Cold water swimming is booming as people look for ways to shock themselves out of pandemic fatigue

• Cold water swimming seminars have quickly sold out, and wetsuit demand has outpaced supply.
• Enthusiasts report feeling alive and socially connected after a year feeling dull and isolated.
• The practice can be dangerous, and benefits may be tied to other factors, like being in nature.

Jake Panasevich stood on his open-air porch wearing nothing but boxer briefs in less than 10-degree weather.

The yoga instructor, who's spent the pandemic with his dog in a Cayuga, New York, family lake house, called it "cold therapy." His neighbors, he presumes, called him a loon.

But while standing there looking out at the ice-covered Lake Cayuga, an even zanier thought crossed his mind: "Wouldn't it be cool if there was a way to get in there?" Panasevich recalls.

He wasn't the first person to have that thought. In fact, he soon learned, a small group had been meeting up at a non-frozen part of the lake, stripping down to swimsuits, and running in.

On February 8, Panasevich drove an hour to the lake's thawed end to join them. He told himself he didn't have to go through with it, or that perhaps he'd just go in halfway. But buoyed by others' courage, he waded in up to his neck - and has been four times since.

"It's given me something to look forward to - or dread - in a time when nothing is going on," Panasevich, 35, told Insider. "It's exhilarating, and you have to be present. All of these things that are going through my mind being isolated during the pandemic are washed away by the cold water."

A post shared by Jake Panasevich (@yogawithjake)

Cold water swimming or winter bathing seems to be enjoying a global boom during the pandemic, with folks looking to break up monotony, form community, and boost their mental and physical health. There's some research in favor of their claims, but the practice can also be deadly. The strongest evidence of its benefits is anecdotal.

"It is bracing. It requires more focus [than warm-water swimming], and conquering it makes me feel like superwoman," Gail McCallen, a 57-year-old decorator in Seattle who began cold water swimming in the Puget Sound this winter, told Insider. "I always feel so alive. "

Cold water immersion can take many forms

Cold water immersion, which has been around since ancient times, can take many forms: Some people plunge in and out; some, like Panasevich, paddle around for five or six minutes, sometimes dunking their heads; and others swim for longer.

Some wear regular bathing suits, and those like McCallen, who swims for 20 to 40 minutes, wear a wetsuit, neoprene socks, gloves, and a hat, and a swim cap. The temperature can be in the 30s or 40s; a typical swimming pool, by comparison, is around 80 degrees Fahrenheit.

Many plunge in groups through well-organized clubs, others pair up with a friend and share a hot cocoa afterwards. It is not recommended to dive solo, nor does doing so hold much appeal. The shared thrill, and potential danger, fuels strong bonds. "We swim and marvel that we survived the cold again and talk," McCallen said, "and it feels like a life again."

There are breathing and other strategies to make the experience safer and more bearable, and, with each plunge, the body and mind acclimate.

Mike Tipton, a researcher at the University of Portsmouth in the UK who studies extreme environments, told Insider his recent webinars on the topic have sold out in a day or two, with one attracting 1,500 attendees. Membership in an open-water swim club near him went from 25 to almost a thousand in the past three months, he said.

In the US, too, wetsuit retailers have struggled to keep up with demand, said McCallen, who was at first forced to order an ill-fitting man's suit due to the short supply.

Tipton, a triathlete and body boarder, expects increased interest has a lot to do with the fact that lockdowns have made it even easier to avoid any physical discomfort when, in fact, that's exactly what our bodies need to adapt and thrive.

The pandemic has "accentuated the fact that we don't really challenge the system very much, and so people are now looking for ways to challenge the system," he said. "I think it's probably part and parcel of why we've got such an increase in the number of people engaging in extreme sports, generally, not just open-water swimming."

The pandemic has also muted people's identities. Who are you if you're out of work or can't be the life of the party or go weeks without interacting with another human being? Life in your own brain can be lonely. "Sometimes having been the house for so long, you don't feel like yourself anymore," Panasevich said. "And I think it shocks you back into reality."

