Experts call this condition “economy class syndrome” – but it can happen to anyone in any class of aircraft.
Deep vein thrombosis, or DVT as it is known, occurs when a blood clot forms in one or more veins.
It can happen at any time, but people who travel on long-haul flights are at greater risk because they sit for long periods of time, said Dr. Benakin V. Parikh, a consultant cardiologist at Harley Street Cardiovascular Centre in Singapore.
“In theory, people who fly in better classes — business class and first class — have more room to move around and stretch their legs. So it's all about the space available on the plane,” he told CNBC Travel.
But Barrick was quick to point out that the so-called “economy class syndrome” doesn’t differentiate between where you sit or how often a traveler flies, he said.
“I’ve treated patients who even traveled business class and had deep vein thrombosis,” he said. “Plus, this could be the only flight of your life if you decide not to fly.”
What increases the risk?
Deep vein thrombosis usually forms in the legs. Symptoms include pain, swelling, changes in skin color and a feeling of warmth, but some people have no symptoms at all, according to the Mayo Clinic.
According to the medical center, people who are obese, over the age of 60, take birth control pills or hormone replacement therapy, or smoke are more likely to develop deep vein thrombosis.
But flying carries its own risks, Barrick said.
“On one in every 5,000 flights, one patient could develop a deep vein thrombosis just because of the risk of flying,” he said.
A 52-year-old former banking executive said he suffered a deep vein thrombosis as a result of a four-hour flight from Singapore to Hong Kong.
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People who travel on long-haul flights are at greater risk, he said, but deep vein thrombosis can develop on short-haul flights.
“People used to think long flights were eight hours long, but there's some data to suggest that four hours is now long enough,” he said.
Former banking tycoon Alok Tapadia, 52, said he suffered a deep vein thrombosis (DVT) as a result of a four-hour flight from Singapore to Hong Kong.
He said he plays badminton three times a week, so he realized something was wrong when he started breathing heavily while climbing the stairs after arriving in Hong Kong.
“One of the escalators stopped working,” he said, so he climbed up. “I had to stop for a while, wondering what had happened to me.”
He was only able to have a medical examination after returning to Singapore, and he still suffered from shortness of breath and an elevated heart rate.
He said doctors told him a blood clot had traveled to the pulmonary artery that connects his heart to his lungs.
This kind of episode really shakes you up.
He said the first scan showed an enlarged heart, which occurs when the heart pumps blood too hard. The second scan resulted in Tabadya being immediately admitted to the hospital's intensive care unit, he added.
He said doctors found he was suffering from a “significant” lack of oxygen and his lungs were completely blocked.
“The doctors said the situation was critical, because there was a lot of pressure on the heart, which could have led to cardiac arrest or a more serious stage at any moment,” Tabadya said.
He said blood thinners do not dissolve the clot fast enough.
So his doctors eventually resorted to cardiac catheterization, which involves threading a catheter through blood vessels near his heart to dissolve the blood clot from the inside, Tapadia said.
Tips to reduce the risk of deep vein thrombosis
Deep vein thrombosis can develop into pulmonary embolism, a potentially life-threatening complication that occurs when a blood clot breaks free and gets stuck in a blood vessel in the lung, according to the Mayo Clinic.
When the clot travels to the lungs, symptoms such as shortness of breath and chest pain can occur, Baric said.
There's no way to completely eliminate the risk of DVT, but there are ways to reduce the risk while flying, Barrick said.
The Mayo Clinic suggests drinking plenty of water, standing and walking around the plane during the flight, moving your ankles while sitting, and wearing support stockings.
Barrick has a simple tip for travelers: Choose an aisle seat.
“It encourages you to get up and start walking more easily because when you're in the middle of the line, you're always worried about disturbing the person (next to you),” says Parikh.
More than a year later, Tapadia said he is back to his normal lifestyle, which includes traveling and playing badminton, though he said he has changed some of his travel habits, starting with the airport.
He said he now walks through the airport instead of taking the escalator. He added that he walks back and forth in the aisles while flying.
Travelers are advised to pay attention to their health and any warning signs.
“This kind of episode really shakes you up,” he said.
