EDITOR'S SUMMARY: Cold water immersion has mental and physical health benefits, yes, but how does it actually feel? If you think it’s akin to a kid eating spinach with their nose plugged, forcing it down because it’s supposed to be good for you … well, you may be right. On the other hand, if you let fear win out, and never give it a shot, you may miss out on an extraordinary life-changing event.
Written by Tracy Reilly
Edited by Nicki Steinberger, Ph.D.
If only there were a simple practice that could positively impact your immune and cardiovascular systems, as well as your mental health. Enter: cold immersion. From tiny tastes of cold with the popular “ice bucket challenge” to raise awareness of ALS (amyotrophic lateral sclerosis), to the extreme adventures of motivational speaker, Wim Hof, aka “the Iceman,” cold water therapy has gained popularity in recent years.
Though “getting chilly” is on the rise, it’s hardly a new health practice. Healing ailments by cold water immersion dates back to 3500 BC. From Open Access Macedonian Journal Of Medical Sciences, “History of the Baths and Thermal Medicine”:
“It was not long before men were discovering the beneficial properties of water, like its healing and disease-protecting effects. Due to its importance, water was seen as magic and considered a gift of the divinity. Egyptians and Israelites used to plunge themselves in the sacral water of Niles and Jordan, Hindus in the Ganges river for healing their soul and body.”
What it feels like: When you take the cold plunge, you’ll likely be faced with three unique experiences—the before, the during, and the after. The “before” is laced with apprehension. Your mind does a self-trickery dance, reminding you how absolutely crazy you are to entertain the idea of dunking into the discomfort of the cold. You question the sanity of it. If you’re fortunate, you say thanks for sharing, strip your clothes off, and enter the water swiftly.
The “during” is when you’re submerged to your neck. Yes, it’s blistering cold, but you’re keenly aware you pushed past your comfort zone, and sure you’re reaping the benefits. Your breath calls your attention, and if you’re a meditator or have worked with mind or breath control, you’re able to slow it down. Instinctively, you’ll push your hands out of the water for relief. The hardest part is over.
With the “after” comes the sparkles—tingling in your body, best described as your cells coming alive. Sure, they were alive before, but now you’re “awakened” on a whole new level. In a flash, you feel the decrease of inflammation.
If you had back pain, it’s gone; if you were slouched over; you’re standing up straight. The bloat in your stomach seems to have disappeared. Confidence and elation surge through your body, your mind, and your spirit. Your psyche is elevated, a’ la “happy dance.” And if you think this sounds “woo woo,” there’s only one way to find out ...
Water and Spirit: From “Cold Plunging Is More Than a Trend — It’s a Latin American Spiritual Practice”:
“‘Water, in all her forms, is medicine,’” Djali Brown-Cepeda, an Afro-Indigenous Dominican Lukumí priestess, tells Somos.
Water is also deeply connected to spirituality.
“‘Water in many Native American cultures symbolizes the origin of life,’” Adina Diaz, a holistic practitioner, tells Somos. “‘Cold water baths are often part of a larger ritual that involves prayer and connection to the natural world. For some cultures, it was a way to prepare themselves not only physically, but spiritually for colder climates.’”
By taking a cold water bath, you can rid yourself of the negative energies blocking your path, according to Brown-Cepeda. “‘In every way possible, water changes lives,’” she adds. “‘As water is the base of this blue planet and the base of our literal, physical existence as humans, water is the base of all things spiritual.’”
The ice bath and cold shower are the most discussed methods of cold immersion, but even dry exposure to cold air with minimal clothing, within social parameters, of course, can be beneficial as it produces similar physiological responses, just more slowly. Body heat transfer in water is nearly 20 times greater that of air, so any physiological or psychological effects appear more intensely and quickly using cold water immersion, than simply exposure to cold air.
Studies have found that “preschoolers who spent many hours outside—not just for naps—took fewer days off than those who spent most of their time indoors.” For parents in Nordic countries, exposing babies to frigid temperatures for health benefits is a cultural given. Babies and toddlers can be seen napping in strollers outside of stores or coffee shops, and even daycare centers keep children outside for hours to play and nap. The belief in places like Sweden is that fresh air, even arctic fresh air, is beneficial.
