A device and a method are disclosed for detecting the danger of a person drowning in a body of water. The device includes a breast belt and a life jacket. The breast belt has at least one physiological condition sensor affixed thereto while the life jacket has an expandable chamber connected to a compressed gas supply via an activating mechanism. As the compressed gas enters the expandable chamber, the life jacket increases in buoyancy. The life jacket also has a water contact sensor, a global positioning system device, first and second body orientation sensors, a transmitter which is capable of sending a signal to a remote receiver, and a control unit capable of receiving real time signals from each of the sensors and evaluating and comparing the real time signals against corresponding ranges of preset acceptable values to determine if the person wearing the life jacket is in danger of drowning. The control unit is capable of forwarding a signal to both the activating mechanism and to the transmitter when a signal from the water contact sensor indicates the person is in the water and the real time signals from the other sensors are outside of corresponding ranges of preset acceptable values. The signal to the activating mechanism opens the compressed gas supply while the signal to the transmitter is relayed to the remote receiver which sounds an audible alarm.