Does cold water immersion really boost immunity, athletic performance?


photo of three pairs of legs seen through ice water
There is insufficient quality evidence in support of cold water immersion’s health benefits, a new review says. Image credit: VISUALSPECTRUM/Stocksy.
  • Wim Hof, a Dutch extreme athlete who has run a half-marathon in the Arctic Circle wearing only shorts, touts his Wim Hof Method (WHM) of cold exposure and controlled breathing as a benefit to physical and mental health.
  • Hof has subjected himself and his method to scientific study numerous times, but a systematic review of those studies had not been done until now.
  • A new review of multiple studies suggests that the WHM may have substantial benefits for reducing inflammation but also recommends higher-quality trials to determine a larger wellness benefit.

The Wim Hof Method (WHM), an unconventional approach to overall mental and physical health that involves exposure to extreme cold and a rigorous breathing rubric, has gained popularity and attention in recent years largely due to the “microcelebrity” status of its namesake founder.

Hof himself, a 64-year-old Dutch athlete, has run a half-marathon in the Arctic Circle wearing only shorts, swum nearly 200 feet under ice (a Guiness World Record), and climbed Mount Everest (nearly 25,000 feet of it) in only shorts and shoes.

The WHM focuses on what it refers to as three pillars:

  1. exposure to cold through daily cold showers or ice baths
  2. hyperventilation and deep, controlled breathing
  3. commitment to mastering these routines.

Hof, who is often referred to as “The Iceman,” has subjected himself and his methods to scientific testing as a way to support its beneficial claims for issues like chronic pain, fatigue, mood, and inflammation.

But until now there had been no comprehensive review of the various studies that have examined the WHM.

Does the Wim Hof method bring any health benefits?

While the WHM has attracted proponents of cold-water plunges and deep breathing techniques, a number of deaths have occurred when people have lost consciousness while attempting certain aspects of it.

Three people drowned in 2023 practicing the breath work, and in 2022 a $67 million lawsuit was filed against Hof for the drowning of a teenage girl who practiced the Wim Hof Method in her pool in Long Beach, CA. That suit is still in process.

A new review, published in PLOS OneTrusted Source, of the WHM that examined nine papers consisting of eight individual trials has suggested that the method shows “promising use” in reducing inflammation but could benefit from “more research of higher quality” to substantiate this idea.

“The findings suggest that the WHM may reduce inflammation in healthy and non-healthy participants as it increases epinephrine levels, causing an increase in interleukin-10 and a decrease in pro-inflammatory cytokines,” the authors write.

“The focus of future studies should further investigate the benefits of WHM in preventing or treating diseases, such as inflammatory disorders, in non-healthy participants and explore the use of [the Wim Hof breathing method] in enhancing exercise performance,“ they note in the paper.

Beware the impact of ‘microcelebrity’ culture on health practices

Dr. Omar Almahayni, one of the study’s authors at the Warwick Medical School at the University of Warwick, United Kingdom, told Medical News Today that given the attention the WHM has gotten thus far, it was important to look at the results of scientific examination.

While the review found potential benefits, he said, there is still more research that needs to be done.

“By delving into the mechanisms behind this method, scientists and practitioners are exploring its potential benefits, considering its growing popularity and claims of health benefits. Understanding how practices like cold exposure and controlled breathing can influence physiological responses and mental well-being can provide valuable insights into the potential for personal growth and healing,” Dr. Almahayani said.

He also noted that Hof’s status as a “microcelebrity” — defined in the review as “an individual that achieves status and social media presence by self-broadcasting about niche subjects to a small community of followers” — warranted such a review.

“The rise of social media and microcelebrity culture may indeed prompt the proliferation of ‘extreme’ health methods that lack scientific backing. Health experts should approach these methods with caution and subject them to rigorous scientific research through randomized controlled trials before endorsing or recommending them to the public. Wim Hof’s willingness to subject his method to scientific testing serves as a positive example of how such methods can be assessed for validity and reliability.”

– Dr. Omar Almahayni

Isabelle Hof, Wim’s daughter and the head of the Wim Hof Method Academy, who was not involved in the review, told MNT that growing interest in the WHM was a result of the benefits it can produce.

“When Wim started sharing his techniques, he and a few others were considered’ freaks of nature.’ People didn’t understand the WHM and its effects at all, but with more understanding, exposure, and more people doing the method, more people are becoming curious,” she said.

