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Do you know that a good hydration during the flight will help you to feel well and less heavy?

Did you know that in 2013 there were 32 million flights registered and 3 billion passengers? This number has doubled in the past 15 years! Therefore, it is important to be aware of the problems that can arise for certain passengers on long distance flights.

In fact, apart from the fatigue and jet lag that most people experience, prolonged immobility and changes in environmental conditions on high altitude flights can increase the risk of blood clots forming in certain people, particularly in the deep calf veins. This can cause a variety of different symptoms in both clinical expression and in severity: pain in the calf, redness/warmth in the affected leg, swelling, pain caused by extended the foot upwards, but also (more severe symptoms that are indicative of a pulmonary embolism) chest pain, shortness of breath, increased pulse rate, etc.

For a better understanding…

risk of dehydration on airplaneAt 10,000 m in altitude, the outside temperature drops to -58°C, the atmospheric pressure drops by 70% (it goes from 1013.2 hPa to 238 hPa), gas pressures decrease (dioxygen and nitrogen), as well as air density. We would not be able to survive in these types of conditions. On a plane, the air is pressurized, but the hygrometry (amount of humidity in the air) is very low which causes the body to dehydrate and the blood to become more concentrated.

This is amplified when alcohol is consumed (increasing the risk of dehydration due to its diuretic effects) and not enough water is ingested. In addition, remaining immobile for prolonged periods of time decreases the blood flow to the heart and increases the risk of blood stasis in the veins in the lower limbs. The cramped spaces in economy class accentuate the situation, especially when our legs are crossed causing a prolonged compression on the front of the thighs. That’s why it’s called the “economy class syndrome”!

All of these things can cause blood clots to form in the veins. It can either trigger a painful local inflammatory response (phlebitis) or migrate, partially or entirely, and cause a pulmonary embolism or stroke. However, feel reassured that this is not very frequent, but certain people are more prone than others; the risk is still there (between 1 and 4 people out of every million).

At risk profiles…

The people who should be taking special precautions are the following: those who have a history of phlebitis, embolisms, heart attacks, heart rhythm problems and passengers taking anticoagulants – but also anyone over 60 years of age, people with varicose veins, pregnant women, women taking birth control or estrogen therapy, anyone who has had surgery in the past 6 months, anyone who is undergoing chemotherapy treatment, anyone with a cast, those suffering from obesity and heavy smokers.

Precautions to take…

For those people that are at risk, and for flights that are longer than 6 hours, we recommend taking the following precautions:

  • Drink water regularly throughout the flight to avoid the risk of dehydration, which causes the blood to become more concentrated
  • Avoid alcoholic beverages (they dehydrate you)
  • Move your legs often (and preferably sit in the aisle seat), don’t cross your legs, get up and walk around at least once every two hours, make sure that the seat doesn’t compress the bottom of your thighs
  • Wear class 2 compression socks (20 à 30 mmHg). Ideally, you should put them on in the morning before you get up and take them off once you get off the plane and start walking around
  • Your doctor may recommend a preventive injection of low molecular weight heparin, depending on the state of your health

As you can see, these precautions are easy to take: drink water and move around! It’s worth it. Safe travels!

Read more about “The good advice to stay healthy abroad

C. Lapandry, F.Lapostolle. Accidents thromboemboliques et voyages aériens. Enseignement médical. 15/03/2004, page 81
F. Lapostolle and al. Severe pulmonary embolism associated with air travel. N Engl J Med 2001; 345: 779-783

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