I should not be surprised if an older sauna-goer asks me to scrub their back, says Alexander Lembke, as he talks me through the workings of Finland’s oldest working public sauna. “You just do it, help them. There you can see how deeply rooted the sauna is here in the community.” Usually Lembke, who describes himself as a “sauna classicist”, undertakes heating responsibilities (a seven-hour process that begins at 7am) at Rajaportti sauna in Tampere naked. But seeing as he has visitors, today he is dressed in swimming trunks and sliders, accessorised with a multitude of maritime-themed tattoos.

I have come to Finland to learn about its sauna culture, a tradition so valued that in 2020 it was inscribed on the Unesco list of the intangible cultural heritage of humanity. My starting place, Tampere, one-and-a-half hours by train north of Helsinki, has about 60 public saunas in a city of around 250,000 inhabitants, earning it the title of “sauna capital of the world”.

‘I feel entirely in the moment’ … Miranda Bryant at Rajaportti sauna, Tampere. Photograph: Krista Keltanen/The Guardian

Unlike in other countries, where saunas are usually marketed as an expensive activity for the few, in Finland they have a far more everyday role. Many people have saunas in their homes; lots of older Finnish people were even born in saunas. But they are also considered a sacred space and a place to find community as well as peace. Finland has topped the world happiness report rankings for the past six years – could its sauna culture have anything to do with it?

Built in 1906, Rajaportti is one of a kind but not flashy. About 15 minutes before opening time a queue forms outside the door, and at 2pm people stream in through the ticket booth, then head to the male or female changing rooms. Soon the sauna – one room divided by a wall with separate sections for men and women (young children can crawl between parents under the gap) – is echoing with voices and the sound of steam from the sauna rocks.

But its function as a sauna is just one aspect of the role it plays in daily life. From therapy room to pub, refuge, debating society and creche, it’s a place where people of all ages connect. Elderly regulars check up on each other if they don’t turn up at their usual sauna time, and young children play in bathtubs on the floor.

A tattoed man in shorts pokes a stove in Rajaportti sauna
‘At the heart of it all is löyly’ … keeping the heat going at Rajaportti sauna. Photograph: Krista Keltanen/The Guardian

Some people come straight from the office for an hour to wash away the stresses of the day on the way home, while others spend hours there with friends over drinks. It can also be a place to feel less alone with your thoughts. One regular told Lembke that he comes to the sauna to “share his melancholy”.

While some saunas have rules governing topics of conversation – discouraging, for example, discussion of politics, business and religion – at Rajaportti, everything goes. “You have left wing, you have right wing, you have punks, you have architects, you have artists; everyone sits up there. And they talk, and they drink. And of course it gets heated sometimes,” says Lembke. “This is how it should be.”

Being based in Stockholm as the Guardian’s Nordic correspondent, and with half my extended family in Sweden, where bada bastu (Swedish for “taking a sauna”) is a popular pastime, this is not my first sauna experience. I have happy childhood memories of darting between sauna and the brackish water of the Stockholm archipelago on a summer evening. On a recent trip to Iceland, on the night of the women’s strike, I went to a sauna in a caravan where, at 15-minute intervals, we were invited to take a dip in the North Atlantic. When a feminist anthem came on, the caravan burst into spontaneous song. But in Finland not only are saunas plentiful – an estimated 3.3m for a population of 5.6 million – but the culture around them is unique. Having originated to fulfil a very practical need for heat and sanitation, the sauna’s significance in Finnish society now goes far deeper – perhaps even to the essence of what it is to be human.

At the heart of it all is löyly (pronounced low-lu), a word that literally translates as steam or heat. But that doesn’t come close to capturing it. Lembke compares the experience of good löyly to an intense hug. “It’s a spiritual thing,” he says. Every sauna has a different löyly and its quality can vary in the same sauna from day to day, or even hour to hour as the heat drops. “If guests come to the sauna they are my hardest critics, and if the löyly’s not good then they are a little bit sad.”

