Signaling is, generally speaking, a means of displaying social status and desirability as a mate, yes?

Ergo, anything that directly fulfills a basic physical imperative other than the reproductive drive is a likely candidate for non-signaling. Hunger, exhaustion, the fight or flight reaction, &c. Of course, all of these can be wrapped in contexts indicating social status, but the actions themselves are likely mostly neutral. e.g., people may brag about their sleep habits for status, but when they do go to bed it's probably because they're tired, not because they're thinking about how it will impress others. It's the talking about sleeping that is doing the signaling here.