You’d be remiss to dive into cold water immersion without mentioning the Dutch king of cold, Wim Hof. He holds several world records in prolonged cold exposure, climbed Mount Everest wearing little more than shorts, and his YouTube videos on breathwork and cold immersion have garnered so much interest that he now offers virtual and in-person trainings and “expeditions.”
Eventually, Hof’s seemingly impossible achievements piqued the interest of scientists. Researchers at Wayne State University studied Hof using functional magnetic resonance imaging (fMRI) and positron emission tomography (PET) to study his brain and body, respectively.
After years of training, his mind-body control was so strong that when researchers sent cold water around his body via a special suit, unlike the control group, his skin temperature stayed virtually unchanged.
In studying his brain, Dr. Vaibhav Diwadkar, professor and one of the study’s researchers found unexpected activation in an area called periaqueductal gray matter, implying this about Hof’s training:
“[It] may lead to tonic changes in autonomous brain mechanisms, a speculation that has implications for managing medical conditions ranging from diseases of the immune system to more intriguingly psychiatric conditions such as mood and anxiety disorders.”
In other words, Hof was able to activate the part of the brain responsible for releasing cannabinoids and opioids simply by using his mind. While Hof’s feats in and out of the lab are mind-boggling, the fact that his method also utilizes extreme breathwork as a key component, is one example of the difficulty in studying cold immersion. It’s hard to isolate which results are due to cold training, which are attributable to breath training, and which arise from both.
Health Benefits and Studies
Another research challenge: It’s impossible for subjects not to know whether they are being exposed to cold water, thus making the “double-blind” criteria, the gold standard of science, impossible. Other studies involve cold water swimming, making it difficult to isolate the benefits of the water temperature from the benefits from the exercise itself.
While further research is called for, there are encouraging findings from cold immersion data thus far. A 2022 research review of 104 cold water immersion studies called the findings regarding the immune system promising, “especially concerning tolerance to stress and respiratory infections.”
Specifically, a German study of cold water swim participants revealed 40% fewer upper respiratory tract infections in the swimmers than the control group, possibly due to increased antioxidative protection and improved circulation. This particular study followed people who were regular cold water swimmers, engaging in the practice at least once a week for five minutes at a frigid 33- to 39-degree water temperature.
The researchers believe this antioxidative protection in the swimmers is due to “repetition of a non-damaging, mild oxidative stress.” Much in the same way you would exercise a muscle, repeated cold exposure “toned” their immune systems.
Considering there are over 60,000 miles of veins, arteries, and capillaries in your body—enough to circle the globe twice—it’s no wonder shocking your system with cold, whether from open water or your shower faucet, would have some kind of effect on your body.
Most studies used a batch of non-cold immersion “participants” as the control group versus a cold immersion group, but a 2020 study used men’s opposing legs for comparison. The study followed nine men who performed endurance training three times a week, after which, researchers had participants immerse one leg in a cold water bath, the other leg not, serving as the control group. After one month of this practice, each participant's cold-immersed leg was found to have significantly higher blood flow to the muscles than the non-immersed leg.
In his book, “What Doesn’t Kill Us,” author Scott Carney talks about the Wim Hof Method and his experience training with Hof. Carney was studied by the Boulder Center for Sports Medicine, and after approximately eight months of practicing Hof’s morning cold showers and breath practice, Carney’s energy usage became much more efficient. The researcher analyzing his test results said, “It’s like you’ve added seven hours of exercise to your routine every week.” Carney said his workout routine had been virtually unchanged—all he added were the cold showers and breathwork.
Seeing how heart disease is the number one cause of death in the United States, if something as simple as a cold shower could improve circulation and cardiovascular health, you might find it’s worth a try.
Since blood is constantly traveling throughout your body, your heart’s work is never done. The harder it has to work, the more taxing it is on your beloved organ. Blood pressure is a good indication of just how hard your heart is working. Having a healthy cardiovascular system can mean more energy as blood oxygen levels increase with a more efficient heart. It can also mean fewer chronic illnesses, and a lower risk for heart attack and stroke.
On the other hand, if you have vulnerability in your heart organ, such as an arrhythmia (irregular heartbeat), guidance for cold water therapy is to proceed with caution. Submersion in extreme cold water squeezes blood from your extremities into the chest and creates a stress response. Your heart rate and blood pressure can increase. For this reason, it’s a good idea to check with your health care practitioner before diving in.
