Abstract: This paper introduces and applies the concept of equivalent illumination to describe the light sources. Three kinds of white light with different color temperatures and three kinds of color light were selected, using the spectral power distribution and the spectral response curves to calculate respectively five kinds of photoreceptor cells corresponding biological rhythm factor, and calculate the corresponding equivalent illuminance, it is convenient to describe the influence of five photoreceptors on the photobiological effects. The physiological monitoring of blood pressure and heart rate was carried out in six kinds of light environment. The rate of change of physiological data before and after illumination was combined with the theoretical calculation to quantitatively describe the photobiological effect of light source on human body. The results showed that the higher the equivalent illuminance of the third type photoreceptor cells, the higher the change rate of physiological parameters, that is, the corresponding light source can produce stronger stimulation. The correlation coefficients of heart rate change and rhythm factor were all higher than 0.90, and the correlation coefficient of systolic blood pressure and rhythm factor were all higher than 0.88, they have good correlation. Therefore, the rate of heart rate change and systolic blood pressure rate of change can be combined with the biological rhythms reflect the light source of non-visual biological effects intensity.

Key words: nonvisual biological effects, biological rhythm factor, equivalent illuminance, light emitting diodes