# Hypoxic Hypoxia - Caused by increased pressure altitude or a blocked airway. Can be thought of as not enough oxygen being able to enter into the lungs. This is the most common occurrence of hypoxia in aviation. # Hypemic Hypoxia - Caused by blood not being able to take up oxygen and transport it. Carbon monoxide poisoning is an example of this. The hemoglobin in your body will bind to the Carbon Monoxide instead of oxygen, and therefore transport it instead. # Stagnant Hypoxia - Caused by the circulatory system not being able to circulate enough oxygenated blood throughout the body. This could be caused by high g maneuvers in airplanes, where the body can't push oxygenated blood into the brain. - Additionally, stagnant hypoxia can be caused by diseases like sickle cell anemia, or hypothermia, which causes blood vessels to constrict. # Histotoxic Hypoxia - Caused by cells not being able to use the oxygen that is transported to it. This can often times be caused by the use of alcohol or drugs which impair cell functions in accepting oxygen. - An example of this would be cyanide poisoning, which directly prevents cells from using oxygen and is fatal. This could also be caused by alcohol or drug use