Blood Pressure

Flying with high blood pressure: what to know before you travel, and the insurance question

If your blood pressure is well controlled, UK guidance says flying is fine. Here’s what a cabin actually changes, which part of the flight moves a reading most, and what you have to tell an insurer.

NK Medically reviewed by Dr Nouman Kazmi, MBBS FCPS ·9 min read

Key Takeaways

The headline question has a short answer, and Blood Pressure UK doesn’t hedge it. High blood pressure shouldn’t stop you travelling or going on holiday, and most modes of transport, flying included, are fine if your blood pressure is well controlled. It doesn’t stop there, though: it still asks you to speak to your doctor before you go and have a reading taken.
A cabin isn’t held at sea level. Commercial aircraft fly at 30,000 to 40,000 feet, and the cabin sits at the equivalent of 5,000 to 8,000 feet, where barometric pressure has fallen from 760 mmHg to about 560. That’s the one thing a flight genuinely does to you for several hours: slightly less oxygen in every breath.
The size of the effect is modest. A 2021 review in the Anatolian Journal of Cardiology reports a non-significant increase in blood pressure in healthy people, with wide variation between individuals, and only a modest increase in people whose blood pressure is controlled. The potential for a big rise, it says, sits with uncontrolled blood pressure rather than with flying itself.
Of the two in-flight studies the review reports, the one that recorded readings stage by stage found the highest systolic and diastolic of the whole flight at takeoff, and the lowest at cruise altitude. That was twelve men, none with known heart disease, so it’s describing a mechanism rather than a population.
Blood Pressure UK offers a working number for when to ask before booking: if your blood pressure is unstable or very high, for example over 180/100 mmHg, talk to your doctor before you make travel plans. The review says flatly that no agreed cut-off for “uncontrolled hypertension” exists, which is why this one belongs to the person who knows your readings.
The British Heart Foundation puts the insurance consequence in a single sentence: if you leave out important information, it could result in a claim being refused. Conditions you live with, conditions or events from the past few years, your medicines, any device fitted, any treatment. All of it gets declared.

In This Article

What a cabin actually changes
The highest reading comes at takeoff
Is it safe to fly, and who asks first
What’s worth doing on the day
The declaration question
Common questions
The bottom line

Flying with well-controlled high blood pressure is fine. That’s the short answer and it holds up. The longer answer is more specific about what a cabin does to you, and it points at a different part of the trip than the altitude would suggest.

What a cabin actually changes

A 2021 review of hypertension and air travel in the Anatolian Journal of Cardiology, written by the cardiologist Kaan Okyay, names the main physiological factor during a flight: the altitude-related fall in oxygen saturation.

The numbers are worth having, because they’re smaller than the view out of the window implies. Commercial aircraft fly at 30,000 to 40,000 feet. The cabin, though, is kept at a relative altitude of between 5,000 and 8,000 feet on a routine flight. At that height barometric pressure has fallen from its sea-level value of 760 mmHg to around 560, and the review puts the fall in inspired oxygen at 4 mmHg for every 1,000 feet. That’s a measure of the air, not of you: it isn’t the number on your cuff.

So a flight hands you slightly thinner air to breathe for a few hours. The review describes that as well tolerated in healthy people, and notes it’s a different matter for passengers with lung conditions such as COPD or pulmonary hypertension, some of whom may need supplemental oxygen, and for people with severe ventricular dysfunction or congenital heart disease, who can be more sensitive to the change.

What follows from less oxygen is a chain rather than a single event. Heart rate, cardiac contractility and cardiac output all rise, and that can shift your blood pressure. Hypoxia widens the blood vessels at the periphery while also switching on the sympathetic nervous system, so two opposing things happen at once. Then the review adds the part that speaks directly to anyone reading this page: in people with hypertension, endothelial dysfunction may blunt that widening, and can even tip the peripheral vessels the other way, into constriction.

