What happens to blood glucose during cold plunge therapy?
Summary
Type 2 diabetes is an metabolic disorder characterized by chronic high blood glucose. It results from mitochondrial damage associated with an imbalance between carbohydrate intake and expenditure.
Insulin resistance is a precursor to Type 2 diabetes, sometimes called "pre-diabetes."
Without changes in diet or exercise, cold plunge therapy will activate brown fat, stimulate non-shivering thermogenesis to clear excess glucose for the production of heat, and improve insulin sensitivity.
Continuous glucose monitoring measurements show better control of blood sugars in Type 2 diabetics that lasts for hours after an ice bath.
An epidemic of insulin resistance
According to Dr. Benjamin Bikman in Why We Get Sick (2020) every leading cause of death from chronic illness in the United States originates in a phenomenon call insulin resistance. Sometimes called pre-diabetes, insulin resistance is an enormous health problem costing more than a billion dollars a day in the United States.
Although the mechanisms of insulin resistance are complex, mitochondrial abnormalities are the primary culprit (e.g., Kim et al. 2008). Defects in mitochondrial DNA are created when excess energy in the form of glucose enters the cell faster than it can be processed, creating a logjam of free radicals that damage mitochondrial DNA. unless the mitochondria get a break from carbohydrates via fasting or a ketogenic diet, cells will shut down insulin receptors at the cell walls to become insulin resistant, slowing down the rate of glucose processing and protecting the mitochondria from further damage. As a consequence, glucose from carbohydrates in the diet will remain in the blood stream longer, resulting in the state of hyperglycemia that constitutes Type 2 diabetes.
Eating more carbohydrates will cause blood glucose levels to spike, signaling islet cells in the pancreas to secrete more insulin. In this scenario, insulin receptors and islet cells are working against each other. The insulin receptors are shutting down to keep glucose away from the mitochondria, while the islet cells are producing more insulin to try and shove the glucose in. The result is a paradox of high blood glucose and high insulin. That is, hyperglycemia is typically accompanied by hyperinsulinemia.
The result is often, but not always, excess fat, culminating in obesity and a myriad of other diseases including cancer, heart disease, erectile dysfunction, polycycstic ovarian syndrome, infertility, and low testosterone.
Basically all chronic illness is associated with high insulin. - @Mangan150
Ice baths controls blood glucose
Several scientific studies have demonstrated that deliberate cold exposure will clear glucose from the bloodstream and improve insulin sensitivity. For example, when a group of middle-aged obese German men spent four hours a day in cool air for ten straight days wearing nothing but shorts and T-shirts, researchers measured improvements in insulin sensitivity of as much as 80%. They concluded:
Cold acclimation for 10 days has very marked positive effects on whole-body and skeletal muscle insulin sensitivity and thereby provide a new avenue to improve the metabolic health of patients with Type 2 diabetes. - Hanssen et al. (2015)
Run your own cold plunge therapy experiment
To better document the metabolic benefits of cold plunge therapy, biohackers have started using continuous blood glucose monitors (CGM) to measure the effects of the ice bath in real time. For example, Kristin Wietzel sent me a screenshot of her blood glucose data during a six minute plunge in 40F water. She reported that her blood glucose started at a healthy, normal 95 mg/dL when she first stepped into the icey water, and then spiked up to 136 mg/dL right away, before coming back down to the same level it was before she got cold.
Kristin's findings are consistent with experiences we've heard from other biohackers performing similar experiments, and they raise the question, "If cold plunge therapy is so good for clearing blood glucose, then why do my levels go UP instead of down?"
The answer is that when you step into the cold, you activate your sympathetic nervous system to initiate a fight-or-flight response. Smooth muscle tissues involuntarily contract, inducing vasoconstriction in your limbs to defend the core body temperature against the cold. Your liver releases a polymerized form of glucose called glycogen into your bloodstream, spiking your blood sugar in case your muscles and/or brown fat should need an instant boost of energy to fuel cold thermogenesis. As you relax your breath and strengthen your parasympathetic response, thermogenesis in either brown fat cells or muscle shivering begins clearing that extra glucose from the blood stream and burning it to produce heat.
Kristin's results are typical of someone who is metabolically healthy, and an experienced cold plunge practitioner. Her insulin receptors and islet cells are in balance, and her blood glucose levels are healthy.
To better understand what happens with someone who suffers from Type 2 diabetes, I turned to Wade Hogg. A former professional athlete, Wade's weight ballooned when he retired from sports. Eventually, without the intense exercise regimen that characterized his former career, Wade developed insulin resistance, and finally full-on Type 2 diabetes.
