PORTLAND, Ore. (KOIN) – Ahead of New Year's Day polar plunges, a doctor with University of Washington Medicine, is sharing advice for navigating icy waters safely.

UW Medicine rehabilitation medicine doctor, Dr. Chris McMullen -- who specializes in sports medicine -- recommends enjoying the water for a few minutes with a group of people, then getting out and warming up.

“Don’t go off by yourself and cut through the ice and jump in,” McMullen warns -- urging polar plunge participants to check with their doctors first for any underlying conditions. 

New Year’s Day often brings cold plunge gatherings during which people step out from the comfort of their cars, shed their winter clothes, and only have bathing suits and towels to “fight off the cold,” as they run into cold rivers, lakes, or oceans, UW explained in a press release.

 “Some come to wash away the old year and jump or splash into the new. Others come to take advantage of reported health benefits of a cold plunge, which range from reducing blood sugar to easing depression,” the university added.

According to McMullen, cold water immersion has been well-studied among athletes and is shown to reduce physical pain; however, jumping into cold water once a year “is another matter.”

“There may be some benefits, but we need to study this a bit more,” he said. 

While more research needs to be done on the “once-a-year plungers,” McMullen says cold plunges in general offer health benefits.

“There have been these proposed health benefits to how it might help someone with their mental health and physical health,” he said. “Some of the potential benefits include reduction in stress [and] reduction in anxiety. There have been some thoughts that it might help with blood sugar regulation.” 

McMullen noted cold plunges can also boost immune system health.

“Repeated cold water immersion has been shown to increase the circulating concentration of certain immune system cells and proteins,” McMullen said. “The limited studies we have on the health benefits from cold immersion suggests that the people who are doing it more on a repetitive basis might see more of those benefits.”  

While there are health benefits to cold plunges, overall, McMullen stresses that people with a history of heart problems, high blood pressure, hypothyroidism, and Raynaud’s phenomenon (in which blood flow is restricted to the hands or feet) to check with their doctor before joining a polar plunge.

“As benign as it may seem, in some cases, cold water immersion can be dangerous,” McMullen said. “We know that people are more likely to drown in colder water than warmer water.” 

UW also warns of “cold shock,” a physiological response that can affect the heart and blood pressure, and causes heart rates jump, stress hormones to spike, erratic breathing, then shivering.

This response is the body trying to keep its core warm, according to McMullen, noting peripheral blood vessels constrict to keep blood flow to vital organs – which can increase heart rate and blood pressure.

To polar plunge safely, McMullen emphasizes staying in the cold water only for a few minutes, especially for first-timers.