Can I Fly with a Blood Clot?

If your blood didn’t clot, you would risk bleeding to death every time you had a minor cut. But if a clot forms where it’s not supposed to, it can be life-threatening.

You should usually be able to travel – including flying – within a few weeks of having a blood clot, as long as you’re on the correct treatment. However, you should always get the all-clear from your medical team before you book that ticket.

Where’s the Clot?

Clots can develop in one of your arteries, which carries blood at high pressure away from your heart to supply. For instance, if you develop a clot in one of the arteries that supplies blood to your heart muscle, the result is a heart attack. If that clot happens in one of the arteries that keeps your brain supplied with vital blood and oxygen, you have a stroke.

But when my patients talk about having ‘had a blood clot’, they’re usually talking about a clot in a vein, which carries blood back to the heart.

A clot in one of the veins deep inside your body – usually in your calf - is called a deep vein thrombosis or DVT (thrombosis is the medical term for a blood clot). Sometimes it causes symptoms such as pain, redness, changes to the skin over the clot and swelling. However, even if doesn’t lead to any symptoms, it’s still dangerous – and that’s because of the risk of part of the clot ending up elsewhere in your circulation.

When this clot has formed, part of it can break off and travel back through the right side of your heart to your lung, where it can get lodged. This kind of clot is called a pulmonary embolus or PE. This can lead to:

• Shortness of breath which comes on suddenly.
• Short, stabbing chest pain which is worse when you breathe.
• Cough and sometimes coughing up blood.
• Feeling sweaty, faint or lightheaded.
• Rapid heart rate.
• In severe cases, collapse or even death.

Why Does Travel Increase My Risk of a Blood Clot?

Blood clots happen when blood flow is stopped. The blood in your veins is at a much lower pressure than the blood in your arteries. That means the walls of your veins are more liable to being squashed as a result of pressure – and when the walls are squashed together, it can slow or completely.

There are two main reasons you’re at higher risk of a DVT or PE if you’re travelling:

• You’re more likely to be sitting still for long periods, without moving. This is especially true in aeroplanes, buses or cars – or on a train if you don’t walk up and down the carriage. Sitting can put pressure on the veins.
• In aeroplanes, oxygen pressure in the cabin is lower than on the ground. While this difference isn’t usually great, it can be enough to reduce the oxygen levels in your blood and slow down blood flow, leading to a DVT or PE.

You’re also at higher risk of blood clots if you’re living with obesity; have cancer or heart failure; are over 60 or have limited mobility;  are pregnant or taking the combined oral contraceptive pill or some forms of HRT; or are dehydrated.

What is the Treatment for a Blood Clot?

If you have a DVT or PE, you’ll be prescribed anticoagulant medication, which makes your blood less likely to clot. The risk of another clot is greatest in the first few months after you have a clot. So depending on your circumstances – whether it’s a DVT or a PE, whether you’ve had a blood clot before, whether you have a blood clotting abnormality etc – you’ll be given anticoagulants for at least 3 months and sometimes long term.

READ MORE: Travelling with Medication

You may also be advised to wear compression stockings, sometimes known as ‘TED’ stockings. It’s important to get the right size – too big and they won’t work, but too small and they’ll be uncomfortable. So it would help if you were measured before you get your first pair.

There are also different classes - you should wear class 2 compression stockings. Before these are fitted, you may need to have a test to check the blood flow in your legs' arteries.

How Soon After a Blood Clot Can I Travel?

Because prolonged travel increases the risk of DVT and PE, you’ll be advised not to fly for at least 2 weeks after your clot. Never book travel until you’ve got the all-clear from your doctor.

The risk of another blood clot is higher with long-haul flights (over 4 hours) and may be greater in economy class because the seats can cut into the back of your knees.

You can travel in a car as soon as your anticoagulation levels are stable. However, remember that long-distance car or bus travel also carries a higher risk of another blood clot than short distance. Build in frequent stops (ideally once an hour at least) to get out and walk for several minutes.

It’s extremely important to take your anticoagulant medicine as prescribed and not to miss any doses if you’re going to fly. Speak to your medical team about wearing compression stockings while you’re flying – this is usually advised when you’re on treatment for a DVT or PE, especially for long-haul travel.

READ MORE: Preparing for Long-Haul Flights

How Can I Reduce My Risk of a Blood Clot When Travelling?

There are lots of simple steps (pardon the pun!) you can take to cut your chance of getting a first – or another – blood clot when you’re travelling.

Seat Selection: Book an aisle seat, so you can get up and walk up and down the air cabin/train carriage every hour or so. You may be able to pay extra for a bulkhead seat, which has more space for you to stretch your legs.

Stow Away Your Bags: Try not to have a bag under the seat in front of you, so you have more room to move your legs around.

Drink Well: Keep hydrated with plenty of non-alcoholic fluid (the trips to the aircraft loo will keep you mobile as well!)

Avoid Alcohol: Don’t drink alcohol – any amount of alcohol can dehydrate you.

Avoid Sleeping Tablets or Sedatives: these may put you into a deep sleep, where you don’t move around naturally. Staying in one position increases your risk of pressure on the veins.

Clothing: Wear loose clothing which doesn’t constrict you – especially your legs and tummy.

Sitting Well: Try and avoid crossing your legs for long periods.

Pack a Tennis Ball:  You can gently roll this up and down your leg to massage the muscles or roll it around under your foot.

On-board Exercises: Exercise your lower legs and ankles. Blood in your lower legs is kept flowing back towards your heart by contractions of your calf muscles. You can usually find a list of exercises in the aircraft on-board magazine on long hall flights. Alternatively, every half hour or so:

• Do 10 circles each way with each ankle.
• Bend and straighten your legs and feet.
• Keep your leg bent and lift your knee up to your chest then lower it. Repeat 10-20 times with each leg.
• Keeping the front part of your foot on the floor, raise your heels as high as possible, then lower down. Then, keep your heels on the floor and raise your toes as far as you can. Repeat 10 times.

In conclusion, being informed and proactive about blood clot prevention can significantly reduce your risk during travel. Simple strategies such as moving regularly, staying hydrated, and wearing compression stockings are effective measures that play a vital role in maintaining your health.

Always consult with your healthcare provider for tailored advice, especially if you have any underlying health conditions or are recovering from a clot. Remember, prioritising your well-being ensures a safer and more enjoyable travel experience.

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