Health Considerations for Long-Haul Flights

By ALPA Staff

As technological developments allow airlines to schedule longer and longer flights, it’s important for both flightcrew members and passengers to consider the effects of being sedentary in a confined space for extended periods. Qantas recently announced plans to operate a nonstop flight between Sydney, Australia, and London, England, in 2025. It’s estimated that travelers will be seated and airborne for between 19 to 21 hours, depending upon the jet stream and weather conditions.

Airline pilots are well aware that temperature, oxygen, and pressure levels fluctuate during flight and can contribute to stress and fatigue and affect well-being. For example, changes in air pressure in the inner ear can impact an individual’s sense of balance. Much of the air circulating in the airplane is drawn from high altitudes where there’s little or no moisture, making the cabin environment extremely dry. In addition, traveling through multiple time zones and being in close proximity to others can take their toll as well.

However, there’s a particular condition associated with long flights that warrants special attention. Sitting motionless for long periods increases the risk of developing blood clots in veins, known as venous thromboembolism. This condition can take one of two forms: deep vein thrombosis (DVT) or pulmonary embolism (PE).

DVTs are blood clots that form in deep veins, particularly in leg muscles, that carry blood to the heart. Sitting for long periods can slow the movement of blood, causing it to pool and creating the opportunity for a clot to form. PE is a complication of DVT that results when part of a blood clot breaks off and travels to the lungs, where it can obstruct blood flow. If not treated, both conditions can result in serious illness, disability, or even death.

The risk of DVT doubles after four hours of being sedentary—with pregnancy, obesity, and genetics increasing the risk of blood clots.

According to the U.S. Centers for Disease Control and Prevention (CDC), nearly half of individuals with DVT exhibit no symptoms. For those who do, it’s common to experience pain, tenderness, swelling, and redness of the skin in the affected part of the body. Signs of PE include an irregular heartbeat, chest pains, difficulty breathing, coughing up blood, and lightheadedness. If you have any of these symptoms, seek immediate medical attention.

The good news is that venous thromboembolism is avoidable. The CDC recommends doing the following every few hours:

• Standing up and moving.
• Stretching in place.
• Raising and lowering your heels while keeping your toes on the floor.
• Raising and lowering your toes while keeping your heels on the floor.
• Tightening and releasing your leg muscles.

If you’re at a higher risk for DVT, consider wearing loose-fitting clothes when possible and medical compression socks or stockings. Also talk to your aviation medical examiner or physician to determine if you’d benefit from taking an anticoagulant as a preventive measure.

The CDC reports that a third to a half of those who’ve experienced DVT may have postthrombotic syndrome, complications caused by damage the clot does to valves in the vein. Fortunately, there are treatment options. Dr. Quay Snyder, president and CEO of Aviation Medicine Advisory Service, ALPA’s Aeromedical Office, notes, “Treatment usually requires putting the patient on blood thinners such as Coumadin or low-molecular-weight heparin (Lovenox).” These medications are temporarily disqualifying for pilots, but the FAA and Transport Canada may issue a medical certification waiver for them.

Pilots who have concerns about their risk of DVT or who need help obtaining a DVT waiver can contact ALPA’ s Aeromedical Office for a confidential consultation with one of the aerospace medicine physicians or speak with their aviation medical examiner.

This article was originally published in the October 2023 issue of Air Line Pilot.