Take care in the air

By ELIZABETH HEATHCOTE

A week in New York, a fortnight in Marrakesh, a trip to India, perhaps? These days, it's not unusual to take two or three long-haul holidays a year, and, in a global world, more of us take eight, 12, even 24-hour flights regularly for work.

Reduced oxygen uptake due to low air pressure, cramped seats, recycled air, semi-institutionalisation, poor food, too much alcohol, anxiety and stress, restricted sleep and a change of time zones all have a detrimental effect on our bodies and minds. But how bad for us can flying be, and how can we reduce the dangers?

Infectious diseases

Recirculated air (the norm is half recycled and half fresh air) has been the focus of periodic health scares about infectious diseases, ranging from colds and flu to tuberculosis and meningitis.

Recycled air is filtered, but still there is a risk, says Dr Peter Barrett. "If you stick 300 people in a small, cigar-shaped box, it's highly likely that diseases will spread."

Dr Richard Dawood, a specialist in travel medicine at Britain's Fleet St Travel Clinic, says the worst problem is when a flight is delayed and the engines, which drive the air recycling, are switched off. There is legislation against this in the US but not in all countries. He is also not convinced about the effectiveness of air filters.

"It is common to go on a long-haul flight and come back with a cold," he says.

So what can you do? Serious diseases are not easy to catch, and someone with TB will look very ill - if that applies to the person sitting next to you, ask to be moved. Drink lots of water - if your mucous membranes are dry you are more vulnerable to infection. And don't even think about wearing a surgical mask. Not only will you look like a weirdo, they are ineffective, says Dr Barrett.

Jet lag

Jet lag, the result of flying through three or more time zones, can leave you exhausted yet unable to sleep. It is the result of your body clock, which controls sleep and hormone production, adjusting to a new time zone.

"The body clock is reset by exposure to light and a hormone called melatonin, which is secreted at night," says Dr James Waterhouse, a body clock expert and senior lecturer at John Moores University in Liverpool.

To adjust, time your exposure to light carefully, he says. If flying west, adjust your lifestyle to that of your destination; if flying east, get up when everyone else gets up but stay indoors until the afternoon to avoid bright light, then get as much bright light as you can in the afternoon and evening.

You can also take melatonin (available on prescription in New Zealand) in the evening but there are accounts of people feeling exhausted or giddy after taking it.

It's a moot question whether messing with your body clock, and thus hormone production, regularly has longer-term consequences. Women flight attendants have more gynaecological problems than other women. They also have higher rates of breast cancer and one explanation is that melatonin disruption caused by jet lag is to blame.

Anxiety and rage

High-profile cases of air rage have added to our awareness of the phenomenon. So, are long check-in queues, delays and being packed in like battery hens driving us mad?

"In reality there's probably only a slight increase in cases," says Professor Robert Bor, a psychologist and author of Stress-free Flying (Qua Books), "but these are becoming more threatening."

Professor Bor puts this down to a combination of factors including alcohol, (which is more potent at altitude - "one drink in the air has the equivalent effect of two on the ground"); poor handling of problems by airline staff, and boredom.

But, he adds, most of us take the stresses in our stride: in most air rage incidents, a history of violent behaviour emerges. "Try to recapture the positive experience," he recommends. "For a few hours you have the opportunity to look down on the world and reflect. It's a privilege."

Deep vein thrombosis

DVT is a potentially fatal condition associated with inactivity, where blood in the lower leg clots. Initially this may cause swelling, or no symptoms at all, but the clots can move to the heart and lungs, causing sudden death. Most at risk are people who have had recent surgery; those with a history of thrombosis, cancer or heart disease; smokers; and women taking the Pill or hormone replacement therapy.

Although a link between flying and DVT is accepted, its causes have yet to be proven: the World Health Organisation is poised to start the first big study. The focus has been on the parlous amount of leg-room, particularly on charter flights, hence DVT's other name, economy class syndrome. The airlines dispute this, pointing out that incidence is higher in business and first class. They say inactivity is the key. WHO will also investigate the effects of reduced oxygen uptake caused by the low air pressure.

Until then, you should take DVT seriously. "There may well be many people who get DVT in their legs but show no symptoms," says Dr Barrett.

Stay hydrated; wear loose clothing; avoid crossing your legs or staying in the same position; try to relax as anxiety may contribute; get up and walk around once an hour.

Some doctors recommend taking aspirin to thin the blood, but this may induce stomach bleeding in some people.

Jetlag