Jet Lag Altitude Sickness Exposure
Although I’ve begun to feel more like a human being again, I’m still recovering from jet lag. When most of us use that term, we believe we are talking about adjusting to abruptly changing from one time zone to another, like going to or from Daylight Saving Time.
I was well into adulthood before I realized that’s only part of it. There are really at least three parts to what we call jet lag. Jumping time zones is only the first part.
Altitude Sickness
Denver is Mile High City, a little over 5100 feet up. Most people fare well enough if they pop up there from sea level, although they may get a few mild symptoms such as tiring more easily than usual or a headache.
South of Denver, Colorado Springs is one of the most popular vacation spots in the USA. Downtown is about 6000 feet high. The Air Force Academy on the north side is around 7000 feet.
Some people aren’t okay there.
Everyone has their own altitude ceiling. That’s an elevation above which your body simply doesn’t want to acclimate. If you go abruptly from a low elevation to a level near your ceiling, you can get altitude sickness but gradually get over it. The first week or two are the roughest. After that, you aren’t aware you’re still working on it while your body ramps up the amount of hemoglobin circulating in your bloodstream until it’s more appropriate for the thinner air, which takes a few weeks.
The first time my then-friend, now-wife visited me, I lived on the north side of Colorado Springs. Her first morning there, she passed out in my apartment. She still felt bad downtown. After I realized what was wrong, we drove (literally) down to Pueblo and spent the day exploring that area. The lower our altitude, the better she felt.
We spent much of her visit in Denver or Glenwood Springs, generally staying below 5500 feet (to be sure) with only short excursions higher.
Altitude ceilings are very individual. My ceiling seems to be around 7500 to 8000 feet. My brother has lived around 10,000 feet.
What does this have to do with jet lag? A lot. The second part of jet lag is altitude sickness.
The cabin of an airplane isn’t pressurized to the equivalent of sea level. In most commercial aircraft, it’s usually pressurized to be like 8000 feet of altitude. There is one major exception, the Boeing 787 Dreamliner, which is pressurized to be like 6000 feet.
Why? To reduce stress on the airframe. Cruising altitude is typically 30,000 feet or so. Air pressure up there is very low. Higher air pressure inside the cabin pushes on the shell of the aircraft, making the shell strive to expand. When the airplane is lower, air pressure outside is higher; this makes the difference between internal and external air pressure smaller and reduces push on the shell. This causes metal fatigue which can eventually make the airframe get stress cracks and fail.
Look at the math. 30,000 minus 0 = 30,000 but 30,000 minus 8,000 = 22,000. That’s much less stress, which translates to much less metal fatigue.
Why is the Dreamliner an exception? Its body isn’t metal. It’s made of carbon fiber, which can tolerate a somewhat larger differential between inside and outside air pressures than metal without significant material fatigue.
The Dreamliner’s cabin air intake and circulation system are also different from standard (the air is fresher) and humidify the cabin air more. These features also help, but cabin air pressure makes a big difference. If you have ever taken a long haul flight in a Dreamliner, you know how much better you feel after such a flight than after the same route on a conventional commercial aircraft. You have less (maybe even no) altitude sickness!
Exposure
The third part is somewhat affected by the Dreamliner’s fresher, less-dry cabin air, but it’s mostly a matter of what everyone around you brings aboard.
Many years ago, due to a combination of volunteer work and a long distance relationship I flew somewhere two or three weekends out of every four. I noticed that I often came down with something after flights that were more than just a one-hour hop. Wearing a face mask never occurred to me as a way to fend off those colds and sore throats.
At one point I got a sinus infection that refused to go away. My doctor kept escalating what we did about it and the damned bug kept resurging. After a while I was doing an exhaustive infection control protocol (I should have bought shares of Lysol), using a prescription-only iodine based soap and still couldn’t knock it. My doctor had me start putting a small amount of Neosporin antibiotic ointment in my nose too. (I should have bought shares of Q-Tips and Neosporin. If you ever try this, I mean small amounts, half as much as the tip of a sharpened pencil. This is very much an off-label use.)
I stopped coming down with airborne infections after long flights.
After we killed off the sinus infection at last, for years I did the Neosporin trick for long flights. Antibiotics in the ointment cannot kill viruses, so I suppose the goo provided a barrier the viruses didn’t get through.
My experience suggested part of what I thought of as jet lag was probably the energy drain of needing to fight off whatever airborne bugs other people exposed me to during the flight.
Note: Those were ordinary viruses. I would never expect such an approach to fend off the nastiest airborne pathogens such as measles, tuberculosis or SARS.
The Dreamliner didn’t exist then. Today, fresher air with a little more moisture in it gives passengers on that type of aircraft a further slight advantage in fending off airborne diseases. The nose does better at that job when it isn’t too dry.
So Jet Lag Is…
Jet lag is really a shorthand term for a bundle of factors, primarily time zone shift, altitude sickness and exposure to pathogens. If we gave it a full name, it would be something along the lines of jet lag altitude sickness pathogen exposure. Quite a mouthful!
We can’t eliminate all those factors, but we can sometimes make choices about how tough one or another of those factors will be.
I didn’t fly on a Dreamliner. I flew on Singapore Airlines, which uses Airbus planes on the route I need. They run whopping HEPA filtration that turns over cabin air at a pace suitable for a hospital. (I also wore my FFP3.) I chose to tolerate more altitude sickness to have better air filtration. As a bonus, the service on that airline is superb even in economy class.
If I had a lower personal altitude ceiling, I might need a Dreamliner instead. As it is, in light of the chorus of coughing a few rows behind me, I’m satisfied with my choice.
I look forward to being fully over the whole discombobulation any time now.
Fascinating. I had no idea about the details of cabin pressure and the Dreamliner differences.