According to one embodiment, a wearable electronic apparatus detects movement of a human body wearing the apparatus. The apparatus causes a first number of light emitters to emit light when a magnitude of the detected movement is less than a first value. The first number of light emitters is among a plurality of light emitters which emit light having different wavelengths, in which the light are received by a light receiver to obtain physiological information. The apparatus causes a second number greater than the first number of light emitters among the plurality of light emitters to emit light when the magnitude of the detected movement is greater than or equal to the first value.
