End on Cold: The Søeberg Principle
If you've spent any amount of time reading our blog or chatting with us at Sauna House, you already know that cold water therapy is one of our favorite topics. We've extensively studied why cold plunges are good for you: the immunity boost, the anti-inflammatory effects and the improvement of blood circulation in the body, and so on. There’s even plenty of research and anecdotal support for its positive impact on mental health.
(If you’re new to cold water therapy, this will bring you up to speed!)
As science continues to uncover the mechanics of what our ancestors have known for generations – that temperature changes can be a tool of healing – we’ll never run out of reasons to try cold water therapy. This is super exciting because it’s not just great for our general wellness, it also shows great potential in treating diabetes and other inflammatory diseases.
But there’s one aspect we don’t talk about enough, and that’s its impact on metabolism.
In this blog, we’re going to dive in. We’ll also cover a cold therapy protocol we can use to improve our metabolism, using what Dr. Andrew Huberman calls the Søeberg Principle, based on a groundbreaking discovery by deliberate cold researcher Susanna Søeberg.
What is the Søeberg Principle?
The Søeberg Principle is: To enhance the metabolic effects of cold, force your body to reheat on its own. Or “End With Cold”.
There are many ways to practice cold therapy. Some people love to get shivering, and then immediately stand under a warm shower or towel-dry themselves. Others love to do this as part of contrast therapy, where you switch between hot and cold baths (or showers or cold/hot rooms). While these are amazing techniques with so many different benefits, they’re not the best way to specifically target your metabolism – and that’s where the Søeberg Principle comes in.
How does it work? And what happens to your body when you allow it to reheat itself?
In our body, we have two different types of fat: brown fat and white fat. There’s also a third kind, beige (or brite) fat, which is basically white fat in the process of “browning”. Here’s what they look like under a microscope:
Source: De GruyterWhite fat cells primarily convert the glucose-derived energy that the body doesn’t need into large lipid droplets, the type of fat that’s really hard to burn, often causing obesity and a host of health problems.
And then you have brown fat.
Brown fat cells, packed with mitochondria, are energy burners, producing heat from smaller, denser fat droplets. The iron-rich mitochondria contribute to its brown color.
What’s special about brown fat is that the mitochondria in it oxidizes fatty acids and glucose, and dissipates energy in the form of heat. That’s called brown fat thermogenesis. Brown fat is primarily an evolutionary adaptation to regulate our core temperature (prevent heat loss) in extremely cold conditions. It’s what keeps you from getting hypothermia in freezing weather.
Leaner people have more brown fat. Research shows a strong negative association between brown fat and body weight, overall body fat, and visceral fat (the fat that surrounds your organs). Scientists are really excited by it because it shows a lot of promise in treating metabolic disorders like Type II Diabetes.
What does this have to do with cold water therapy? Well, a few things can activate brown fat thermogenesis (or fat burning): certain functional ingredients, exercise, and cold.
When we’re exposed to cold, either through an ice bath, a winter swim, or a cold plunge, a number of systems activate almost immediately to adapt. Your blood vessels contract to make a surface around you to avoid cooling your vital organs too fast. This is a cold shock, and it’s a life-saving adaptation.
Enter brown fat. According to Dr. Søeberg, brown fat thermogenesis activates almost as soon as there's a temperature change to keep your core temperature up. This kicks your metabolism into high gear, leading to many of the beneficial effects of cold water therapy.
Remember the third type, “beige” fat? Most of us have that in abundance. That behaves exactly like brown fat when exposed to low temperatures: it burns energy. Muscular exercise, and cold exposure, both, can “brown” white fat - and burn it too!
When you don’t resort to warming yourself up externally, say via towel drying, jumping into a sauna, or putting on a jacket, your brown and beige fat pulls all the weight (literally and metaphorically) in driving your metabolism.
Practicing cold water therapy with the Søeberg Principle
If you’re just starting out, or want to try this at home, here’s what Dr. Huberman suggests: Get into a cold shower. The temperature should be uncomfortably cold but safe to stay in. After 2-3 minutes, turn it off, step away, leave your arms hanging loosely by your sides (basically, don’t hug yourself), and dry yourself out in the air for about 1-3 minutes. If that fails to induce shivering, repeat the process until you do shiver.
“If you want to use deliberate cold exposure to increase metabolism,” he says, “you should get to the point where you shiver in the cold exposure or immediately after.”
Shivering is the most important part of cold water therapy. When your muscles shiver, they release succinic acid, which when it accumulates, “is sufficient to elevate thermogenic respiration in brown adipocytes.” (Adipocytes is the scientific term for fat cells) That’s why it’s so important that you do not warm yourself up externally while you’re aiming to boost your metabolism.
P.S. There’s an amazing interview with Dr. Søeberg on the Huberman Lab podcast that goes into more detail. Tune in here!
But wait: is shivering good for you?
Dr. Søeberg’s research says yes. Her study found that winter-swimming men, combining cold-water immersion with a hot sauna, burned more calories during cooling than controls, despite similar activation of brown fat. This is good news. The more you practice cold therapy, the better your metabolism will be in the long term.
To learn her specific techniques, sign up for her 3-week Thermalist Cure course or pick up one of her books. We recommend Winter Swimming, an exploration of this aspect of Nordic culture and a perfect balance of rigorous science writing and art. (Get it here.)
Test out the Søeberg principle at Sauna House!
At Sauna House, we have the perfect setting for you to practice cold therapy as taught by Dr. Søeberg. Heat up in the sauna, and then take a cold plunge right after!
But safety always comes first. If you’re new to cold water therapy, start slowly with Dr. Huberman’s protocol. Dr. Søeberg says that people new to deliberate cold exposure will experience a longer cold shock – and her recommendation is no more than 11 minutes of cold and 57 minutes of heat exposure in different sessions over a week.
When you’re starting out, it’s better to err on the side of caution and go very slowly. We always recommend that you consult with your doctor before trying out cold therapy and do plenty of research before you “take the plunge.”