High flying - without fear

A number of recent fatalities following long-haul flights have increased public concern about onboard health risks. Rebecca Gooch presents the definitive guide to staying safe in the skies

You've delivered Fido to the kennels, you've packed the flip-flops and turned off the gas. Frazzled by the preparation of going on holiday, all you want to do is get there. But first there is the little matter of being cocooned in a metal tube at 35,000ft for several hours with a few hundred strangers. Unnatural, certainly. But unhealthy? Myths and speculation about the possible physical effects of flying long-haul have been bandied about for years. But with news that British lawyers representing 30 victims of the potentially fatal condition Deep Vein Thrombosis (DVT) are to issue legal proceedings against a number of airlines, anyone about to take a plane for that fortnight in the sun might want to know what's scaremongery and what's sensible concern.

British Airways has responded by updating its "Well Being" programme, with a range of measures designed to maximise passenger comfort and awareness, including a new set of exercises designed by the pilates company, Body Control Pilates Group. There have also been concerns raised about air quality, transmission of infection, reduced oxygen, dehydration and even cosmic radiation. Last year the House of Lords report on Air Travel and Health studied all these aspects and found "no substance in the extreme claims about health risks from air travel". So here's what you need to know about arriving healthy after a short-hop or long-haul.

Deep vein thrombosis

DVT is caused by blood clots that can form when blood pools – most often in the legs – during long periods of inactivity.

According to research by John Scurr, consultant vascular surgeon at London's Middlesex Hospital, one in 10 older air travellers may develop small, symptomless clots, that they're not even aware of, which dissolve naturally. But occasionally, hours or days later, small pieces of clot may detach and cause a potentially fatal pulmonary embolus. Generally, the risk goes up once you reach 40. But there are many known factors, such as personal or family history of DVT, abnormal clotting, certain forms of cardiac disease, hormone treatments such as the pill and HRT, pregnancy, recent major surgery or injury – particularly to the lower limbs or abdomen, and recent immobilisation for a day or more, which bump up your susceptibility.

With air travel, it is the prolonged immobility which adds to the risk, and at the moment there's no evidence that any other aspects of the flight environment might add to that risk. "Immobility and identifying whether you could be at risk are the key things," says Dr David Flower, British Airways' senior occupational physician and an authority on DVT, who has played a key role in developing BA's "Well Being" programme.

"Seated immobility is the key thing," he says. "I've heard of somebody who used to be a milkman, then became a taxi-driver and within three weeks of sitting all day developed a DVT. A teacher had been sitting for 12 hours and got a DVT. The consensus is that travel alone is never enough. But along with the known risks there are also soft risk factors like obesity and smoking, and if you get an "X" in too many boxes, your risk of developing DVT rises."

What you can do:

"It's a good idea to move every two hours," says Lynne Robinson, director of the Body Control Pilates Group which designed BA's new in-flight exercises. "One very important sitting exercise acting on the calf pump, to prevent DVT, is to sit tall, take your foot back underneath the seat a little, keeping it in line with your knee and hip. Then push the toes and ball of your foot into the floor, hold for a count of five and release. Then push your heel into the floor for a count of five and release. Repeat these actions with the knee at a right angle and the leg stretched out a little. You should feel the work deep in your calf."

The Wellman Clinic (020 7637 2018) has a DVT Pre-Travel Screen, which tests blood for three genetic factors which make people more prone to clots than others. Some doctors suggest taking aspirin 24 hours before a long flight, but it's not suitable for everyone. An alternative is pine bark supplement (Pycnogenol), which works like aspirin to reduce the potential of clotting.Graduated compression stockings may also help. Those with varicose veins should get medical advice to ensure correct fitting. Aromatherapists suggest a few drops of geranium oil (an anticoagulant) on a moist tissue, stroked up your legs from your feet.

