I don’t consider myself a biohacker, but I do intentionally engage in practices that I believe will extend my healthspan and lifespan. Cold plunges are one of them. Cold exposure goes into the bucket along with things like resistance training, intermittent fasting, sun on your skin, and sauna—all stimuli that stress the body and prompt it to become stronger and more resistant to chronic and acute health issues.
I’m tempted to say that cold plunges are an easy way to challenge your system, but if you’ve ever stepped up to the edge of an icy stream or cold pool, you know there’s nothing easy about forcing yourself to get in, sink down to your neck, and make the intentional choice to stay there. Veteran cold plungers and winter swimmers will tell you that over time your body acclimates so it becomes easier to tolerate the cold. You’ll even come to eagerly anticipate your next plunge. That’s all true. But there will always be a part of your brain that tells you, “You don’t have to do this. C’mon, stay warm and dry.”
Each plunge requires you to overcome that little voice. It’s not easy, but it’s simple in the sense that just about everyone can find a way to harness the power of cold. And everyone should because the benefits of cold exposure are pretty impressive:
Reduces inflammation by lowering pro-inflammatory cytokines and increasing anti-inflammatory cytokines
Triggers the release of immune cells that can ward off illness
Converts white fat into more metabolically active brown or beige fat
More than these physical benefits, the fact that it’s not easy is arguably the biggest upside of all. The mental fortitude you build when you intentionally and repeatedly put yourself in uncomfortable situations is undeniable. One of the most profound disconnects between our modern world and the one our ancestors inhabited is just how comfortable we are most of the time. We now have to go out of our way to simulate the physical and mental challenges that for most of history were just a part of everyday life.
I’ve been regularly immersing myself in cold water for years now, and I’m convinced that that’s one of the reasons why I still feel as good as ever mentally and physically. Here’s how to get started.
How I Cold Plunge
Early in the day, I like colder temperature for shorter duration. Generally that means water in the mid to low 40s for a minute or two. (That’s Fahrenheit; 4 to 7 degrees Celsius.) Get out, lightly towel off, dress. Don’t do anything special to warm up. Go about your day energized and refreshed.
Later in the day, I like a little less cold (48 to 51 degrees F, 8 to 10 degrees C) but for a longer duration, anywhere from 3 to 5 minutes. If it’s after 6 p.m. and my intention is to prepare myself for a better night’s sleep, I want to be a little chilly (shiver slightly) after I get out, but only for 20 or 30 minutes. If you overdo it, shivering into the night can be a bit uncomfortable (and I have done that). So if I feel I’ve gone too long, I might take a warm shower to bring my body temperature up a bit. Sometimes I hit the sauna for 12 minutes before I plunge. That can buy me a few more minutes in the cold.
My favorite is in summer to plunge for a few minutes and then air dry in the warm sunshine. Depending on where I’m at in the world, I might do my plunges in an unheated swimming pool, lake, or ocean. More recently, I received a cold plunge tub (looks like a bathtub) for my home by Plunge, and I’ve been having fun playing around with the ability to manipulate the temperature.
Now, this is just what I prefer. I crafted this protocol, if you can call it that, by looking at the research, talking to friends who are experts in performance and recovery, and mostly doing what feels good to me. I’m not overly concerned with getting it “right” every time. And I don’t really plunge for exercise recovery. I do it for the mental challenge and the great feeling after I get out. The “buzzy” feeling and energy I enjoy afterward tell me I’m accessing the benefits.
Cold Plunge Best Practices
When I talk to people about cold exposure, first they tell me how much they hate the cold and could never do it. Then they all have the same questions: How cold does the water have to be? How long do I have to stay in? How often? Can I just take cold showers instead?
First, the water should be cold enough to make you want to get out. That’s not specific, and that’s kind of the point. Hormetic stressors only work when they fall in that Cinderella zone between too much (so stressful that they do more harm than good) and not enough to force the body to adapt. Everyone’s “just right” place will depend on their personal cold tolerance, baseline health, and how many other stressors they’re juggling.
Likewise, optimal time and frequency are also somewhat subjective. Generally, I like to stay in for a few minutes each time. More if the water is a bit warmer, less if it’s really frigid. Stanford neuroscientist and popular podcaster Andrew Huberman suggests that 11 minutes total per week, broken up into two to four sessions, might be best for boosting metabolism. Ten to fifteen minutes per week seems like a reasonable goal to me.
