Crushed by those sitting next to you? Don't succumb to the withering stares of your fellow passengers - stand up for yourself. Writer Wendy Champagne takes to the air with a walk down the aisle.
You're travelling on an over-booked flight from Sydney to London. You chose a window seat. Ten hours and three meals into the flight, the lights are dimmed and the window shades pulled low. So much for proximity to the stars!
The two passengers next to you are fast asleep and the guy in front of you has tilted his chair back so far it feels like he's laying in your lap.
You begin to notice pins and needles in your right foot and tightness in your calf. You twist your foot around a little but the sensation remains. You look over at the couple next to you - there's no way you can unsettle them to walk around the cabin and stretch your legs.
Big mistake! One that may have grave consequences.
Economy Air Syndrome (deep-vein thrombosis) is a condition where blood clots develop in the deep veins of the legs after sitting through long flights in cramped airplane seats.
It's not unique to air travel - medical experts have known for decades that sitting in a cramped position can lead to the formation of blood clots in the legs - and incidents have been reported after automobile trips or even after evenings at the theatre.
The first report on the subject appeared in 1940 and it described an increase in deaths from pulmonary embolism in Londoners forced to sit for hours in air-raid shelters during the Blitz, when German planes bombed the city during World War 11.
The term Economy Air Syndrome was coined by aerospace medical experts in the United States. Dr Stanley Mohler, Director Aerospace Medicine Program at Wright State University of Medicine says the condition is a stealth problem, "It is almost completely unknown and it sneaks up on people."
The most common symptom is pain in the calf muscles developed during or shortly after a long airplane flight. It may feel like a muscle cramp but it can indicate the formation of a blood clot.
Typically the clot dissolves and the pain subsides after air travellers reach their destination and have an opportunity to walk around.
Unfortunately for others, like the 28 year-old bride-to-be Emma Christofferson, who died in September after a 20-hour flight from Sydney to London, some clots break away and move up to the lungs blocking the pulmonary artery and causing death.
One particular study conducted by Roderick Kraaijenhagen and his colleagues, published in last year's Lancet, disputes the connection between air travel and deep-vein thrombosis.
But Dr Mohler's 1986 study at London's Heathrow airport found that 18 per cent of 61 sudden deaths among long-distance fliers that years resulted from blood clots.
Who is at risk?
Everyone is at risk, but the risk of blood clot increases if you have varicose veins or cancer, recent leg injury or bed rest, if you're pregnant, overweight, elderly or tall, a smoker, taking a contraceptive containing oestrogen, have a history of blood clots or a rare genetic predisposing condition.
What are the signs?
The most common signs are limb pain and swelling. Less common signs are warmth and redness over the clot in the calf. However, many cases are asymptomatic and are only diagnosed if the patient develops symptoms suggesting a pulmonary embolism.
What can you do to prevent DVT?
It is a fact that airlines are cramming seats closer together on long flights and flight attendants are generally disapproving of passengers who wander the aisles.
So the first thing you can do is try to book a bulkhead or aisle seat for your journey. Avoid alcohol and caffeine as both contribute to dehydration on long flights. Wear loose clothing; no knee-length socks. Take off your shoes and put on those complimentary blue socks and exercise your calf muscles while seated by clenching your toes or circling your ankles.
But most importantly, if you are relegated to a window or middle seat deep inside the chaos of economy class on a long flight, disregard the withering stares of flight attendants and neighbouring passengers and make a point of getting out of your seat and stretching your legs every few hours.
References: Travel and the Risk of Thrombosis: Kraaijenhagen et al. The Lancet Vol 356. Dr Mohler, Wright State University School School of Medicine Cramped Seating, Long Flights Increase Risk of Blood Clots, Susan Okie, Seattle Times
