In the book of “LED Lighting: Technology and Perception”, the author talks about the relationship between CRI and circadian stimulus (CS) and processes a series of experiments.

The results indicate that CRI (Ra) does not affect the CS as distinctly as CCT (WW = CCT<3500K, NW = CCT 3500K≤NW≤5000K, and CW = CCT≥5000K), essentially it is more about the weighting of the spectral power distribution within the circadian sensitivity.

High CRI indeed brings more comfortable visual feelings and it helps with reducing fatigue of the eyes, but we should differentiate clearly that it would be a different story when talking about circadian lighting.