Exposure to cold for health purposes as a practice started long time ago, we are talking centuries, and recently it has become popular in the modern world too. You might have heard of Wim Hof, also known as The Ice Man, who is a Dutch motivational speaker, famous for his ability to endure long periods of time under very low temperatures. The man holds a record for running a barefoot half marathon on ice and snow. Impressive, right? He is one of many advocates for using exposure to cold as a practice which promotes health. What is it?
Cold exposure could be done in a number of ways. Cold showers at home or immersing one's body in water at temperature about 15°C or lower are popular ways. Whole-body cryotherapy, where one is exposed to cold air for a few minutes at a temperature of as low as -178°C is another way.
Can the body adapt?
When exposed to it extreme cold triggers a number of physiological responses from the human body collectively known as a cold shock response. At a moment like this the goal of your body is to reduce heat loss and increase heat production as much as possible. Over time these physiological responses, or cold shock response, can lead to adaptations like decreased inflammation, improved mood and cognition, improved metabolic health. Also, with time the body reduces the cold shock response because it adapts to practice.
You know how when you immerse yourself in cold water you gasp and you start breathing fast and shallow? This is part of the cold shock response. It is known that if you engage in cold exposure regularly your body will get used to the cold and this effect will be reduced. One study conducted with young healthy men examined how long it would take for that to happen. Twelve men were split in two groups. The first group did two 3-minute-long cold-water immersions at 10°C with four days in between. The second group did the same but on the in-between days they did a total of six more 3-minute-long immersions at 15°C. On the fifth day the second group presented 49% decreased respiratory frequency and 15% decrease in heart rate compared to the first day. Now this is adaptation!
Brown fat
People have three types of body fat tissue: white, beige and brown. They have different functions. White fatty tissue, which is the one we normally have most of, is responsible for storing fat and releasing it as energy when needed. Brown fat is involved in thermogenesis (burning fat to warm up the body when it's cold). Beige fat can have the properties of both depending on environmental needs.
It is known that cold exposure activates brown fat. One study found that after twenty days of two hours of cold exposure per day the participants (healthy men) had 45% increase in brown fat volume and their bodies were burning more than twice the amount of brown fat for heat than before. This suggests that cold exposure could potentially affect metabolism and improve metabolic health.
Metabolic health
Metabolic health relates to the ability of your body to perform metabolic functions. For example digesting the food you eat and absorbing the nutrients without abnormal spikes in insulin levels or blood sugar, without causing inflammation. You know how there is always this one guy who wears shorts in the winter and is not cold? Well, it could be because his body makes good use of fat and burns it to warm him up rather than keep storing it for future needs.
One study found that overweight men with type 2 diabetes had improved insulin sensitivity after cold exposure suggesting that regular cold exposure could aid in weight loss but still, more studies are needed.
Exercise and cold exposure
Cold exposure (cold showers, ice baths) is often used after workout to aid recovery and reduce inflammation. But bear in mind that hot and cold exposure have different effects and you have to think about what your goal is when using either of both as a therapy.
If you are training for strength, cold exposure after workout could be a great addition because it can reduce inflammation and you would be ready to hit the gym next day again. If you are training for muscle building, note that for muscle growth to happen there needs to be inflammation. And since cold exposure reduces it, your muscle gain would slow down. Heat exposure however, for example a hot shower or sauna, temporary increases inflammation which is exactly what you need to grow muscle. Different temperatures can affect us in many ways and I personally find the topic very interesting. More research is needed for the potential use of cold exposure to treat metabolic diseases.
As always, thank you for reading! References: