Abstract: Various implementations include systems and approaches for determining user oxygen saturation level, and in certain cases, performing an action based on that determination. Particular aspects include a monitoring system having at least one pressure sensor for detecting air pressure in an environment proximate the at least one pressure sensor, and a processor coupled with the at least one pressure sensor, where the processor is programmed to receive air pressure data from the pressure sensor about the environment, determine an oxygen saturation level for a user in the environment based on the air pressure data, and in response to determining the oxygen saturation level of the user has met one or more predetermined conditions, perform an action.