A physical activity data collection system includes one or more accelerometer units in communication with a data collection unit, where the data collection unit, includes one or more infrared sensors configured to provide an output indicative of a pulse rate of a user of the physical activity data collection unit. The data collection unit may also include at least one temperature sensor configured to provide an output indicative of at least a body temperature of the user and at least one accelerometer configured to provide an output indicative of movements of the user. The system may also include a microcontroller configured to evaluate the outputs of the two or more infrared sensors at a plurality of power levels select at least one of the two or more infrared sensors for data collection and reduce an amount of power applied to infrared sensors other than the at least one of the two or more infrared sensors selected for data collection.