Which sounds like it should add up to something you’d feel. It doesn’t, mostly. In healthy individuals those mechanisms produce what the review calls a non-significant increase in blood pressure, with high variability from one person to the next. In people whose blood pressure is controlled, only a modest increase was observed. The potential for a significant rise, it says, sits with uncontrolled blood pressure rather than with flying itself.

The review is also plain about what it’s built on. Most of the data on cardiac responses during flight, it says, comes from retrospective studies or small observational trials. So the numbers here describe a mechanism, not a rule about your own flight.

12 men

were monitored stage by stage through commercial flights in one of the two in-flight studies the review reports, and their highest systolic and diastolic readings came at takeoff, not at altitude. The lowest came at cruise. Oxygen saturation did fall, reaching its lowest point two hours into the cruise, and heart rates didn’t change much across the flight. A separate study of 22 physically active men, free of any pathological condition and taking no medication, recorded a 6% rise in blood pressure and a 24% rise in heart rate across a flight. Both of those were small studies of healthy men, so this is a mechanism worth knowing rather than a figure you’d expect to see on your own cuff.

The highest reading comes at takeoff

That pattern is the useful part of the review, because it puts the pressure peak in the stretch of the flight where the air is thickest.

The review’s own explanation doesn’t rest on oxygen at all. Alongside the altitude effect it lists the stressful factors that come with flying: increased anxiety, particularly during takeoff and landing, changes in body position driven by acceleration and deceleration, and aircraft noise, which has been shown to affect the mood state of cabin crew. It treats all three as confounders for blood pressure changes, in passengers and crew alike.

Read next to the takeoff finding, that’s fairly ordinary. The moment most likely to move your number comes with the boarding queue, the acceleration and the noise, well before the quiet stretch at cruise altitude.

It also means a flight isn’t a fair day to judge yourself by, in the same way as the half hour after a big meal. A single reading taken in an unusual hour describes the hour, and that’s all. What describes you is a run of readings taken in ordinary conditions, so a travel day is better treated as a gap in the record than as a result.

Is it safe to fly, and who asks first

Blood Pressure UK answers the general version in a line. High blood pressure shouldn’t stop you travelling or going on holiday, and most modes of transport, including flying, are fine if your blood pressure is well controlled. It adds two things worth doing anyway: speak to your doctor before you go and have your blood pressure checked, and consider taking a home monitor with you.

For the specific version, it offers a number. If your blood pressure is unstable or very high, for example over 180/100 mmHg, talk to your doctor before you make any travel plans, because they’ll want it under control first. If you’re going to be away for more than a few weeks and you take blood pressure medicines, it asks you to speak to your doctor about that too, so you leave with enough.

The review declines to give a number at all, and says why: there is no cut-off blood pressure value for “uncontrolled hypertension”. Uncontrolled hypertension does appear on the generally accepted list of reasons not to fly, but nobody has fixed where the category starts. So one source gives you a number to act on and the other says the line can’t be drawn in general. They end up in the same place: the question belongs to whoever has seen your readings.

For context on what the words mean here, the NHS puts high blood pressure at 140/90 or higher when checked by a healthcare professional, and 135/85 or higher when checked at home. Those are resting readings taken under ordinary conditions, so they’re not the standard a departure-lounge reading has met.

If your blood pressure is well controlled, you don’t necessarily need a check just before you travel. That’s Dr Sarah Jarvis, Clinical Director of the Patient Platform, in comments carried on the travel insurance comparison site Medical Travel Compared. If your most recent readings have been raised, or you haven’t had a check for more than six months, see your GP or practice nurse for a reading before you go. That’s a trigger you can check tonight, against your own last six months.

There’s an insurance reason for the same appointment. AllClear, which sells travel insurance for pre-existing conditions, points out that you need to be considered fit to travel for a policy to be valid, and that a doctor who thinks flying is unwise now may be able to suggest a better time or a small change of plan instead.

