And we'll skip the seatbelt instructions, too. I know you know how to click together a bloody seatbelt. Our seatbelts work like every other one you've ever used, and if you can't figure it out, well, perhaps you shouldn't be out in public unsupervised. Instead, why don't you pay attention to some health tips that might actually be useful?”
Don't you wish airline pilots would give it to you straight like that? I sure do. Recently, I took a 12-hour flight from Los Angeles to Auckland, New Zealand, and as it turns out, 12 hours is a long time to spend on a plane, especially if you're seated next to a hulking rugby player whose taut triceps nudge you into an awkward diagonal position. The good news is that this (seemingly interminable) discomfort gave me plenty of time to consider what is really worrisome about an extended flight. And you know what? The location of the personal flotation device is not high on the list.
In fact, the Transportation Safety Board of Canada, among others, has concluded that even in the rare circumstance that such a device is required, it is highly unlikely that it will be used unless the passenger is actually wearing it beforehand. I'm not interested in advice that makes flying even more uncomfortable (such as wearing a life vest for an entire overseas flight), so let's focus on more tangible threats.
Deep vein thrombosis (DVT): We all know that DVT is a common and potentially deadly condition and that prolonged immobility is a major risk factor. But how common is airline DVT, dubbed by some as Economy Class Syndrome? We don't know for certain, but some estimates are staggering.
Lancet published an analysis that estimated that one million cases of DVT related to air travel occur in the United States each year and that 100,000 of these result in death. (2001;357:1485.) A more recent review article by Gavish and Brenner put the risk on flights six and a half hours or longer at three to 12 percent. This is a pretty stunning incidence, equaling approximately one DVT for every one to four rows of economy seats in a Boeing 777. The American College of Chest Physicians, on the other hand, estimated a lower incidence, calling the risk “mild” in its 2008 and 2012 guidelines.
It's thought that the risk of DVT is due not only to in-flight immobility but also the relative hypoxia in the cabin. Risk factors for all DVTs include age over 40, being female, pregnancy, oral contraceptive use, lower limb varicose veins, obesity, and genetic thrombophilia. The college has recently added sitting in window seats to this list (Grade 2C evidence) while also observing that Economy Class Syndrome may be a misnomer because those in first class have the same DVT risk as those in the back of the plane.
Even the absence of risk factors does not put you in the clear. A Norwegian study in The Lancet in 2000 observed a substantial hour-by-hour increase in blood clotting factors (two- to eightfold) occurred in all 20 healthy subjects studied in a simulated (hypobaric) environment.
Even if Economy Class Syndrome is a misnomer, and some incidence estimates are overblown, it seems that DVT prevention advice would be a useful aspect of an in-flight safety program (more helpful, perhaps, than a reminder to stow your tray table in an upright position). The trick to prevention, as we all know, is to keep those legs moving! Any combination of methods will help:
* Graduated compression stockings for high-risk patients at 15-30 mg of Hg.
* Calf and ankle exercises such as pumping up and down on the balls of the feet for two to three minutes every half hour.
* Frequent walks up and down the aisles.
Some evidence suggests that patients in high-risk demographics may benefit from a prophylactic anti-thrombotic, with low-weight molecular heparin likely being the best (but not-so-convenient) choice. A comparative study by Cesarone et al published in Angiology found that heparin given two to four hours pre-flight was statistically superior (no DVTs in 82 subjects) to controls (4/82) and aspirin alone (3/84). The current American College of Chest Physicians guidelines, however, do not recommend routine anti-thrombotic therapy, even for high-risk patients. It's not likely that we will soon see Leg Care Clinics popping up in international terminals to offer a quick pre-flight shot of anti-DVT elixir.
Dehydration: It's so easy to get dehydrated when traveling. The dry air of a pressurized cabin, the mile-high altitude, and the stress and exertion of it all conspire to rob flyers of fluids. With dehydration can come fatigue, grumpiness, a wicked headache, and (perhaps) an increased risk of DVT. What is the best way to stay hydrated? Common sense dictates that one avoids excessive alcohol and limit caffeinated beverages. But what about drinking water? One study found that in-flight blood viscosity is better controlled with an electrolyte-enhanced beverage (110 mg sodium and 30 mg potassium per eight ounces) than water alone. (JAMA 2002;287:844.)Perhaps your flight attendant should be serving Powerade rather than punchless coffee? That's not likely to happen, so bring packets of sports drink powder to mix with flight beverages.
The dry air of a plane can parch external body parts, too, like the nose, eyes, and skin. A bloody nose or corneal abrasion at 30,000 feet is not going to help anyone sit back and enjoy the flight. At-risk folks should bring petroleum jelly for their nostrils and liquid tears for their eyes.
Dry skin can be a real issue, too, and believe it or not, this has been documented in the literature. A French study of eight volunteer airline passengers observed that in-flight skin capacitance decreased rapidly on the face and forearms, with the most pronounced changes on the cheeks where it decreased by up to 37 percent. (Skin Res Technol 2011 Oct 18; ePub.)How about some aloe vera to go with that moist towelette?
The good news about arid airline air is that it helps keep infectious organisms at bay. I wouldn't worry too much about the cabin air circulation, but would, of course, worry about a febrile-appearing lady with a productive cough sitting right next to me.
Physical abuse from your surroundings: I am well aware that carry-ons can tumble out of the overhead storage bins and that tall guys like me can bonk their heads, but accidental strangulation by a fellow passenger? That hadn't occurred to me until several hours and two movies into our flight to Auckland. I sat crookedly next to my large and slumbering neighbor and resolved to fall asleep. Suddenly, though, a fire-siren-like scream rocketed through the cabin and a log-sized arm pinned my neck against the seat. Fortunately, the arm relaxed, and I breathed again as my seatmate stood up, still screaming, and starting shaking the row in front of him. It all looked like an impromptu Ma-ori war dance, the Haka.
Luckily for me and for the whole economy class, this hulking fellow had some equally large friends with him, and they jumped to his (and my) aid. Later, as they mercilessly ribbed him, I learned that he had taken a double dose of Ambien, which had contributed to a very realistic nightmare. Why hadn't my captain warned me about this?
So there you go, a brief guide to keeping the skies health-friendly. And don't forget, systematic reviews have established that “tampering with, disabling, or destroying the lavatory smoke detectors is prohibited by law.”
Kia ora (cheers) from New Zealand.
Dr. Ballard is an associate emergency physician at Kaiser-Permanente in San Rafael, CA, and the chair of the CREST ED Research Network. His writing credits include co-authorship with Angela Ballard of the award-winning travel narrative A Blistered Kind of Love: One Couple's Trial by Trail (Mountaineers Books, 2003) and authorship of The Bullet's Yaw (IUniverse, 2007). Dr. Ballard writes a biweekly-medical column for the Marin Independent Journal, which he posts on his blog: http://incisionanddrainage.blogspot.com. He is currently working at Starship Children's Hospital in Auckland, New Zealand.© 2012 Lippincott Williams & Wilkins, Inc.