'A kill or a cure?'

Tipton says cold-water immersion is a double-edged sword he refers to as "a kill or a cure." On the "kill side," the activity comes with a host of well-documented dangers, like drowning, cardiac arrest, and hypothermia.

Getting in cold water is hard on the body. When it comes to cold water specifically, getting in is hard on the body. It first evokes the "cold shock response," or the fight-or-flight reflex that sends blood to your heart and the brain, quickens your breathing, speeds up your heart rate, and prompts you to shiver and gasp.

"If you're jumping into cold water and you gasp and it's timed wrong, you can actually get cold water in your lungs and that's very dangerous," exercise physiologist Emily Johnson told US News.

If you put your head under cold water, you'll also experience a "diving reflex," which contradicts the cold shock response by telling the body to breathe more slowly and slow down its heart rate. Taken together, the responses can lead to a heart arrhythmia or even death.

In rare cases, cold water immersion, particularly for longer periods of time, can cause tetany, a condition in which the heart freezes and stops.

Cold water immersion is linked to a host of benefits, but it's unclear if something else may be responsible

But winter bathing devotees find ways to manage those risks - the basics are starting with short, not-entirely-frigid immersions, wearing appropriate gear if you choose, going with a group, making sure you don't have a heart or other condition that could put you in more danger, and changing into warm, dry clothes immediately afterwards.

The benefits, enthusiasts say, are well worth it. For one, they report feel alert and alive, thanks to the same fight-or-flight response that can put them in danger, Tipton said. "There's this euphoria that happens," McCallen said.

Some cold-water swimmers also seek the metabolism boost, and others boast of improved immune function. But, Tipton said, it's difficult to parse what really accounts for fewer reported sick days.

In one of his recent studies, for instance, he and colleagues found swimmers tended to have fewer respiratory tract infections than their live-in, non-swimmer partners, but it didn't seem to matter whether the water was warm or cold. "Perhaps it's the exercise," he said.

The third main purported benefit of cold-water immersion, and the one that excites Tipton the most, is reduced inflammation. That helps the body better deal all kinds of stressors and reduces the likelihood of heart disease, inflammatory bowel disease, type 2 diabetes, Alzheimer's, depression, and more.

A case study co-authored by Tipton describes a 24-year-old new mom with severe depression and anxiety whose symptoms had resisted treatment, including multiple medications, for seven years. She then tried cold water immersion as a therapy.

"After the second one, she was thoroughly miserable," Tipton said. But "by the sixth immersion, she was ecstatic. She said she's the happiest she'd been since her child was born." Afterwards, she took up cold-water swimming and remained good mental health and drug-free a year later.

"It's easy to poo-poo anecdotal evidence as a scientist," Tipton said, "but it is a form of evidence." The question remains, though, what's really the cause: The physical activity? The nature? The feelings of connection? The sense of accomplishment? The distraction? The post-dunk slice of cake? Or, the cold?

"We need to find out what the active ingredient is," Tipton said.

Eventually, identifying it may lead to treatments using a minimal effective dose strategy, especially for people with conditions like dementia for whom swimming in an icy lake is out of the question. "What if you only had to immerse a hand or a foot to have these beneficial effects?" Tipton asked.

But right now, converts to the activity don't care so much what's making them feel great. They're embracing feeling great in a year of feeling, well, terrible. "There is something empowering about beginning something new when life is limited," McCallen said.

While she'd been a summer lake swimmer for much of her life, this winter was the first time she continued open-water swimming through the seasons. "At the end of the summer, I really just couldn't face the shortening days of gray and rain, and the end of swimming," said McCallen, who's also been out of work throughout the pandemic.

"So I asked some questions, bought a wetsuit and the things I needed, and kept swimming," she said. "Some days, I think it has saved my life."