Specifically this is about flying and your body.
People simply were not meant to fly.
It may be a cliche, but it's true. Evolution has done a great job of adapting your body to its environment. That environment, however, is not a pressurized aluminum tube hurtling through the stratosphere at 500 miles per hour.
I'm not a doctor, just a guy who drives airplanes for a living. My Air Force training did involve a fair bit of aerospace physiology, so I have a workingman's knowledge of what flying does to your body.
This diary is geared towards passengers rather than pilots. A lot of my trips involve a "deadhead" on a commercial airliner so I spend more time than I care to sitting in the back. Fortunately I'm usually so tired that I sleep through the whole experience.
Hopefully I can give you some tips to make your next flight a bit less unpleasant.
Let's start with the obvious. The first thing you probably notice about airliners is that they're noisy. A set of earplugs is a good accessory to bring and may also make it easier to sleep.
Some airports may even require you to walk out on the tarmac to board the plane. This is especially true with the small regional jets and turboprops. I always put earplugs in if I have to go out on the tarmac. I need to save what little hearing I have left.
You may also notice your ears popping as the plane gains altitude. This is normal. The air in your inner ear and sinus cavities expands as the cabin altitude goes up and some of it has to come out to equalize the pressure. Normally they'll take care of themselves on the way up. It's on the way down that they may give you trouble. More on that later.
Your digestive tract is another story. The cabin altitude of an airliner may reach 8,000 feet at cruise altitude. That can cause any trapped gas in your digestive system to expand noticeably. You need to let it out. This is not the time for modesty. It can actually cause cramps and discomfort to keep that bottled up. So let 'er rip.
Certain foods can really aggravate this problem. Beans, of course, as well as cabbage, broccoli and onions are just a few. Best to avoid these before flying. Save the hummus and sauerkraut burrito for another time.
The Air Force used to put us in an altitude chamber and pump air out of it to take us up to 42,000 feet! They don't take you nearly that high any more because they figured out it's bad for you. They also used to put us through a rapid decompression but they decided that's bad for you too. I'm surprised they didn't make us run with scissors while we were at it.
The descent phase is where your inner ear and sinuses are likely to give your trouble. As the cabin altitude goes back down, air tries to get back into your inner ear and sinus to equalize the pressure.
Unfortunately it's a lot tougher for air to go in than it was for it tom come out. Just the way things were put together. Sometimes we have to help the process along. Chewing gum can help, but the best technique is something called a "valsalva".
What's a valsalva? Well, it sounds funny and it looks funny but it works.
Remember when you were a little kid and your tried to make your eyes bug out by holding your nose and mouth closed and blowing? No? Just me? Hey the internet wasn't invented yet. We got bored.
Anyway you get the idea. Pinch your nose and blow with your mouth closed. You should feel your ears pop. You may have to do this multiple times during the descent. Tilting your head to one side or the other while you do this can help. This stretches the Eustachian tube that connects your inner ear to your throat.
Where you'll really end up hating life is if you fly with a bad head cold. This is where you can end up with an "ear block" or a "sinus block". You really don't want this to happen to you.
Trust me. I've this happen to me a couple times and "excruciating" barely does it justice. A sinus block feels like someone driving a hot knife through your face. An ear block can actually cause your eardrum to burst on the descent. It almost happened to me once. All I could do was think "Oh man this is gonna hurt!" but finally I was able to get it cleared.
If you get a bad ear or sinus block I'd suggest seeing a doctor. It can actually do some damage. I recall the Air Force took an x-ray of my head and grounded me for a few weeks after I had one of these. I don't remember exactly how long but I do remember how much it hurt!
The best advice is: don't fly with a bad cold! As a backup I keep a bottle of nasal spray in my bag just in case.
If you want to see an example of this: take an empty plastic water bottle and tightly seal it while you're at cruise altitude. By the time you land it will likely be crushed. That's how much pressure is being exerted on your ear and sinus cavities.
