YOU'RE taking a seat on a plane headed for Martinique, Maui, Bora-Bora. You fasten your seat belt and turn to the woman next to you. She sneezes, then dabs her red nose with a tattered tissue.
You know instantly that you may as well forget the beach, get off the plane and go home. Nursing the cold you're bound to catch from her will be easier in your own bed and old jammies.
I can't tell you how often I've confronted this situation in my travels, often made worse by harried pre-departure days when I'm tying up things at the office and packing into the wee hours of the morning. Stress and exhaustion -- thought to be immune system suppressants -- almost inevitably are among my carry-ons, making it all the easier to catch cold on a plane, in a hotel room or at a tourist attraction. Brush your hand against a banister where germs lurk, then touch your face and you're dead bait for a cold.
It's enough to make a traveler stay home. If you've ever had a cold on the road, you know what I mean. The runny nose and scratchy throat are aggravating, but the mental dullness is even worse, draining the joy out of a tropical sunset, the "Mona Lisa" or the Taj Mahal. You fight an internal battle between carrying on with your sightseeing and caving in.
Even if you succumb, it's hard to replicate the comforts of home that help you get over a cold -- the herbal tea, warm down comforter and afternoon soaps operas -- in a faraway hotel room.
I remember a call from my sister, who came down with a monster cold several years ago in a Paris hotel. She was so hoarse that I barely recognized her voice, and I contemplated telephoning the front desk to get medical help for her. As it turned out, the clerk there came to her assistance without my summons. He gave her a jar of honey from his family's farm and advised her to mix it with hot tea.
The healing power of honey notwithstanding, it's lunacy to rely on the kindness of strangers to help you avoid and combat colds. People you meet are the germ carriers from whom we catch colds by taking in contaminated droplets through the mouth, eyes and nose.
The more contact you have with them, the more likely it is that their viruses will infect you, which is why the enclosed, hothouse environment of an airplane puts travelers at especially high risk. A 2002 UC San Francisco study suggests that about one in five travelers catches cold within a week of flying.
The same study, however, showed that recycled air on most newer jets, passed through efficient filters, isn't necessarily the culprit. Drs. Scott Gold and Robert Pincus, co-founders of the New York Sinus Center, say that low humidity in flight adversely affects the lining of the nose, making the body less able to defend itself against pathogens.
Enforced proximity to people who have colds, particularly on long-haul flights, is another, probably more significant, factor in the spread of germs, Gold and Pincus say. They suspect that travelers sitting as far as three rows away from a cold sufferer are in danger of infection. Thus they advise those who have colds to postpone their trips to keep from spreading germs and urge those who end up near snifflers to avoid catching cold by asking for other seat assignments. But neither scenario is likely in the real world of full flights and nonrefundable tickets.
Joe Graedon, coauthor of "The People's Pharmacy," has several other ideas on avoiding a cold when you travel:
* Take your leave calmly, making sure you get ample rest. "We know that traveling is stressful and that stress makes you vulnerable, whether you're going to Grandma's house or New Zealand," Graedon says.
* Pack a surgical facemask and wear it if you end up next to someone with a runny nose. Though cold viruses are tiny enough to breach most masks, we tend to get infected by touching our faces with hands that have contacted things cold sufferers have touched, such as airplane armrests. Wearing a mask makes it harder to touch your face, diminishing the chances of introducing your neighbors' pathogens into your system.
* Wash your hands often, using the hospital protocol: 30 seconds of soap and water, which is about the amount of time it takes to sing the "ABC" song very slowly. Put a paper towel between your hand and the doorknob as you leave the lavatory so you don't pick up germs and undo all the good you just did.
* Drink plenty of non-caffeinated, nonalcoholic beverages to stay hydrated.
* Conquer jet lag as soon as possible, using exercise, exposure to sunshine, melatonin, short-acting sleeping pills or whatever works for you. "If you can't get a decent night's sleep," Graedon says, "your immune system caves in."