Soviet hardware is notoriously robust in certain surprising respects. We got a pair of Riga
class escorts in the seventies, to balance out the acquisition of western fighting ships, and it turned out that those at the time modern steam turbine ships were ideal for installing a steam sauna aboard. (Plus they each came equipped with a piano, demonstrating the cultural sophistication of Homo sovieticus
FWIW, when I first saw blueprints of Kirk's vessel as a kid, I thought "regulation pool" had something to do with regulating the ship's functions, say, managing the thermal loads - and the crew just took the opportunity to enjoy the lukewarm water...