A computer-implemented method, data processor and computer program product determine exposure levels to external stimuli. At least one environmental condition is monitored and an external stimulus event is identified based on the at least one environmental condition. An intensity level of the external stimulus event is determined to exceed a predetermined threshold. An exposure level of the external stimulus is determined by integrating the intensity level over time. At least one human biometric quantity of a user is measured and a personal exposure level limitation is determined for the user based on the measured at least one human biometric quantity. When the exposure level exceeds the personal exposure level limitation, the user is warned of the exposure level. The human biometric quantity is one of: heart rate, blood pressure, body temperature, glucose level, blood oxygen level, muscle activity, electrolyte level, and lactic acid level.