Christopher and Julie Rice sat naked in the sauna, sweating in its 180-degree heat. In the crisp air outside, they then played a few hands of cribbage and noshed on pickles and smoked fish. Steam rose from their wet hair.

The details, three years later, seem etched in their minds.

It was the night they fell in love with sauna. The night, they say, sauna saved their marriage.

“It was nice to be unplugged, nice to be together and to talk,” Julie said recently. “We put all our worries, all our grudges aside. We were able to say, ‘What’s going on? How can we move forward?’ ”

Nakedness bred vulnerability, opening up something in the Rochester couple’s marriage, which was then marked by resentment. Their first sauna-destination trip — inspired by a chance steam a month before — led to another, then another. Between watching YouTube videos on sauna methods and reading old tomes on sauna culture, the couple started a Facebook group to share their new obsession and a website to tell their story. Clicks came, at first, from curious friends and family, but with each trip and each post, the Rices discovered — and helped build — a sauna-loving community.

Today, some 2,300 people subscribe to their private Facebook group, dedicated to wood-burning sauna. More than a few have invited the Rices to sweat alongside them.

The ancient Finnish tradition of sauna is trendy these days, as millennials have embraced its ritual. Mobile saunas, with their rent-a-session model, have popped up in Minneapolis and beyond. But the Rices, like the purists in their group, are anti-trend.

They celebrate the wood chopping and fire building required for a traditional sauna, praising the resulting scent and soft heat. Electric saunas don’t have the same effect, they argue.

Infrared saunas? Don’t get them started. Christopher, 40, refuses to call them saunas, referring to them instead as closets.

“A log sauna in a rustic, natural place — that’s what I love,” Christopher said. “I have yet to see an infrared closet set in the middle of the forest.”

The couple spoke at Camp du Nord’s first weekend for sauna enthusiasts last year, an event they helped inspire. This year, the gathering kicks off Oct. 11 near Ely, Minn. Its star: the YMCA camp’s legendary wood-burning sauna, built in 1933 by Finnish carpenters beside Burntside Lake. That’s where the Rices — quickly ticking off their bucket list — jumped into a hole in the ice, known in Finnish as avanto.

The couple’s Facebook page helped Emily Weise, a program director at Camp du Nord, realize “that there was this subculture of sauna lovers out there” who value the log sauna, “the oldest building here at camp.” Weise first took a sauna at Camp du Nord when she was a 5-year-old at the family camp.

But the Rices’ enthusiasm has given her a greater appreciation for the tradition, she said. Online and in person, Christopher is “so curious and interested and always keeping the conversation going.”

‘What’s this nakedness thing?’

The Rices, who were married in 2005, didn’t grow up with saunas. They claim no Finnish heritage. They didn’t even know much about starting fires.

Then there were cultural oddities. Nudity was one.

“There’s this aspect of being naked that was, even for us as a married couple, still kind of awkward,” said Julie, 38. “We have such an odd relationship with nakedness in the U.S. It took a little bit for me to relax.”

“We don’t come from some hippie background,” Christopher chimed in.

“We’re not free spirits,” Julie added.

“Both our families are like, ‘What’s this nakedness thing?’ ” Christopher said.

But they’ve learned, converting friends, relatives and Julie’s mother, who is from Cambodia, along the way. The Facebook group has helped. It’s a place where sauna lovers can share tips, photos and offers of saunas for sale. And they ask questions ranging from newbie to nerdy: What’s the best sauna temperature? Does anyone have a Harvia stove?

“What about sauna seat covers?” one member posted recently. “Do people use them? Just a towel? Decoration? Too fancy/urban? Just right?”

The most liked response: “Saunas are self-cleaning and one of the most sterile environments. Modern people are too squeamish. Sitting in others’ buttsweat? Yours is sweating, too.”

That online community has led to in-person meetups. Christopher and Julie have been invited to saunas in Wisconsin, northern Minnesota and Finland, partly because of the business they run: They take 360-degree photos of interiors, a sauna lover’s dream documentation. The couple used to travel for food — to Texas for barbecue, for example — but now plan trips around rentals with awesome saunas. They’ve trekked several times to Michigan’s Upper Peninsula, to an area where half the population boasts Finnish heritage.

Before, “if we ever stayed at a rental, we made sure it had a gas stove. We wouldn’t stay anywhere with a bad cooking setup,” Christopher said. “Now it doesn’t matter. Could be a dilapidated trailer somewhere, but if it has a nice sauna, we’re good.”

Like nakedness, meeting up with strangers felt new to the Rices.

But they’ve enjoyed friendly hosts and fascinating conversations with people who, like them, appreciate the rich tradition more than the health benefits. A recent study by the Mayo Clinic found that regular saunas could be as beneficial as exercise, reducing high blood pressure, cardiovascular disease and other conditions.

That study, sauna purists point out, focused on folks sauna bathing in traditional ways.

“Once people figure out that something is healthy, that pretty much guarantees we’re going to ruin it,” Christopher said. Fish oil tablets are a great example, he continued. “We find some way to make a pill. Infrared is mostly that — it’s like the pill form of sauna.

“If we found out that sauna was just a little unhealthy, we’d still do it,” he added. “If we found out that people who do sauna, on average, live three years less, we would still do it.”

‘Good for their family’

On a chilly September morning, the Rices’ four children emerged, steaming, from a barrel sauna. They stood under the hose-turned-shower and then — one by one, noses pinched — submerged themselves in a 118-gallon stock tank filled with cool, clear water.

This sauna-loving couple have sauna-loving kids. Sauna-smart kids, too. “Afterward, you feel fresh, clean,” said Rebecca, 12, the oldest, wrapping herself in a towel. “And you feel like you want to take a nap!”

This sauna is not, technically, owned by the Rices. But it demonstrates the spread of their sauna evangelism. Last summer, Julie told her neighbor and friend Martha Rypstra about a barrel sauna one of their Facebook group friends had for sale. Rypstra and her husband had never taken saunas before. But they had heard their dear friends talking about them for two years.

A few weeks later, the friends were ripping apart the backyard, replacing an overgrown garden with a rock patio.

“Julie and I did everything with four kids each in tow,” Rypstra said, laughing. The first time the pair took a sauna, they didn’t have a shower or a tub. “We just sprayed each other with a hose.”

“I thought, ‘This is great. This is something I can do.’ ”

Rypstra also witnessed how sharing the sauna love had knitted the Rice family together. “I saw that it was good for their family, it was something that connected them,” she said. “It was something they could all enjoy together.”

Three years after their first sauna, Julie and Christopher are in a better place. A good enough place that they could write about how bad things were. In an essay on their website, Julie detailed how, to the outside, their family seemed perfect, but they were really “like two strangers living in the same house.” Sauna changed that.

“It’s hard to be defensive and cruel when you’re sitting naked next to someone, sweating profusely, feeling your heart pounding in your chest,” Julie wrote. “It’s hard to think about anything mean-spirited when the water hisses on the rocks and löyly dances through the sauna.

“It’s hard to hate someone when you’re cooling down next to the lake, drinking lemonade, watching the sunset, and feeling euphoric.”

In their friends’ backyard, the Rices swapped stories and stoked the fire. The first time the Rices’ oldest kids took a sauna, “I didn’t like it,” said Nahlah, 10. “It was too hot.”

“But now that heat would be cold to us,” Rebecca said. “Because we didn’t know what we were doing.” As their parents’ obsession swelled, taking them from one tiny Midwestern town to another, they’ve learned.

“Basically everywhere we go,” Rebecca said, “my dad’s like, ‘Is there a sauna in the area?’ ”