CHICAGO - Good news for budget-minded travellers: There's no proof that flying economy-class increases your chances of dangerous blood clots, according to new guidelines from medical specialists.
Travellers' blood clots have been nicknamed "economy class syndrome" but the new advice suggests this is a misnomer.
The real risk is not getting up and moving during long flights, whether flying coach or first-class. Sitting by the window seems to play a role because it makes people less likely to leave their seats, the guidelines say.
Still, even on long flights, lasting at least four hours, the risk for most people is extremely low and not something to be alarmed about, said Dr. Gordon Guyatt, chairman of an American College of Chest Physicians' committee that wrote the new guidelines.
The group, based in Northbrook, Ill., represents more than 18,000 physicians whose specialties include lung disease and critical care. The guidelines were released online Tuesday in the group's journal, Chest. They're based on a review of recent research and other medical evidence on deep vein thrombosis, blood clots that form deep in leg veins.
SEE: Six reasons sitting is bad for your health. Story continues below:
Back in October, researchers from the University of Missouri published results suggesting that sitting throughout most of the day may put individuals at higher risk for diabetes, obesity and non-alcoholic fatty liver disease -- even if you clear time for daily exercise.
As HuffPost editor Amanda Chan reported back in June, a study in the American Journal of Epidemiology found that women who sat six or more hours a day were nearly 40 percent more likely to die over a 13-year-stretch than those who sat less than three hours. As for men? Sitting for more than six hours was linked with an 18-percent higher risk of death.
An August study from the British Journal of Sports Medicine found that every hour you sit in front of the TV, you can slash your life expectancy by nearly 22 minutes. And watching the tube for six hours a day? That type of seriously sedentary behavior can cut your life expectancy by five years.
As MSNBC reported, sitting may be responsible for more than 170,000 cases of cancer yearly -- with breast and colon cancers being the most influenced by rates of physical activity (and inactivity). But according to that article, a little bit of walking can go a long way. "For many of the most common cancers, it seems like something as simple as a brisk walk for 30 minutes a day can help reduce cancer risk," Christine Friedenreich, an epidemiologist with Alberta Health Services told MSNBC.
As our UK compatriots recently wrote, researchers have found that putting pressure on certain body parts (i.e., your bottom) can produce up to 50 percent more fat than usual. HuffPost UK reported: "In a bid to explain why sedentary behaviour causes weight-gain, scientists believe that the precursors to fat cells turn into flab (and end up producing more) when subjected to prolonged periods of sitting down, otherwise known as 'mechanical stretching loads.'"
Not too long ago, Men's Health covered a study in the journal Medicine & Science in Sports & Exercise, in which researchers from Louisiana found that people who sit for the majority of the day are 54 percent more likely to die of a heart attack. Indeed, the investigators found that sitting was an independent risk factor for serious cardiovascular events.
Yet another study shows sitting too much is simply unhealthy. It found those who sat for more than 11 hours a day were 40 percent more likely to die in the next three years than those who sat less than four hours per day.
Flights lasting at least eight hours are riskiest, the guidelines say.
Muscles in the lower legs help push blood in the legs and feet back to the heart. Sitting still for extended periods of time without using these muscles puts pressure on leg veins and blood "tends to sit there," which can increase chance for clots to form, said Guyatt, a researcher at McMaster University in Hamilton, Ont. These clots can cause leg pain, swelling and redness, and can be life-threatening if they travel to the lungs. They can be treated with blood-thinning drugs, but may cause permanent damage to leg veins.
Most people who develop these clots have risk factors, including obesity, older age, recent surgery, a history of previous blood clots or use of birth control pills.
The average risk for a deep vein blood clot in the general population is about one per 1,000 each year. Long-haul travel doubles the chance, but still, the small risk should reassure healthy travellers that they're unlikely to develop clots, said Dr. Susan Kahn, a co-author of the new guidelines and a professor of medicine at McGill University in Montreal.
Travelling by bus, train and car may also increase the risks, the guidelines say.
Besides taking a stroll down the aisle during flights, doing calf exercises including flexing and extending the ankles while seated can help prevent clots, Kahn said.
The guidelines recommend these precautions and use of special compression stockings only for people at increased risk for clots. They advise long-distance travellers against using aspirin or other blood thinners to prevent blood clots.
American College of Chest Physicians' journal: http://www.chestjournal.org