Pronunciation: [ɹɪdˈa͡ʊt] (IPA) 
The spelling of the word "redout" can be a bit tricky. Its correct spelling is actually "Redouté," which is a French surname. The pronunciation of Redouté is "reh-doo-tay," with the 'é' at the end being a unique sound in the French language that is similar to the 'ay' sound in the English word "play." It is important to remember the proper spelling and pronunciation to avoid confusion and ensure accurate communication.
Redout is a term used in aviation and aerospace physiology to describe a physiological event experienced by pilots and astronauts. It refers to a condition where an individual's blood accumulates in the head due to increased gravitational forces, resulting in a reddening or flushing of the face. Redout is the opposite of blackout, where blood pools in the lower parts of the body and the brain is deprived of sufficient blood supply.
During high-speed maneuvers, such as rapid acceleration or pulling high G-forces, the body's cardiovascular system struggles to properly distribute blood to maintain normal brain function. This can lead to a redout, causing blurred vision, increased pressure and pain in the eyes, and a sensation of blood rushing to the head. These symptoms can be incapacitating, preventing pilots from effectively controlling the aircraft.
To counteract redout and prevent loss of consciousness, pilots and astronauts employ various physiological measures. These include wearing anti-g suits, which apply pressure to the lower body and legs, helping to prevent blood pooling, and performing specialized breathing techniques, such as the M1-Graviton maneuver, to counteract the effects of gravity. Training and physical conditioning are essential to enhance resistance to redout and maintain performance under high gravitational forces.
In summary, redout is a physiological condition that occurs during high G-forces, characterized by the accumulation of blood in the head, causing a red/flushed appearance. It is a crucial consideration in aviation and aerospace operations, as it can impair vision and cognitive function.
The word "redout" does not have a commonly accepted etymology. However, it is believed to be a combination of the words "red" and "out", likely derived from the phrase "blackout". The term "blackout" refers to a loss of consciousness or memory, often used in the context of extreme acceleration experienced by pilots. Similarly, a "redout" refers to a phenomenon where a person's vision becomes completely or partially red due to excessive gravitational forces. It is primarily associated with high-speed acceleration in aviation or spaceflight. Although the exact origin of this term is unclear, it is believed to have emerged in the context of aviation and extreme G-forces experienced by pilots.