Two questions a page can’t answer for you

Medication timing across time zones is the first. The review’s instruction is to settle it with your own doctor before a flight that will shift your body clock. No source we have puts a rule in writing, because the answer depends on which drug you take and how far the clock moves. Your GP or pharmacist will settle it in one conversation. The second is whether to travel at all when recent readings have been unstable, which is the one Blood Pressure UK routes to your doctor before you book.

What’s worth doing on the day

The review ends with a table of general recommendations for air travellers with hypertension. It’s gathered from the aviation-medicine literature rather than from any one clinic, and most of it is unglamorous.

Ideally, have your blood pressure under control before you travel. Carry enough medication for the length of the trip in your hand luggage. Skip the alcohol and the caffeinated drinks, both of which carry a dehydration risk at altitude, and drink enough water instead. Approach the airline meal with mild suspicion, because airline food is often high in sodium, and the review notes that the extra sodium load could be a problem for travellers sensitive to fluid shifts. Avoid anything constrictive around your waist and legs. Bend and stretch your legs now and then to keep the blood moving, get up and walk around every two hours, and tell the cabin crew if you develop any serious cardiac symptoms.

Able2Travel, a travel insurer, adds one practical booking-stage step that the clinical list doesn’t: you can request a low-sodium meal when you book the flight, rather than negotiating with the trolley on the day.

Worth doing before you pack

The British Heart Foundation asks for extra medicine and a copy of your recent prescription in both your hand luggage and your checked bag, in case a bag goes missing, plus copies of any important medical documents. The Welbeck heart clinic adds a smaller version of the same insurance: photograph your medicine, or write the names down, so a pharmacy abroad has something to work from. Staysure notes that liquid medication over 100ml needs checking with your airline first, since you may need a letter from your doctor or pharmacist.

On clots, the pages here don’t say the same thing. Staysure says that if you have high blood pressure your risk of deep vein thrombosis on a long flight might be slightly higher. AllClear lists a blood clot among the complications of high blood pressure you wouldn’t be covered for if you hadn’t declared the condition. Both of them sell travel insurance. The Welbeck heart clinic, which doesn’t, makes the ordinary point about immobility and dehydration on long-haul flights without attaching it to blood pressure at all. And the clinical review makes no clot claim in either direction: it gives the movement and clothing advice above for circulation generally, and stops there. The British Heart Foundation has its own page covering whether you can fly, deep vein thrombosis and travelling with medicine, and on the clot question that’s the one to read.

The declaration question

Of the nine results on the first page when we searched this in October, five were travel insurers or brokers, so most of the advice to declare your condition arrives from people who sell policies. That doesn’t make it wrong, and the test is easy enough to run: the two UK sources here with nothing to sell say exactly the same thing.

Blood Pressure UK asks you to tell your travel insurance company that you have high blood pressure, to make sure you’re covered. The British Heart Foundation sets out what “tell them” actually covers, and it’s broader than the condition itself: any health condition you currently live with, any condition or event from the past few years such as a heart attack or stroke, any medicines you take, any device fitted such as a pacemaker, ICD or loop recorder, and any other treatment such as heart surgery or a stent. The number of past years varies by insurer.

Then the BHF puts the consequence in one sentence, and it’s the sentence worth remembering: if you leave out important information, it could result in a claim being refused.

Three details on that page are easy to miss and cost real money.

The first is that your GP can help you fill the form in. The BHF suggests talking to them before you buy a policy, since they can help you answer the medical questions, and if you need a practice appointment anyway, it’s the same appointment.

The second is about the person next to you. If you’re travelling with a partner, family member or friend who has a heart or circulatory condition, you may have to declare their condition on your policy, because you might need to cancel the trip over their health. If it wasn’t declared when you bought the cover, the BHF says, your insurer may not pay the cancellation claim.

The third is that the free card isn’t the cover. The Global Health Insurance Card has replaced the EHIC, it’s free from the NHS website, and it does include medically necessary treatment for a pre-existing or chronic condition in the EU. An EHIC still works until it expires. But the BHF repeats the government’s line that anyone travelling abroad should hold travel insurance as well, for accidents and illness. If you want help finding a policy rather than a quote, it points at the MoneyHelper and British Insurance Brokers’ Association directories.

