When was the last time, in a non-sexual context, that you saw a friend naked? Showering together after high-school sports practice? We prudish Americans are quite unlike the Finns, whose sauna tradition is the subject of this charming, intimate, and very candid documentary. Its subjects mostly speak while naked or half-toweled and sweaty; occasionally they flog one another with birch boughs. But mainly, as if in a high-temperature church confessional, they slowly drip out words of discontent, pride, failure, and sorrow. It’s all very laconic and Scandinavian, like outtakes from an Aki Kaurismäki film. Almost all the subjects are male (as are filmmakers Joonas Berghäll and Mika Hotakainen), and their pent-up camaraderie may not be so affecting to women accustomed to easier intimacy among sisters. We hear of new fatherhood, bad marriages, bereavement, and career disappointments, often washed down with cold beers (the cause of prior grief, in at least some cases). A few stoic tears are shed, and a folk song is finally sung. Says one guy to his buddy, “Solitude is the worst thing. Knowing you are not alone is an incredible relief.” By the end you realize Steam of Life isn’t about saunas, but friendship.