Health issues a pilot or crew member may experience in flight is Hypoxia. Hypoxia is caused by not having enough oxygen supplied to the body. There are four types of Hypoxia; Hypemic, Hypoxic, histoxic, and stagnant hypoxia.
Hypemic Hipoxia: This type of hypoxia occurs when there is not enough oxygen in the blood. Hypemic actually means "not enough blood". Your blood cells serve as transportation for oxygen, the lack of blood cells transporting oxygen results in hyperemic hypoxia. Candidates for hyperemic hypoxia can be an anemic person, or a blood donor. This lack of blood volume is what prevents oxygen from moving in the body fluidly.
Hypoxic Hypoxia: A clear example of hypoxic hypoxia is a blocked airway. Not being able to breathe. Hypoxic hypoxia results from oxygen not belong available for the body to inhale.
Stagnant Hypoxia: Stagnant means "not moving". This hypoxia results when the oxygen in the body is not moving to the tissues of the body. An example of stagnant hypoxia can relate to an extremity of the body falling asleep. This reaction is caused by the loss of blood flow to that extremity. Cold temperatures, excessive acceleration and G forces can create this type of hypoxia.
Histoxic Hypoxia: This type of hypoxia results in the impairment of cellular respiration. The blood cell are unable to use the oxygen that is available to them. Histo means tissues or cells where as toxic obviously means poisonous. This type of hypoxia is resulted by alcohol and drug use. "Research has shown that drinking one ounce of alcohol can equate to about an additional 2,000 feet of physiological altitude" according to the pilot handbook provided by the FAA.GOV website.
Symptoms to be aware of when hypoxia occurs are: cyanosis, headache, decreased reaction time, impaired judgement, euphoria, visual impairment, drowsiness, light headed and dizzy sensations, tingling in the fingers or toes, and numbness. When these symptoms occur, you should immediately decrease elevation or begin supplemental oxygen. When a pilot or crew member experiences hypoxia, they may not know that they are experiencing it. They can develop a false sense of security and will have have a hard time interpreting the instruments.
