I am standing behind a partition rope, waiting for the theatre to open. An excited hum rises off the crowd, and there is jostling when the stewards throw open the doors. As a theatre critic, I have stood in countless such queues. I should not feel the fear that I do, but there is one vital difference here: audience members are wearing nothing more than bath robes and flip-flops.

And then they’re not even wearing those. All clothes are discarded as they race to claim a seat on the tiered wooden benches inside the auditorium and lay down towels to mark their spot. In a matter of minutes, there is a neatly arranged room of almost 200 naked people sitting in a heated amphitheatre, waiting for the show to begin. I am as disrobed as the rest of them.

This is not an anxiety dream. It is aufguss in action: a theatrical experience inside a huge sauna where gym-fit performers throw essential oils on to a central stove and wave towels in choreographed ways. They combine this ritual with a 15-minute drama involving costume changes, music and movement. The audience zips out between acts to dunk themselves in freezing cold water before running back in for the next show.

Facebook Twitter Pinterest Heightened emotions … Italy champion Michael Niedermaier performs Mission Home. Photograph: Thermen Berendonck

It is the final day of the week-long world aufguss championships at Thermen Berendonck, a stunning sauna complex in Wijchen, near Nijmegen, where nearly 100 contenders and 11 European countries compete for medals. Surveying the room, I see friends chatting, couples clasping hands. Some banter and clap. No one avoids eye contact or stares at their feet. This could be any spirited theatre crowd, were it not for the nudity.

The first acts seem to be channelling Las Vegas pizzazz crossed with Eurovision camp, but I slowly put my cynicism aside

There are several languages being spoken. Many are wearing woollen hats, which I am later told serve to keep body temperature levelled. The hats look comical in the sea of bare flesh, but I am too dry-mouthed to laugh. Two men in Viking caps make space for me on the crowded lower benches. I break out into a sweat the minute I am squeezed in between them, not only because it’s so snug but also because the heating is cranked up to 85 degrees and the stewards are about to seal the doors.

The acts vary from adaptations of The Picture of Dorian Gray and The Life of Pi to original scripts that include a Danish production about polluting the oceans and a show about the suffragette Emily Davison, whose protest at the Derby in 1913 led to her death.

Facebook Twitter Pinterest Towel choreography … an aufguss performance. Photograph: Thermen Berendonck

The auditorium is a state-of-the-art, tile-panelled sauna with surround sound and a large screen as a backdrop. The acts are heavy on showmanship and special effects including smoke and floor lighting, and the actors speak English. The first few acts seem to be channelling Las Vegas pizzazz crossed with Eurovision song contest camp, but slowly I put my cynicism aside.

Britain is not a competing country here and while aufguss might inspire snickering among some buttoned-up Brits, it is part of a booming European industry that intersects wellness with the arts. According to Martijn Vanhoorelbeke, a juror at the aufguss and three-times former Belgian champion, the benefits include not just the detoxifying effects of a sauna but emotional catharsis, too. He regards it as a “total experience” of the senses: “Aufguss does what other kinds of theatre cannot do with the smells [of the oils], the sounds and sights, the feeling of the heat as well as the emotional drama of the story and the effect of all of those things combined.”

We are more vulnerable when we are more exposed, he adds, and so the experience not just bring out physical toxins but “emotions rise up, too.”

He gets a standing ovation, which is a bold move from a naked audience

He might be right. I am instantly drawn into an adaptation of Billy Elliot. It is by Ondrej Sochurek, a dancer and circus performer from the Czech Republic who begins with a high-octane routine to Duran Duran’s Wild Boys in an imaginary boxing ring before switching to Swan Lake, in which his towels turn into beating swan’s wings. Astonishingly, it works, and by the end it is not just Sochurek’s rosemary and bergamot infusions that are misting up my eyes. I am not the only one moved: he gets a standing ovation, which is a bold move from an entirely naked audience.

Facebook Twitter Pinterest Woollen hats are worn to keep body temperature levelled. Photograph: Thermen Berendonck

He is followed by Poland’s Marcin Ciesielski, whose upbeat show, The Shoemaker, combines comic skits with tap dance and ballroom. Suffragettes, by Italy’s Charoulla Demetriou and Salvadori Morgana, is dark yet exhilarating, with its rousing message of gender equality and stark image of Davison’s death projected on to the screen.

The nudity takes on a different dimension in the context of this drama. There is no hint of giggling. The suspension of disbelief changes the tone of the room. Michael Niedermaier, an Italian champion who is a sauna master at Preidlhof Spa Hotel in South Tirol, thinks that aufguss heightens emotions and could help people overcome embarrassment around nudity. Sabrina Telfser, also at Preidlhof, agrees: “If people are introduced slowly and correctly to the experience, the shyness can be overcome.”

Vanhoorelbeke has recently been helping Britons do just that by running aufguss training sessions in Brighton, which may not instantly dismantle entrenched views around nudity, but may chip away at the English reserve. I had feared that the sight of such nudity en masse would conjure scenes reminiscent of Carry On comedy in my mind. How wrong I had been, and what giddy liberation I felt as I floated off for my cold shower.