At 6:30 a.m. on a frigid Sunday, most Chicagoans are still fast asleep. But one group of friends are already amped up.
The air temperature is well below freezing. Lake Michigan is choppy and the water is nearly frozen.
But Steve Hernan, the leader of the self-nicknamed "Lake Monsters," is ecstatic.
"Thirty-five Fahrenheit — that's one degree centigrade, there we go," Hernan said after dropping a thermometer in the water. "The good news is it doesn't get much colder than this, so it's not like we will be surprised next week."
In a few minutes, he and his swim buddies will hop in. But first comes the extra layers, as Hernan says keeping the core warm lets them be in the water longer. Then there's the shea butter, which provides an extra layer of protection to the exposed skin. Next up, hot water goes inside gloves and booties.
When it's this cold, the prep work makes all the difference.
"I try to relax as much as possible," Hernan said. "Tension is the enemy."
Hernan, who founded the group in 2007, has been waking up at the crack of dawn nearly every weekend for 15 years.
"As a father of two young kids, it's one of the few times I just get some quiet time, to be honest," Hernan said.
Even in the dead of winter, the 55-year-old manages to swim a quarter of a mile.
"You come out, your temperature after about 10 minutes just drops, so you start to shiver," Hernan said. "Then all of a sudden it'll stop, and you'll just be so relaxed, kind of like semi dreamy, idyllic state of kind of relaxation."
The science on cold-water immersion is inconclusive, but anecdotal evidence suggests it may have mental and physical benefits.
Mike Tipton of the University of Portsmouth in the U.K. has been studying this for decades.
"The benefits you hear from people who are engaged in open water swimming are that it alerts them, awakens and sets them up for the day," Tipton said. "Immersion in cold water stimulates what we call the cold shock response, and that releases a lot of stress hormones. It's part of the fight or flight response, and that includes adrenaline, cortisol."
But the jury is still out on how exactly that's beneficial.
In the meantime, Tipton urges people to get a medical check-up before taking the plunge.
"People wouldn't step out of their door and just go run a marathon, and this is as stressful as that," Tipton said.
Hernan is aware of the risks.
In the wintertime, he stops posting the time and location of the swim meet ups online. Instead, those who want to come need to email him first.
"I've got a winter swimming guide that I send to them that talks about gear, that talks about preparation, that talks about what to expect so that way they can make the decision, and then they're kind of qualified coming out," Hernan said.
Hernan, a business analyst, keeps a meticulous photo archive of his group swims, including meet ups in some of the roughest conditions imaginable. He also keeps a spreadsheet with the names of all 559 Lake Monsters, each of whom has an assigned number.
"They'll send me a note and they'll say, 'Hey, I'm going to be in town Steve. This is Fred, you know, Lake Monster 43,' or whatever. And it's like, right on," Hernan said.
Because Lake Michigan is a different beast in the winter, Hernan has one more nickname for those who brave it all year round.
"Congratulations, you are now an ice monster," Hernan said.
To date, there are only 31 ice monsters. As a reward, Hernan hands newly minted members a sticker that says 32.1 degrees.
"It's the lowest the lake gets that you can still swim," Hernan said.
For Hernan, the nicknames are all about creating a sense of community. He says that's his true legacy with Open Water Chicago, a group of like-minded swimmers who trust and encourage each other to keep coming out, week in and week out, no matter how cold it gets.
Ben Schamisso
