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Hypoxia

You placed a great deal of emphasis on the quality and integrity of your equipment and flying skills. Now it's time to put emphasis on the integrity of the most important, yet weakest, link in your system, . . yourself. While you are piloting your craft (whichever type that might be) you are performing a rewarding yet demanding task. This is a time when you can't afford any performance compromise from the most important component of your system. . . YOU !.


Whether you're standing at the Gold Hill launch, 12,500 feet above sea level in Telluride Colorado, or 12,500 feet msl in the cabin of your plane, you need air. To be specific, you need supplemental breathing oxygen. Without it, your brain (YOU), the most important component of the system, will operate at only a fraction of its capacity. You will loose your precious mental capabilities at a time when you need them most, during some competition or simply free flying, when judgment is important to your and others' safety. This phenomenon, in which altitude affects your physical and mental abilities, is known by many proficient pilots as hypoxia.

What is hypoxia ? As Webster (in his dictionary) defines it; "hypoxia \hip–'äk–se–ah, ª–'päk–\n [NL, fr. hypo– + ox– + –emia ]: deficiency of oxygen reaching the tissues of the body - hyp o ox o ic \–sik\ adj".

As many medical reference manuals and books define it;
Hypoxia : the effects of an insufficient supply of oxygen pressure on the body and tissues that includes the loss of mental judgment and cause of physical dysfunction.

The word "hypoxia" is derived from "hypo" meaning "under" and "oxia" referring to "oxygen". Hypoxia is a relatively new word not in many of the older dictionaries still in use today. The medical aspects of hypoxia are also somewhat new and still a very good subject for undergraduate studies. The advent of the Air Force has been responsible for almost all we know about it. What is known is that it is real, dangerous, and most of all, not something to ignore. You can live for weeks without food, days without water, but only minutes without oxygen. You do not store oxygen in your body, therefore, you live only as long as you can replenish the oxygen consumed by your metabolic process. Oxygen is the most important element for your survival and quality of personal performance.

Recognition of hypoxia and its dangers Hypoxia does not hit you all at once. It comes on slowly, at a speed that is mainly a function of your altitude and somewhat of your condition. The higher you go, the faster hypoxia will take effect. Experiencing any of the effects indicating the onset of hypoxia is just as, if not more, insidious as the condition itself. Simply put, once you have convinced yourself you are experiencing hypoxia, it's simply to late. You are now mentally and physically operating at a fraction of your capacity and losing more at a fast rate. Oxygen is needed now. Oxygen will prevent this dangerous phenomenon.

A list of the most common indications (symptoms) of hypoxia pilots may or may not recognize:
1 an increased breathing rate
2 lightheadedness or dizziness.
3 tingling or false warm sensations in appendages
4 sweating
5 reduced field of view, tunnel vision
6 blue coloring of skin, fingernails and lips
8 behavior changes
9 inability to warm extremities

If you think you can detect and control the effects of hypoxia without oxygen, think again; you're wrong, potentially dead wrong. The two most dangerous aspects of hypoxia encountered by all types of aviation are its gradual onset and the false feeling of well-being called euphoria. Since this obscures the pilot's ability and desire to be critical of himself (his judgement), he most likely will not recognize the symptoms that would otherwise be obvious. The hypoxic pilot commonly believes he and things are getting progressively better as he, unfortunately, nears total collapse.

Many high altitude chamber experiments have shown that a person affected by hypoxia may recognize only a fraction of its known indications. In fact, some experienced pilots don't even report experiencing any effects at all while they are obviously incapacitated. This is where the insidious nature of hypoxia is so dangerous. Many pilots black-out or faint in flight each year from hypoxia. In reviewing many of the so-called pilot error deaths and serious accidents, in which no tangible explanation was found for cause, they may in fact have been caused by hypoxia. The only answer to preventing or reversing the effects of hypoxia is oxygen.

Prevention and factors of hypoxia Pilots have found that a good way to protect themselves from hypoxia is to be constantly aware of the problem and use the altimeter as the primary guide for the use of oxygen. It is recommended that pilots use oxygen as they fly at altitudes over 10,000 feet. Many factors influence when, how, where and what the indication of hypoxia will be. Your diet and health play an important role in your altitude tolerance. What you eat or drink is also a factor. Some foods and beverages, mostly the junk and pre-processed variety, may 'out-gas', from your digestive track an oxygen-depleting agent resembling the properties of carbon monoxide, lowering the ability of your blood system to absorb and deliver oxygen, thus lowering your altitude tolerance. Although there is not much medical data on this subject, many serious pilots have indeed noticed a difference when they eat a good balanced diet.

Recovery from hypoxia Recovery from mild hypoxia can be rapid, usually within 15 to 20 seconds, after oxygen is administered you will witness a remarkable change. Dizziness from head and body motion may occur during the recovery making piloting a craft more difficult. A pilot recovering from moderate to severe hypoxia is usually quite fatigued and can suffer from a degradation in mental and physical performance for many hours. Headache and nausea may also occur. The continued use of oxygen helps recovery many times over.

At what altitude will I get hypoxia ? This is the most difficult question to answer. You can suffer from the effects of hypoxia at almost any altitude where there is a quick altitude gain of about 8,000 feet. Quick in this case is about 150 ft/min. It's the loss of oxygen (pressure) on your body that causes your blood to lose some of its ability to absorb oxygen and possibly out-gas (lose oxygen), resulting in hypoxia.

Many who live at lower altitudes have blood that is conditioned to a point where the oxygen collecting factor is lower than what is needed for the altitude gain. This can be compensated by "high altitude conditioning". The mechanism of this conditioning is not well understood, but does seem to work where moderate altitude exposure and exercise are performed. Many proficient pilots have become (somewhat) conditioned through their flying and can withstand more exposure without ill effects. It would be a good and responsible practice for you, the pilot in command, to follow the FAA 'recommendation' for non-registered pilots and craft to use oxygen starting at pressure altitudes of 10,000 feet above sea level.

What can I do to limit the effects of hypoxia ? This is the second most asked question and is also just as difficult to answer. We can't spell out a definitive set of do's and don'ts, but we can point out a few factors that are medically known to affect one's altitude tolerance. If you smoke and drink alcohol or generally are not in good health, hypoxia will be a danger and should be considered. Where you live can also be a factor to how sensitive you will be in experiencing hypoxia. Being in good health and practicing healthful habits may limit the effects of hypoxia.