Colder temperature and shorter time builds psychological resilience.
Summary
The right time & temperature for your ice bath depends upon your goals.
Sometimes the anticipation of the cold is worse than the actual experience of the ice bath.
Even a 15-second ice bath will stimulate the central nervous system, create a cold shock response, and build psychological resilience.
How much cold exposure should you do?
No one knows the "right" amount of cold.
Andrew Huberman, PhD often cites 11 minutes per week as a good rule of thumb for maintaining the metabolic benefits of ice baths, but he also acknowledges that no one really knows. The number comes from a survey of Danish winter swimmers who reported that, on average, they spent 11 minutes per week in the icy fjords of Denmark (Søberg et al. 2021).
Nonetheless, the science of cold exposure dosing hasn't established any reliable metric for establishing a minimum effective or recommended dose. At this stage, we're all just sharing experiences of what is working for us, and emphasizing that people have to experiment for themselves to find out what works for them.
Confounding things further, there are lots of ways to practice cold water immersion. You can do it at 34F, like Joe Rogan, or at 50F like Huberman prefers. You can get your cold in the shower, in the lake, in the ocean, or in a Morozko. You can move your body (as Huberman suggests) to make little currents in the water that will extract more heat, or stay still and meditate.
Nevertheless, Mike Mutzel of High Intensity Health pointed out to me that when you have to buy 100lbs of ice, or travel to the mountain lake, you're not likely to do your cold very often and you aren't likely to feel it was worth the big investment if you only stay in the cold water for a few seconds.
For example, Mike Mutzel of High Intensity Health describes how he got started on cold plunge therapy with a stock tank full of ice and winter swimming. However, when Mike got his Morozko, he realized that having more convenient access to the cold increased the frequency of his practice.
Mike says, "I find that I use my Morozko way more than I did my DIY stock tank."
Mike's early experiences habituated him to longer sessions. After all, when you've taken the trouble to drive to the lake, or buy ice, you can't help but feel like you should stay in the cold water for whatever feels to you like a loooong time.
So a lot of people want to know when they've been in long enough. To help them track their cold dose, I introduced a mathematical model for measuring cold in my previous article 'Guide to Optimal Ice Bath' but I didn't answer the most common question I get from ice bath owners:
How long should I stay in my ice bath?
My usual practice is just 2-4 minutes a day, but longer when I'm shooting a video. At those short durations, I rarely shiver because I'm well cold-acclimated. But because I plunge at 34F, with ice floating in the water, I always feel the gasp reflex.
A good rule of thumb for beginners is go cold enough to gasp, long enough to shiver.
Once you start shivering, you can be sure that you've activated your brown fat and boosted your metabolism. While the time under temperature that induces your shivering will be unique to you, depending upon your level of acclimation to the cold, when you're starting out, shivering is a sure way to be certain that you're getting full metabolic benefits.
After 7-10 days of daily cold plunge practice, your body will become acclimated by recruiting new brown fat. The problem, according to Mike, is that he has to stay in the freezing water a long time to induce shivering. Then, after such a long ice bath recovery from that much cold dose takes a long time and he doesn't want to "shiver the whole day."
Because the most challenging part of the ice bath is the first 30 seconds (if not the moment right before you plunge), you can get the mental benefits of the ice bath in a short plunge, without the shiver. That is, the mental challenge of the ice bath comes long before the metabolic challenge, so to get the psychological benefits of cold plunge therapy, you don't have to wait for shivering.
Especially during the winter, when it's tempting to skip the ice bath altogether, you can still get benefits from a quick, 45 second dip. Mike demonstrates this technique in his Instagram post.
I sometimes use Mike's technique at the start of a chilly winter day. To help talk myself into my Morozko, I might tell myself "I'm only going in for 20 seconds this morning."
Of course, I often stay in for a whole two minutes, because once I've gotten over my anticipatory anxiety, the ice water is always more comfortable than I've imagined it.
And that's the point.
In Set Your Forge to a Temperature That Frightens You, I made the point that the psychological benefits of the ice won't kick in until your anxiety does.
Microdosing deliberate cold exposure
There's no way you're going cut a hole in the lake ice, or buy 100 lbs of bagged ice from your local Kwik-ee-Mart, just so you can do a 45 second ice bath to start your day with a sense of psychological accomplishment.
For "microdosing cold" you need a ice bath, or something like it.*
And why would you want to do that?
Author Mel Robbins claims that a 47 second ice bath helps her manage anxiety, and research on the effects of cold water therapy and depression support her experience (e.g., van Tulleken 2018). For example, one study found that patients using cold therapy recovering from heart surgery experienced less anxiety during chest tube removal, despite experiencing equivalent levels of pain (Aktaş & Karabulut 2018).
As Joe Rogan discovered:
The mental benefits (of the ice bath) are huge. The mental toughness that you get from the experience from purposefully suffering, in a way that is actually going to benefit you, I think it contributes to your mental resiliency. - Joe Rogan via Instagram.
* It was Scott Carney, author of What Doesn't Kill Us, who first coined the term "micro-dosing cold."
References
Søberg S, Löfgren J, Philipsen FE, Jensen M, Hansen AE, Ahrens E, Nystrup KB, Nielsen RD, Sølling C, Wedell-Neergaard AS, Berntsen M. Altered brown fat thermoregulation and enhanced cold-induced thermogenesis in young, healthy, winter-swimming men. Cell Reports Medicine. 2021 Oct 19;2(10).
Van Tulleken C, Tipton M, Massey H, Harper CM. Open water swimming as a treatment for major depressive disorder. Case Reports. 2018 Aug 1;2018:bcr-2018.
Aktaş YY, Karabulut N. The use of cold therapy, music therapy and lidocaine spray for reducing pain and anxiety following chest tube removal. Complementary therapies in clinical practice. 2019 Feb 1;34:179-84.
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.