Wade's CGM results are typical of someone in the advanced stages of insulin resistance, and consequently at elevated risk of cardio-vascular disease, cancer, Alzheimer's, and other life-threatening illnesses. Notice that his blood glucose levels are in poor control prior to his ice bath, peaking at 252 mg/dL in the morning, and hovering just above 200 mg/dL right up until he submerges in the ice bath.
Unlike Kristin, Wade does not experience a blood glucose spike. Shortly after 11A, as he enters the ice bath, his blood glucose readings drop immediately. In fact, they get close to the same level as Kristin's (146 vs 136 mg/dL, respectively).
Wade's levels drop because he already has elevated blood sugars at the time of his sympathetic activation. His liver doesn't need to release glycogen.
Science of Cold Therapy for Insulin Sensitivity
Everyone understands that exercise benefits metabolism. What few people grasp is that a four minute cold plunge confers many of the same benefits as exercise, in a shorter period of time. Scientist refer to cold plunge therapy as an exercise mimetic, because it mimics many of the same effects as exercise.
One of the world's leading researchers on cold plunge for metabolism in Deni Blondin, PhD at the Université de Sherbrooke in Quebec, Canada. He recently reviewed the body of literature on cold plunge therapy for reversing insulin resistance and concluded:
Cold-stimulated thermoregulatory responses may be the closest exercise mimetic and, in some instances, may potentially even exceed the therapeutic potential of exercise training. - Ivanova & Blondin (2021)
When a Type 2 diabetic patient can't exercise, or won't exercise, cold plunge will confer many of the same metabolic benefits plus activate brown fat for long-lasting metabolic health. In response to the cold, insulin receptors in a Type 2 diabetic open up and flood shivering muscles and brown fat with the glucose they need to generate heat through cold thermogenesis. And now, instead of resulting in a electron logjam at the mitochondria that result in free radical damage, the mitochondria burn the excess glucose as fast as they can to generate heat in an attempt to keep the body warm. According to Blondin, the rate of carbohydrate metabolism during cold exposure can be three to six times a thermoneutral baseline.
The effect is even more powerful in those with Type 2 diabetes than in lean, metabolically healthy individuals. In effect, the ice bath retrains Wade's metabolism to restore the glucose/insulin balance that has long been absent. What's more, deliberate cold exposure recruits new brown fat, which are packed with new mitochondria. In the process of mitochondria synthesis, error-correction mechanisms of mitochondria DNA reproduction select for only the best copies, improving the quality of Wade's mitochondria overall and potentially reversing the free radical damage that is signaling his insulin receptors to shut down.
As more data from clinical trials emerges, I won't be surprised to find that cold plunge therapy increasingly becomes recognized as the fastest route to reversal of Type 2 diabetes. In fact, one successful case has already been documented in the article Ketosis & Ice Baths Reversed My Type 2 Diabetes in which author AJ Kay both reversed her own T2D diagnosis, and applied what she learned about metabolism to save her cats.
References
Bikman B. Why We Get Sick: The Hidden Epidemic at the Root of Most Chronic Disease--and How to Fight It. BenBella Books; 2020.
Hanssen MJ, Hoeks J, Brans B, Van Der Lans AA, Schaart G, Van Den Driessche JJ, Jörgensen JA, Boekschoten MV, Hesselink MK, Havekes B, Kersten S. Short-term cold acclimation improves insulin sensitivity in patients with type 2 diabetes mellitus. Nature Medicine. 2015 Aug;21(8):863-5.
Ivanova YM, Blondin DP. Examining the benefits of cold exposure as a therapeutic strategy for obesity and type 2 diabetes. Journal of Applied Physiology. 2021 May 1;130(5):1448-59.
Kim JA, Wei Y, Sowers JR. Role of mitochondrial dysfunction in insulin resistance. Circulation Research. 2008 Feb 29;102(4):401-14.
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.
I came across that claim about ice baths reversing type 2 diabetes, and it's definitely caught my attention. It's fascinating to think about alternative approaches to managing such a complex condition. However, I'd approach it with a healthy dose of skepticism until more concrete evidence and studies support it. In the meantime, it's essential not to disregard the established treatments like Metformin tablets for diabetes management. These medications have been extensively researched and proven effective in controlling blood sugar levels. It would be interesting to see if there's any potential synergy between unconventional methods like ice baths and conventional treatments like Metformin.