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How Flying Seriously Messes With Your Mind and Body (bbc.com)
dryriver writes: BBC Future has an interesting piece about how traveling in an airliner does strange things to people's minds and bodies, such as far more people starting to cry while watching even mildly emotional movies on airplanes than what is normal, some passengers experiencing decreases in acuity of sight, taste and smell (airline meals are over-seasoned to compensate for this), unusual tiredness or desire to sleep, your skin drying out by up to 37% percent and possibly becoming itchy, and some people breaking wind far more often than they normally would. Here is an excerpt form the report: "There can be no doubt that aircraft cabins are peculiar places for humans to be. They are a weird environment where the air pressure is similar to that atop an 8,000ft-high (2.4km) mountain. The humidity is lower than in some of the world's driest deserts while the air pumped into the cabin is cooled as low as 10C (50F) to whisk away the excess heat generated by all the bodies and electronics onboard. The reduced air pressure on airline flights can reduce the amount of oxygen in passengers' blood between 6 and 25%, a drop that in hospital would lead many doctors to administer supplementary oxygen. There are some studies, however, that show even relatively mild levels of hypoxia (deficiency in oxygen) can alter our ability to think clearly. At oxygen levels equivalent to altitudes above 12,000ft (3.6km), healthy adults can start to show measurable changes in their memory, their ability to perform calculations and make decisions. This is why the aviation regulations insist that pilots must wear supplementary oxygen if the cabin air pressure is greater than 12,500ft. A study in 2007 showed that after about three hours at the altitudes found in airline cabins, people start to complain about feeling uncomfortable."
For those that didn't RTFA, it seems tomato juice tastes much better on a plane. I fly a lot and can say almost every airline also carries spicy tomato juice for bloody marys too.
My wife just asked me the other day why I always get tomato juice on a plane but not at home. Thank goodness for slashdot in helping me become more self-aware.
I've only flown on a 787 once, but it's a huge improvement over any other standard-class flight I've been on. The higher pressure is really noticeable - I got about 4 hours of work done, and slept soundly for much of the rest of the time. Oh, and it was the only flight I've been on (including in business) where the skin on the lower halves of my legs didn't dry out and remain itchy for a week afterwards.
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The Boeing 787 and Airbus A350 supposedly feature improvements in cabin air pressure, with pressurization to 6000 feet equivalent, as well as increases in humidity.
Unfortunately, they still aren't that common.
Not sure about the A350, but the 787's composite fuselage allows for higher humidity, too.
Water and aluminum equals corrosion, so aluminum airliners fly with extremely dry cabin air because the cold outside would cause condensation on the aluminum, leading to corrosion and planes falling apart much faster.
Which isn't a good thing.
But composites apparently aren't (as?) susceptible to water-caused corrosion (or degradation), and I bet they don't conduct heat was well so there's less condensation in the first place.
Higher humidity means less impact on the mostly-water meatbags inside the sardine can.
Years (Christ, decades!) ago I was an engineer at Boeing and we looked into some report that said something like "people experience nosebleeds on aircraft 840% more often" and we talked to doctors who traced it to low humidity in the cabins. We designed a humidifying system (corrosion wasn't a problem, but the duct work had some ordinary steel components that needed to either be replaced or they would rust quickly). The system design predicted a system weight of about 200 pounds, and management figured no one would want it so they killed the project there. They were probably right; American was ordering planes with a brushed aluminum finish because they didn't want the weight of the paint on the aircraft.
Fascinating post, article and lots of good comments on this - thank you.
With the caveat that I don't know what I'm talking about [ ! ] the article got me thinking about the way that our senses operate differently at altitude. Essentially, this means, "at a significantly different atmospheric pressure"... So obviously the first thin to think about is : what, exactly, is that pressure difference? Well, according to this calculator, at mide.com,
https://www.mide.com/pages/air...
A "typical" air pressure at sea level might be 101.325kPa[kiloPascals], in which case the corresponding air pressure at 8,000ft would be approximately 75,250 kPa - which is approximately 75% of sea level pressure. OK, for a "starting point", I'd hope we'd agree that this delta is sufficient for physical and chemical reactions to be potentially altered.
Then I got to thinking about passengers from a physiological perspective. Essentially, the human being is a mass of semi-permiable membranes. Yes, there is plenty of chemistry going on within us - turning foods into energy, for example - but it also stands to reason that our 5 senses are going to be quite sensitive to changes in pressure... For example - a reduced atmospheric pressure will mean that inhalations bring fewer air molecules in to our lungs, which would also surely involve changes in our sense of smell. OK, I don't know how pressure differential would impact the dispersal of scent chemicals in a gas mix, but there is likely to be a difference...
Our sense of taste is going to be based on diffusion and/or osmosis, as the chemical trace signatures of what we eat are absorbed and processed by the cells in our taste buds. But of course the actual mechanics of tasting are going to be based on chemicals being transferred into saliva and then offered up to the taste processing centres on our tongues. Whether the underlying processes are osmosis or diffusion, or a mix or variation is almost secondary to the point that there will be something like this underpinning the necessary chemistry that drives the sense of taste. Mess with partial pressures, absorption rates, osmosis or diffusion rates and it rather makes sense.
If we were sensitive enough, we might even expect to witness a very slight change in the sense of touch... Just as we know that limbs can swell in low pressure, so sub-cutaneous blood capillaries are going to change and this should impact our touch. Would sight be impacted? Perhaps, if the lower atmospheric pressure caused a slight outward swelling of our eyes?
The thing that really interests me, though is the comment from TheRaven64, where they observe that Gin & Tonic is "one of the few alcoholic beverages that tastes better at low air pressure." Describing something as "tasting better" is way too subjective for us to be likely to reach a consensus upon, but the observation of the change, alone, might be enough to suggest that there could be ways of compensating for altitude-related changes to our senses by altering the composition or chemistry of what we eat...
Lastly - just as a final thought - I wonder if gravity [or the absence of it] plays a part in our senses too? OK, so the reduction in the gravity we experience between sea level and 40,000ft might not be enough of a difference, but we could theoretically extrapolate by looking at feedback from astronauts as to whether ultra-low gravity environments impact their senses... I'd be very interested to know if we've got any readers who can better explain the relationship between the change in what we sense during a flight and the environmental impact on our physiology - I've just been guessing in this post, but suspect there's some pretty interesting material here somewhere...
I stupidly went diving once when I had a bit of a cold, got really nasty squeeze in my palate at the top of my mouth when ascending. I lost my taste for about 2 months afterwards as a result, even eating chocolate basically just felt like having mud in my mouth.
I now take the "Don't dive even if you have a minor cold" thing seriously now, as no doctor could help, and I genuinely was beginning to wonder if I'd lost the sense of taste for good.