A tiny crew of brain cells keeps blood pressure steady while you sleep, wake and move

Your blood pressure is not meant to sit still — it has to rise and fall smoothly as you sleep, wake and move, without swinging wildly. Researchers at the University of Virginia, writing in Circulation Research, have found a small group of brainstem cells, called C1 neurons, that act like a steadying hand. In freely moving rats, the cells switched on rapidly at waking, stayed busy during dream sleep and worked harder during activity. When the team selectively removed them, the animals' average blood pressure barely changed — but it swung far more from moment to moment. The finding explains a hidden part of how the brain keeps circulation calm through the day's transitions, and may one day help doctors understand conditions where that automatic control breaks down.