top of page

Cancer & Mitochondria

Updated: 3 days ago

Dean Hall says cold water swimming cured his cancer

DISCLAIMER: Nothing in this article constitutes medical advice. Morozko ice baths do not diagnose, cure, or treat any disease, nor have any claims made in this article been evaluated by the FDA. Dean Hall's experience is not typical.


  • In 2013, Dean Hall was dying of an incurable leukemia. Resolved to do something before he died that would inspire other cancer patients, he swam the entire length of the cold Willamette River in Oregon. When he finished, his leukemia was gone.

  • Dean's amazing recovery reinforces that deliberate cold exposure and exercise will inhibit tumor growth by starving cancer cells of glucose, and killing them with ketones.

  • Since his reversal, a number of scientific studies have been published that explain the mechanisms of Dean's reversal.

  • Dean remains 100% free of cancer to this day.

The will to live what life he had left

One day in 2013, Dean Hall looked at himself in the mirror. He saw his swollen lymph nodes and shrinking muscles and thought to himself, "You know, if I let the leukemia take me, no one would ever know that I gave up."

He was despondent and depressed, like many of the people who suffer from cancer. He'd already survived one cancer diagnosis, only to lose his first wife of 30 years to an inoperable brain tumor. But in that moment he reminded himself that he still had a 21-year-old daughter.

Dean decided that death was a not a luxury he could afford.

He resolved to do something he'd fantasized about as a kid. Something that might inspire other cancer patients.

He would swim the English Channel before he died.

So Dean called his doctor and told what he planned to do. His doctor said, "Dean if you get in a public pool, with your immune system worn down from leukemia, it will kill you,"

In other words, Dean Hall had nothing left to lose.

Cold exposure as metabolic therapy for cancer

What Dean didn't know when he began training for his cold swim is that the combination of cold exposure, exercise, and ketone production could kill his cancer. Just six years earlier, researchers had hypothesized that cold water swimming could "stimulate anti-tumor immunity" by activating the body's own natural killer cells (Shevchuck & Radoja 2007). It's a hypothesis that has been popular at least since the 1930's, when Russian mystic Porfiry Ivanov famously claimed that cold exposure cured him of terminal cancer he suffered in middle age. He lived to the age of 85, dying in 1983 after gaining a cult-like following to whom he proselytized about the health benefits of cold exposure, hunger, and exercise.

However, it wasn't until 2022 that researchers in Sweden (Seki et al. 2022) demonstrated that the mechanism by which deliberate cold exposure inhibits tumor growth is likely activation of brown fat. As I wrote in Ice Bath Cryotherapy for Cancer, this new study demonstrated that "mice implanted with colorectal tumors and subjected to 4C cold air exposure lived longer and experienced slower tumor growth than mice kept at warmer temperatures. The researchers attribute this to the fact that cold exposure activates and recruits new brown fat, and clears glucose from the blood stream."

The majority of cancers have a gene that is up-regulated for glucose metabolism, because glucose is the only food that is so energy-dense it can fuel cancer's unmitigated growth. As such, Thomas Seyfried, PhD describes cancer as a metabolic, mitochondrial disease (Seyfried 2015, 2012). According Seyfried, mutations in the nucleic DNA of cancer cells are a symptom of cancer, not the cause.

The real cause of cancer is disorders of cell metabolism that originate in the mitochondria.

In his popular book, Tripping Over the Truth (2017), Travis Christofferson summarizes a devastating critique of genetic theories of the origins of cancer, and postulates instead a convincing metabolic theory. According to Christofferson, cancer cells are unique in that they obtain energy exclusively by fermenting glucose (a simple sugar), whereas normal cells can metabolize either glucose or fat. Whereas the genetic theory of cancer claims that cancer originates from mutations in the cell DNA, the metabolic theory states that it originates from defects in the mitochondria that provide energy to the cell.

This has profound implications for treatment of cancer. Based on that fact that tumor cells compete for finite stores of glucose within in body, depletion of glucose can "suppress systemic growth of malignant cell types," including leukemia (Ye et al. 2018). Further, Seyfried's work has demonstrated that ketones inhibit tumor growth (e.g., Seyfried et al. 2014), suggesting that Dean's cold water swimming both starved his cancer by depriving it of glucose and killed it by putting his metabolism into ketosis.

Swimming in miracles

In 2014, Dean Hall became the first person to swim the entire 184 miles of the Williamette River that flows through Portland, Oregon. It took him over 3 weeks, and you can read more about it, in his own words, in his new book The Wild Cure. Then, in 2017, he swam the entire length--over 150 miles--of the Shannon River in Ireland.

