Heat and Cold Exposure and the Søberg principle

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Dr. Susanna Søberg, cold therapy expert and writer of Winter Swimming: The Nordic Way Towards a Healthier and Happier Life describes how cold therapy could be of massive importance to optimising your life and increasing longevity. Cold therapy could just be one of the most important tools to building resilience in our bodies, both mental and physical. The benefits of cold therapy (and heat therapy) are seen through cold resilience, blood pressure decreases, metabolism and insulin sensitivity increases (insulin insensitivity causes type 2 diabetes so this is important). Mental health improvements will be seen through decreases in depression, anxiety, and risk of Alzheimer’s (due to decreased inflammation).

Less Before winter, more before summer:

To preface everything you are about to read surrounding the effects of heat and cold exposure, its best you understand the everyday science behind Scandinavian culture. The phrase which simply translates to “less before winter, more before summer” shows the way the culture prepares themselves for harsh winters and warm summers, according to Søberg. In the approach to winter, Scandinavians traditionally wear less layers, such as a t-shirt and shorts in the cold, but not quite freezing temperature, while in the build-up to the summer they wear more layers to be more prepared for the heat. Moreover, in the 1950s to present day, Scandinavian parents often put their babies outside to sleep in order to improve cold resistance and build the immune systems. This activates what is called the “brown fat” early on, and it’s much better than it sounds.

Brown fat, what it means and why it is so important:

The brown fat are healthy tissues around the organs in the body which, when activated, increase the metabolism, as well as all the other physiological benefits previously mentioned. Also, brown fat is plastic, which means it can grow (and shrink), the more brown fat our bodies possess, more benefits will be seen. As soon as we get cold, our brown fat is activated, as proven by both human and rodent studies. This works as a domino effect in our body: As our muscles shiver in the cold, our temperature increases, which initially signals an increase in the metabolism in the body. Cold receptors then send a signal to the brains cold regulator (hypothalamus), which then sends a message to the body to activate the brown fat cells. A more rapid decrease in temperature (such as in a cold plunge, or even a cold shower) speeds this process up.

The Dive Reflex:

Submerging in cold water activates this principle, which activates the parasympathetic and sympathetic nervous system. This, in turn slows down oxygen consumption in the body to prevent hypothermia, while also activating serotonin and other chemicals in the brain (you will feel mentally well afterwards). Scott Sivier, regular ice bath user, noted the feeling of mental clarity after using ice baths: "After using my ice bath, I always feel more mentally clear, it definitely helps my focus and overall wellbeing." Cold exposure in showers, or just going outside in the cold doesn’t activate this, however they are still beneficial to activating brown fat and activation of cold receptors. For the best results and activation of cold receptors, a cold plunge is the best option.

Incorporating heat exposure:

Up to 30 minutes in a sauna will lower the risk of cardiovascular disease, however benefits will plateau past this threshold. 10-15 minutes of sauna per session is best advised, which exposes the cells to healthy stress, increasing heat shock proteins, which repair cells in the body. The perfect protocol for sauna would be 57 minutes total per week to reap total benefits of heat therapy.

The Søberg principle:

The Søberg principle, as theorised by Susanna Søberg, is to end on cold when switching between hot and cold exposure. This principle will force the body to heat itself back up, which is proven to create a further increase in metabolism. Moreover, your brown fat and muscles will be activated for longer due to an increase in the mitochondria in the cells, as well as keeping neurotransmitters (such as dopamine, adrenaline, and serotonin) active for longer. By doing this, the body will become even more effective at getting warmer when out of the cold, not at all dissimilar to the Scandinavian cold resilience cultural protocol.

Implementing a protocol:

The perfect protocol for heat and cold therapy, as advised by Søberg, is simple. No more than 11 minutes of cold exposure (by cold plunge), and 57 minutes of heat exposure (by sauna) per week is best advised. While in the plunge, make small adjustments and movements in your body, to force your body to never become comfortable in the cold, further increasing cold resilience. Spread these minutes over the week with 4-5 sessions, starting on sauna and finishing with a cold plunge for best results following the “Søberg principle.” Spend between 2 and 3 minutes in the plunge at a time, and 10 to 15 minutes in the sauna. When your body’s resilience builds, decrease the temperature of the plunge, or increase the time spent inside while continually moving (do the inverse for sauna temperature). Using this protocol, in injunction with exercising and eating well, will ensure a better and more optimised lifestyle.