We can probably thank the Dutch adventure athlete Wim Hof — also known as “The Iceman” — for elevating icy plunges from a once-a-year New Year‘s pastime to a widely popular health and fitness trend.
He and other cold-water enthusiasts rave about the benefits, claiming that frigid showers, baths and swims can speed recovery, numb pain, prevent colds and lift mood. So, is it time to take the plunge? The answer likely depends on your current state of health, along with your goals. Let’s examine the science and cold therapy options.
What is cryotherapy?
“Cryo” comes from the Greek word krýos, which means icy cold. Thus, “cryotherapy” and “cold therapy” are interchangeable — and describe several methods for cooling down the body.
Ice application: Apply ice or a cold pack to a part of your body.
Cold showers: Stand in a stream of cold water with the hot water turned off.
Cold water immersion (CWI): Submerge or “cold plunge” yourself into a tub or body of water that’s 60 degrees Fahrenheit (15 degrees Celcius) or colder.
Whole-body cryotherapy (WBC): Use an expensive chamber that blasts you with freezing air — no water required.
The health benefits of ice baths and cold plunges
So, does the science of cryotherapy live up to the hype? For the most part, no. For a study published in Nature Scientific Reports, researchers asked study participants to try the Wim Hof method — which involves cold water exposure, breathing exercises and meditation — for 15 days. However, the study revealed no positive changes in blood pressure, heart rate, heart function or mood. In addition, while other scientific evidence seems to point to some benefits of cryotherapy, much of the research is too weak to support many of the claims with confidence. Moreover, consideration must also be given to the lengths you’d need to go to achieve, at best, a modest beneficial effect.
Still, assuming you are using cryotherapy in a safe manner, there’s no reason that you can’t enjoy the practice or feel that it provides you with a measure of fortitude.
Here is where the science stands on several cryotherapy claims and different types of applications:
Ice packs or cold plunges and athletic recovery
For many years, if an athlete was recovering from an injury, experts recommended icing. It was the “I” in the RICE formula, which stood for rest, ice, compression and elevation.
“The science and practical applications of icing have changed during the past two decades,” says Andrew Jagim, Ph.D., a sports medicine specialist with Mayo Clinic.
Instead of always reaching for ice, Jagim recommends a nuanced approach:
- Use ice immediately after suffering an acute injury. That’s when it can help reduce swelling and pain.
- Avoid or minimize icing after the first few days, as ongoing cold therapy may slow healing and delay recovery.
Similarly, cold therapy may help to reduce pain and soreness after hard training sessions or during periods of back-to-back competitions. When used consistently over time, however, cold therapy could potentially harm performance, says Dr. Jagim.
“If an athlete has an intense two-week period of practice or a three-day tournament and they are struggling with pain or soreness, I may recommend adding ice baths post-workout or throughout the day,” he says. “But I would advise against using them every day throughout an entire season or training cycle as research shows that they may hinder long-term adaptations in athletes, particularly for strength and muscle growth.”
Cold showers and immunity
It’s said that Thomas Jefferson submerged his feet in cold water each morning. In a letter he wrote to a physician, Jefferson noted the habit helped prevent the common cold.
Many of today’s cold-water enthusiasts make similar claims. The theory is that cold immersion and other short-term stressors — sometimes called “micro stressors” — may help train the immune system to become more resilient and better able to handle more significant stressors like injuries or infections.
In one of the few studies that tested this theory, researchers assigned 3,018 office workers to several intervention groups. Some workers served as a control and made no changes to their morning routines. Other office workers added a 30-, 60-, or 90-second blast of cold water at the end of their typical morning shower. After 60 days, the workers who took cold showers had taken 29 percent fewer sick days and reported increased energy levels.
Though those results seem promising, it’s not clear why the people in the study took fewer sick days. Because the researchers didn’t track markers of immunity, it’s not clear what physiological changes may or may not have occurred or influenced the outcomes. As such, much more research is needed to know with certainty whether cold showers or plunges truly benefit immunity. In the meantime, if you enjoy short cold showers, there’s little reason to avoid them.