Cold exposure—swimming in arctic waters, sitting in the snow wearing little to nothing for as long as possible—has become the extreme sport du jour. But that’s not what we’re talking about here. There is no medal for long-distance endurance in the cold plunge. Do what feels right. I have stayed in too long a few times (to set records for myself) and then regretted it because I overstressed my body. The idea is a brief hormetic stress and immune boost. Doing too much can have the opposite effect.
Cold plunges versus cold showers
Years ago, cold showers were all the rage. Now cold plunges rein supreme. Both have their merits, but I’m partial to plunges over showers. Fully immersing yourself in cold water is the most efficient way to stimulate the vasoconstriction and hormone release we want. In a cold shower, the water only hits some of your skin, so you don’t get as cold as fast. It’s too easy to “cheat” by keeping more of your body out of the water (even unintentionally).
That said, cold showers are certainly better than nothing, and it doesn’t have to be either-or. You can do both. Studies have also found cranking your thermostat down to 62 degrees Fahrenheit (19 degrees Celsius) for a couple of hours a day stimulates brown fat.1 That’s not even that cold. You can also take advantage of nature’s thermostat and go outside in cold weather slightly, not dangerously, underdressed.
Nothing entirely takes the place cold water immersion, though, especially when it comes to the mental benefits of doing hard things. Yes, you have to steel yourself to crank the faucet all the way to cold if you’re enjoying a nice warm shower. But it’s not the same as fully submerging yourself.
Crafting Your Cold Plunge Routine
Here is how I would start incorporating cold plunges if I was a beginner:
Start slow. Gradually work your way up to colder and/or longer plunges (to a point—you can only go so cold and so long before it becomes dangerous).
Aim for 10 to 15 minutes per week as a baseline.
For the biggest benefits, submerge up to your neck and keep hands and feet under (or alternate dunking them in and out).
When you get out, dry off and allow your body to warm up naturally if possible. Dress in climate-appropriate clothing, but don’t blast the heater or start chugging tea unless you’re shivering uncontrollably. Some shivering is to be expected.
Supplement cold plunges with less intense cold exposure via turning down the thermostat, taking cooler showers, and going outside slightly underdressed. Be aware of your total stress load. Don’t overdo it.
Adjust your plunges based on your subjective experience each time.
I’ll say it again: this is not a competition. What is tough for you might be easy for someone else, and vice versa. What’s tolerable for you today might feel almost unbearably difficult for you next week if other life stressors pile up.
The goal with each plunge is to challenge yourself in a way that feels hard but adaptive. If you’ve ever purposefully put yourself in a hard situation—cold exposure, training for a marathon, climbing a mountain, or anything else where you butt up against your ability to endure—you’re familiar with wanting to quit and simultaneously wanting to continue because you feel yourself getting stronger in the moment. That’s the razor’s edge you’re aiming for. If it just plain hurts, cut the plunge short. Come back another day.
As you become more accustomed to cold plunging, experiment. Play around with water temperature, duration, and time of day. You might incorporate breathing exercises to bring a meditative aspect to your plunges (never practice controlled hyperventilation in water, though). Try getting in and out multiple times. Move your limbs around underwater. This disrupts the pocket of warm water that forms near your skin’s surface and makes the plunge feel colder.
The beauty of cold exposure is that you can start mild and get more intense, monitoring how you feel along the way. Cold plunges of the type I’m talking about here are generally safe, but they are stressful. If you are concerned about your ability to handle the stress, listen to your gut or talk to your doctor.
Plunging in very cold water elicits a cold shock response. This can be dangerous for people who have asthma or cardiovascular conditions. I’d caution even the most hale and hearty readers, if you decide to take this to extreme levels, take the time to acclimate to cold water and learn proper safety precautions. The Outdoor Swimming Society is a good place to start.
All right, that’s what I do. I’m interested to hear what you’re up to. Who among you is already doing regular cold plunges? Who wants to start?
Mark Sisson is the founder of Mark’s Daily Apple, godfather to the Primal food and lifestyle movement, and the New York Times bestselling author of The Keto Reset Diet. His latest book is Keto for Life, where he discusses how he combines the keto diet with a Primal lifestyle for optimal health and longevity. Mark is the author of numerous other books as well, including The Primal Blueprint, which was credited with turbocharging the growth of the primal/paleo movement back in 2009. After spending three decades researching and educating folks on why food is the key component to achieving and maintaining optimal wellness, Mark launched Primal Kitchen, a real-food company that creates Primal/paleo, keto, and Whole30-friendly kitchen staples.