Jean Baptiste Faure was one of the greatest French baritones of the late 19th Century. He created the main baritone roles in such operas as L’Africaine, Hamlet and Don Carlos.
His book “La voix et la Chant” was published in 1886, and contained this insight:
It is a mistake to believe that you have to take very large breaths in order to sing. Speakers in a discussion – even if the discussion becomes animated and reaches fever pitch – do not take in larger amounts of breath. And yet their voices remain vibrant and strong.
So when you sing, it is not the amount of air you introduce into the lungs that is most important, but it’s the discerning way you make use of it afterwards.
Also, please realize that there is always a provision of natural air in the lungs. By taking in large breaths, we are acting as if the lungs were absolutely empty. This new amount of air that we then introduce proves to be much more than we need.
Singers should initiate their sound with no more worry about breathing than a speaker has at the beginning of his speech.
This may sound strange, but students who actually test this process will soon convince themselves of the uselessness of great intakes of breath.
Faure, Jean-Baptiste. La voix et le chant: traité pratique. H. Heugel, 1886.