Tommy Lloyd
Author: Tommy Lloyd, Managing Director

Tommy has over 15 years experience within the insurance industry, and his primary focus is helping travellers find the right cover for their medical conditions.

6 min read

5 conditions which may affect whether you can fly or not

Setting off on holiday often involves boarding a plane – and if you’ve had a recent bout of ill health, that chance to jet off and revive and relax in the sunshine can be just what the doctor ordered.

There are certain circumstances, however, where it might not be medically advisable to fly. This doesn’t necessarily mean you will never be able to travel by aeroplane again; simply that doctors might advise you delay flying until you have better recovered.
These things often vary according to individual cases, and it’s crucial you discuss your health and any concerns about travelling with your GP before planning your trip.

But here are 5 conditions that might affect whether or not you can fly.


1. Heart conditions

People with heart conditions may be advised to wait until their health is stable enough before flying. “Aeroplane cabins are not the same pressure as the air at sea level. Broadly speaking, this translates to less oxygen inside the alveoli of your lungs - meaning less oxygen getting transferred into your blood,” explains GP Dr Martin Saweirs, an adviser to the Dr Morton’s medical helpline (

“A healthy person usually has oxygen saturation in their blood of around 95-99% when breathing room air. On a long flight, this can drop to around 90%, but a healthy person can cope with this. However, when one has a heart condition, usually the body has a higher oxygen demand and can sometimes not tolerate this drop in oxygen levels well.”

Whether you’re advised not to fly will largely depend on individual circumstances. However, as a guide, Dr Saweirs says: “Restrictions on flying can be: Not at all permitted - for things like unstable angina and unstable heart failure; permitted after four to six weeks - for a complicated heart attack; or seven to 10 days for an uncomplicated heart attack.”

2. Recent head injury

Head injuries aren’t usually a reason not to fly. However, if you’ve only very recently suffered a head injury, and if you’re still recovering from a major head trauma, it’s certainly advisable to discuss it with your doctor before travelling.

“People flying after concussion have sometimes reported headaches or worsening of symptoms, but these usually settle,” says Dr Saweirs. “If a head injury’s been severe enough to cause bleeding on the brain, it’s advisable not to fly unless this has stabilised. If this required an operation (which usually involves drilling a small hole in the skull to remove the blood) this precludes flying for at least seven days. This is again due to gas being allowed to enter the skull, and allows time for it to be reabsorbed, instead of potentially expanding on a flight.”

Calm Ocean

3. Deep vein thrombosis

Deep Vein Thrombosis (DVT) can potentially affect anybody, but certain risk factors – including being over 40, certain contraceptive pills, family history, pregnancy, smoking and obesity - are known to increase the likelihood of developing the condition.

If you have a history of DVT, your doctor may advise you delay flying again, or offer guidance on avoiding another clot. “Due to immobility, the risk of a DVT doubles after a long-haul flight, and this risk significantly increases if you have a history of previous blood clots,” says Dr Sara Kayat, a fellow GP and Dr Morton's helpline adviser. “Specialist advice needs to be sought before someone with a history of clots can fly again, and they may be required to take blood thinning medication to prevent further clots as a result of the flight.”

4. Recent surgery

“It can depend on the type of surgery as to when it’s safe to travel again, but most have an advised timeframe, which can be found on the airline websites, or by speaking to your doctor,” says Dr Kayat.

Dr Saweirs adds: “Recent surgery is often an issue when flying, due to gas expansion. In any surgery, some part of the body is generally opened to be operated upon. This allows gas to be introduced into the body's cavities. In the reduced pressure of an aircraft cabin at cruising altitude, this gas can then expand if it’s not had time to adequately be reabsorbed into body, which can lead to serious medical problems.”

5. Breathing problems

Common conditions that affect breathing, such as asthma, providing they are stable and well-managed, should be fine to fly with.

However, there are a number of potentially severe and chronic breathing conditions, including chronic bronchitis and emphysema, where it’s advisable to discuss any plans to fly with your doctor. As Dr Saweirs points out, as with heart conditions, drops in air pressure in the cabin can potentially cause issues. “People with lung problems often do not cope as well with the drop in oxygen levels,” he says, so some people “may need further assessment, depending upon your level of breathlessness on a day-to-day basis, and oxygen can be provided on aeroplanes if arranged in advance. The one absolute lung issue that is it not permitted to fly with is something called a pneumothorax - air in your chest that is outside your lung cavity. This can lead to air expanding and putting life-threatening pressure on your lungs within your chest.”

With the right travel insurance for medical conditions and correct advice from a doctor, risks can be lowered significantly.

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