Wim Hof & Brown Fat
The Science of Cold Resilience: Insights from the "Iceman" Study
In 2018 PLOSone published the study “Frequent Extreme Cold Exposure and Brown Fat and Cold-Induced Thermogenesis: A Study in a Monozygotic Twin”, which investigated the physiological differences between Wim Hof and his twin, who leads a more sedentary lifestyle. It explored the effects of extreme cold exposure on brown adipose tissue (BAT) activity, cold-induced thermogenesis (CIT), and other metabolic factors.
The study was conducted in the following manner: Methods: The Iceman (subject A) and his brother (subject B) were studied during mild cold (13uC) and thermoneutral conditions (31uC). Measurements included BAT activity and respiratory muscle activity by [18F]FDG-PET/CT imaging and energy expenditure through indirect calorimetry. In addition, body temperatures, cardiovascular parameters, skin perfusion, and thermal sensation and comfort were measured. Finally, we determined polymorphisms for uncoupling protein-1 and b3-adrenergic receptor
Key Findings:
Comparable BAT Activity: Despite Hof’s frequent extreme cold exposure, both twins had similar BAT activity levels, comparable to young adult men. This challenges the assumption that extreme cold exposure alone enhances BAT function.
High CIT in Both Subjects: Both subjects showed remarkably high CIT levels (~40%), far exceeding the typical range observed in young adults (7–30%). This suggests that their breathing technique, inspired by g-Tummo meditation, contributed significantly to heat production.
Breathing Techniques and Thermogenesis: Increased glucose uptake in respiratory muscles indicated that Hof's breathing practices contributed to higher CIT. This method, involving isometric respiratory muscle contractions, could generate substantial heat. The study found a significant increase in glucose uptake in respiratory muscles during cold exposure (4x higher than in thermoneutral conditions). This suggests that isometric contractions associated with g-Tummo breathing significantly contributed to heat generation.
Insulative Responses and Comfort: Hof demonstrated better cold tolerance, maintaining a more stable core temperature and experiencing less discomfort during cold exposure. His vasoconstriction response was also more pronounced in specific areas like the arms.
No Shivering Observed: Both twins avoided shivering during the experiment, a stark contrast to typical responses in similar conditions. The delay of shivering may result from increased respiratory muscle activity.
Conclusions:
The study concluded that frequent extreme cold exposure does not necessarily enhance BAT activity or heat production during mild cold conditions. Instead, techniques like g-Tummo breathing may play a pivotal role in thermoregulation. These findings open doors to exploring non-shivering thermogenesis strategies for improving cold resilience and possibly managing metabolic conditions. This research underscores the interplay between lifestyle, physiology, and genetics, offering insights into the body's adaptability to extreme conditions.
