By Dr. Mercola
While living in a climate-controlled environment has its benefits in terms of keeping us comfortable, it can actually have surprising impacts on health. There’s a compelling body of evidence showing exposure to harsh conditions can be highly beneficial. In fact, extreme temperature variations appear to help optimize many biological functions.
This is the time of the year, as we transition into winter, when you can take full advantage of the many magnificent benefits that regular cold exposure can have to improve your health. One of the mechanisms by which cold exposure or cold thermogenesis aids weight loss and reduces your risk of diabetes and other chronic disease is by inducing brown adipose tissue (BAT).
BAT, which is incredibly mitochondrial-dense, helps improve your mitochondrial function. One of the physiological functions of body fat is to be used as fuel to heat your body if you have active BAT metabolism. This is accomplished by uncoupling the mitochondria from producing ATP and actually producing heat instead. By regularly exposing yourself to cold, you build up a mitochondria-rich tissue in brown fat and help your body generate heat, which actually lowers your blood sugar and decreases insulin resistance.
Beige fat is a derivative of brown fat and is recruited through your white fat, which can then be used to heat your body and maintain a more active-passive metabolism. Indeed, the conclusion I reached after many decades of studying health is that burning fat as your primary fuel is a key to preserving and maintaining your health. There are a number of ways to reach this goal. You can do it through diet, and in my new book, “Fat for Fuel,” I explain how to do that. But there’s also a tremendous synergy with cold thermogenesis.
Cold Exposure Increases Whole-Body Metabolic Rate
A recent study1 in Bioscience Reports looked at the impact of cryotherapy — exposure to cold — on the mitochondrial structure in BAT and skeletal muscle, both of which are thermogenic sites. As explained in this study:
“Mitochondria are very dynamic organelles that undergo dramatic remodeling in response to increase in local energy demand within a cell. The mitochondrial architecture (including cristae density, compactness, length, shape, and size) is a reflection of their level of activity, and thus it is also an indicator of cellular energy status. It is believed that organs involved in thermogenesis within the mammalian body elevate their metabolism in response to cold adaptation.”
While BAT and muscle both generate heat, they do so using different mechanisms. In BAT, heat generation is based on mitochondrial metabolism. In muscle, mitochondrial metabolism plays only a secondary role by supplying energy to the muscle. In other words, mitochondrial metabolism is directly responsible for BAT-based thermogenesis, but only indirectly linked to thermogenesis in skeletal muscle.
Together, these differing thermogenic processes allow your body to maintain a constant core body temperature. As your body adapts to increasingly colder temperatures, several things happen, which together results in an increase in your overall metabolic rate:
Oxygen consumption increases
Enzymatic activity in the mitochondria of your muscle is upregulated
Fibroblast growth factor 21, IL1α, peptide YY, tumor necrosis factor α and interleukin 6 are induced, and appear to play an important role in coordinating the various physiological adaptations to cold, and in the cross-communication that occurs between BAT and muscle
Insulin and leptin are downregulated
BAT becomes browner
The number of mitochondria increases
Health Benefits of Cryotherapy
The fact that cold thermogenesis increases the number of mitochondria and improves their overall function accounts for many of the health benefits associated with cryotherapy. For example, cold thermogenesis has been shown to:2,3,4
Strengthen joint tissue
Support weight loss efforts by increasing metabolism
Increase blood circulation
Speed rate of recovery following joint or muscle injury6
Provide temporary relief lasting about 90 minutes from pain associated with arthritis7
Reduce pain and swelling following injury
Enhance benefits of physical therapy
Reduce pain associated with migraines when applied to the back of the neck for about 30 minutes10
Improve muscle function and strength
Boost mental focus and attention by increasing production of norepinephrine in your brain.
Norepinephrine can be increased twofold just by getting into 40 degree F water for 20 seconds, or 57 degree water for a few minutes11
In addition to increasing norepinephrine, cold thermogenesis also forces your body to produce cold shock protein, known as the RNA-binding motif 3 or RBM3, in your brain. Interestingly, when you’re exposed to cold, you actually degrade synapses (the connections between neurons), but RBM3 completely regenerates them. This has been shown in hibernating animals like bears and squirrels, and research shows that by increasing RBM3, Alzheimer’s onset can be significantly delayed — at least in rodents.12
Studies have also been done on human cells, showing that RBM3 does get activated when your brain cells are exposed to cold, and that the temperature change needed is only about 1.5 degrees Fahrenheit. More research needs to be done, but preliminary work such as this suggests cold thermogenesis could have a neuroprotective effect.
