Dr Sarah Jarvis, MBE
Author: Dr Sarah Jarvis, MBE, General Practitioner (GP)

Dr Sarah Jarvis is the Clinical Director of the Patient Platform, an active medical writer, broadcaster, and the resident doctor for BBC Radio 2.

7 min read

What are flight socks?

Flight socks are a type of medical compression sock which are specifically designed to be worn during flights. These socks provide graduated compression, meaning that the pressure on the feet is greatest at the ankle and gradually decreases up the leg. The increased pressure helps to reduce swelling, fatigue, and discomfort associated with long or frequent flights.

Flight socks also help to improve circulation throughout the legs by pushing fluids back up toward the heart, helping to prevent Deep Vein Thrombosis (DVT). Some flight socks even contain specially designed padding in areas where leg muscles often become sore during long flights, providing additional comfort.

Flight socks come in various styles - some are calf-length, while others go all the way up to just below the knee. They usually feature adjustable straps or closures which allow for a more customized fit and can be worn on both legs or just one depending on an individual's needs.

What is Deep Vein Thrombosis?

Deep veins can’t be seen on the surface of your skin – they’re not the same as varicose veins. Instead, deep veins in your legs pass through the muscles of your calf and thigh. They carry blood back to your heart. Because the pressure in these veins is low, they can be easily squashed – this can stop blood from flowing freely. In addition, using your legs makes the muscles contract, and this helps the blood flow back toward your heart.

Following major leg surgery in particular, many people are immobile and put pressure on their deep veins by sitting still. This can cause the blood to stagnate, leading to a clot. This clot can break off, travelling to the lung where it gets lodged. The result is a potentially life-threatening pulmonary embolus (clot on the lung)

If you’re on a long-haul flight in particular, sitting still for long periods can also increase the risk of a DVT. DVTs don’t always cause symptoms and often disappear without you knowing you’ve got one. However, it’s worth knowing when you need to take steps to reduce your risk.

Am I at risk of Deep Vein Thrombosis?

You may be at higher risk of DVT if you:

  • Have had surgery (particularly on your legs or pelvis) in the last couple of months.
  • Have recently had a severe illness, such as heart failure or a heart attack.
  • Have a long-term medical condition that limits your mobility.
  • Have been confined to bed or a wheelchair for any length of time in the weeks before you fly.
  • Are pregnant.
  • Are taking the combined oral contraceptive pill or tablet forms of Hormone Replacement Therapy (HRT).
  • Have cancer.
  • Are overweight or living with obesity.
  • Have a leg in plaster because of a broken bone.
  • Have had a DVT or pulmonary embolus in the past.
  • Have a close relative who has had a DVT or pulmonary embolus.
  • Are over 60, especially if you’re not very mobile.
  • Become dehydrated.
  • Have a blood clotting disorder that makes you more prone to blood clots.
  • Are over 190cm or under 160cm tall.
A view down the aisle of an airplane

Do you need flight socks?

The risk of DVT on even a long-haul flight is much smaller than some other risk factors, such as major surgery or cancer. However, the combination of long-haul flights and these other risk factors can make you especially prone to DVT.

If you don’t have any risk factors for DVT, the risk for flights under 4 hours is tiny. That means you’re likely to get little or no benefit from wearing flight socks, especially for short-haul flights.

If you have any of the risk factors above, you may want to consider flight socks for flights over 6 hours in particular. Some studies suggest that they may reduce your risk of having a DVT during travel by over one-third to more than half.

Tommy Lloyd

Did you know?

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.

Flights socks could also have a surprising benefit - a peaceful night's sleep, but not necessarily for the wearer. Studies by the University of Toronto in Canada have shown that wearing flight socks to bed allows for less fluid to work its way up the body to the neck, which can result in snoring-related conditions. So, if you’re one of those estimated 3 million people that suffer from snoring, or rather if you’re one of the 3 million that suffer from snoring partners, it could be worth buying a pair of flight socks. Do let us know if it works!

How do I avoid a DVT when travelling?

Doctors recommend that everyone takes sensible precautions to keep their blood flowing during flights, especially on long-haul flights.

Do consider the flowing:

  • Keep moving. It’s particularly important to move your calves, as your calf muscles keep blood flowing through your veins when they contract. Most airlines have examples of exercises you can do regularly in your seat to keep blood flowing – you can usually find these in the in-seat magazine. Examples of exercises you can do at least every half hour include:
    • Ankle circles: Lift your feet and twirl your foot, as if you’re drawing circles in the air. Do this in both directions for 15-30 seconds with each foot.
    • Knee lifts: Lift your knee towards your chest with your knee bent. Repeat 20-30 times with each leg.
    • Foot pumps: with your heel on the floor, bend your foot to bring your toes as far as possible towards you. After holding for a couple of seconds, push the ball of your foot down hard to the floor and raise your heel as far as you can, keeping the ball of your foot on the floor. Repeat for a minute, alternating feet.
  • Keep yourself hydrated. Dehydration makes your blood thicker and more prone to clotting. Take regular non-alcoholic drinks – your urine should be pale straw-coloured when you go to the toilet.
  • Consider an aisle seat. This makes it easier for you to get up regularly and walk up and down the aisle.

And some sensible suggestions to avoid:

  • Don’t take sleeping tablets. When you sleep under the influence of sleeping tablets, you tend to be more immobile and you put more pressure on your veins.
  • Avoid alcohol. Any amount of alcohol acts as a diuretic, making you pass more water. This makes you more prone to blood clots, as well as feeling groggy and irritable.
  • Use the overhead compartment. Avoid putting large luggage under the seat in front of you, as it prevents you from moving your feet.

In the past, doctors have suggested taking a single aspirin tablet before flying. Aspirin works to make your platelets (which help your blood to clot) less sticky – so the theory was that this might reduce the risk of DVT. In fact, studies have shown that aspirin doesn’t reduce your risk of DVT during travel.

If you’ve recently had a DVT, or have had a pulmonary embolus or multiple DVTs in the past, your medical team may suggest that you take a blood-thinning injection called heparin to reduce the risk of DVT during a long-haul flight.

You can read more in my full guide on travelling after a deep vein thrombosis.

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