“As interest in WHM grows, we’re encouraged by the expanding community of individuals exploring its benefits. We aim to empower individuals to explore WHM confidently and responsibly, recognizing its potential to enhance well-being,” she emphasized.

‘No one-size-fits-all aproach’ to the Wim Hof method

Dr. Almahayani said any future research on the WHM needs to focus on specific parameters in order to support its wide-ranging claims for health.

Firstly, increasing the number of participants in trials is essential to ensure statistical significance and generalizability of results.

”Moreover, maintaining focus solely on the Wim Hof method while employing objective outcome measures will help elucidate its specific effects more clearly,” Dr. Alamahayani said.

“To address potential biases and enhance methodological rigor, future trials should adhere to pre-published protocols, incorporate larger sample sizes, account for loss to follow-up, and implement blinding of outcome assessors,“ he advised. “By adhering to these guidelines, future research can provide a more comprehensive understanding of the Wim Hof method’s efficacy and potential applications.”

Isabelle Hof maintained that that one weakness of the review stems from the fact that the Wim Hof Method team was not involved in the training protocols for a number of the trials. Additionally, given the unique needs of each person, she said, the WHM should not be treated as a blanket technique.

“Like any other physical and mental training, there is no one-size-fits-all approach. Different protocols are needed depending on the individual or target group and their desired outcome. Every individual’s physiology has unique conditioning and, as such, requires a tailored training approach to optimize physical and psychological well-being.”

– Isabelle Hof

“A bodybuilder cannot build larger muscles with 10 kilos of weight, whereas someone who never exercises can. This is why different groups of people require different training protocols. The desired outcome is also crucial in determining the appropriate training protocol,” she cautioned.

10 Herbs That Help Boost Immunity: Current Studies


(Fitzke/Shutterstock)

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Our immune system is complex and protects us from infection and disease. Many parts of the body work separately and together to keep us healthy, but stress, lack of sleep, poor nutrition, and other factors can wear down our natural defenses.

Let’s look at 10 natural and easily obtained herbs that can boost our immunity to help keep us healthy as we push through the last months of winter cold.

1. Astragalus

Epoch Times Photo
Astragalus root (Shutterstock)

Astragalus, also called Huangqi, is a root used in ancient Chinese medicine to strengthen and regulate the immune system. It was given for many conditions, including respiratory infection, hay fever, asthma, and chronic kidney disease.

A systematic review of studies finds that astragalus regulates our immune function, promotes the proliferation of immune cells, stimulates the release of cytokines (which control the growth of immune cells), and influences the secretion of immunoglobulin (antibodies) and conduction of immune signals.

The National Institutes of Health (NIH) reports that astragalus may be safe when used “orally and appropriately,” and doses up to 60 grams daily for up to four months have been used without reported adverse effects. Possible but uncommon side effects include rash, itching, nasal symptoms, or stomach discomfort.

2. Cinnamon

Epoch Times Photo
Cinnamon is the inner bark of the “true” cinnamon tree. (Shutterstock)

Cinnamon is a powerful antibacterial and antifungal spice that can help our immune system fight off infection. This aromatic spice can also relieve symptoms of autoimmune disorders.

One study finds that cinnamon offers significant relief of rheumatoid arthritis and multiple sclerosis symptoms, while findings from another one show cinnamon and its ingredients can be recommended to manage COVID-19 infection.

3. Black Pepper

Epoch Times Photo
Black pepper. (anna1311/iStock)

One of the most common spices and used almost every day in cooking, black pepper has also shown promise against cancer.

A study confirmed that black pepper extract significantly enhances the cytotoxic activity of natural killer (NK) cells, and strongly suggests that it can exert immunomodulatory and antitumor action that can promote the maintenance of a healthy immune system.

Another in vitro study found that the active ingredient in pepper, called piperine, boosts the immune system to slow the replication of breast, prostate, and colon cancer cells, and could induce cancer cell death.

4. Garlic

Garlic,Cloves,On,Rustic,Table,In,Wooden,Bowl.,Fresh,Peeled
Garlic is a versatile plant that counts as an herb, a spice, and a vegetable. (Krasula/Shutterstock)

Used as both a spice and food for thousands of years, researchers have found that garlic offers a broad range of health benefits, especially as an immune system booster.

A systematic review of studies finds that garlic appears to enhance immune function by stimulating certain immune cell types, including macrophages, lymphocytes, and natural killer cells.

