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What to Look For in an Ice Bath

Updated: Jan 23

Three important things (to me)


  • There are now so many choices for ice bath or cold plunge equipment that it can be hard to sort them all out. No one knows what's right for you, except you.

  • The Morozko has three features that are important to me: 1) freezing temperatures, 2) ozone disinfection, and 3) electrical grounding.

  • Until you're ready to purchase your own ice bath, you might prefer to use a public spa or wellness center. Use the tips at the end of this article when you're selecting a public plunge provider.

Ice Bath Invention

When we invented the Morozko ice bath back in late 2018, there was no such thing anywhere in the world as an ice bath that made ice. There were some do-it-yourself (DIY) videos for converting chest freezers, and lots of advice about how to buy ice from the corner store to make a one-time ice plunge out of an old garbage can or stock tank, but there was nothing practical for people who wanted to practice an ice bath every day.

Now there is.

And the Morozko is still the only ice bath in the western hemisphere that makes its own ice. Nevertheless, the market for cold plunge equipment has exploded in the last three years, as several competing cold plunge companies have developed their own offerings to serve a growing demand. It's gotten confusing for consumers who are trying to sort through the cacophony of heavily advertised options and spectacular claims of revolutionary new technologies that are really just repackaged versions of the same chiller attached to an inflatable pool.

No one can tell you what equipment is right for you. Only you can decide that for yourself. Among all the different variables to consider, like cost, appearance, availability, no one can say what features you're willing to pay for or sacrifice except you.

However, I can share what was important to me about the Morozko. There are three things that rise to the top: 1) temperature, 2) water quality, and 3) electrical grounding.


In Set Your Ice Bath to A Temperature That Frightens You I talked about the difference between an ice bath and a cold plunge.

The difference is ice.

The cheapest way to build a cold plunge is to purchase a separate chiller unit from China that draws water from a tub, cools it down, filters it, and returns it to the tub. That's so inexpensive because it doesn't require the invention of anything particularly new. The chiller/pump/filter are all one piece, and the only thing left to do is figure out how to attach it to the tub.

The downside of this approach that you have to pump the water to chill it, and that means that you can't chill it below 32F -- because ice doesn't pump. The upside is that all the manufacturing is done overseas.

What's uncertain is just how cold the water can get. Although the controls on the chiller might go all the way down to 39F, that doesn't mean the water will reach that temperature. The chiller isn't sized to accommodate the thermal load of the bathers, the surrounding air, the water pipes, and the tub. All it knows is that it's working as hard as it can. It doesn't know whether it's actually keeping up with the load.

For most people, that's OK, because a cold plunge in the high 40's F is still plenty cold enough for beginners to feel the gasp reflex, get some cold shock response, and activate their brown fat. Nevertheless, in How To Increase Brown Fat I wrote that it takes less than ten days of whole-body, deliberate cold exposure to acclimate to the cold by building new brown fat.

With every cold exposure, your body adapts and improves its defense of core body temperature. For example, in Are You Getting Enough Vasoconstriction? I described how a cold plunge can be a workout for the smooth muscles that control blood flow to your extremities. As these muscles get exercise, their function improves. The same is true for all aspects of your body's thermoregulation. More brown fat = more thermogenesis, and better tolerance of lower temperatures.

A regular practice of deliberate cold exposure will acclimated you to the cold, and lower the temperature that represents your thermal comfort line. As I wrote, in How Often Should You Ice Bath?, you're cold dose depends on your cold acclimation. The more you practice cold exposure, the colder the water has to be to get the same cold shock value.

I keep my ice bath at about 34F, with ice floating at the top. That's probably too cold for most people, but I find that if I let the temperature get up over about 39F, I get bored. I need the ice around my neck and the shock of the freezing water to activate my central nervous system. It takes about 5-6 min at that temperature

So when it comes to temperature, you might find that starting with a less expensive cold plunge is a good way to go, just to see if the same cold acclimation process applies to you. When you practice every day, you might find yourself dropping the temperature setting on your plunge to colder and colder, so you can still get the same benefit, until you reach the bottom limit. At that point, you're probably ready to graduate to an ice bath.

If you're an occasional cold plunger, rather than three to five times a week, then you'll probably still feel the rush of the gasp reflex and the cold shock response, even if your water is in the mid-40's F, because you will remain less cold acclimated. Research shows that you'll still experience many of the metabolic benefits, if not the full range of psychological.

Water Quality

The cheapest way to get started with ice baths is the way that I got started -- buy a stock tank, a garbage barrel, or an old plastic tub, fill it up with ice, and jump in.

The downside to that approach for me is that you have to keep changing the water, or it will get disgusting. You can delay the frequency with which the water has to be changed by adding chlorine bleach to disinfect it, but then you're bathing in chlorine. When health is you primary concern, adding chlorine exposure to your practice is not moving you in the right direction.

In Ozone & Cold Water: A Perfect Match, I talked about the dangers of chlorine oxidation, and why it's still the standard in public pools, spas, hot tubs, and municipal water systems -- even though ozone is a stronger, superior disinfectant. The problem with ozone is that is degrades so quickly at warm water temperatures that it provides no residual concentration for disinfection between dosings. By comparison, chlorine degrades slowly, so it has longer staying power for protecting warm waters from pathogens.

