Are Ice Baths and Cold-water Swimming Good for Your Health?

• The cold-shock response

Getting in cold water, “is a very shocking experience,” Massey says. You gasp for breath as your heart rate, blood pressure and stress hormones spike. This can happen in even mildly chilly water, but peaks at 50-59-degrees Fahrenheit, Massey and her colleagues have reported. In swimmers, cold shock diminishes with repeated dips. That kind of adaptation could, theoretically, help people handle other stresses in life, Massey says. But cold shock also can be dangerous, occasionally triggering heart rhythm problems. That’s one reason people with heart conditions should check with their doctors before going in cold water, she says. Cold shock also can lead to drowning if people gasping for air put their heads under water.

• Diving response

If you do put your face in the water, you also can trigger the so-called diving response, which “has a real calming effect,” and causes your heart rate to fall, Massey says. But if your heart is still racing from cold shock, that’s like hitting the brake and accelerator at the same time, and could increase the risks of heart rhythm problems, she says. Once the cold shock passes and “you can speak in full sentences,” it’s safe to get your face wet, she says.

• A cooling body

Cold water can immediately reduce pain by numbing nerves, says Dominic King, D.O., a sports medicine specialist at Cleveland Clinic. Also, as blood vessels constrict to limit heat loss, blood flow is reduced, lowering inflammation, at least temporarily, he says. Some studies also show dramatic increases in mood-lifting brain chemicals, such as dopamine. Regular cold exposure produces additional physiological changes, including an increase in brown fat, which may increase calorie burn and have other metabolic effects, Mercer says.

• Hypothermia risks

Stay in too long and you risk hypothermia, a dangerously low body temperature, says Mark Harper, M.D., a consultant anesthetist at Sussex University Hospitals in the United Kingdom and Kristiansand in Norway. How long is too long differs, says Harper, the author of Chill: The Cold Water Swimming Cure. For example, he says that when he jumps in a cold lake after a long bike ride, he stays warmer longer than if he just got out of a car. In general, he and Massey say, benefits peak after a few minutes, while risks rise. Signs of hypothermia, such as mumbling speech and fumbling movements, require medical attention, she says.

• Aftereffects

Your body temperature may fall even after you get out of the water, so it’s important to get into warm, dry clothes quickly and to avoid driving until you are sure you are OK, Massey says.

Sulek, the cold-water swimmer, says she and her friends have safely gone into water so cold that they need to break ice to get in, near her second home outside Bratislava, Slovakia. In winter, she says, they wear scuba gloves, booties and hats, and get out after a few minutes. Then, they run to one of their houses and sit by a fire. The rewarming, she says, is one of the best parts: “You feel a glow inside.”

Mazur and Richland, the Colorado couple, say they see their plunges in icy tubs as part of their meditation practice.

“It's a great way to get out of your mind and get into your body,” Mazur says. “It clears my head. It’s just kind of the next level.”

It’s about “really tapping into the possibilities of what our minds and bodies are capable of,” Richland says.

Tips for trying cold-water immersion safely

If you want to try cold-water immersion in the safest way possible, Dominic King, D.O., of the Cleveland Clinic, offers six tips to get started.

1.   Check first with your doctor, especially if you have an injury, heart disease, high blood pressure, diabetes, breathing problems or any condition that limits cold tolerance. Even if you feel safe, always have other people nearby when you get in cold water.

2.   Get a water thermometer and use it in your home bathtub. For most people, a starting temperature of 65 to 68 degrees will be plenty cold.

3.   If you aren’t ready to put your whole body in, start with your feet and legs and work your way up. Once you can sit for 30 seconds, try next time to sit longer or to lower the temperature, by adding ice, if needed. Don’t go colder and longer at the same time. While some people like the challenge of using much colder water, King says there’s no evidence for benefits below 55 degrees Fahrenheit or so.

4.   Focus on breathing. “Try really deep slow breaths to stay calm and reduce stress.”

5.   Have warm towels and clothes ready to use when you emerge. Maybe do a little light exercise to warm up. Drink fluids, because cold exposure can cause dehydration.

6.   Another option: Try a cold shower, which tends to be less intense. If you find that miserable, cold immersion might not be for you.

Whole-body cryotherapy is offered in many fitness clubs and spas.

Jacob Ammentorp Lund / Getty Images

Whole-body cryotherapy

If a little cold water might be good for you, how about cold air – very cold air? That’s the idea behind so-called whole-body cryotherapy (WBC). The version offered in many fitness clubs and spas involves standing or sitting for two to four minutes in a super-cooled room or in a one-person chamber that leaves your head sticking out. Temperatures inside can be as low as minus 300 degrees Fahrenheit, according to the U.S. Food and Drug Administration (FDA).

You’ll find online claims that cryotherapy can reduce soreness after exercise, lift mood, help with weight loss and tighten skin. Some providers have touted benefits for people with conditions including asthma, Alzheimer’s disease and multiple sclerosis, the FDA said in a consumer update published in 2016.

At that time, the FDA said there was no convincing evidence for any of the claims. It has not updated its advice since then. It’s plausible that very cold air might have some health benefits, just as cold water seems to, but

“I just don’t know how much of an effect,” says cold-water researcher Mark Harper.

Some research has looked at whole-body cryotherapy for treating muscle soreness in athletes and found no advantages over cold water, says researcher Heather Massey.  One review of four muscle pain studies found the research was of “very low quality.” A review of 10 studies of people treated in super-cooled rooms, with their heads and bodies exposed, found preliminary evidence that the treatment eased mental health problems, especially depression. But the researchers said larger studies with longer follow-up were needed.

The American Academy of Dermatology warns that whole-body cryotherapy users have reported frostbite, rashes and other cold-related injuries. 

Because of such risks, it’s “really important exposure is very short – a maximum of a couple of minutes,” Massey says, and that users wear warm footwear, thick gloves and, if needed, a hat or headband to protect the ears. Costs for cryotherapy vary, with single sessions typically advertised for about $40-$65.