A physical activity data collection unit includes one ormore infrared sensors configured to provide an output indicative of a pulserate of a user of the physical activity data collection unit, at least onetemperature sensor configured to provide an output indicative of at least abody temperature of the user, and at least one accelerometer configured toprovide an output indicative of movements of the user. The physical activitydata collection unit can also include a microcontroller configured todetermine a pulse rate, a body temperature, and movement characteristics ofthe user of the data collection unit based on outputs from the one or moreinfrared sensors, the at least one temperature sensor, and the at least oneaccelerometer determine a physical exertion level of the user based on oneor more of the pulse rate, the body temperature, or the movementcharacteristicsof the user and store, in a memory, data indicative of the physicalexertion level during a time period during which the physical exertion levelexceeds a predetermined threshold.
