Humans flying at 10,000 feet aren't exactly the most
versatile,
survivable creatures on this planet. This is probably due to the fact that we evolved to be most effecient at about
sea level. There is an array of sicknesses and ailments that can affect a pilot while in flight, and it's best to know what they are and how to avoid them. I will discuss the most pressing ailments only briefly, as they are most likely detailed in-depth in other nodes - I have sorted them in order of frequency.
- Hypoxia is best defined as not getting enough oxygen to your body cells and tissues, including your brain. This usually occurs at higher altitudes (10,000 feet) in unpressurized aircraft, and afflicts you without warning. One of the first symptoms is a feeling of well-being or euphoria; this is why there are oxygen masks in airliners, and why you must wear them even if you feel fine. Symptoms include loss of vision(!), hearing, numbing of the extremities, and even death. There is an excellent in-depth writeup on Hypoxia. It is also interesting to note that people who smoke are twice as susceptible to Hypoxia, feeling the effects at a mere 5 or 6 thousand feet.
- Ozone Sickness is another high-altitude sickness (30K+ ft). Unlike Hypoxia, there is a wide variety of symptoms that read like the back of an experimental drug, ranging from hacking coughs to vomiting.
- Carbon Monoxide poisoning occurs when exhaust from the engine of the aircraft (or any other vehicle for that matter) seeps into the cabin. What you probably don't know about the infamous poison, however, is that as altitude increases, your susceptibility to it increases dramatically. Lighting as few as 3 cigarettes at 8,000ft can be lethal. (note I said "lighting," actually smoking them is not necessary)
- Hyperventilation, or overbreathing, upsets the natural balance of oxygen and carbon dioxide in the brain. This is usually caused by stress or anxiety, which is not unheard of in airplanes. This usually results in a form of Hypoxia... Which is why you shouldn't freak out on an airplane. You might die if you freak out! So stop freaking out!
- Decompression Sickness occurs when changing altitude quickly (or in the worst-case scenario, rapid decompression due to an accident or fault in a pressurized aircraft). The rapid change of air pressure results in various gasses trapped in your body cavities to expand or contract. In some cases, the pain involved will render you unconscious; some cases have been known to cause physical damage. In the case of rapid decompression, you are also likely to suddenly experience hypoxia (see above).
- Evolved Gasses such as nitrogen are always present in body fluids. They will form bubbles in your blood when decompressing quickly (eg: descending altitude), and has been the subject of many a gory movie. Scuba divers everywhere will know the effects of nitrogen and "The Bends."
- Vision problems are often a problem with pilots. As they fly above the white, reflective clouds, they are exposed to much more sunlight than any other person. As well, in misty, foggy, or hazy situations, the eye loses a focal point and it is hard to focus on anything outside of the aircraft. An example that possibly only I have experienced, is when you have your face very close to a mesh screen on your patio door or in a window. It takes you a few seconds to focus your eyes onto the screen, and sometimes you actually need to touch the screen to "straighten your eyes out."
It is advised that all pilots study the effects and symptoms of all altitude-related sicknesses and take preventative measures. As per always, fly with a co-pilot and it is recommended that one person on board have a first aid certificate. And passengers, remember: Don't freak out in an airplane - it might kill you!