But in cold water, ozone works great. The colder temperature slows down the ozone degradation, allowing more time for disinfection.

There are lots of different ozone generation technologies. For real ozone therapy, like those from Simply O3, you need to start with pure oxygen, so you can get super-concentrated ozone. But for water treatment, it's OK to use the ambient air -- you just need to add energy to the oxygen in the air to excite the electrons enough to convert O2 to O3.

One of the oldest technologies for ozone production from ambient air is to use a continuous spark -- an electric arc. Newer technologies will generate ozone from an intense ultraviolet light, or use a combination of these. Both of these technologies can be made to work, and there are lots of ozone generators built for hot tubs that claim they work.

They don't work.

When designing the water treatment system for Morozko, I tested half a dozen spa-type ozone generators. There were only two that produced anywhere near the ozone that the manufacturers claimed and the one by Del Ozone was better -- so that's the one I choose. The others were essentially frauds, and you might wonder how they could get away with it?

Well, to measure ozone requires some training in water chemistry equipment. You have to know your way around an oxygen-reduction-potential (ORP) meter and how to interpret the results. It's not all that hard -- I learned in graduate school when I was studying environmental engineering -- but it's a specialty piece of equipment that almost no one has at home. Without an ORP meter, consumers might never question the manufacturers of these terrible hot tub ozone generation units, and because the temperatures in the hot tub are so warm, even if the ozone did work, the change in water quality or chlorine demand would be minimal.

Any cold plunge manufacturer that tells you that you have to add additional chemicals, like bleach or hydrogen peroxide, or change the your water on a regular basis to make sure it's clean -- well, that's a manufacturer that either doesn't know how to measure ORP, doesn't know what it means, or doesn't care. Of course, that's not good enough for me.

Electrical Grounding

In The United Kingdom, they call it earthing, because electrical grounding means being in electrical contact with the earth. I've written two articles about this called Ice Bath Grounding Therapy and another called Your Ice Bath Should Give You Grounding Therapy.

Nonetheless, it's probably time for a third article, because the topic is so important, so overlooked, and new experimental results from a scientist who goes by the handle @jessicagenetics have been posted online. She's examining her own blood before, right after, and long after grounding with bare feet in grass, and her slides illustrate the powerful effects of grounding n blood coagulation.

Our bodies are evolved to expect electrical contact with the earth. When we're not in contact for too long, because of our shoes, or automobile tires, or plastic carpets, a static charge builds up on our red blood cells that caused them to coagulate. You can see in Jessica's slide on the left how the blood cells are agglomerated together before she does her grounding.

Those red blood cell clumps change the viscosity of the blood, making it more prone to clots and increasing the risk of stroke, heart attack, and deep vein thrombosis. In her slide on the right, you can see how the red blood cells are free from agglomeration and able to flow more freely after grounding.

There is no substitute for grounding. You can't get it from your diet, or from exercise, or from a supplement.

And you can't get grounding from a plastic cold tub.

Walking barefoot outdoors will put you back into electrical contact with the earth, and discharge you static electricity. However, the best way to ground is in the water, because water is a much better conductor than grass or dirt.

Because I live in Phoenix AZ in a high-rise apartment, I'm a long way from ground. And in the summer when it's hot enough to fry eggs on the sidewalk, walking around barefoot outdoors isn't a viable option for me.

So instead, I ground in my Morozko. Because the metal tub is in electrical contact with the water, and connected to the ground wire in my building, the water itself in the Morozko is grounded -- and so am I.

What to look for in a public plunge

The price tag is still a big obstacle for many people who want to practice cold-water immersion therapy on a regular basis. As a way of getting started without breaking their budget, lots of people are now using the ice bath or cold plunge equipment at a public spa or wellness center.

Many of the considerations about what to look for are the same. You want to find one that is cold enough for you, clean enough for you, and grounded.

In Cryotherapy vs Ice Bath, I wrote about how water quality concerns might motivate centers to offer cold-air cryo, instead of cold water immersion. Nonetheless, ozone disinfection, filtration can make the ice bath sanitary and safe – even in public baths that are shared with others. Still, there a couple of things that will offer additional reassurance:

  1. Public baths are typically regulated by local Boards of Health. Reputable ice baths spas will post instructions to bathers that require showers prior to entering, communicate warnings and safety instructions to patrons, and list prohibitions. Look for a facility that provides showers, and insists that customers use them prior to the ice bath (or sauna).

  2. Be sure that the ozone disinfection system is operating during business hours. You'll know when you see bubbles in the water returning from the filtration system.

  3. Consider facilities that add Epsom Salt to their ice baths. The salt will help replace magnesium used during cold thermogenesis, and provide extra protection against pathogens.

To find a commercial provider that offers the Morozko ice bath, click to the Find A Morozko page.


About the Author

Thomas P Seager, PhD is an Associate Professor in the School of Sustainable Engineering at Arizona State University. Seager co-founded the Morozko Forge ice bath company and is an expert in the use of ice baths for building metabolic and psychological resilience. Subscribe to for more information from Seager on taking charge of your own physical & mental health.

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