Should you take the cold plunge?

Is an icy plunge good for you or should you give this trend the cold shoulder?

If you're training for, say, a marathon, cold-water immersion might help with pain relief and build grit, said Andrew Markwith, MD, an orthopedic surgeon who specializes in sports medicine with Cape Cod Healthcare’s Falmouth Orthopedic Center. And it will certainly give you bragging rights.

“It’s something that proponents say can have benefits for recovery from training, especially endurance sports,” he said. “It can help build mental resilience. And for some people, it’s just to say, ‘Hey, I jumped in the ocean on January 1.’”

What It Is

A cold plunge is submerging the majority of your body up to the shoulders or neck in water that’s cold enough to be uncomfortable, about 45 to 60 degrees, Dr. Markwith said. The actual temperature will vary for each individual. It could be an ice bath in a trainer’s room or a cold-water swim off a Cape beach.

When your body hits the cold water, it releases several chemicals, he said. Those include adrenaline, which will make you feel alert or even a bit agitated, and dopamine, a neurotransmitter that makes you feel good. “And it does, in the very short term, temporarily increase metabolism, but there’s no evidence that this leads to weight loss. It’s a very short-lived increase in metabolism,” he said.

How do you know if the water is cold enough?

“You’re trying to target a temperature that elicits, ‘This is really cold and I feel like I need to get out of the water, but if I stay a little longer, I still feel like I’m safe,’” he said, quoting Andrew Huberman, a neuroscientist and podcaster from Stanford University in Palo Alto, California, whose lab researches and promotes cold plunges.

What Research Says

Much research on cold plunges is still inconclusive, according to a 2022 review published by the National Institutes of Health. Norwegian researchers looked at 104 studies on voluntary cold-water immersion but found they were mostly focused on small groups of people and lacked good methodology, such as controlling for gender and water temperature. They concluded that there was increasing evidence cold-water immersion reduced insulin resistance and body adipose tissue (which is made up of fat cells) and might offer some protection against cardiovascular diseases and obesity. However, they recommended more research using bigger groups and more controls.

Who Should Do It?

If you’re curious, and your health allows it, try a cold plunge, Dr. Markwith said, recommending that experimenters follow Huberman's guidelines. For example, gradually decrease the water temperature and increase the time you spend in it.

“One of the [Huberman] guidelines I found helpful was that if you’re going to do a program, try to target 10 to 11 minutes per week with a goal of two to four sessions per week. Each one can be a couple of minutes,” Dr. Markwith said.

Cold plunges might be a bad idea for some people, such as those with hypersensitive skin or Raynaud’s, which causes the arteries in the hands and feet to constrict in response to cold, he said. Anyone with cardiac issues should check with their cardiologist. And people with mobility issues might want to think twice.

“If you get cold in the body, the muscles can lock up. There’s a drowning risk in the ocean,” he said.

Cold-water immersion might also be a bad idea for weightlifters. “It can actually limit recovery if someone is doing a lot of strength training or weightlifting,” he said.

Health concerns aside, there’s only one way to find out if cold immersion is right for you: Plunge in.

“I think an easy way to just get started is to just go ahead and do one of those polar plunges,” Dr. Markwith said. “Get into the ocean, get up into your waist, get up to your shoulders and see if you can stay in there for 30 seconds. Then, get out and just see, is this something for me or not?”