According to old Finnic spirituality, all humans have at least three souls or three parts to their soul.
These are ‘itse’ (self), ´luonto´ (nature), and ´löyly´. Yes, you noticed… The last one is our familiar löyly, which is used to denote ´life force´ of any living thing.
You and I, we all have this löyly according to ancient Finnic faith, and if we lose it, we die.
Hence, while the self (itse) and nature (luonto) souls take care of things like personality, charisma, luck and so on, <löyly> is the one we depend on for dear life. It makes our hearts pump, our blood flow, our bodies warm and so on.
In Finnic tradition, this idea of life force is anthropomorphically extended to saunas as well, so as we throw water onto the hot kiuas stones, what rises up is the life force of sauna itself, the healing löyly of gods, which is often called the “sweat of Väinämöinen”.