Away on business:  how to avoid in-flight colds and manage jet lag.

 The flight is packed, the bone-dry air is recirculating inside the cabin for the umpteenth time, and someone is having a coughing fit five rows away.

 Sound familiar?

What can the traveller do to guard  against something as common as the cold or as stealthy as SARs, or potentially, Avian flu?

 A recent study from California  found that about one in five passengers came down with a cold within one week of a flight.  This is about four times  higher than the cold-strike rate in the general population at any given time. 

Cabin air is a combination of fresh and recirculated air, a mixture designed to conserve fuel that would otherwise be spent on air-conditioning if fresh air alone was used.  It also has a slightly lower percentage of oxygen in it than normal air, which can compromise people with heart or lung conditions, and makes most of us feel intellectually dull.  Ironically, since smoking has been banned on flights, the airlines have been able to reduce the number of times they freshen the cabin air:  good for their bottom line, but not great for our health.  

Cabin air quality is  also very low in humidity, which further serves to dry out the mucous membranes of passengers, ie, eyes, nasal passages and the linings of the mouth and respiratory tract.  People who have asthma or tend to get sinusitis are particularly at risk. Dry mucous membranes mean that the tissue layer that is the barrier between your inside and the outside environment is more vulnerable to penetration by bugs: viruses and bacteria.

 The most common way to get an infection  from  day to day is by touching your face – nose, mouth or eyes.  The organisms involved get on your hands and are then easily transmitted to your eyes, mouth and nose and get into the body through those dried out mucosal membranes. That is why something as simple and washing your hands is so vital. You can also inhale microbes, but more bugs are on surfaces than floating in the air.

 The best defense is therefore trying to keep your mucous membranes moist.  Here are some strategies:

•  When travelling, drink more water than normal.  Avoid dehydrating beverages if you can, such as alcohol and coffee, and everytime you do drink one, follow with a water chaser.
  
• Wash your hands frequently and avoid touching your face.  If it's too difficult getting to the bathroom, use antimicrobial moist towelettes
  
• Keep your eye surfaces moist by using eye drops every few hours.
  
• Take a tiny water spray with you (security regulations permitting) and spray the insides of your nose regularly.  If you are prone to sinus infections try to rinse out your nasal passages with saline solution during and after a long flight.
  
•  Many people swear by coating their nostrils with Vaseline, as this helps to prevent dehydration.  Some people also use a cotton bud to coat the inside of the nose with an antibiotic cream, such as Bactroban.
  
• In general, avoid touching areas that other people have touched, with your hands or with your face.

 Jet lag.

If you cross three or more time-zones, you'll probably experience the disorientating feeling known a jetlag.  Your biological clock might not adjust for several days; difficult if you have to be on your toes for meetings or presentations.  Going east affects you more than going west, as it is easier for you to re-set your clock backward than forward.

Lots of research has been done on jet lag over the past ten years, and the following are some of the major findings.

• Try to get up and go to bed earlier for 3 days prior to an eastward trip and later for a westward one.
• Change your watch to your destination time zone as soon as you board the plane. If you are on medication that need to be taken regularly, wear two watches.
• Drink plenty of water and non-caffeinated, non-alcoholic beverages during the flight. Two glasses an hour is ideal.
• Sleep as much as you can during the flight, even if you don't feel sleepy, as this seems to make it easier to slip into a new time zone
• Sleep medication taken on a long flight may help you feel more rested when you land.  Stilnox is a good choice (prescription only).  Have a trial run with any unfamiliar medication before you go.  Some people may feel worse if they take medication though, especially if the flight is less than 5 hours.
• A recent trial found that Viagra can help prevent jet lag, but this may introduce a new set of problems.  If you take it anyway, you could try it (half the usual dose); if you've never taken it before, don't take it for the first time on an aeroplane in case you get one of the (rare) nasty side effects.
• Try to book a flight that arrives late in the afternoon, and after you land stay up until 10 pm local time.  If you arrive earlier in the day, nap in the afternoon, but for no more than two hours.
• When you arrive, eat only a snack, not a big meal, and try to adopt  a normal breakfast-lunch-dinner meal schedule as soon as you arrive
• At aircraft cabin pressure, the air in body cavities expands.  Favorite places for this to happen are the ears, sinuses and teeth.  If you have erosion in a tooth from decay, you may develop severe pain at altitude.  If you'd rather not see a dentist urgently at your destination, have it sorted out before you go. If you have a head cold or ear condition, changes in air pressure during ascent or descent can cause discomfort.  Pinch the nose, shut your mouth and blow out very gently to equalize the pressure. Swallowing, sucking sweets or chewing gum can also help.  If you are tempted to fly with an existing ear infection, don't: permanent ear damage is more depressing than missing out on a meeting.  Get a medical clearance before you fly.
• Cabin pressure also causes the air in your gut to expand, hence the feeling of bloatedness and /or excessive wind.  Eat small portions regularly, and move around the cabin as much as possible to help this.
• Get out in the sunlight or bright light as much as possible, as there is strong evidence  that this helps to re-set your body clock faster  (remember sun-protection though)
• Use earplugs and eye shades to help you sleep
• If possible, stay in the same hotel or same area as on previous trips, as familiarity helps with sleep and overall orientation.
• Melatonin.  This is the 'hormone of darkness' as it's produced naturally in your brain at night, and helps control your body's sleep/wake cycle.  It has therefore been explored as a way to prevent jet lag.  It is available only on prescription in Australia, but can be bought over the counter in the USA, where it is not regulated by the FDA and therefore may be of variable quality. A recent  meta analysis of 16 trials involving 500 people concluded that it makes no significant difference, but some people swear it works for them.  If you do try it, take a dose  on the plane at the time your ought to be going to sleep in your destination, and when you arrive, take it half an hour before retiring for  the first 3 to 4 nights.