Pilots of high performance aircraft may be exposed to positive acceleration (+Gz). This type of acceleration displaces blood in the head to foot direction. As the pressure in the vessels of the lower body increases, the vessels dilate, and a major proportion of the blood from the upper part of the body is shifted into these lower vessels. The pooling of blood in the lower extremities translates into a reduced cardiac output provoking the cardiovascular system to maintain adequate blood flow to the central nervous system and thereby maintain normal brain function. The symptoms of acceleration stress may lead to +Gz induced loss of consciousness (G-LOC) with potential fatal consequences. According to a survey done in 1986, approximately 12% of the Navy aircrew have experienced G-LOC inflight. When G-LOC descriptive data is available, it is usually limited to the particular investigator's research interests. Most research regarding G-LOC does not include the symptoms typical of this event. Specifically, the subject's psychological reaction to the G-LOC episode itself is often ignored. Understanding the physiology and mechanism of G-LOC is necessary to develop methods to avoid such an event. However, until an infallible method to prevent G-LOC is developed, G-LOC will occur. Hence, the thrust of G-LOC research should include understanding recovery from unconsciousness: to include G-LOC's psychological sequelae. Positive acceleration, Induced loss of consciousness (G-LOC).