Cryotherapy and pain
Icing restricts blood flow, slows nerve signaling and reduces swelling, all of which may turn down the volume of pain.
As mentioned earlier, icing immediately after suffering an injury can offer short-term relief. It’s also OK to reach for an ice pack to soothe the temporary discomfort of a headache or a tendonitis flare-up. However, for long-term treatment of injuries, such as muscle or joint strains, continual icing may delay the healing process. In this case, icing may repetitively reduce the blood flow and signaling mechanisms needed to facilitate tissue healing. Interestingly enough, heat therapy may be more beneficial as it can improve circulation, help promote healing, facilitate recovery from exercise and improve cardiovascular health.
Ice baths and metabolic health
Habitual cold-water immersion may help to reduce or change fat tissue, according to laboratory research done on rodents. These changes theoretically could lead to other downstream health benefits, including reduced cholesterol and improved blood sugar. However, just because rodents become a little leaner doesn’t mean that the same thing will happen in humans, were it to be studied.
Mental benefits of ice baths
Though research remains in its infancy, cold water therapy may help to lift fatigue and mood, possibly by triggering the release of endorphins and noradrenaline in the brain.
Based on one small study of 33 adults, a five-minute dip in cold water boosted feelings of alertness and attentiveness and decreased perceived distress and anxiety.
In another small study, when young adults immersed a hand in cold water for three minutes, they felt less sleepy — despite having awoken in the middle of the night — and could complete math problems more quickly than study participants who immersed a hand in warm water.
These studies are not only small but offer scenarios for achieving benefits that are far from practical — unless you really need to solve math problems at two in the morning. Larger-scale, randomized controlled trials in humans are needed to know whether this effect might extend to more realistic and routine situations.
Is cold plunging dangerous?
Scientists know much more about the dangers of cold temperatures than they know about the benefits.
Sudden submersion in chilly water can trigger a cold shock response that causes you to gasp and hyperventilate. If your head is underwater, this involuntary gasp and disruption to normal ventilation patterns could lead to drowning. The cold shock response also increases breathing, heart rate and blood pressure, all of which could pose health risks for people who are susceptible to cardiac events. In addition, when exposed to freezing water and frigid ambient conditions, you can develop hypothermia (dangerously low body temperature) or frostbite.
However, these dangers mainly apply to open-water swims and plunges out in nature.
“If someone adds ice to their bathtub and temporarily submerges themselves into water that is only 50 to 60 degrees Fahrenheit, there likely isn’t a big level of concern or risk for any adverse effects,” says Dr. Jagim. “However, if someone walks across a frozen lake in sub-zero temperatures, cuts a hole in the ice, jumps into 30-degree to 40-degree waters, and then exits the lake into a cold and sub-zero environment while being wet, the risks would be significantly higher.”
To minimize the risks:
- Consult a healthcare professional to make sure it’s safe for you to cold plunge.
- Try home-based cryotherapy, such as a 30-second cold shower or short-duration submerges in a bathtub with cool water before opting for open-water swims or ice plunges in the middle of a frozen lake.
- If you do try open-water plunging, always do it with others. Bring extra towels and clothes to quickly dry off and rewarm your body.
Are ice baths worth it?
To help people weigh the pros and cons, Dr. Jagim uses the analogy of cooking dinner.
Exercise, a nutritious diet, sleep and stress management are the veggies, whole grains and meat of the main course. Cold plunges and other cryotherapies serve as a potential garnish.
Focus on the entree before worrying about the garnish.
– Andrew Jagim, Ph.D.
If you decide to try cryotherapy, experiment at home with someone nearby — and do so in your shower or bathtub, before trying it in open water.
Start with brief submersions of 30 seconds to a minute. Eventually, if desired, you can work up to 5 to 10 minutes at a time. Similarly, in the beginning, use cold — but not freezing — water.
Relevant reading
Live Younger Longer
Most of us want to live a long, healthy life, but how do we do that? Drawing upon lessons from his own life, Mayo Clinic cardiologist Stephen Kopecky offers a holistic, evidence-based approach to preventing common diseases and chronic illnesses and living a longer life of pleasure and purpose.
