To answer this question, we first must understand how the body manages the cold…
“Thermogenesis” is the term for the body’s temperature regulation system. It’s one of the ways our body keeps us alive. In a nutshell, the brain and body work together to regulate our temperature through hormones and neurotransmitters. Everyone has an internal thermostat that sits just behind the nose. This thermostat receives signals from receptors from our skin and inside our body. The signals tell the thermostat to release hormones and chemicals to help us adapt to the temperature it’s experiencing and, in very simple terms, stay alive. Deliberate Cold Exposure trains our thermoregulation to become more efficient at heating the body and prepare for next time.
So, how does the body create heat?
1. Mechanically, where we shiver to burn glucose in the muscles
2. Metabolically, by stoking the furnace and burning brown fat (energy-dense fat)
Both 1 and 2 can occur at the same time and happen alongside vasoconstriction. This is when blood vessels constrict to drive greater blood flow to the core, and away from the cold skin's surface. The more we adapt to the cold, the more it trains our metabolism to burn brown fat, and the more we can change our biology over time.
Turning white (storage) fat into brown (fuel) fat using deliberate cold exposure
We can train our bodies to become fat burners. Deliberate Cold Exposure is responsible for changes to our metabolism, both immediately and for hours afterward. Burning brown fat is the body’s most efficient way to get warm. Think of it as a fuel, ready to fire up the furnace fast. What’s often missed and important to remember is that ongoing adaptations are happening inside the body hours after your cold dip, where the body is preparing to burn more brown fat stores for next time.
It’s important to note that cold exposure isn’t a magic answer to weight loss. A healthy diet and increased exercise are the first ports of call here. However, layering in cold exposure as a third pillar to ensure the metabolism is working to burn fat throughout the day is unquestionably a good idea, if you’re up for it.
Cold water immersion for improved body fat.
The activation of thermogenesis (burning brown fat), in people with obesity or type 2 diabetes may be an effective therapeutic strategy to aid in weight loss and improve metabolic health . People with higher percent body fat typically have less brown fat. However, cold exposure increases brown fat volume by turning white fat (storage fat) into brown fat (fuel). Making it a hot area of exploration for weight management.
Deliberate Cold Exposure improves insulin sensitivity.
A separate study of overweight men with type 2 diabetes found that they had increased brown fat mass and activation with an improved insulin sensitivity after cold exposure. Peripheral insulin sensitivity increased 43% and in turn, muscle glucose uptake also increased. This is interesting because it suggests that cold exposure appears to be a potential therapy for diabetes .
It is this effect that brown fat appears to have an impact on glucose metabolism, independent of age, sex and body fat percentage that is interesting scientists. In a study where subjects were placed in a cold room while there their feet were placed on an ice block (sounds fun!), the group who had stores of brown fat had lower HbA1c (a marker for long term blood glucose control problems) and lower cholesterol compared to the participants who didn’t have brown fat stores in their bodies. .
Increasing brown fat activation using cold water immersion.
Recent work by Susana Soeberg  researching young men who are regular winter swimmers revealed that an 11-minute total of cold exposure, per week, increased a number of metabolic processes:
1. The men experience an increased caloric burn, due to increased core metabolism, by going into cold water up to the neck. Covering the vagus nerve (side of the neck) is considered, important to do. Increases in core body metabolism (burning calories), though small, were statistically significant, and only capture half of the story.
2. The more interesting benefit was observed in fat storage over time. The male participants felt more comfortable in extreme cold due to their cold training. This was observed due to the increasing amount of brown fat that Deliberate Cold Exposure creates, converting white fat (which has a low metabolic output) into storage fat, to brown fat (a fuel source), preparing the body for future exposure. This increased the participants’ overall core metabolism every day, turning them into fat burners.
This is huge and re-frames how we see the cold. Beyond a one-hit fat-burning tool whilst in your ice bath, you’re actually changing your underlying metabolism beyond a single exposure. 
This is because norepinephrine (released when we get into the cold) binds to white fat receptors on the surface of white fat cells. Some neurons sense cold on the skin which directly release norepinephrine into the fat cells under the skin to set off a huge set of immediate and ongoing gene expression changes. Genetically changing the white cells to brown fat cells. It shows us that white fat has a plasticity and an ability to change should we ask it to  .
If you want to continue reading, check out our FREE Deliberate Exposure Guide.
1. brown fat and human obesity management https://dx.doi.org/10.1111/nyas.12304
2. Cold acclimation recruits BAT in obese humans https://dx.doi.org/10.2337/db15-1372
3. Cold acclimation improves insulin sensitivity https://dx.doi.org/10.1038/nm.3891
4. Impact of BAT on glucose metabolism https://dx.doi.org/10.1038/ijo.2013.206
5. Cell, Susana Soeberg - https://www.cell.com/cell-reports-medicine/pdfExtended/ S2666-3791(21)00266-4
6. Implications for non-shivering thermogenesis: https://pubmed.ncbi.nlm.nih.gov/21490370/
7. Adipose plasticity: https://www.cell.com/cell/pdf/S0092-8674(21)01454-9.pdf
8. BAT contributes to energy expenditure during cold exposure: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3266793/