Figure 2.
Human subject undergoing lower body negative pressure (LBNP, (A)). A standard experimental protocol consists of stepwise reductions in pressure inside the chamber (B). The protocol is terminated with a precipitous fall in systolic blood pressure to <80 mmHg accompanied by concurrent subjective symptoms (e.g., dizziness, loss of peripheral vision, disorientation, impaired responsiveness) (C). Releasing the negative pressure in the chamber returns central blood volume and pressure to normal, optimizing safety for the subject (C). Modified from References [4,7].