If you’ve been to our studio, you’ve probably heard us talk about brown fat and its incredible benefits and its ability to prevent and overcome age related, metabolic, brain related diseases.
While I often struggle to stop talking about my favorite adipose tissue (the scientific name for fat), I’ve recently received a few clarifying questions that inspired me to dive deeper into why brown fat is something you should care about.
So here’s the ultimate guide to brown fat and how it relates to cold plunging.
Brown Fat Overview
We are all born with plenty of brown fat, but we lose almost all of it by the time we reach our teenage years. In fact, a recent study showed that 95% of people over 50 have no detectable brown fat. Once it’s gone, there’s only one way to grow it back—regular cold exposure.
As adults, most of the fat in our bodies is white fat, which our fuel system uses to store energy. But brown fat is completely different. It contains plenty of mitochondria, the powerhouse of our cells. These mitochondria generate heat to keep your body warm during your ice bath, giving brown fat its distinctive color. And the fuel to keep you nice and warm comes from burning sugar and fat.
This mechanism may be why brown fat has been shown to:
- Play a role in treating obesity and promoting healthy cholesterol levels.
- Treat insulin resistance and improve your body’s ability to regulate blood sugar.
These incredible benefits alone are reason enough to make brown fat activation a key part of your health routine. But there’s more: keeping your body warm is not the only trick brown fat has up its sleeve. So let’s have a look at how what role brown fat plays in hormone production and cascades:
Brown Fat and Hormone Cascades
Although research on brown fat has only gained momentum in recent years, researchers are quickly uncovering new reasons to keep your cold plunge routine front of mind. One of these discoveries is the role brown fat plays in hormone production.
According to Ben Bikman, PhD, “Over half of all the thyroid hormone in the body is coming from brown fat.” This explains the positive impact brown fat activation has on modulating thyroid function and metabolism. Brown fat secretes other hormones as well, such as FGF21, which has been shown to reverse cognitive deficits in animal studies. This may explain the positive impact of brown fat activation on brain health, including protection from Alzheimer’s disease and dementia.
We’ve established that brown fat is an absolute powerhouse in fighting age-related diseases, including insulin resistance, Alzheimer’s, obesity, heart disease, and more. Now, let’s discuss how brown fat get’s activated.
How Do Ice Baths Activate Brown Fat?
The process by which the body signals brown fat to activate has only recently been revealed, and it’s quite fascinating!
You might think our temperature-sensing cells, called thermoreceptors, would signal brown fat directly, but they don’t. Instead, they send signals to the hypothalamus, which then activates brown fat through the sympathetic nervous system. How cool is that?
The sympathetic nervous system (as opposed to the parasympathetic system) is our ‘stress’ system, responsible for our fight-or-flight response. Its activation is designed to prepare our body for physical action as quickly as possible by increasing heart rate, metabolism, and blood pressure while making us more alert. In addition, the liver is triggered to release glycogen (sugar) and fat cells into your blood to provide fuel for action.
Sympathetic activation also produces norepinephrine, which often doubles or triples during an ice bath. Interestingly, it’s the norepinephrine that activates the brown fat. The brown fat then starts burning fat and glycogen to produce heat.
And that’s how the magic happens.
Curious about how to maximize brown fat activation? Great! That’s what we’ll write about next week! 🙂
