An anonymous reader writes MIT researchers develop technology that can monitor people's breathing and heart rate through walls. 'Their latest report demonstrates that they can now detect gestures as subtle as the rise and fall of a person's chest. From that, they can determine a person's heart rate with 99 percent accuracy. The research could be used for health-tracking apps, baby monitors, and for the military and law enforcement.' The report describes how they extended their through-wall technology to up to five users and how they track vital signs.