The issue of how long a human voice can actually blab has not been studied in the same way. The larynx, a.k.a. voice box, is like any other muscle, more or less—those who don’t use it much and then try will be quite hoarse the next day; in contrast, those who are used to talking and talking and talking are in fine shape to keep talking even more. One might worry that we are raising a generation of the weak-voiced, given the presence of email and Twitter and et cetera for those who once enjoyed a good long two-to-three-hour chat on the phone. A veteran speechifier like Cruz, though, raised in the good old Ma Bell days, probably right now feels like a 10- and 15-mile runner who just pushed out and ran a first marathon—tired and achy and extremely self-pleased. But wanting to speak softly for just a little while. His risk for polyps and the sort of damage actors and singers seem to get is likely low, unless he makes a weekly habit of yakking away.

He need not worry about other aspects of his health, either. As long as he was sipping a little water, perhaps munching a piece of cheese, he will be able to withstand the semi-rigors of 21 hours without a lot of calories with no problem at all. Kidneys and heart and liver—all should sail right through.