- Jet Lag
- Deep Vein Thrombosis (DVT)
- Why is it sometimes called "Economy Class Syndrome"?
- How frequent is DVT and is it becoming more common?
- Are some people more at risk of having a DVT than others?
- Can I do anything to reduce my risk of getting DVT while travelling by air?
- What are the symptoms of a DVT?
- General Health and Safety Tips
Passengers travelling to a destination several time zones away, will probably experience jet lag, as the body’s internal circadian clock is only able to reset itself at a rate of about 1 hour per day. In most people, the circadian cycle tends to be slightly longer than 24 hours. Hence, most people have fewer problems with westward travel (lengthening day) than eastward travel (shortening day). The most common symptoms of jet lag are fatigue, headaches, insomnia and appetite problems.
There is no cure for jet lag, but we recommend that you try the following to minimise its effects:
- Jet lag can be worsened by insufficient sleep before the journey, therefore it is important to try and get a good night’s rest before your flight.
- If you are on a very short trip (48 hours or less), you may find it more convenient to remain on home time, rather than trying to adjust to local time.
- Eat light meals at the local meal times.
- Avoid caffeinated drinks for 4 hours and alcohol for 2 hours before going to bed to prevent interrupted sleep.
- Try to sleep at the local night time and only have short naps during the day if you are tired.
- For westward travel, late evening exposure to bright light helps delay the onset of sleepiness.
- For eastward travel, early morning exposure to light helps promote sleepiness in the late evening.
Deep Vein Thrombosis (DVT)
Thrombosis is the formation of blood clots within vessels. Blood does not normally clot within vessels and the development of such clots may lead to problems. Thrombosis can potentially occur in any blood vessel and may have fatal consequences if it obstructs the flow of blood to a vital organ. In the context of air travel, we are concerned with thrombosis occurring in the deep veins of the lower legs.
The deep veins of the lower legs are situated in the muscles of the calf. Compression of the veins by muscular contraction, cause a pumping effect (the muscle pump) aiding the return of blood to the heart. If the muscle pump is not working (e.g. due to immobilization), the blood flow in the veins may decrease (known as venous stasis) to the point where small clots may form. Most of these are too small to cause problems. However, they may sometimes enlarge significantly or link up to produce a large obstructive thrombus.
Immobility in a seated position is an obvious predisposition to DVT as the veins of the legs can get compressed and cause stasis. DVT is known to occur in passengers on long-distance road or rail journeys as well as those by air. The common factor in all of these is immobility rather than the environment. Pressurized cabins and high altitude of aircraft have no impact on the risk of developing a DVT.
Why is it sometimes called "Economy Class Syndrome"?
The term "Economy Class Syndrome" was first used in 1977 in a paper entitled "Pulmonary thromboembolism after travel". It is, in fact, an inaccurate term as there is no firm link between air travel in any class per se and the development of DVT. Long periods of immobility in trains, buses and automobiles carry similar risks. The House of Lords report recommends the use of the more appropriate term "traveler’s thrombosis".
How frequent is DVT and is it becoming more common?
The normal rate of occurrence in the general population in the UK is 1 per 1,000 to 1 per 10,000 people every year, depending on age. According to the Wright Study 1 in 6,000 passengers develop DVT after periods of immobility of 4 hours or more.
Are some people more at risk of having a DVT than others?
There are certain predisposing factors that are well known to contribute to the risk of having a DVT. These are:
- Increasing age over 40 years old
- Pregnancy *
- Previously or currently suffering from malignant cancer *
- Blood disorders which lead to an increased clotting tendency *
- Heart disease or blood vessel disease *
- Personal or family history of DVT or pulmonary embolism*
- Recent surgery or major injury, especially below the waist level *
- Oestrogen hormone therapy, including oral contraception *
- Previous / recent immobilization *
- Depletion of body fluids causing increased blood viscosity
- Varicose veins
Obviously, if more than one of the above applies, the risk of having a DVT is further increased. If this is the case, or you have any one of the conditions marked '*', we suggest you seek the advice of your doctor before flying.
Can I do anything to reduce my risk of getting DVT while travelling by air?
As the major cause is immobility, you can do quite a lot to reduce this, and hence minimize your risk of getting DVT. Some suggestions are:
- Walk around the cabin, if safe, once every 2-3 hours to break up long periods of immobility. Moving around the cabin during long flights will help to reduce the period of immobility, although this may not always be possible. Any potential health benefits must be balanced against the risk of injury if the aircraft were to experience sudden turbulence.
