Colleen & Jason Wachob

mbg Co-Founders and Co-CEOs

By Colleen & Jason Wachob

mbg Co-Founders and Co-CEOs

Colleen & Jason Wachob are Co-Founders and Co-CEOs at mindbodygreen, and authors of the book “The Joy of Well-Being.”

outdoor shower

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May 17, 2023

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Most of the existing research on cold exposure and its many health benefits is on full-body, up-to-the-neck immersion in an ice bath, pool, or other cold body of water. The reason for this is purely practical—it’s simply easier to control all the experimental variables that way. In an immersion tank, you can more precisely measure the effects of cold because you can control the temperature and how much skin is exposed to water versus air, regardless of differences in body weight, height, and surface area, whereas in a shower, you can’t really control for any of those things.


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Since the science is just beginning, researchers haven’t yet gotten there. But that doesn’t mean that you can’t still get the benefits of cold exposure other ways; it just means that there are no evidence-based protocols—yet.

Most of the researchers and experts we talked to agree the important part about cold exposure—no matter how you do it—is to get uncomfortable.

Andrew Huberman, Ph.D., a neuroscientist from Stanford Medical School and the popular host of the podcast The Huberman Lab, says, “You want to get uncomfortably cold, but not dangerously cold.”

In other words, you want to get to the place where your mind is screaming to get out, but your body can still stay in the cold safely, without tipping over into hypothermia or tissue damage. That might sound vague, but this is one of those practices that is really about listening to your body and adjusting as needed.

There are plenty of ways to intentionally build cold exposure into your life. Here are some general guidelines to think about whether you are taking an ice bath, jumping in the ocean, or partaking in a cold shower:

Safety first

If you have any heart problems or a family history of heart problems, talk to your doctor before trying cold immersion or exposure. The benefits of this practice come from the extremes that it pushes your body to in terms of hormetic stress, but one person’s hormetic (safe) stress is another person’s cardiac stress. In rare cases, cold-water immersion has been linked to dangerous cardiac events1 like heart arrhythmias.

One way to reduce this risk may be to start at higher temperatures, and as your body becomes increasingly adapted to the cold, you can handle lower and lower temperatures more safely. Also, if you have a circulation disorder, like Raynaud’s, this practice probably isn’t for you. Again, when in doubt, it’s always a good idea to talk to your doctor. Be smart about anything you try.


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How cold is cold enough?

There is no definitive number, but among experts the consensus seems to be that brown fat activation happens when you get below 59 degrees Fahrenheit (fifteen degrees Celsius). That being said, what counts as “uncomfortable” for a person without much brown fat might be above this temperature range, so you have to experiment a little with your comfort/discomfort zone. Shivering also is a good indicator that you’re cold enough.

How long is long enough?

We’ll dive into specific recommendations in a minute, but a general principle—whether you’re going for a walk in the wintertime without a jacket or taking a cold shower—is that the lower the temperature you’re exposed to, the shorter the amount of time you need to be exposed to it.

Keep this in mind when adjusting to how the temperatures might change throughout the year. For instance, in the wintertime, the cold water you can get in your shower could be ten to twenty degrees colder than what you’d get in summertime.


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How much of my body needs to be in the water?

As much as possible! If you’re fully immersed, going in up to your neck is plenty. If you’re in a cold shower, some people prefer to duck their heads in and out, thus avoiding a headache.

How long before I see the benefits?

If we’re talking about mood, the answer is immediately. Every instance of cold-water exposure will boost your dopamine2 and norepinephrine3 and may offer benefits like mental clarity and improved mood.

The effects of brown fat take a little longer to see because brown fat itself takes longer to accumulate. No one knows for sure how long; Susanna Søberg, Ph.D., author of an important study on winter swimming and metabolism4, believes that after just one season of swimming twice a week, you may see a benefit. Consistent cold-​water exposure over time will help you build up your brown fat stores and see the greatest overall metabolic benefits.


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What time of day should I do this?

A cold-​water plunge or an icy shower are certain to wake you up, so common sense tells us that the best time of day for this would be in the morning.

The science behind this is rooted in the fact that after the body’s reaction to that initial cold, it will start to heat up and elevate your core temperature as well as dump adrenaline and dopamine into your bloodstream. This is an added bonus of focus if you have an important morning meeting. But because your body wakes up and becomes more alert as your core temperature rises, don’t try a cold shower right before bed.

Excerpted from The Joy of Well-Being by Colleen Wachob and Jason Wachob. Copyright © 2023 by Colleen Wachob and Jason Wachob. Reprinted with permission of Balance Publishing, an imprint of Hachette Book Group. All rights reserved.


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