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Every year about 2 billion people make aircraft journeys, and the issue of jet lag has always been a point of discussion. Jet lag describes the temporary disruption to the circadian rhythm associated with long-haul flights which causes physical symptoms such as daytime fatigue, insomnia, loss of appetite, digestive complaints like constipation, lapses in psychomotor coordination and sluggish mental performance. 

Jet lag occurs as a result of a disturbance in the synchronization of your body's internal clock. According to the jet lag studies carried out by Dr. Waterhouse and colleagues published in 2007, this is a result of a discrepancy between the time zone in the suprachiasmatic nucleus of the hypothalamus and the new light-dark cycle, and the synchronization problems this causes in the brain. Jet lag is a manifestation of the difficulty the body has in adapting to the change in the light/dark cycle. 

In a simulation study carried out by Burgess and colleagues in 2003 and published in the Journal of Biologic Rhythms, in order to set the circadian rhythm appropriately, it was shown to be of benefit to go to bed 1 hour earlier and to be exposed to bright light upon waking up for 3 days before traveling east. It was also shown in the study that the more time you apply this phase therapy and plan your sleep before traveling, the more effective it will be. It has the potential to prevent jet lag altogether. 


  • Waterhouse J, Reilly T, Atkinson G, Edwards B. Jet lag: trends and coping strategies. Lancet 2007; 369: 1117-29. 
  • Burgess HJ, Crowley SJ, Gazda CJ, Fogg LF, Eastman CI. Preflight adjustment to eastward travel: 3 days of advancing sleep with and without morning bright light. J Biol Rhythms 2003; 18: 318-28.

The cabin environment can affect passengers of different ages and conditions of health in different ways. Flight cabin pressure can directly affect the digestive system. Many people who fly fear that it is just them affected by gas and bloating, and embarrassed, they suffer in silence. 

Low cabin pressure leads to gas expanding. According to Boyle's law, gas expands by 35% when it is 8,000 feet above sea level. Even though the cabin pressure set on aircraft used by modern airlines endeavors to save passengers from the effects of the real pressure at cruising altitude, the change in pressure means it is still as if the body has instantly climbed a tall mountain. 

Despite the hypothesis that spaces in the body filled with air can be affected by pressure when flying, it is only really felt in the ears and as bloating. These spaces include the inner ear and sinuses, the intestines, the pleural spaces of the lungs, some dental fillings, and the skull. Because take-off and landing are quite gradual processes, the change in pressure is quite slow and so the effects on the body are limited. 

Several studies have been carried out on complaints of gas and bloating. In their study carried out in 1995, Enck and colleagues looked at the difference in indigestion complaints between ground staff and cabin crew. In 2000, Vejvoda and colleagues showed in their study that the rate of complaints of bloating was much higher in cabin crew working on long-haul flights compared with ground staff. The study published by Hinninghofen and colleges in 2006 underlined that what you eat while flying is directly related to gastric emptying time, and at an altitude of 2,500 m, gastric emptying time is negatively affected, thus increasing the chance of indigestion. The study also showed that gastric emptying time is extended by around 50 minutes, and this leads to more gas, bloating and nausea. 

So, studies show that these problems are common when flying, and that you are certainly not alone. 


  • Hinninghofen, H., Musial, F., Kowalski, A., Enck, P., 2006. Gastric emptying effects of dietary fiber during 8 hours at two simulated cabin altitudes. Aviat. Space Environ. Med. 77 (2), 121-123.  
  • Vejvoda, M., Samel, A., Maas, H., Luks, N., Linke-Hommes, A., Schulze, M., Mawet, L., Hinninghofen, H., 2000. Study on strain, workload, and circadian rhythm in cabin crews during transmeridian flights. Research Report 2000-32. Deutsches Zentrum für Luft-und Raumfahrt (DLR), Cologne. 
  • Enck, P., Mueller-Sacks, E., Holtmann, G., Wegmann, H., 1995. Gastrointestinal problems in airline crew members. Z. Gastroenterol. 33, 513-516.

When flying, swelling of the feet can be a direct result of age, the health of vein walls, anatomical composition, pregnancy or varicose veins. The muscles which prevent fluid retention need to move in order to do their job. When sitting for long periods, blood flow stops as a result of reverse pressure, and fluid begins to gather in extremities. 

In 1996, Shuster and colleges first published their research on feet swelling during flight in the respected medical journal, The Lancet. A study was conducted which featured a simulated flight of 12 hours, with one group having a daytime flight, the other having a nighttime flight. 

The results of the research showed that water retention occurs more severely at night. The condition was seen most commonly in women over 30 and those with varicose veins. The study underlined the impact of in-flight ambient temperature and cabin pressure, and indicated that the condition is a natural result of these. 

Scientists also state that exercises and massage while flying can have a positive effect on the condition. It was also highlighted in the research that wearing tight socks before traveling makes the condition worse. People who suffer from feet swelling are advised to wear loose-fitting socks and to do exercises which work the ankle. 