Another randomized controlled trial looked for evidence that aged garlic extract could boost human immune function against respiratory infection.

While the number of study participants who caught a cold or flu wasn’t significantly different, researchers found that the garlic group reduced cold and flu severity. Participants also experienced a reduction in the number of symptoms, and the number of work or school days missed.

5. Holy Basil

Epoch Times Photo
Holy basil leaves. (bdspn/iStock)

Different from common basil, holy basil is native to India and is a component of Ayurvedic medicine. Research finds holy basil can inhibit the growth of multidrug-resistant bacteria that include Staphylococcus, Enterococcus, and Pseudomonas.

A different randomized controlled trial also confirmed that holy basil boosted crucial immune factors in the participants’ blood.

6. Rosemary

Epoch Times Photo
Rosemary. (Nataliia K/Shutterstock)

Rosemary contains rosmarinic acid, which has been shown to modulate our immune response to have anti-allergy and decongestant properties. In a study with 29 participants, those given rosmarinic acid had decreased amounts of immune cells in nasal mucus, which reduced nasal congestion.  

A review of studies concluded that rosemary has significant antimicrobial, anti-inflammatory, antioxidant, and neuroprotective properties.

7. Ashwagandha

Ashwagandha root
Roots and powder of Ashwagandha (Eskymaks/Shutterstock)

Ashwagandha is a small woody plant native to India and North Africa that is used in Ayurvedic medicine. A clinical trial found that five participants who took 6 milliliters of ashwagandha root extract twice daily for 96 hours showed significant increases in immune cell activity.

A randomized, double-blind, placebo-controlled trial found that ashwagandha extract significantly improved the immune profile of healthy subjects by modulating their innate and adaptive immune systems.

Researchers concluded that ashwagandha could be used to boost the immune system of people at risk for infection and during “widespread infections.”

8. Black Cumin Seeds

Epoch Times Photo
Black cumin (nigella sativa or kalonji) seeds (Ulada/Shutterstock)

Black cumin seeds, also called black caraway, have a long tradition of use for therapeutic purposes.

A study identified compounds in black cumin seeds that can positively affect our immune signaling pathways, showing that this could be used as a dietary supplement to activate our immune responses.

A comprehensive review concluded that through a compound called thymoquinone, black cumin seed promotes immunity and cell survival, acts as an antitoxin, and can lessen the side effects of certain drugs.

9. Black Elderberry

Epoch Times Photo
Black elderberry (TYNZA/Shutterstock)

Black elderberry, also called Sambucus nigra, refers to several varieties of the Sambucus tree, which has clusters of white flowers and black or blue-black berries.

A  placebo-controlled, double-blind study of 312 plane travelers concluded that those who took elderberry supplements had significantly reduced cold duration and severity compared with passengers given a placebo instead.

A systematic review of studies from 2018 found that black elderberry supplements were effective to treat the symptoms of upper respiratory infection.

10. Echinacea

Epoch Times Photo
Echinacea flowers. (Shutterstock)

Echinacea refers to a group of flowering plants belonging to the daisy family. There are different species, but Echinacea purpurea is the most common.

A review of 16 studies found that echinacea was more effective than a placebo in preventing and treating upper respiratory infections.

Another review that looked at 14 studies found echinacea reduced the odds of catching a cold by almost 60 percent and decreased the symptom duration by nearly one-and-a-half days.

Are Immune-Boosting Herbal Supplements Safe to Use?

It’s important to get herbal supplements from a reputable brand.

“Echinacea and most herbal products are extremely variable,” Dr. Nima Majlesi, director of medical toxicology at Staten Island University Hospital, part of Northwell Health in New York, told The Epoch Times. He added that the labeling of products in health food stores can be incorrect due to a lack of FDA regulation.

People with allergic reactions to the contents of these supplements are the most obvious group that should avoid them.

“The fallacy of ‘it’s natural so it’s safe’ is truly concerning and we need to change the way we think about this,” said Majlesi.

Many drugs are based on natural compounds, and those compounds could have toxicity and potential for adverse effects just like prescription or over-the-counter drugs, he noted.

But overall, “these products are generally very safe, especially if taken for a short duration,” Majlesi said.

Majlesi advises that the best way to use most of these products is:

  1. Discuss whether it is safe with your health care providers, especially if you have medical issues or take medications daily.
  2. If they feel it is safe, and you want to try to improve your symptoms, consider a short course during specific times at recommended doses.