What happens in Type 2 diabetics 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) the leading causes of death from chronic illness all originate in a phenomenon call insulin resistance. Although the mechanisms of insulin resistance are complex, mitochondrial abnormalities are the primary culprit (e.g., Kim et al. 2008).
According to the mitochondrial theory of insulin resistance, excess energy in the form of glucose enters the cell faster than it can be consumed, creating a logjam of free radicals that damage the mitochondria. Thus, shutting down insulin receptors at the cell walls may be the body's desperate attempt to slow the transport of glucose to mitochondria, protecting them from further free radical a damage. As a consequence, blood glucose levels remain higher than normal, 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.
"Basically all chronic illness is associated with high insulin." - @Mangan150
Ice baths control blood sugars
Several scientific studies have demonstrated that deliberate cold exposure will clear glucose from the bloodstream and improve insulin sensitivity. For example, Hanssen et al. (2015) concluded that:
"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)
As the metabolic benefits of deliberate cold exposure become better documented, biohackers have started using continuous blood glucose monitors (CGM) to measure the effects of the ice bath. For example, these results (at left) are from Kristin Wietzel's 6 min plunge in 40F water.
She reports 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 deliberate cold exposure is so good for clearing blood glucose, then why do my levels go UP instead of down?"
The answer is this: when you step into the cold, your smooth muscle tissues involuntarily contract. Your sympathetic nervous system activates a flight-or-fight response that instructs the liver to release glycogen stores into your bloodstream, in case your muscles should need an instant boost of energy. That's the initial spike.
As you relax your breath and strengthen your parasympathetic response the brown fat cells in your body begin 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 exposure practitioner. Her insulin receptors and islet cells are in balance, and her blood glucose levels are healthy.
The results on the right, however, are different. This is Wade Hogg, who is using the Morozko ice bath to treat his Type 2 diabetes.
Wade's 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 achieves whole body cold water immersion.
Then, shortly after 11A he enters the ice bath and 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.
In response to the blood, his insulin receptors open up and flood his 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 Wade's body warm.
In effect, the ice bath retrains Wade's metabolism to restore the 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.
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.
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.