Air quality

The air you breath as you hunker down for your in-flight G&T is different from the usual lungful on the ground. There's less oxygen, 50 per cent of it is recycled, and it's far less humid than you'll be used to, which can lead to superficial dehydration – the sore eye, tight skin syndrome we all feel after four hours in a 747. That G&T will also have nearly twice the effect at altitude as at sea level. You can pick up an infection on a plane just as you can in any crowded place. But can those same bacteria and viruses be endlessly recycled back into our faces, leading to us inhaling "second-hand germs"? Not according to the World Health Authority, who investigated global concern about the possible spread of tuberculosis on planes, and reported "no evidence that air circulation facilitated transmission of infectious disease aboard aircraft."

On board, the total volume of air is exchanged every two to three minutes, providing 20 cubic feet per minute per passenger, half of which is recirculated through High Efficiency Particulate Filters which remove bacteria and virus particles.

"These Hepa filters are 99.9 per cent efficient and are the same as those used in operating theatres," explains Dr Flower.

"And as for dehydration, for people with normal homeostatic mechanisms, it is superficial rather than central. In an eight-hour flight you will lose about 100mls of liquid, which given the litres we've got circulating is negligible. But because the humidity is 5-10 per cent, when we're used to 30-50 per cent, lips, tongues, eyes and skin may feel dry. " Moisturisers, artificial tears, lip balm and drinking for comfort is all you need to do. Drinking plenty of water is common advice. "But being told you need a pint every two hours is one of those myths that is very hard to undo," Dr Flower adds.

What you can do:

Some people suggest drinking carrot juice to combat the reduced oxygen. Tea-tree oil, a natural antibiotic, dropped on to a hankie and sniffed, might help protect you from any bugs flying your way. Dr Richard Dawood, who runs the Fleet Street Travel Clinic, takes a flu jab before flying long-haul and advises passengers to keep nasal passages moist using a saline spray.

Radiation:

We all live with background radiation without it being a significant health risk. But what about the cosmic radiation which passes through an aircraft at altitude which we then absorb? Exposure will depend on the route, altitude and type of aircraft. But BA calculate that on average, in one hour on a long-haul aircraft you will receive a five microsievert dose, and one to three microsieverts on a short-haul aircraft, dependent on the altitude reached – all way below the annual one millisievert limit recommended by the International Commission on Radiological Protection.

It tots up to about 200 hours flying a year on sub-sonic trans-equatorial routes before travellers are over the limit. The House of Lords study concluded that "flying exposes passengers and crew to more radiation than generally experienced at ground level, but the doses received are of very little significance to health."

What you can do:

Patrick Holford, nutritionist and founder of the Institute for Optimum Nutrition, recommends taking at least 30mg of each of the B Vitamins the day before flying. "They help your brain and body adapt to the new time zones, and the unseen stresses of flying such as radiation."

He also suggests taking an anti-oxidant complex, available from most health food stores. "Anti-oxidants protect you from radiation, which weakens your immune system and is part of the reason you feel tired during and after flying. Being tired, you won't digest food very well, so taking a digestive enzyme such as Easigest with your meal will assist the process."

Other tips:

Visiting the dentists before flying is not a good idea. Your bodily gases expand inside the pressurised cabin, so a tiny air pocket under a filling will expand, causing pain until you get down to earth. For the same reason, eating wind-producing foods like curry, cabbage, turnips or beans the night before a flight is unwise. Tight waistbands, corsets and figure-hugging clothes will also make life more uncomfortable.

If you've got a cold, the pressure change during descent could cause Eustachian tube "lock" – your ears won't "pop". This could cause pain and even eventually lead to a burst ear drum. Nasal decongestants can help, or try holding your nose and swallowing, pinching the nose and drinking, yawning or simply opening the mouth wide.

Because of their anatomy, babies and small children are less affected by barotauma (trauma due to pressure), but crying or sucking will help. Dr Dawood suggests relieving a child's ear pain by gently pinching the nose, placing your lips around the mouth, then blowing gently.

Information about BA's 'Well Being' is at www.britishairways.com/health