Dr. Massimo Ferrigno, Associate Professor of Anesthesia at Harvard Medical School Brigham and Women’s Hospital had this to say:
“The shock of cold water against the skin triggers a fight-or-flight response. The adrenal glands pump out extra epinephrine (adrenaline) and other stress hormones. They cause blood vessels supplying the skin to narrow. This conserves heat, but it shifts even more blood to the chest, taxing the heart.”
Studies show that participants in cold immersion benefit from improved mood, both immediately following immersion and lingering afterwards. One case reports a woman with a seven-year history of depression and anxiety, unresponsive to medication, tried cold water swimming and felt improvement immediately. She sustained a new foundation of wellness over a year later, having reduced and eventually discontinued her medications.
In a broader study, “The Science Behind Cold Water Plunges,” when a group of Finnish swimmers were compared to non-swimmers, results showed improved memory and mood, along with a decrease in tension and fatigue, in the swimmers who engaged in cold water swimming an average of four times per week.
The idea of alleviating stress by blasting yourself with cold water at the end of an otherwise pleasant shower may seem counterintuitive, but scientifically, the benefits make sense. Cold exposure increases noradrenaline in both the blood and brain, which causes an increase in your heart rate and blood pressure.
Upon feeling the cold, your skin’s receptors are thought to send “an overwhelming amount of electrical impulses'' to your brain, which may have an anti-depressive effect.
According to neurobiologist Andrew Huberman:
“Virtually any stimulus that delivers more epinephrine, norepinephrine, and dopamine to our system will sharpen mental acuity and elevate our mood, and will do so for some period of time.”
In his two-hour discussion on cold immersion, Huberman states that most stressors only increase norepinephrine and epinephrine, but that deliberate cold exposure also dramatically increases dopamine.
He goes on to cite a study in the European Journal of Applied Physiology, “Human physiological responses to immersion into water of different temperatures,” where researchers found a 530% increase in norepinephrine and a 250% increase in dopamine, but no increase in cortisol. The implication is that while the body is clearly “stressed” in cold immersion, it is a “use stress” versus a “distress,” that increased cortisol would indicate.
If you’d like to drop body weight or boost your metabolism, take a look at a type of fat you’ve likely never heard of: brown fat. While it may sound like tasty drippings left by a roast, it’s actually a unique type of fat stored inside your body.
Mostly found in babies and young children, it serves as protection from cold since their bodies are smaller and incapable of (or ineffective at) the warming tool we take for granted: shivering. Brown fat helps regulate body temperature, and is more metabolically active than white fat.
White fat cells are necessary, insulating organs and providing energy stores, but when we carry excess fat, it’s that white fat that’s providing a little too much “insulation.” It used to be thought that brown fat only existed in babies and young children, but studies have shown that brown fat can indeed exist in adults, and increase with cold exposure.
Brown fat is not only good at burning white fat when the body experiences a deficit, but it’s good at creating that deficit. Similarly, beige fat works to convert white fat to brown fat, creating more potential for metabolic changes.
As Huberman described:
“Neurons that sense cold are in a position to communicate via other neurons directly to the fat cells and release norepinephrine into those fat cells, causing white fat cells to convert to beige and brown fat.”
So while a small increase in metabolism is expected as the body burns calories to increase its core temperature after a cold “dip,” it may be the increase in beige and brown fat that could affect your metabolism longer-term because of the sustained function they provide.
It’s not just the time you spend in the cold water that matters, but the timing of the experience. When your body is exposed to cold in this manner, afterward, it tries to warm itself up. That’s why the vascular system gets a workout from a cold burst: Blood vessels constrict upon feeling the cold in an effort to keep blood near crucial organs, then dilate to send the blood throughout the body again when the cold ceases.
In doing so, it can actually raise your core temperature. Since your temperature drops at bedtime, based on circadian rhythms, it’s best to do a cold shower immersion in the morning. Doing cold immersion at night, your body’s core temperature increase could throw off your normal nighttime temperature drop and interfere with your sleep.
