A method is presented for determining onset of hypoxia of an occupant in an aircraft. The method includes measuring a physiological parameter of the occupant and comparing a value based on the physiological parameter with a threshold value. The method also includes measuring a pressure within a cabin of the aircraft and comparing the pressure with a pressure threshold value. The method also includes determining onset of hypoxia of the occupant based on both of the comparing steps. The method also includes communicating an alert to the occupant using a device detectable by one or more senses of the occupant. An apparatus is also provided for determining onset of hypoxia. The apparatus includes a pressure sensor to measure the pressure, a pulse oximeter to measure the physiological parameter, an alert device to communicate the alert to the occupant and a processor to perform one or more steps of the method.