But Dean has taken cold water swimming to an extreme level that most people don't even begin to contemplate. What can people learn from Dean's experience of complete remission without radiation, chemotherapy, or surgery?

Without swimming all day in freezing rivers, you might be able to manage your cancer risks with a combination of fasting from carbohydrates, exercise, and deliberate cold exposure.

No-carb fasting

Fasting from carbohydrates does two things that promote the destruction of cancer cells:

  1. Fasting starves the cancer cells of the glucose they need to metabolize. As a consequence, the cancer cells die and are reabsorbed into the body in a process called autophagy.

  2. As blood glucose levels drop, the body switches to fat metabolism instead -- i.e, burning lipids released from white fat cells to sustain body operations in a process called ketosis -- producing ketone bodies that are toxic to cancer cells, but healthy for normal cells (e.g., Seyfreid et al 2003).

Well documented cases of people on hunger strikes indicate that even lean people can survive for weeks without eating, metabolizing fat alone. At the extreme, one obese man maintained a medically supervised fast for over a year without eating any food at all. Fortunately, most people can achieve a state of ketosis in just a few days, by eating only healthy fats and protein, in what is called a ketogenic diet. For example, ketosis has long been prescribed for controlling epileptic seizures in children, and is increasingly reocognized as a remedy for mental health disorders (Palmer 2022).


The systemic health benefits of exercise are well recognized. Exercise improves your muscle tone, metabolism, brain function, and likely delays ageing. What's even more incredible is that intensive exercise stimulate the production of cancer-fighting compounds in your bloodstream.

For example, Canadian researchers ran an experiment in which they collected blood from male subjects "prior to, 5 min, 1 h, and 24 h after a single bout of high-intensity interval exercise on a cycle ergometer" (Kurgan et al. 2017). When they exposed lung cancer cells to the collected post-exercise blood serum, they observed an "inhibition of cell proliferation and survival." They speculate that the mechanisms involve reduced levels of IGF-1 (insulin-like growth factor) and/or increased levels of IGF-1 binding protein.

In other words, Dean's extensive exercise regimen may have acted to inhibit tumor growth by modifying hormonal action, as well as correcting metabolic/mitochondrial disorders. But you don't have to be an extreme athlete to get the cancer-fighting benefits of exercise. One study showed that leisure time physical activity is associated with a nearly 50% reduction in the risk of cancer (Moore et al. 2016)

Ice bath

You may have already read Tim Ferris's 2016 article 'EXCLUSIVE: Unpublished Material from NYT Magazine Story on Cancer Metabolism' in which he describes the metabolic theory of cancer and the difficulty associated with publishing the results of studies investigating metabolic theories in mainstream or popular media. What Tim doesn't discuss is the role that cold exposure might play in accelerating metabolic treatments of cancer.

The relationship between cold exposure and cancer remission is still comparatively under-investigated. There are principally three mechanisms by which deliberate cold exposure will help defeat cancer:

  1. glucose starvation,

  2. ketone body production, and

  3. mitochondria restoration by recruitment of new brown fat

The first two mechanisms are common to exercise and cold exposure, however the third is unique to deliberate cold exposure. so we'll focus on the way that these mechanisms relate to brown fat.

Glucose starvation

The body has two ways of generating heat to maintain normal core body temperatures when exposed to cold. The first is shivering in the muscles, which most people have experience with when they're feeling cold. However, the second is called non-shivering cold thermogenesis, and it happens exclusively in brown fat.

Generally speaking, there are two types of fat (adipose tissue) in the body. White fat is for storing energy, and brown fat is for burning it. Because most clinical trial subjects live in Western, Educated, Industrialized, Rich, and Democratic ("WEIRD", Henrich et al. 2010) countries where climate control is ubiquitous, by the time these subjects reach adulthood, they have very little brown fat remaining in their bodies. However, a practice of regular cold exposure will both activate brown fat and recruit more (Oulett et al. 2012, Søberg et al. 2021). In the competition for blood glucose, the body will feed brown fat during cold exposure, compared to tumor cells (Seki et al. 2022). Therefore, cold exposure may cure cancer by reducing blood sugar levels, and starving cancer cells of their only energy source.

Cold exposure for inducing ketosis

Repeated cold exposure recruits brown fat, obviating the need for shivering. Regular plungers know this. After a few weeks of forging, our customers report that they no longer feel the shiver reflex after several minutes in freezing cold water. What that means is that their bodies are burning white fat lipids (e.g., triglycerides) as well as glucose in their new brown fat cells -- just to maintain body temps during and after their ice bath.