Your inner ear is also responsible for balance and equilibrium. It's a pretty amazing little setup that can detect acceleration and rotation. Without it you would have a hard time even standing up.
Those semicircular thingies in your inner ear detect motion about the lateral, vertical and horizontal axis.
Remember the game you played as a kid where you put your head down on a baseball bat, spun around a bunch, and then tried to run across the yard? That's what we did for entertainment before video games. Yeah, back in the day wasn't all it's cracked up to be.
Anyway, what that game did was get the fluid in your inner ear all spun up. Once you stopped spinning and tried to run, that fluid kept sloshing around in there and hilarity ensued.
The Air Force had a (slightly) more high tech version of this called the "Vista Vertigon". This little torture device was a T-33 cockpit mounted on a swivel. That should give you an idea of how old this was if they used a T-33. You wouldn't be able to see outside and this thing would very smoothly and silently spin around. Meanwhile the radio would tell you to make certain flight maneuvers.
You actually wouldn't realize that the device was spinning - until the radio told you to change your transponder setting, that just so happened to require bending over to reach it......
Whoa Nelly! What was that! As soon as you moved your head your internal "gyros" would tumble and it would feel like you were tumbling end over end. Hilarity, and sometimes vomit, would ensue.
In later years I learned to reach down and change the setting with a pencil so I wouldn't have to move my head. If you ain't cheating you ain't trying!
Speaking of puking, airsickness is mostly a product of your inner ear and not your stomach. My non-scientific explanation is that after your inner ear gets bounced around enough your body doesn't like it and lets you know in various ways. One of which happens to be through your stomach.
At least you don't have to worry about airline food making you sick. They generally don't feed you any more.
Some think your body interprets the data as having been poisoned and that's why you puke. Sounds plausible to me. I'm sure there's someone around here with a bunch of initials after their name who knows more about this.
If you're prone to airsickness avoid rapid head movements. If you start feeling queasy try looking straight ahead. Slow your rate of breathing and try to think happy thoughts. Point that little air vent (called a "gasper" by the way) at your face.
Hopefully you're not sitting next to me. I'm a sympathetic puker. It'll be a total barf-o-rama back in row 12!
The lesson here is that when you're flying, your ground-based senses can mislead you. A maneuver at one G (the force of gravity) will feel just like level flight if you have no external reference. Bob Hoover used to demonstrate this by doing a one G barrel roll with a glass of water perched on the dash - and not spilling a drop.
Another hazard of long flights is dehydration. The cabin air is pretty dry and you need to keep drinking water. Unfortunately this will require getting up to pee at some point and we all know how much of a pain that is.
You may have been told that the cabin air is recirculated and that guy sneezing ten rows in front of you is going to give you his cold (or worse). Actually only a small percentage of the air is recirculated. I wouldn't worry too much unless he's sitting right next to you.
In case you haven't noticed, Americans are getting bigger and airline seats are getting smaller. They're also getting closer together. Airlines call this "seat pitch". By squeezing the seats closer together they can cram a few more sardines into the can. Good for profits, not so much for your body.
It's believed that sitting in an airline seat for long periods of time can cause blood clots in your lower extremities (bad). If you can, try to get up once in a while. At the very least be sure to stretch periodically.
Lastly let's talk a bit about "jet lag". If you're crossing multiple time zones you've probably experienced this. It takes roughly a day to adjust for each time zone. Go to Europe for a week and right about the time you're getting used to it you'll have to come home and repeat the process. It's generally easier to adjust going West than going East.
Most flights to Europe leave the US in the evening. If you're able to sleep on the way over you'll have a leg up when you get there. I've tried to "power through" the first day and found myself almost face down in my dinner. Your body is light sensitive so getting out in the daylight helps your body adjust. Likewise try to avoid light when you're trying to sleep.
Flying isn't any fun these days. I can only imagine what a time traveler from 1970 would make of today's airline experience. Hopefully you've picked up a few tips to make a little less unpleasant. If you see me, I'm the tired looking guy in the airline uniform with his eyes glazed over drooling on himself. Try not to wake me up.