Two complementary approaches are presented to help to understand how CPU loading affects the sensitivity of an electronic device to ESD (electrostatic discharge) stress. Both approaches rely on synchronized noise injection while the software is running at the desired load. One of the approaches monitors the device's current consumption while the other monitors the device's electromagnetic field to synchronize noise injections. These approaches revealed that as the CPU loading increases, the device becomes more active and hence more susceptible to ESD stress. Moreover, it was observed that, in each loading condition, the device randomly became susceptible. These complementary approaches enable the capturing of high/low active intervals as well as the injection of noise voltage to the desired activity, thus, allowing for the analysis of the effect of CPU loading on ESD susceptibility.