A group of bare-chested men sit outside at a picnic table with beers, at Ranjaportti
‘We’re talking about feelings – and history’ … socialising at Rajaportti. Photograph: Krista Keltanen/The Guardian

The concept of löyly is something I only begin to grasp when I go into the sauna. After washing with buckets of fresh water from a basin on the bottom floor, I ascend the stairs to the top level, where the temperature is about 80C. As the men next door pour water on the stones, I start to feel the löyly. The taste is aromatic and slightly bitter, a bit like green tea, and it smells like birch. But the intensity of the “hug” is almost overwhelming, and after a few minutes I have to go outside. This is the best part, standing in my acorn-shaped sauna hat, towel and sliders, looking around at the snow and feeling the cold rain on my skin. Skin tingling, chest and temples gently pulsating, I feel entirely in the moment.

“We’re going to spend our evening with our families, so it’s just a nice way to start the weekend,” says social worker Anita Kontukoski, 49, who is sitting on a bench outside, catching up with a friend. She has an electric sauna at home, but lately, with energy prices so high, it has been more convenient to come here. Usually, she comes on a Friday afternoon straight from work. “That’s the best way to start your free time and forget all the stresses of the week.” During the summer months, her friend Mia Surakka, 49, a nature photographer, saunas every day in her summer cottage, but in the winter she goes once a week. “Sauna for Finnish people is really important; for most, they couldn’t live without it.”

Nearby, a group of men, all teachers, are congregated around a picnic table in towels, drinking beers. They usually sauna at home, but have travelled from nearby Pori to soak up Tampere’s sauna culture. They enjoy the opportunity to catch up with each other and strangers. “Not politics, not religion, not sports, just life,” says one. “We’re talking about feelings – and history, of course.” Do saunas serve as a unique place for Finnish men to talk about their emotions? “I think so – and with a little bit of alcohol,” says Harri Nurmela, 55, pointing to the can in front of him (which is, in fact, 0%).

Across town, the light is already starting to fade as we reach Rauhaniemi folk spa, where a line of bodies progresses unflinchingly from the sauna into the 3C water of the neighbouring lake. It looks unimaginable at first, but once I have been in and out of the sauna, following them seems like the natural thing to do – until I’m submerged and struggling not to shriek. Afterwards, though, I feel euphoric and ready to do it all again.

Miranda Bryant standing by the lake at Rauhaniemi folk spa.
‘I feel euphoric’ … Miranda Bryant heading from the sauna to the lake at Rauhaniemi folk spa. Photograph: Krista Keltanen/The Guardian

The crowd here is younger, and the saunas are gender-neutral and require swimwear. Maiju, Paula and Milja, aged between 39 and 42, are in Tampere for the weekend from Helsinki with colleagues.

They say saunas are a place where they don’t have to worry about how they look, and where everyone is equal and stripped of status. Also, while pregnant women are often advised to avoid saunas in other countries, in Finland it is considered a normal activity during pregnancy and accompanied by young children.

“Especially when we are just about to go into labour,” says Paula, 40, a product manager. “Sauna, sex and cleaning are the things you should do before [giving birth],” she says, to a chorus of knowing laughter. Her youngest child, who is two, is “a really big sauna fan”, she says. “He’s sitting there with us for a long time. At least 10-15 minutes, depending on how hot it is.”

People in swimming gear standing and sitting outside the sauna at Rauhaniemi
‘A line of bodies unflinchingly progresses from the sauna into the 3C water’ … at Rauhaniemi folk spa. Photograph: Krista Keltanen/The Guardian

Tampere’s public sauna legacy goes back to the early 19th century, when the city was an industrial centre, out of a need for a communal place for primarily working-class people to wash, says Tuomas Paloniemi, from the tourism bureau Visit Tampere. “They needed to bathe, and bathrooms or private saunas were not so common in those residences.” By about 1820, there were more than 100 public saunas in the city, he says.

