Do you really need to wear compression stockings on a long-haul flight?

If you want to feel comfortable on a long-haul flight, good preparation is essential. Many TikTokers recommend adding one thing in particular to your pre-flight to-do list: putting on compression socks.

Compression socks, also known as compression stockings, are often associated with aging because they promote circulation, which can decrease over time. But a recent TikTok trend involves people showing off their compression socks and encouraging others to keep them on even on long flights—regardless of age or health condition.

“I travel a lot,” said one creator whose video has been viewed over 220,000 times, “and one of my most important tips I can give you – no matter what class you’re traveling in – it’s always important to wear those compression socks.”

But can wearing compression socks on long-haul flights really have health benefits for everyone? Here’s everything you need to know about these socks, including who should wear them when flying.

Compression stockings are tight-fitting socks designed to increase circulation and prevent blood clots by gently compressing the calves and feet, thereby stimulating blood flow.

The gentle pressure of the compression stockings “pushes fluid from the feet and lower legs back toward the center of the body,” said Dr. David Steensma, a hematologist and chief medical officer at Ajax Therapeutics. Health“Compression reduces swelling in the feet, ankles and lower legs.”

Most compression stockings are made of elastic fabric and reach up to the calf, thigh or waist. They are available in different voltage levels, from low – less than 20 millimeters of mercury (mmHg) – to high – over 30 mmHg.

Socks with relatively low levels of compression are available over the counter, but socks with higher levels of compression may require a prescription.

Doctors sometimes recommend compression stockings for flights because they can stimulate blood circulation. Sitting for long periods, such as on a night flight, can put a strain on your circulation.

“During a flight, blood flow in the veins can become sluggish and pool in the lower legs,” said Leo Reap, DO, a hematologist at Ascension Michigan, Health“This increases the risk of a blood clot, especially if the flight lasts longer than four hours.”

Blood clots in the veins can cause deep vein thrombosis (DVT), which leads to complications over time.

“Blood clots can injure veins and cause vein dilation, including the formation of varicose veins,” Steensma said. “Veins can be permanently blocked from returning blood to the center of the body, causing long-term swelling.”

The risk of a blood clot is “relatively proportional” to the length of the flight, says Reap. It is highest on “transatlantic flights, where people are usually not moving for long periods of time.”

The American Society of Hematology recommends compression stockings for people who fly for four hours or more and are at high risk for developing a blood clot. This includes those who:

• Recently operated
• Do you have a history of venous blood clots?
• Recently had a baby
• Have an active malignant disease

However, Reap said compression stockings can be helpful for anyone, regardless of age or medical history.

“They are useful on any flight to relieve swelling or discomfort in the lower extremities,” he said. “They can improve comfort during the flight and are useful for anyone traveling for more than four hours.”

There are no major risks associated with wearing compression stockings, “apart from possible slight discomfort if stockings are worn that are too tight,” Reap added. However, Steensma said they could also cause mild skin irritation or small bruising.

It’s important to find socks with a compression level that’s appropriate for your circumstances, Steensma said. Consult your doctor to determine the right compression level for your risk level.

“People in the high-risk group with previous blood clots and chronic swelling may need up to 40-50 mmHg,” says Steensma. “If you are in a high-risk group for blood clots, you may be able to get a prescription for compression stockings and insurance may cover part of the cost.”

All compression stockings should be snug to provide firm pressure, but not painfully tight. “It’s important to avoid bunching or rolling up,” Steensma explained. “They should fit smoothly around the foot and leg.”

Many socks feature graduated compression, cushioning, breathable materials and other features that improve comfort.

Compression stockings can reduce the likelihood of swelling and blood clots, but wearing them is not a guarantee that blood clots will not form during the flight.

“The benefits of compression stockings are limited, so blood clots can form even when wearing these stockings,” warned Steensma.

For this reason, experts recommend taking additional measures to increase blood circulation when traveling.

The CDC recommends that passengers walk around the plane every two to three hours to prevent blood clots. Reap recommends walking up and down every hour. He also says it’s a good idea to keep your circulation going by drinking plenty of fluids and doing regular calf exercises while sitting on the seat.