As times became more desperate, and it became obvious to the Anu that the energies around this planet were causing them serious problems, they learned that there were ways in which they could hide from the effects, and at least lessen the impact.
One such way was to go into a stasis chamber, where their bodies were preserved as their minds were unconscious, until the energies had subsided. This method was effective, and the Anu used it for their entire stay on Earth up until very recent times, yet it was not enough to protect them from the energies.