Goal: To explore the historical and modern literature on vocal warm-ups as it relates to skill acquisition and fatigue resistance.
Results: Historical texts (Vaccai, Concone, Panofka, & Marchesi) do not directly address warm-ups in a physiological sense. Physiological rationale is considered in Richard Miller's books in 1977 & 1986.
Thoughts: The concept of vocal warm-ups as something other than skill acquisition is a modern concept and despite approximately 45 years of research on the topic there is little concrete evidence for or against the practice outside of its benefit for skill acquisition. In historic pedagogy, it seems clear that there was no need to vocally prepare to sing vocalises.
Reference: Hoch, M., & Sandage, M. J. (2018). Exercise Science Principles and the Vocal Warm-up: Implications for Singing Voice Pedagogy. Journal of voice : official journal of the Voice Foundation, 32(1), 79–84. https://doi.org/10.1016/j.jvoice.2017.03.018