Medical Travel Compared, which compares policies for a living, offers a view from the other side of the counter. Non-declaration of a pre-existing condition is one of the most common reasons travel insurance claims get rejected, and the Financial Ombudsman Service hears from holidaymakers about rejected claims every week. And a 2014 survey it cites, which we haven’t seen first hand, found one in twenty holidaymakers over 50 had failed to declare a medical condition to keep the cost down. On that cost, its own position is that your premium won’t necessarily move very much, since the price also turns on your age, how many medicines you take and the rest of your history.

People don’t usually leave it off on purpose. Dr Harikrishna Patel, quoted on AllClear’s own page, describes high blood pressure as something people get used to living with and don’t give a second thought to, and then names the mismatch:

Travelling invariably means a disruption to routine and possibly a change in time zone, so tablets may be delayed or missed altogether. Heat, physical exertion, change in diet or a tummy upset can all have an impact. So what might be a stable medical condition at home could potentially be a problem abroad that results in a medical emergency claim.

That’s the case for a two-minute declaration, and it has nothing to do with how your readings have looked this month.

Matter BP Tracker

“Has it been stable?” is a question about a record

Blood Pressure UK suggests a reading before you go and a monitor in the bag. The Matter BP Tracker keeps each reading with the date and the note you write beside it, so “first morning, 32 degrees, slept badly” is still attached to that number when you get home. It’s also the quickest way to see how long it’s been, which is what tells you whether that GP conversation is due.

Open the BP Tracker → Readings and notes·Charted over weeks

Common questions

Can you fly with high blood pressure?

Yes, if it’s well controlled. Blood Pressure UK says high blood pressure shouldn’t stop you travelling or going on holiday, and that most modes of transport, flying included, are fine when your blood pressure is well controlled. The 2021 Anatolian Journal of Cardiology review reaches the same conclusion from the clinical side: high-altitude exposure is well tolerated by people with hypertension, apart from those whose blood pressure isn’t controlled or who have another serious cardiovascular problem alongside it. Both still ask you to speak to your own doctor first, and Blood Pressure UK suggests having a reading taken before you go.

Does flying raise your blood pressure?

A little, and less than the altitude suggests. A cabin is held at the equivalent of 5,000 to 8,000 feet, where barometric pressure has fallen from 760 mmHg to around 560, so every breath carries slightly less oxygen. That sets off a chain: heart rate, cardiac contractility and cardiac output all rise, and hypoxia widens the peripheral vessels while also switching on the sympathetic nervous system. In healthy people the review reports the net result as a non-significant increase in blood pressure, with wide variation between individuals, and only a modest increase in people whose blood pressure is controlled. One in-flight study of 12 men found the highest readings at takeoff and the lowest at cruise altitude.

Is there a blood pressure reading that’s too high to fly?

Not one you can act on alone, and the two sources here don’t agree on whether one exists. Blood Pressure UK offers a working threshold for when to ask: if your blood pressure is unstable or very high, for example over 180/100 mmHg, talk to your doctor before you make any travel plans, because they’ll want it under control first. The 2021 review takes the other view, stating plainly that there is no cut-off blood pressure value for “uncontrolled hypertension”, even though uncontrolled hypertension appears on the generally accepted list of contraindications to air travel. The practical reading of that is to take recent readings to your GP and let them decide.

Do I have to declare high blood pressure on travel insurance?

Yes, and more than the diagnosis. The British Heart Foundation says insurers will ask about any health condition you currently live with, any condition or event from the past few years such as a heart attack or stroke, any medicines you take, any device fitted such as a pacemaker, ICD or loop recorder, and any other treatment such as heart surgery or a stent. Its warning is one sentence long: if you leave out important information, it could result in a claim being refused. Blood Pressure UK gives the same instruction. Your GP can help you answer the medical questions if the form is unclear.