  • Shuster S. Jet flight leg and hypobaric pressure. Lancet. 1996 Oct 5;348(9032):970. PubMed PMID: 8843849. 
  • Shuster S. Jet flight leg. Lancet. 1996 Mar 23;347(9004):832-3. PubMed PMID: 8622363.

Human beings live in an environment with stable direction and magnitude of gravity force. Passengers may, directly or indirectly, perceive vibrations, motion and centrifugal forces during flight. In addition, the turbulence in a flight may create a linear movement on the vestibular (balance) system. Vertical or circular movements in the vestibular system are accompanied by particular complaints, such as nausea and dizziness. Balance problems may also lead to motion sickness.

The study titled “Airsickness and aircraft motion during short-haul flights” conducted by Turner et al. on 923 passengers in 38 flights revealed out that vomiting is reported by 0.5% of passengers and nausea is reported by 8.4%. The study found positive correlations between symptoms and low-frequency lateral and vertical motions. Moreover, it is reported that selection of seat or demographics of passenger are not directly correlated to those findings.

Studies on airsickness emphasize the importance of reducing exposure to vibration and seeing the horizon line. The Health Info articles on airsickness published by University of Maryland and Mayo Clinic recommend passengers to prefer seats over the wing or the front section.

The Flight Phobia video that is shot within scope of the Fly Good Feel Good project will guide you to cope with the airsickness. Moreover, our ginger teas may help preventing the nausea. Have a nice flight.


  • Turner M, Griffin MJ, Holland I. Airsickness and aircraft motion during short-haul flights. Aviat Space Environ Med. 2000 Dec;71(12):1181-9.
  • Schmal F. Neuronal mechanisms and the treatment of motion sickness. Pharmacology. 2013; 91(3-4):229-41.

Have you ever felt in a long-haul flight that your contact lenses dried or even your eyes are irritated? The condition is caused by the environmental conditions of the cabin. Passengers with contact lenses may face such problems due to pressure alterations in the cabin.

Aircraft cabin exposes the passengers to low atmospheric pressure, oxygen and humidity as well as dry air. The underlying cause is the artificial low atmospheric pressure that is created to fly at an altitude of 35 thousand feet. Those conditions may cause ocular discomfort in passengers with contact lenses especially in flights lasting longer than 3 hours. Studies report that moisturizing eye drops approved to be used with contact lenses may help curb the dry eye during flight. As the dry eye causes irritation and infection, passengers who wear contact lenses are recommended to remove lenses aboard.

You should also be careful not to fall asleep with contact lenses on your eyes during the flight. Contact lenses stiffen due to partially low oxygen and dry air, resulting in the risk of corneal abrasions. You are recommended to keep your contact lenses and irrigation solutions in your bag during flights. The 100 ml limit set for liquids aboard does not apply to lens solutions, but such solutions should be declared at the security check. You may also prefer travel type lens solutions or smaller packages. If you do not have small packaged lens solution, you may need to pour some of the solution to another container. This approach may go up in flames regarding infection.

Preferring eyeglasses rather than contact lenses especially in long-haul flights can be much healthier.


  • Backman H, Haghighat F. Air quality and ocular discomfort aboard commercial aircraft. Optometry 2000; 71(10):653-6.
  • DeHart RL. Health issues of air travel. Annu Rev Public Health 2003; 24:133-51.

There are hundreds of studies conducted on nausea and vomiting that are among the most important symptoms of the motion sickness. The underlying causes of those symptoms include environmental factors that influence the vestibular (balance) system, such as vibration. It is known that vibration and vertical motions cause nausea in passengers in a flight.

Natural solutions can be used for nausea – a symptom of the motion sickness. Ginger has been used as a wide-spectrum antiemetic agent (that curbs the nausea) in traditional medicine for more than 2000 years. Various pre-clinical and clinical trials show that ginger poses antiemetic effects on various factors, which induce nausea. Although there are studies reporting that same effect does not apply to everyone, many research reports claim that ginger is a natural anti-emetic substance. A study conducted by Lien et al. in 2003 demonstrates that the ginger is efficacious in alleviating the nausea induced by circular vection. It is, therefore, reported that ginger can be a new agent in prevention and treatment of motion sickness.

Within scope of the Fly Good Feel Good project, detailed information about ginger teas is available at Special Teas page. You can try our special teas to cope with nausea during flight.


  • Lien HC, Sun WM, Chen YH, Kim H, Hasler W, Owyang C. Effects of ginger on motion sickness and gastric slow-wave dysrhythmias induced by circular vection. Am J Physiol Gastrointest Liver Physiol. 2003; 284(3):G481-9.
  • Ernst E, Pittler MH. Efficacy of ginger for nausea and vomiting: a systematic review of randomized clinical trials. B J Anaesth. 2000;84(3):367-371