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Plunge Ice Baths: Exploring the Hot/Cold Contrast Therapy Trend

by Liz Vaccariello

I Tried an Ice-Filled Plunge Tub and Sauna and Here’s What I Learned

I’m a cold baby, the person at the pool who walks tentatively from the stairs end of the pool to the deep end, shivering with every inch exposed to the water. But when Plunge, the three-year-old maker of high-end ice plunge baths and, now, saunas, invited me to try its products, I jumped at the chance to try one of the fastest growing trends in wellbeing. Thermal hydrotherapy involves exposing the body to extreme temperatures, such as spending time in a sauna or steam room followed by immersing oneself in a cold plunge or ice bath.

I figured a report from the extreme trenches of hydrotherapy would give me a chance to understand and learn about the physiological and psychological effects of transitioning from a 200-degree sauna to a 48-degree ice bath. My body survived—even thrived—during the experience. I can’t say the same for my Apple Watch.

To understand the effects of hot/cold contrast therapy, I wanted to first understand the physiological responses the body has to extreme temperature exposure.

“Both saunas and cold plunges create a form of micro stress on the body,” explained Dom Cianciotto, director of experiences for Plunge.  “When exposed to cold, the body produces adrenaline and norepinephrine, triggering a response to escape the cold environment. Similarly, in a sauna, extended exposure can lead to an increase in heart rate and a feeling of urgency, known as the urgency barrier. Crossing this barrier can result in a sense of calm, even euphoria.”

Once the initial stress response subsides, the body produces dopamine, serotonin, and endorphins, leading to a sense of wellbeing and post-exposure euphoria. This release of hormones helps restore balance and contributes to the positive effects of the therapy, which range from elevated energy, active muscle recovery, reduced inflammation, and immune support. Cold plunging has also shown the ability to increase your baseline dopamine, which is the molecule in our brain and body linked to motivation. And plenty of anecdotal evidence suggests cold plunging also elevates mood and energy.

Plunge emphasizes pranayama to maximize the benefits of hot/cold contrast therapy, specifically intense preparatory breathwork, a cooling down period, and calming breathing techniques. Sitting on towels before my session, Dom taught me a reset breath to be used specifically in the ice bath: breathing in sharply through the nose twice, followed by an audible sigh out. These exhales will intentionally lower your heart rate, which might start climbing during the cold. Repeat as necessary.

I was ready to go.

It was getting hot on the fancy NYC rooftop where the plunge event was being held, so we started with the plunge. In the spirit of not embarrassing myself in front of the plunge pros, I put two feet in, crouched, hands on the edges, then sat right down and leaned back. Maybe it was the adrenaline of being watched, but it was not an awful feeling. I focused on enjoying the relief of the cold on my hot skin, and checked my heart rate, which had gone up just 10 beats per minute. “Right now, your body is producing adrenaline and norepinephrine to get you out of this environment,” he said.

I did the reset breaths, and at the 45-second mark felt like relaxing my shoulders and leaning back into the tub. Dom told me that within 30 to 90 seconds most first timers feel like they’re alright, and the heart rate starts to come down. I felt most acutely uncomfortable in my thighs. They ached and felt like pins and needles, but the feeling started to dissipate by minute two. Since this was my first time, Dom didn’t want me to stay in longer than five minutes. He said the long-term benefits do not support anyone enduring more stress to their body than that. I was just starting to feel relaxed, but at the end of minute four, it was time to sauna.

After the cold plunge, the heat of the freestanding Plunge Sauna felt calming, even cozy, as I sat back on the ergonomic backrest in the stand-alone, glass-fronted wooden structure (retails for around $11K; users can control the temp, which can go to 230 degrees, with the company’s mobile app).

“Watch your heart rate and check in with yourself—if you feel like you’re gonna pass out, get out,” Dom advised. “But if you just feel a little bit uncomfortable, stay in. After anywhere from eight to 14 minutes, this feeling too should subside.”

I made it for eight minutes. I never felt woozy or weak. But I could feel the heat on my nostrils as I breathed in, and my Apple Watch (which I kept on to check my heart rate) powered down from the temperature.

Back into the ice bath for me!

The whole 30-minute experience made me feel proud for crossing the discomfort barrier. The breathing techniques will be useful in all sorts of settings, not least of which is the next time I tiptoe into a chilly swimming pool. And while I’m not ready to invest ($5,000 for the home plug-in unit that cools, filters and sanitizes) in the Plunge myself, I’m game to try the cold plunging when I come across it in my spa and hotel travels. I also have been ending my showers with an invigorating few seconds of cold. 

For all readers, it’s crucial to approach extreme temperature exposure with caution and respect for your personal limitations. Specific caution for people who take beta blockers or have high blood pressure. It is essential to check with your doctor, listen to your body, avoid prolonged exposure if not accustomed to it, and consult with a healthcare professional before engaging in any new wellness practices.


Deep below the surface, our world is cold, dark and content. Colors are fickle. Red disappears first as you descend, followed by the yellow of the sun. The hundred shades of blue last the longest but eventually there is only black—and the candied ooze of the ocean floor.

These are early words in the stunning, transformative, metaphysical story about an intelligent life form that lives entirely under water and what happens when one tribe stumbles upon a sunken corpse. From accomplished journalist and nature writer James Sturz, this lyrical novel is “poetry, fantasy, love, war, mystery and philosophy,” Jean-Michel Cousteau of the Ocean Futures Society says.

Sturz is based in Hawaii, and has covered the underwater world for The Atlantic, The New York Times Magazine and Men’s Journal, among other places. Sturz was first to cover the newly opened Rosewood Kona Village spa in this month’s Where to Go Next newsletter. His feature on the history and beauty of water therapies will appear in Organic Spa’s Art of Wellbeing bookazine this fall.

Preorders for Underjungle are available now. Released August 1 from Unnamed Press.

Header photo credit: Tawni Bannister

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