Will declaring it make my travel insurance much more expensive?

Not necessarily. Medical Travel Compared, which compares policies for a living, says your premium won’t necessarily change very much, because the price also depends on your age, how many medicines you’re taking and the rest of your health history. It’s worth comparing a few. The BHF suggests the MoneyHelper and British Insurance Brokers’ Association directories if you want help finding a policy rather than a quote, and notes that brokers must tell you their commission if you ask.

Can I take my tablets and a blood pressure monitor in my hand luggage?

Yes, and the clinical advice is to carry enough medication for the whole trip in your hand luggage rather than the hold. The British Heart Foundation goes further and asks for extra medicine plus a copy of your recent prescription in both bags, in case one goes missing. Blood Pressure UK suggests taking a home blood pressure monitor away with you. One thing to check before you fly: Staysure notes that liquid medication over 100ml needs clearing with your airline, and you may need a letter from your doctor or pharmacist.

I’m flying across time zones. When should I take my blood pressure tablets?

That one belongs to your GP or pharmacist, and it’s a quick conversation. None of the sources here puts a rule in writing, because the answer depends on which medicine you take and how far the clock moves. The 2021 review says the same thing: settle medication timing with your own doctor before a flight that will shift your body clock. Staysure makes the same point from the traveller’s side: a GP can help you adjust the schedule safely if you take your medication at a set time of day. Worth asking at the same appointment as the pre-travel reading.

The bottom line

If your blood pressure is well controlled, Blood Pressure UK says flying is fine, and the clinical review agrees that high-altitude exposure is well tolerated by people with hypertension apart from those whose blood pressure isn’t controlled or who have another serious cardiovascular problem alongside it. That’s the answer, and it hasn’t changed.

What’s more specific is where the flight actually bites. The cabin sits at 5,000 to 8,000 feet and hands you thinner air, but of the review’s two in-flight studies, the one that recorded readings stage by stage found the peak at takeoff and the trough at cruise. So the hour that moves a number is the busy one, not the high one, and the review puts anxiety, acceleration and noise in the same list as the oxygen.

None of which you need to manage on the day. Carry the tablets in your hand luggage, keep the water coming, stand up every couple of hours, and let the holiday be a gap in the record rather than a result. Two jobs are worth doing before you go. One is a GP conversation, if your recent readings have been raised or you haven’t had a check in six months. The other is a full declaration to the insurer. That one takes two minutes and it’s the one that gets claims paid.

Continue Learning

References

Okyay K. Systemic arterial hypertension and flight. Anatol J Cardiol. 2021 Aug 1;25(Suppl 1):S7–S9. doi:10.5152/AnatolJCardiol.2021.S104. Available at: pmc.ncbi.nlm.nih.gov
Blood Pressure UK. Practical matters: work, travel, going out and your sex life. Available at: bloodpressureuk.org
British Heart Foundation. Travel insurance with a heart or circulatory condition. Page updated 1 March 2025. Available at: bhf.org.uk
NHS. High blood pressure (hypertension). Available at: nhs.uk
Medical Travel Compared. Travelling with high blood pressure. Published 10 March 2026, carrying comments from Dr Sarah Jarvis, Dr Albert Alahmar and Julie Ward. Medical Travel Compared is a travel insurance comparison site. Available at: medicaltravelcompared.co.uk
AllClear. Flying with high blood pressure. Last updated 26 January 2026, quoting Dr Harikrishna Patel. AllClear sells travel insurance. Available at: allcleartravel.co.uk
Staysure. Can you fly with high blood pressure? Tips for travelling safely. Posted 23 December 2024. Staysure sells travel insurance. Available at: staysure.co.uk
Welbeck Heart Health. High blood pressure and flying. Available at: welbeck.com
Able2Travel. 5 tips for flying with high blood pressure. Posted 25 April 2025. Able2Travel sells travel insurance. Available at: able2travel.com

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