Common Cryotherapy Methods
There are a number of different cold thermogenesis methods available. Some high-end spas and gyms will have cryotherapy booths, along with saunas. But you can also take advantage of cold thermogenesis at home by:
Applying an ice pack or cold gel pack
Applying an iced towel (simply wet a towel and freeze it) or massaging the area with ice cubes
Taking a cold shower or alternating between cold and hot in your shower
Taking an ice bath
Exercising in cold weather wearing few articles of clothing
Jumping into an unheated pool following sauna or exercise
Bathing in the ocean when water temperatures are low
Turning down the thermostat in your house in the winter to about 60 F
Keep in mind that cold thermogenesis treatment should not last for more than a few minutes, to 10 or 20 minutes after you have acclimated, and is contraindicated for pregnant women, young children, those with high blood pressure and/or a heart condition. Cold causes acute vasoconstriction, which can be potentially dangerous if you have high blood pressure or heart failure. A quick cold shower would probably be OK, but avoid ice baths or other extreme cold water immersion techniques.
As a general rule, listen to your body. Individual tolerance for hot and cold temperatures vary widely, and if you push it too far you can do yourself harm. That said, over time you will become acclimated to the cold, which will allow you to withstand colder temperatures for longer periods of time.
Wim Hof, aka “The Iceman,” is a perfect example of this. He’s exposed himself to cold on a daily basis for decades. As a result, he’s now able to withstand the cold for much longer periods than one might consider normal, because his body can generate more heat.
Again, the ability to generate more heat is a direct result of increased BAT and, secondarily, improved thermogenesis in your skeletal muscle. The more mitochondria you have in your fat tissue, the more fat you’re able to burn and the more heat your body can generate, which translates into an increased ability to withstand cold for longer periods of time.
One of the simplest ways to improve your BAT metabolism is taking cold showers, which you can do on a daily or near-daily basis. The initial tensing you experience is part of your body’s attempts to heat itself back up. Try to suppress this initial instinct and relax instead. Just how long it takes to build up BAT is still unknown, but we do know that BAT is generally a seasonal tissue.
In the winter, your body generates more of it as a way to boost its ability to stay warm. In the summer, you have less. A primary issue is, how often do you activate it? Without environmental stimuli, meaning exposure to various temperature extremes, your body will not create this metabolically or energy-rich tissue since it has no reason to do so. Taking an ice-cold rinse each day, year-round is a simple way to consistently activate your BAT metabolism.
When to Avoid Cryotherapy
There is one important caveat worth mentioning. When you’re doing strength training, the oxidative stress generates reactive oxygen species (ROS) that actually help increase muscle mass. If you expose yourself to cold within the first hour after strength training, you suppress that beneficial process, so avoid doing cold immersion (such as a really cold shower or ice bath) immediately after strength training.
On the other hand, spending some time in the sauna after exercise may actually help increase muscle mass. It’ll also help with detoxification, allowing you to sweat out toxins that can wreak havoc on mitochondrial function in general. As explained by Rhonda Patrick, Ph.D., in a previous interview:
“This is what’s important to understand: Exercise is a stress on the body. You’re making ROS. You’re generating inflammation. But that’s a good thing because it’s a short burst, and you want it … There’s a one hour timeframe from the time you stop exercising [in which inflammation peaks].
That is the stressful period. But then as soon as an hour hits, the stress response kicks in and you start to have a potent anti-inflammatory [response]. You start having an antioxidant response from activating all these good genes that stay activate for a long time.
What happens is that because the cold also is causing an anti-inflammatory response, it’s important that you don’t get that anti-inflammatory response too soon, because you need some of that exercise-induced inflammation. You want that inflammation to happen to get the anti-inflammatory response. That’s important for the strength training.
The inflammation you generate during the strength training is part of the mechanism for making more proteins in the skeletal muscle. If you blunt that, then you’re going to blunt the effects of the strength training. The question is then can you do it an hour or two hours later? Studies have shown, yes, you can do cold exposure, cold water immersion and actually get some performance enhancements even from doing [that].”
Cold Thermogenesis Is a Simple Way to Optimize Your Health
When it comes to improving your health, many of the simplest strategies can have a significant impact. Regularly exposing yourself to cold temperatures can catalyze a wide variety of beneficial changes in your biology that can go a long way toward optimizing your health.
One of the things I do regularly, nearly every day when I am home, is to take a 30-minute 170 degree far-infrared sauna and then jump in an unheated pool and swim five laps. In the summer the water is in the 80s but it can go down to the 40s in the winter. It is absolutely amazing how good you feel after coming out of the pool when it’s winter. It’s incredibly invigorating.
Regularly exposing yourself to these kinds of extreme temperature variations will help improve your mitochondrial function, which we have now come to realize is a foundational aspect of good health, disease prevention and longevity.
Remember, mitochondria are the energy generators in your cells, and if they are not functioning well, or if damaged ones are not efficiently replaced by new, healthy mitochondria, any number of health problems are sure to ensue. Cryotherapy is one effective form of mitochondrial therapy. A number of other strategies, including dietary interventions, is detailed in my book, “Fat for Fuel.”