Finland’s sauna tradition is believed to go back to the first settlements after the ice age, when people are thought to have dug holes in the ground and covered them with animal skins. During the iron age, saunas are understood to have been built from logs, resulting in a chimneyless smoke sauna that remained popular until the 1930s, after which continuously heated saunas, followed by electric saunas, started to gain traction. In the past, as well as washing, they were used for cooking, making clothes, socialising, looking after the sick, burial preparations and giving birth. In the 1950s, traditional public saunas in cities almost disappeared, but in recent years there has been a resurgence.

Janne Koskenniemi, the executive director of the Finnish Sauna Society, says: “You could say that we had a little bit of a dip in the popularity of saunas in the 70s or the 80s, even maybe in the 90s.” This he puts down to a surge in poor-quality saunas that were built in apartments (“You know a bad sauna when your head is burning and your feet are cold”). But now, rising numbers of communal saunas are being built in flats and there has been an increase in new public saunas. While some are directed at tourists, younger Finns, he says, are increasingly attracted by the physical relaxation and mental health benefits.

Miranda Bryant smiling while in the lake by Rauhaniemi
‘I struggle not to shriek’ … in the lake by Rauhaniemi. Photograph: Krista Keltanen/The Guardian

Sauna definitely contributes to Finland’s happiness levels, Koskenniemi says. He compares the impact of regular sauna-going to having therapy. “When you’re in the sauna you’re naked in the physical sense, and you’re naked with your thoughts and your standing in society. It’s just you.”

At the society’s sauna house in Helsinki, where they have three smoke saunas, they try to maintain the customs and culture of the original saunas, as well as exploring the potential of new technology. Becoming a member here isn’t easy as there is a waiting list of hundreds, but I am invited to visit on women’s evening, as the guest of board member Ritva Ohmeroluoma.

She waits for me in a towelled onesie, and we immediately undress and wash before going for my third sauna of the day, this time a smoke one. The experience is amazing. The scent is incredible, the löyly completely different from the first two, and the heat is intense. The dark lighting makes it easier to forget about the absence of swimwear as we chat about the Unesco application, which she led. Between saunas, we go out on to a long metallic walkway, past the rustling reeds, to dip in the dark waves of the Baltic (water temperature: 6C). In the cafe, women sit around a fire reading newspapers, snacking on open sandwiches.

“We eat and we sleep and we go to sauna; it’s equal to us,” says Ohmeroluoma. “We have been doing this for 8,000 years.” As a young child, she used to attend the public sauna every Saturday with her family. “My mother and my grandmother went to the ladies’ section and I went to the men’s because I felt more free over there. My grandmother was always saying: ‘Don’t burn yourself with the hot water. Don’t touch the kiuas [sauna stove]!’” When Ohmeroluoma had her own children, she started taking them to the sauna when they were less than a month old. “In Finland it’s open to everybody,” she says.

That’s not to say high-end options don’t exist. In Helsinki there is SkySauna, where saunas are on a big wheel, and Allas Sea Pool, where you can look out to the harbour. For death metal fans, there’s even the Bodom Bar & Sauna in Espoo.

But it is at my final stop, at Sompasauna, a free-of-charge sauna by the sea in Helsinki, open all day and night every day of the year, that I find the greatest sense of peace. Inside one of their three saunas, with a small window looking out to the Baltic, people keep streaming in until there are about 20 of us. I close my eyes and listen to the hum of strangers’ chatter and the sparks of the logs in the fire, and realise I can feel the relaxing effects of the löyly.

Student Iida Korpela, 26, comes most days. “I don’t know any place in Helsinki or the whole of Finland where there are so many different people – young, old, students, foreign people, people from different socioeconomic backgrounds,” she says, sitting at a piano under a wooden shelter. “When you’re in the sauna you don’t have your fancy clothes; we’re all just people in the sauna. That’s the best part.”