negative acceleration stress

Negative acceleration stress refers to physiological changes in the human body when the direction of acceleration is from feet to head. This can cause a rush of blood to the face, throbbing headaches, and visual disturbances such as eyes feeling like they are protruding or objects appearing red. The blood pressure in the skull rises, potentially leading to temporary cardiac arrest or impaired respiration due to pressure on the lungs. While experienced pilots may tolerate these effects better, prolonged exposure can lead to unconsciousness. This is distinct from deceleration, which is the abrupt slowing of a moving object and can cause a range of injuries from shock to organ damage.12