An optical pulse rate detector includes at least one emitter, a photodetector, and an adaptive filter. The emitter transmits light at a first light output level and a second light output level into body tissue of a user. The photodetector receives reflected light from the body tissue and produces a voltage indicative of an amount of the reflected light. The adaptive filter receives a first output signal from the photodetector indicative of an amount of the light at the first light output level reflected from the body tissue and a second output signal indicative of an amount of the light at the second output level reflected from the body tissue. The adaptive filter removes the second output signal from the first output signal to generate a pulse rate signal indicative of a pulse rate of the user.
