In this activity about how the body regulates blood pressure (page 117 of the PDF), learners make and compare measurements of heart rate and blood pressure from three body positions: sitting, standing, and lying. Learners are also challenged to think about how the circulatory system might behave in a microgravity environment (i.e. astronauts in space). The lesson guide, part of NASA's "The Brain in Space: A Teacher's Guide with Activities for Neuroscience," includes background information, evaluation strategies, and handouts. Note: cost of materials does not include cost of stethoscope or sphygmomanometer; these may be borrowed from a nurse.