Embodiments provide physiological measurement systems, devices and methods for continuous health and fitness monitoring. A wearable strap may detect reflected light from a user's skin, where data corresponding to the reflected light is used to automatically and continually determine a heart rate of the user. Based on signals associated with the user's heart rate, the system may detect the location of the wearable strap on the user's body, and then adjust its analysis of the reflected light data to determine the heart rate of the user.
