By Will Stone Sauna enthusiast Michael Calcagno, second from right, sits inside a clear-walled wood-fired sauna during the Seattle Sauna Festival in November. Sauna use has taken off as a health practice and scientists are studying its benefits. Mike Kane for NPR hide caption Saunas have captured the wellness zeitgeist, attracting a new generation of followers eager to tap into the benefits of the age-old practice. The upswell of public interest has fed a growing industry dedicated to offering the sauna experience, and inspired festivals in cities like New York, Minneapolis and Seattle. "It is my mental reset – my control, alt, delete," says Ana Hernandez, who launched a mobile sauna business after the pandemic and organized Seattle's first ever sauna festival this past fall. Turnout for the two-day event ended up being three times what they'd anticipated.…