If your motivation for trying cold exposure is to increase metabolism, dunking in the morning before eating, so that your body is in a fasting state, may produce a slightly higher metabolism since norepinephrine and epinephrine are already elevated when fasting.
For an extra metabolic boost, it’s also important to allow your body to reheat itself after your cold shower. By forcing your body to do the work, rather than turning the water temperature back up, your brown fat kicks into gear to regulate your temperature, increasing your metabolism. If you can remain in the cold until you shiver, that small action can provide even further activation of brown fat.
If what you’re after is a mood boost, Huberman suggests you can increase the impact of the dopamine rush by drinking 300 mg of caffeine 60-120 minutes before your cold exposure. Caffeine activates dopamine receptors so that when your body gets that burst of dopamine upon cold immersion, the dopamine binds to those receptors and becomes useful for the brain.
Is Cold Immersion Right for You?
If the rewards of cold plunging pique your interest, it’s worth exploring. If you’re a “water baby,” you’ll feel right at home. If you’re curious, and brave enough to find out what your body can withstand, and even more so, your mind, it’s an adventure worth embarking on.
Cold immersion can change your breath involuntarily at first, so it’s best to be cautious when plunging into frigid waters while swimming. The bottom line for beginning any cold exposure, whether an ice bath, open water, or cold shower is the same: Take it slow. Don’t push yourself too hard too fast.
If you want to ease into the experience of open (cold) water swimming, the Outdoor Swimming Society suggests starting in a season when the water is cool but not cold (around 60 degrees or higher), then continuing to swim as water temperatures dip, rather than starting in winter.
“Outdoor Swim Coach” Rowan Clarke recommends keeping your first cold swim session short and to “expect your breathing to feel much more difficult than in the pool, and your limbs heavier.”
Also, you don’t have to “swim” to plunge; in fact, they are two entirely different escapades. If you’re not a swimmer and have no intention of grabbing goggles and fins, you can still be a cold water enthusiast. A dip is a dip, and can last as long as it takes your body to get in and out of the water.
Caveat for athletes: If your primary goal is to increase muscle mass, research shows that cold immersion can actually be detrimental. A paper published in The Journal of Physiology, “Human physiological responses to immersion into water of different temperatures,” discussed studies showing “cold water immersion attenuated long term gains in muscle mass and strength,” meaning your muscles may not get the same growth they would with passive recovery. If you’re simply looking to decrease muscle soreness and recovery time by calming post-workout inflammation, plunge on.
Ways to Implement This Radical Practice
Since you might not have barrels of ice handy, and dedicated cold immersion tubs can be costly and cumbersome, the most practical method to achieve cold exposure benefits is by taking freezing cold showers. The largest study of this practice was done in the Netherlands in 2015 with a randomized trial of 3,000 participants in which the cold shower group ended their normal showers with a blast of cold water for 30, 60, or 90 seconds for 30 consecutive days.
In the end, the cold shower group showed a reduction in sickness absence of 29% compared to the control group of “normal” shower-goers. The duration didn’t seem to make a difference, so again, it’s recommended to start slow.
In his book, “The Wim Hof Method,” Hof recommends starting with just 15 seconds of cold water at the end of your normal shower, building up to 30 seconds in the first week, then adding 30 seconds each week through week four.
Alternatively, or in conjunction with … If you’re ready to take the big plunge and invest in a cold water tub, there are all kinds of DIY videos with tips, tricks, and suggestions; even types that avoid the expensive and cumbersome requirement of ice. If you’re more inclined to purchase a tub, reviews of ice baths abound on YouTube, as well.
Other ideas for sustainable cold water immersion—not in the least less wonderful— include the following:
- Taking dips in the magnificent ocean
- Gliding gently in a rushing river or calming creek
- Jumping around in an icy cold lake
- Joining a local spa/springs/resort that has a cold plunge
- Venturing out to discover a natural cold spring in the mountains
No doubt there is much left to learn regarding the specific mechanisms of cold immersion impacts, but if you’re seeking to decrease inflammation, and improve your mood, metabolism, immune system, and mental resilience, you’d be hard-pressed to find a more affordable, less time-consuming technique to implement. Give it a whirl if you want to be invigorated like never before. You just might end up “feeling like a million bucks.”
Published on May 25, 2023
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