Stranger events live within the annals of history, philosophy, and the queerest imaginings of Man, sir. [Jeeves offers the smallest of head tilts along with a quirk of his lips.]

And perhaps its normal processes are guided by the unknown entity Ms. Chell indicated as keeping watch over the communications on this network? But then, the body does continue to function and regulate our anatomy even without consciousness. I would hope whatever sympathetic nervous system might exist would maintain at least vital processes within dreaming worlds. That would be the purview of a world's brain more than its heart, though, unless we might consider them one and the same for the purpose of this thought experiment.