Interest in public saunas and bathhouses is growing in major cities, as spa-goers look to sweat out stress and businesses see an opportunity, Bloomberg reports (gift link).

• A wave of startups is reviving ancient bathing traditions at a cultural moment when people want to unwind, connect and ditch alcohol.

🔥 A few trends are colliding and propelling people to the sauna, which can be paired with cold plunging for those inclined.

• Biohacking and longevity culture, amplified by podcasters and influencers including Joe Rogan, have normalized contrast therapy.
• 📵 People craving booze-free, phone-free rituals want places to be seen and to feel something physical.

Entrepreneurs see margins: Startup costs are high, but maintenance and efficiency costs are relatively low.

🧘 "Today's chic new bathhouses aim instead to take the place of the coffee shop, pub or nightclub — spaces where people can gather, meet and sweat. You're likely to find muscly young professionals, colleagues having work meetings or couples canoodling on first dates," Bloomberg's Madison Darbyshire and Eleanor Thornber write.

🎟️ A new generation of high-design operators is treating saunas like boutique hospitality, complete with memberships and programming.

• The Altar and Lore Bathing Club are opening in New York. Othership and Bathhouse are planning more U.S. locations, and Arc in London programs DJ-scored sauna nights.
• Spanish group Aire Ancient Baths is expanding in North America and has locations in Chicago, New York and Toronto, with a Los Angeles opening set for this year.

💪 Beyond the social aspect, some research links regular heat exposure and temperature contrast to cardiovascular benefits.

• 😌 The clearer return is emotional — endorphin highs, the triumph of a cold plunge, and an intimate setting that lowers the barrier to talking with strangers, or silently suffering together.

🧖‍♀️ Natalie's thought bubble: I plan an annual trip to Virginia's Korean King Spa with friends, perfectly timed this past weekend before the snowstorm.

• I've been committed to the ritual for years, starting in Brooklyn with a more traditional Russian banya in Flatbush and the trendier Bathhouse in Williamsburg.
• 🌿 While traveling, I've dabbled in all sorts of shvitzing: temazcal in San Cristóbal de las Casas; hammam in Marrakech; and the popular Japanese spa, Ten Thousand Waves, in Santa Fe, N.M.

The bottom line: Whether it's Finland or Flatbush, saunas are becoming a new third place.

Finish Line reader Bob Schumacher of Wheaton, Ill., is on a South Pole cruise and sends this image he took today near Sprightly Island, Antarctica.