Cold plunge to boost metabolic health

Cold plunging, also known as cold water immersion or cold water therapy, involves immersing the body in cold water for a short period of time. While it is a practice that athletes have traditionally used to enhance recovery and improve performance, cold water immersion may also offer a range of health benefits, including the potential to increase the production of brown fat.

Brown Fat vs White Fat

Brown fat, also known as brown adipose tissue (BAT), differs in color from white adipose tissue (WAT), which makes up the majority of the fat in the human body. BAT is significantly more metabolically active than WAT because it has a higher concentration of iron-rich mitochondria, which also gives the tissue a brown color. However, the mitochondria in BAT differ from those in other body tissues. BAT mitochondria are made to "waste" energy in the form of heat rather than capturing it and converting it to chemical forms (ATP) that the cell can use to support its typical functions. Brown fat is thought to have a number of health benefits, including improving insulin sensitivity and potentially aiding in weight loss.

There is evidence to suggest that cold exposure may increase the production of brown fat in humans. One study found that exposure to cold temperatures for several weeks increased the amount of brown fat in participants compared to those who were not exposed to cold temperatures. This was done using an infrared camera to capture a thermal map of the skin surface before and after the cold plunge.

Activation of BAT on Energy Consumption

Activation of BAT has been shown to increase energy expenditure and contribute to weight loss. When activated, BAT consumes energy in the form of fat and glucose to produce heat, which can increase the body's overall energy expenditure. This is thought to be one of the mechanisms by which BAT may help to regulate body weight and metabolism.

BAT absorbs more glucose per gram than skeletal muscle after brief moderate cold exposure when BAT is most active. However, when taking into account the combined mass of each of these tissues, the skeletal muscle will have a far more significant impact on metabolism than BAT does.

Conclusion

A well-established and reliable mechanism of BAT activation is the foundation of cold exposure therapy. Increased BAT activity has been linked to temperature variations, even during certain seasons. Nevertheless, despite active BAT's excellent metabolic capability, adults' overall contributions to total energy expenditure are pretty modest. Compared to shivering and nonshivering activity in skeletal muscle, BAT activity only makes up a tiny portion of cold-induced increases in energy expenditure. In other words, the justification for cold treatments may hold up at the cellular and molecular levels. Still, it breaks down when we consider the little effect cold-induced BAT activation has on human whole-body energy expenditure.