- Move your legs and feet for 3 or 4 minutes per hour while in your seat to get the muscle pump working and avoid stasis.
- Do some stretching exercises when waiting to use the washroom.
- Avoid wearing tight clothing around the upper thighs and body.
- Don’t place hand luggage where it restricts the movement of legs and feet.
- At risk individuals should consult their doctor about preventive measures which may include consuming low dosage of soluble aspirin, wearing anti-embolism stockings or even taking anti-coagulant therapy for those at highest risks.
- Avoid commencing an air journey in a dehydrated state (e.g. after drinking a lot of alcohol, having a hangover or being exposed to very hot weather for long periods).
- Drinking coffee, tea and alcohol only in moderation as these are diuretics and may cause dehydration.
Our inflight magazine, Discovery, and inflight safety video also includes tips and exercises to do inflight to help prevent DVT.
What are the symptoms of a DVT?
The most common features of a DVT are:
- Pain or tenderness of the calf muscles.
- Swelling of the leg, especially if it is only on one side. Most people have a small degree of swelling of both feet after a long journey, but this is often due to the accumulation of water as a result of gravity and will soon recover.
- Increased skin temperature and/or redness of the leg.
- Dilation of the veins right below the skin of the leg.
If you experience any of these after your flight; we suggest you consult a doctor to exclude DVT.
For more information you may consult the following useful Links:
- World Health Organization Publication: International Travel and Health Chapter 2 http://www.who.int/ith/en/
- The Aerospace Medical Association Publication: Medical Guidelines for Airline Passengers. http://www.asma.org/publications/medical-publications-for-airline-travel
The above content provided by Cathay Pacific is for information purposes only. They shall not be used, copied or republished by any persons except expressly authorized by Cathay Pacific. Cathay Pacific has carefully reviewed the contents and taken all steps we consider reasonable to ascertain their accuracy. We do not claim the contents to be comprehensive on the subject matter and they shall not be relied on by any persons who may have an interest in the subject matter. Neither shall they be treated or substituted for medical advice by any persons in relation to the subject matters. We advise and encourage any interested party to the subject matter to seek qualified professional (medical or otherwise) advice for any concerns that he or she may have in the subject matter of the contents.
General Health and Safety Tips
You can reduce your chances of getting sick or injured while travelling by following these recommendations:
- Use sunscreen with both UVA and UVB protection.
- Be careful about food and water as Travellers' diarrhoea is the most common illness affecting travellers. You can minimise the risk by:
- Washing hands with soap and water before eating or handling food.
- Avoiding foods or drinks purchased from street vendors or other establishments where unhygienic conditions are present.
- Avoiding raw or undercooked meat and seafood.
- Avoiding raw fruits and vegetables unless you’ve peeled them yourself.
- If handled properly well-cooked and packaged foods usually are safe.
- Tap water, ice, unpasteurized milk, and dairy products are associated with increased risk for Traveller’s Diarrhoea. Safe beverages include bottled or canned drinks, hot tea or coffee, and boiled or purified water.
- Insect bites can be painful and cause allergic reactions or become infected. Some also spread diseases such as malaria or dengue fever. Prevent mosquito and other insect bites:
- Use insect repellent on uncovered skin when outdoors, especially during the day.
- Wear long-sleeved shirts and long pants when outdoors at night in areas with malaria.
- Clothing may also be sprayed with repellent for greater protection.
- Stay in hotels or resorts that are well screened or air conditioned.
- Avoid animal bites by not handling or petting animals, especially dogs and cats. If you are bitten or scratched, wash the wound immediately with soap and water and seek medical attention to determine if medication or anti-rabies vaccine is needed.
- Try not to take risks with your health and safety. Make sure to follow local laws and customs.
- Limit alcohol intake, and do not drink alcohol and drive. Some countries have very strict laws against drinking and driving.
- Always wear a seatbelt, if one is available.
- Wear protective gear when doing adventure activities.
- Use caution when swimming and participating in other water activities.
- Do not share needles for tattoos, body piercing, or injections, to avoid infections such as HIV and viral hepatitis.
- Practice safe sex to reduce the risk of HIV and other sexually transmitted diseases.
- Keep feet clean and dry, and do not go barefoot, especially on beaches where there may be animal waste, to prevent fungal and parasitic infections.
- When traveling with small children, make sure an adult is watching them at all times. Pay careful attention to their health and safety.