The people who immerse themselves in an ice hole in Lake Harriet every day of the frigid Minneapolis winter call it "magic."
The icy dip gives them time to meditate and commune with nature, an excuse to take a break from the kids, to howl at the moon, to start the day with a feat of grit and induction into a social circle with an unfailingly positive WhatsApp group chat.
Swimmer Nicholas Garbis describes the physical sensation of remaining submerged several minutes as "borderline hypothermia." "Your blood moves from the surface inward," he said. "All the veins and arteries constrict and they leave like a few millimeters of your tissue there that serve as your own personal neoprene, essentially."
For many who dip in the ice holes of Lakes Harriet and Cedar, friends and family don't always understand what would possess someone to endure such extremes. But researchers want to know more about the benefits that keep the regulars coming back.
In January Dr. Kaja Plucinska of Rockefeller University's Cohen Laboratory of Molecular Metabolism gave the group a presentation on current research on brown fat — a type of body fat located in the deep neck area that produces heat and burns calories in cold conditions.
"Controlled exposure to cold such as ice water dips or cold showers has been linked with improved health and well-being," Plucinska said in a statement. "A wealth of anecdotal evidence suggest a number of health benefits in individuals practicing exposure to environmental cold, including reduced inflammation, improved blood flow, reduced fat mass and overall improved metabolism."
The Rockefeller researchers are investigating the presence of blood biomarkers of brown fat in young New Yorkers, using a cooling vest, in hopes of using brown fat as a means of predicting cardiometabolic health. That study requires validation in a larger group of people, which is where the Minneapolis ice water immersion group — with its mixed-gender and -age cohort — comes in.
Starting this summer, the researchers will collect blood samples from polar swimmers who dip at minimum twice a week for a month in winter. They aim to profile different classes of blood-signaling molecules in the polar swimmers during summer and winter, as well as in a control of group of people who do no repeated cold exposure at all.