In laboratory experiments, mice fed a diet supplemented by exogenous ketones have shown resistance to tumor growth (e.g., Pof et al. 2014). Since then, clinical trials in humans have shown that a ketogenic diet is well tolerated by cancer patients, and improves treatment outcomes (Tran et al. 2020). Nonetheless, as I wrote in Ice Bath for Fast Keto, the fastest way to stimulate production of your own ketones is an ice bath. Thus, a combination of low-carbohydrate fasting and cold exposure may inhibit tumor growth by inducing the body to produce its own, natural ketones (without deleterious side effects).

Cold exposure for mitochondria restoration

It is already well established that cold exposure recruits brown fat, to increase metabolic capacity for thermogenesis -- i.e., burning white fat for the generation of heat (Hanssen et al. 2016). What's more, brown fat contains extra mitochondria that govern cell metabolism, supercharging the capacity of the brown fat cells to burn the lipids stored in white fat cells (Harms & Seale 2016). While the processes by which old mitochondria are recycled, mitochondria damage is restored, and new mitochondria to populate new brown fat cells are beyond the scope of this article, cold exposure may contribute to a cure for cancer by correcting in defective or malfunctioning mitochondria. Essentially, cold exposure induces the conditions by which the body repairs the defects in mitochondria that are at the beginning of a complex causal chain resulting in cancer. It may stop cancer at its source.

Ice baths for cancer risk

Morozko isn't the only one who is catching on the elaborate, expensive, misguided ruse that is the current approach to cancer research. In cold exposure, there is no blockbuster drug costing patients $100K a year. No expensive radiation machines. No multiple rounds of designer chemotherapy targeting a patient's specific genome. No gene therapy.

There is no money to be made in curing cancer with the immune response, defense, and health mechanisms with which your body is already equipped. And no financial incentive to perform clinical trials on what might be the greatest benefit/cost approach to treatment of the second leading cause of death in the United States.

If your concern is not treating cancer per se, but preventing it in the first place, you can read about my experiences with keto and ice baths when I was confronted with the possibility that I was at elevated risk for prostate cancer in my article What Happened to My Testosterone After Using Ice Baths to Treat my Prostate.



Thanksgiving morning I got a text message from a customer in New Jersey who bought a Morozko so she could practice cold water therapy twice a day in the hope that it would help manage her ovarian cancer.

She'd already been through four rounds if chemotherapy that made her miserable, and her tumors hadn't gone away.

Her doctors recommended a fifth round of chemo.

She decided she'd had enough ofchemo, so she reached out to Dean Hall, who referred her to me. She wasn't sure she could do cold water therapy, but after trying a 15 second swim in the cold Atlantic Ocean, she was hooked.

She's been doing ice baths twice a day now for several weeks, and for the first time her cancer blood markers dropped without chemo therapy.

She called it a "small win" because she knows she has a long way to go in her recovery. But she's already happier and enjoying her life.

She texts me every day now to update me on her progress and she tells me that she feels great.


Roxanne tells me that she had a PET scan after two months of doing ice baths and a ketogenic diet. Her tumors have grown and there are some new spots on her scan. Her CA-125 blood markers are back up, instead of down.

She's very discouraged.

Although chemotherapy wasn't working and her ice bath regimen helps her feel fantastic, her cancer is still progressing and she's scared. Her experience thus far serves to remind use that ice baths are not a cure for cancer, and that your individual experience is the most important indication of what works for you.


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.

9,964 views4 comments

Recent Posts

See All


Dean Hall
Dean Hall
Oct 01, 2019

Thanks Thom for your intelligent and articulate explanation of my radical remission and how others can assist their healing from not only cancer, but many chronic diseases with the use of the Morozko Forge! I am dedicated to standing by your side and confronting all naysayers. I am living-proof that Morozko is medicine!


Some studies show that populations that are exposed to cold have lower rates of cancer, despite a lack of access to modern medical infrastructure. For example, a 2003 letter to Cancer Epidemiology, Biomarkers, and Prevention titled 'Inuit Are Protected Against Prostate Cancer' attributes remarkably low rates of cancer among Inuit males to their traditional diet, which is rich in high omega-3 fatty acids. The cold and the fat metabolism both suggest that glucose starvation and production of ketones -- the natural chemotherapy.


Anjan Katta
Anjan Katta
Sep 29, 2019

Thomas do you thus see in the data that Inuit, Siberians, people living in cold northern latitudes have less incidence of non-benign cancer? Do you see people in less cold regions have higher incidences of non-benign cancers?

Data from the past before heating and cooling technologies became so prevalent and cheaper would be most interesting.



Here's one more journal article describing the hypothesis that cold exposure therapy is toxic to cancer cells. The mechanisms were thought to be activation of the sympathetic nervous system, and the adrenal/thyroid system. But that was back in 2007 and we've learned more about metabolic theory since then.

bottom of page