a doctor first. Avoid abruptly taking them off their medication if you think they need to come off it. Again, visit or discuss with the doctor before taking action.

Keep a medication calendar, and record every time your loved one takes a dose of their medication. Although prescriptions inform patients how much to take in each dose, doctors change doses regularly, depending on the patient’s response to the drug. You can make a record of any changes on the calendar.

If you’d like to find out more about blood pressure and topics related to blood pressure, sign up for the Aktiia newsletter.

The best time to take blood pressure medication

Originally, it was thought the evening was the best time to take blood pressure medication; recent research, however, has revealed this isn’t the case. In addition, the research showed there was no meaningful difference in hospitalisation for heart attacks, strokes or vascular death between the people who took their medication in the morning and those who took it in the evening.

Changing the time of the dose

Although it’s becoming acknowledged that a patient can take their medication at the time that suits them, and that there are findings indicating the time of day doesn’t affect the impact of the dose, a patient should take their medication at the same time each day. If they’re taking it at night-time, there’s no reason to change suddenly or vary the times. It is important to maintain the routine as prescribed so the physician and you can have an accurate idea of the effects of taking the medication at a certain time of day. If you decide they should change the time of their dose, speak to their doctor first for advice.

Losartan and lisinopril

If you are taking a medication such as losartan or lisinopril, and wonder what is the best time to take the medication, studies have shown little difference in taking the medication at a specific time of day. It’s much more important to take the medication regularly at the same time of the day. If your loved one takes it in the morning, then make sure they take it in the morning every day. If, after consultation with your physician, the plan is to change the time to take it in the evening, then ensure they start taking it in the evening, at the same time, every day.

Often people are taking medications for cholesterol and blood pressure at the same time. These classes of medications generally do not have significant interactions, but always seek guidance from their physician.

Supporting someone who may have high blood pressure

When you’re supporting someone who has issues, or potential issues, with their blood pressure, you should remember to take care of yourself as well. As they say, you can’t pour from an empty cup, and merely supporting someone who may have blood pressure issues can make all the difference. When caring for someone else, there are certain things you should do regarding:

Watch for highs and lows

Sometimes blood pressure medication can lower blood pressure too much. If your loved one experiences dizziness, fainting, nausea or complains of blurred vision, take them to the doctor. If the systolic number rises to 180 or more, or if the diastolic number rises to 110 or more, seek immediate medical assistance.

Monitor their blood pressure regularly

Monitoring their blood pressure is important to determine whether they’re at any risk and whether any changes in their routine, medical or otherwise, are having any effect. Using Aktiia’s optical blood pressure measuring technology, which we discuss further below, will help you to take consistent readings of their blood pressure and gain a comprehensive, reliable overall picture of their blood pressure. Buy the Aktiia blood pressure monitor on our product page

Take the trips to the doctor recommended

If your loved one has already been diagnosed with high blood pressure, their doctor may want to see them routinely. They’ll want to check that lifestyle changes and medication are having the desired effect, so don’t let your loved one miss appointments. If you’re already managing their blood pressure well and monitoring it regularly, the doctor may wish to see them less frequently.

Taking regular, reliable blood pressure readings for your loved one with Aktiia’s optical blood pressure monitoring technology

One of the big questions when it comes to taking blood pressure readings is: when is the best time to take a reading?

Although there are certain times when blood pressure is much higher, such as when a person exercises, or much lower, such as early in the morning, the best approach to taking readings is to take several readings per day and do so at the same time each day.

You can find out more about the best time to take blood pressure in our post on the topic in the Aktiia knowledge base, but to gain a consistent, reliable picture of your loved one’s pressure, we’ve developed special blood pressure monitoring technology which operates differently to conventional blood pressure measuring devices. The device uses an optical sensor to measure the pulsation of the arteries beneath the skin, analyses the ‘shape’ of the pulsation and extracts the information the pulsation contains to provide readings throughout the day and night.

The automated, continuous operation allows you to achieve around 20 to 30 measurements per day, providing you with a comprehensive overall picture of your loved one’s blood pressure and its range. You can then take any necessary steps to help them lower their blood pressure, which you can do following advice from a doctor. Visit a dietitian as well for recommendations regarding the person’s diet. Lowering the amount of salt is one measure you could take, as is supplying them calcium, magnesium and potassium, which you can find in dairy products such as low-fat dairy products and yoghurt.

If you’d like to find out more about our blood pressure monitoring technology, feel free to get in touch. We’ll be happy to advise you on how you can use the technology to help you and your loved one manage their blood pressure safely and reliably.

Disclaimer: This article provides educational information only. To assess your blood pressure accurately, it’s important to measure it in the target range throughout the day. This article does not replace medical advice, and if you have concerns about your blood pressure, please consult a healthcare professional.


Does Does Blood Pressure Inevitably Rise With Age, May 2012 –

Neuroanatomy, Nucleus Suprachiasmatic, July 2022 –

Blood pressure: does it have a daily pattern? June 2022 –

Could white-coat hypertension harm your heart? Nov 2019 –

What is labile hypertension? Feb 2021 –

What is masked hypertension, Jan 2016 –

What time should you check your blood pressure? January 2022 –

High Blood Pressure Medication Guidelines, August 2022 –

How and when to take losartan, February 2022 –

Common questions about losartan, February 2022 –

How and when to take lisinopril, February 2022 –

About lisinopril, December 2021 –

Evening dosing of blood pressure medication not better than morning dosing, August 2022 –

Taking Blood Pressure Medication at Night May Protect Your Heart, November 2019 –

Hypertension: What You Need to Know as You Age, June 2020 –

Hypertension Care: How do I Care for a Loved One with Hypertension? January 2021 –

Your Guide to Lowering Blood Pressure, May 2003 –

Masked hypertension, Dec 2017 –

High Blood Pressure: The Role of the Family, August 2020 –

Medically Reviewed

dr jay shah photo

Renowned cardiologist, physician leader, and angel investor.

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