How does cold exposure affect metabolism?

Andrew Huberman described the effects of cold exposure on metabolism in a few different discussions. In one study involving young men who underwent deliberate cold exposure for 11 minutes per week, there were statistically significant, although not large, increases in core body metabolism. These effects were mediated by increases in brown fat thermogenesis and core body temperature. Deliberate cold exposure, both acutely and over the long term, seems to affect the types of fat we store and how that fat influences metabolism throughout the day. Brown fat, also known as thermogenic fat, serves as the body's means to increase core metabolism, can help individuals stay lean, and acts as a reservoir for heating the body when confronted with cold 1.

Additionally, Huberman noted that metabolism increases during and immediately following cold exposure are due to caloric burn, but the more lasting metabolic effects come from the conversion of white fat cells, which store energy, into beige and brown fat cells, which are more metabolically active. This process can have a significant impact on an individual's overall metabolism 2. Furthermore, Susanna Søberg also discussed the benefits of cold exposure in reducing inflammation, potentially preventing lifestyle-related diseases, and interacting with other physiological activities such as fasting and the body's response to heat 3.

For more comprehensive details on the metabolic effects of cold exposure, Huberman referred listeners to a review titled "Adipose Tissue Plasticity in Health and Disease," which outlines the pathways and mechanisms from cold exposure to norepinephrine effects, and the conversion of white fat to brown fat 2.