Most divers are aware of the problems associated with flying after diving, but seldom give much thought to what can happen while they’re up in the air before going diving; not least is the risk of catching that most common of all contraindications to diving fitness: a cold.

While aircraft preflight briefings highlight the whereabouts of your personal lifejacket and oxygen mask — items of safety equipment that seem more in keeping with escape from a sunken submarine — they never seem to explain just where it is that they’ve hidden the parachutes, or how to protect yourself if the passenger next to you is constantly sniffing, snorting and sneezing.

In the close confines of an aircraft cabin, there’s always the possibility that cold bugs will find your nasal passages more attractive than those of the original host, set up shop and then develop into a full-blown cold that’ll coincide with the start of your long-planned dive vacation.

Unwilling to let nature take its course — and prepared to risk the dangers of diving with congested lungs and sticky ears — some divers turn to pills, potions and decongestants to reduce the discomfort and help the equalisation process.

Often containing antihistamines or pseudoephedrine, some of these preparations can produce unwelcome side effects that, among other things, may cause anxiety, vertigo, drowsiness, a heightened susceptibility to nitrogen narcosis and even increase the risk of oxygen toxicity; conditions that, at best, can take the gloss off any dive.

Seldom considered a life-threatening illness on the surface, the common cold — and the remedies used to treat it — can be just that when the desire to dive overrules common sense and the ability to say, “As much as I want to do this dive, I can't ’cause my nose is blocked.”

_Diving since 1961 — with a background in military, commercial, recreational and technical diving — David Strike has dived extensively throughout the Asia-Pacific region, is a Fellow of the Explorers Club and the organiser of the biennial OZTeK Diving Conference. _