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Introduction to Glider Flying > Introduction to Glider Flying > Medical Factors Associated with Glider Flying > Hypoxia > Histotoxic Hypoxia
The inability of the cells to effectively
use oxygen is defined as histotoxic hypoxia. The oxygen may
be inhaled and reach the cell in adequate amounts, but the cell
is unable to accept the oxy-gen once it is there. This impairment
of cellular respiration can be caused by alcohol and other drugs,
such as narcotics and poisons. Research has shown that drinking
one ounce of alcohol can equate to about an additional 2,000
feet of physiological altitude.
High-altitude flying, which glider pilots encounter
when mountain wave soaring or thermal soaring at high elevations,
can place you in danger of becoming hypoxic. Oxygen starvation
causes the brain and other vital organs to become impaired.
One particularly noteworthy attribute of the onset of hypoxia
is the fact that the first symptoms are euphoria and a carefree
feeling. With increased oxygen starvation, your extremities
become less responsive, and your flying becomes less coordi-nated.
The following are common symptoms of hypoxia.
• Headache
• Decreased Reaction Time
• Impaired Judgment
• Euphoria
• Visual Impairment
• Drowsiness
• Lightheaded or Dizzy Sensation
• Tingling in Fingers and Toes
• Numbness
• Blue Fingernails and Lips (Cyanosis)
• Limp Muscles
As hypoxia worsens, your field of vision begins to narrow, and
instruments can start to look fuzzy. Even with all these symptoms,
the intoxicating effects of hypoxia can cause you to have a
false sense of security and deceive you into believing you are
flying as well as ever. The treatment for hypoxia includes flying
at lower altitudes and/or using supplemental oxygen.
All pilots are susceptible to the effects of
oxygen starvation, regardless of your physical endurance or
acclimatization. When flying at high altitudes, it is paramount
that you carry avi-ator’s breathing oxygen in your glider
and have it readily accessible. The term “time of useful
consciousness” is used to describe the maxi-mum time you
have to make rational, life-saving decisions and carry them
out at a given altitudewithout supplemental oxygen. As altitude
increases above 10,000 feet, the symptoms of hypoxia increase
in severity, while the time of useful consciousness rapidly
decreases. [Figure 1-12]
Since symptoms of hypoxia vary in an individ-ual,
the ability to recognize hypoxia can be greatly improved by
experiencing and witness-ing the effects of it during an altitude
chamber “flight.” The FAA provides this opportunity
through aviation physiology training, which is conducted at
the FAA Civil Aerospace Medical Institute (CAMI) and at many
military facilities across the United States. To attend the
Physiological Training Program at CAMI tele-phone (405) 954-6212
or write:
FAA/AAM-400
Aerospace Medical Education Division
P.O. Box 25082
Oklahoma City, OK 73125
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