In a world obsessed with new wellness trends, some of the most powerful practices are also the oldest. Heat bathing, through Japan’s onsens or Finland’s saunas, has been tied for centuries to relaxation, recovery, and community. Modern research suggests these rituals may also help explain why two very different countries consistently rank at the top for longevity and happiness.

As fall arrives, I have been reflecting on my summer travels, including a trip to Japan where I ventured beyond the usual Tokyo–Kyoto path to Beppu in Kyushu. Beppu is famous as the hot spring capital of the world, with steam rising from vents in the streets as you walk through town.

There, I tried some of its most unusual bathing traditions: sinking into a thick mud onsen that coats your skin, lying buried up to your neck in the warmth of a sand bath, and resting in a herb-infused chamber where steam carried the scent of botanicals into my pores. Each was surreal and restorative, transforming bathing into something more than hygiene. It felt like ritual, medicine, and meditation all at once.

This reminded me of another journey a few years back to Finland, where I experienced sauna culture in its purest form. Nearly every Finnish household has one, about three million saunas for a population of 5.5 million, and UNESCO has even recognized the sauna as intangible cultural heritage. One of my most memorable sessions ended with plunging straight from a wood-fired sauna into the icy sea, a shock that left me buzzing with clarity.

Finland tops the global happiness rankings, while Japan leads in life expectancy. Could these heat-bathing traditions, practiced daily in both cultures, be part of the story?

Whether in a 90°C Finnish sauna or a 40°C Japanese onsen, passive heat exposure activates many of the same systems as light exercise. Heart rate rises, blood vessels dilate, and stress-response proteins are released. Research shows consistent benefits: lower blood pressure, improved arterial flexibility, and better sleep quality. Over time, these small effects may accumulate into meaningful health gains.

Sauna is one of the oldest continuous traditions in Finland, with archaeological evidence dating back more than 2,000 years. Early saunas were dug into the ground or built as log huts, heated with wood-burning stoves and used not only for bathing but also for childbirth, healing, cooking, and even preparing the dead. Over time, the sauna became woven into Finnish identity as a place of purification, recovery, and social connection.

Traditionally, the sauna was also seen as sacred. It was the cleanest room in the home, used for life’s milestones from births to funerals. People treated it with church-like respect, believing it housed protective spirits known as the saunatonttu. It was also a social equalizer, where farmers and nobility shared the same steam.

Even food had a place in sauna culture. Families cooked simple meals like sausages or baked bread using the heat of the stove, a practice that continues today in playful forms such as wrapping food in foil to steam on sauna rocks.

Today, sauna is not a luxury but a rhythm of life. People use it for recovery after work, family bonding, and even business meetings. Modern research confirms many of its benefits. A 20-year study from the University of Eastern Finland found that men who used the sauna 4–7 times per week had far lower risks of sudden cardiac death, stroke, and dementia compared to those who went only once. Beyond heart health, sauna sessions also reduce stress and improve mood through endorphin release and the meditative rhythm of heating and cooling. Correlation is not causation, but the science aligns with what Finns have known for centuries. Sauna makes you feel better today and maybe healthier tomorrow.

Japan’s hot spring culture also stretches back millennia, with onsens referenced in ancient Shinto texts and Buddhist practices that viewed bathing as both purification and healing. Many onsens are located near temples or shrines, and for centuries they were considered places of spiritual renewal as well as physical recovery. Over time, public bathhouses made bathing more accessible, turning it into a daily social ritual for ordinary people.

Because Japan is so volcanic, its hot springs are especially mineral-rich. Depending on the source, onsen waters can contain sulfur, iron, sodium chloride, or carbon dioxide, each believed to offer different therapeutic effects, from improving circulation and skin health to relieving joint pain. The combination of heat, minerals, and ritual makes onsens a uniquely holistic practice.

Modern research now supports what Japanese culture long believed. A nationwide study found that people who bathe in hot water more frequently have lower risks of cardiovascular disease. Other research ties immersion bathing to improved circulation, glycemic control, and mental health.

Unlike the fairly standardized Finnish sauna, onsens vary dramatically. From Beppu’s mud and sand baths to outdoor mountain baths, each one offers a slightly different sensory and social experience. That diversity makes the practice endlessly engaging and perhaps part of why it has endured for centuries.

Finland and Japan are vastly different societies, yet their bathing traditions converge on three pillars:

• Social connection: Both sauna and onsen are communal practices that strengthen bonds and trust.

• Recovery and sleep: Heat exposure enhances relaxation and supports better rest.

• Connection to nature and ritual: Whether it is a sauna beside a frozen sea or an onsen in a volcanic valley, these traditions embed people in restorative environments and rituals.

These habits alone do not explain Finland’s happiness or Japan’s longevity, but they fit neatly into broader cultural patterns that emphasize balance, recovery, and community.

Both Beppu and Helsinki bring these traditions to life in unforgettable ways. Here are a few places worth visiting if you find yourself there:

Beppu, Japan

• Takegawara Onsen: Historic bathhouse dating back to 1879, famous for its indoor baths and unique sand baths.

• Koudai Onsen: Known for mineral-rich mud baths that are believed to improve circulation and skin health.

• Kannawa Steam Bath: A steam bath that channels volcanic steam through layers of herbs, creating a natural aromatherapy experience.

• Hyotan Onsen: A modern complex offering a wide range of baths, from cave-style pools to waterfalls, ideal for sampling many styles in one visit.

Helsinki, Finland

• Löyly: A striking seaside sauna that blends Nordic design with tradition. Features wood-fired saunas, sea plunges, and a restaurant.

• Sauna Boats (Saunalautta): Floating saunas that drift through the archipelago, complete with wood-fired heat, decks, and sea swimming. Popular for groups and social gatherings.

• M/Y Fortune Sauna Cruise: A vintage vessel refitted with a traditional wood-burning sauna, cruising Helsinki’s coastline for a mix of steam, views, and community.

• SkySauna on SkyWheel Helsinki: A novelty experience, the world’s only sauna gondola on a Ferris wheel, with panoramic views of the city and harbor.
  

Onsen culture has not taken root in the States yet, but cold plunges have gained popularity and saunas are now following. In the past, there were only a few Russian bathhouses, Korean spas, or the occasional gym sauna scattered around. Now, dedicated sauna spaces are starting to appear in New York City. Places like Othership, Bathhouse, and Akari are aiming to make saunas more mainstream. As third spaces and health-longevity culture grow, I expect we will see many more across the country.

Sauna and onsen are not magic bullets. They are simple, repeatable habits rooted in culture, nature, and community. They deliver both immediate calm and long-term benefits, a reminder that health and happiness are often found in the oldest rituals.

Since these trips, I have tried to make more space for these practices, seeking out saunas wherever I can. It is not the same as sitting in a volcanic valley in Beppu or plunging into the Baltic in Helsinki, but the effect is familiar: heat and cold reset my body and clear my head. More than health metrics, these moments are about presence. Shared with strangers, friends, or experienced alone, they slow time down and turn simple routines into something meaningful.

In the end, happiness and health may not come from chasing the new. They may come from returning to the oldest rituals, with heat, water, and the time to slow down.