The ninety degree shift does not cancel the effects of old age upon the physical body, but it does enable warriors to retain control of all their faculties, their knowledge, sobriety, and power, right up to and even beyond the moment of physical death. This is every warrior's reward for having been willing to fight impeccably right up until the final breath.
Théun Mares Cry of the Eagle: The Toltec Teachings Volume 2