13. Cold Exposure: Why and How to Do It

TL;DR: Take a cold ass shower for a few minutes each day and learn to relax under it to take control of your nervous system and become stronger mentally and physically.

Introduction

Most of us lead comfort-centric lives nowadays far from the ravages of nature. This lack of stress that our ancestors were exposed to has made us weak and susceptible to disease. In addition, most people experience a state of chronic stress that wears their bodies down and makes them even more susceptible to stress over time. Cold exposure is an excellent way to both give us beneficial stress, and control our chronic stress response.

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Cold exposure activates deep areas of the brain like the brain stem, causing it to release compounds like adrenaline, opioids, and endorphins. Our bodies also create much more mitochondria in our muscles, and turn our white fat into brown fat to help us heat up. Further benefits include strengthening the immune system by creating more white blood cells, and likely strengthening the cardiovascular system. Perhaps most importantly, the cold has a powerful psychological effect of teaching us control over our fight or flight impulse, which can greatly reduce our chronic stress day to day. For more on stress management, check out our articles being present, gratitude, and meditation.

This article will outline what cold exposure is, an understanding of how to use stress to our advantage, the benefits of cold exposure, and an easy cold exposure routine to suit most people.

What Is Cold Exposure?

Cold exposure is exposing the body to low temperature stress in order to make it stronger.

Typically, one exposes oneself to temperatures between 0 – 15 celsius / 32 – 60 fahrenheit or lower by submerging oneself in water or exposing oneself to air for anywhere from seconds to hours [1]. Typically cold water exposure lasts between 1 and 10 minutes, and cold air exposure can last hours.

Cold exposure has been used in naturopathic medicine since ancient times, including in India, Egypt, China and other places [2].

Good Stress & Bad Stress

As we have become civilized, we have increasingly distanced ourselves from raw nature and its difficulties. As we built up technologies that made our lives more and more comfortable, we shrunk our comfort zone and reduced the stress on our bodies from infection, temperatures, predators and more. Our bodies adapt to whatever they are exposed to, and so by erecting barriers between us and nature we reduce the stress on ourselves. Our bodies have adapted to this reduced stress by gearing down its resilience since that strength is no longer needed – a “use it or lose it” type of deal.

We often hear of stress in a negative connotation and we are told it’s good to “de-stress” and “cut down on stress”, or “stress kills”, which is true to a certain degree. However, it is more important that we focus on the amount of stress we are exposed to, and the type.

Amount of Stress

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Too much stress for any person is damaging. On the flip side, without stress, we become like the mindless and soft people from WALL-E. If we want to be our best, we don’t want a zero stress lifestyle. In fact, the only way to get stronger in any way – physically, mentally, or spiritually is through exposing ourselves to stress. Right in the goldilocks zone we have something called eustress – the optimal amount of stress to make us strong, but not wear us out.

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Type of Stress

Our nervous system operates in two modes: sympathetic mode (fight or flight), and parasympathetic (rest and digest). We ideally alternate between the two by entering sympathetic when we need to exert effort, and then healing and rebuilding after that effort in parasympathetic mode. Running from a tiger could be seen to be the ultimate sympathetic mode, and sleeping could be seen as the ultimate parasympathetic mode.

Chronic stress is reacted to much differently by your body than intense bursts of stress – aka acute stress. Chronic stress comes from being constantly worried or upset about something like work, relationships or existentialism, and this stress can last for the entire day. This long term stress keeps your body in sympathetic mode, which means it is not in the ideal state to rest and repair. Over long periods of being in predominantly sympathetic mode, our body wears down making us weak and susceptible to diseases of all kinds.

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Acute stress on the other hand, like running, lifting weights, exposing ourselves to cold or heat, or making a big presentation all occur over short periods of time. We are designed for this stress because we have a long history of needing to be – think running from a predator, or hunting. After the burst of stress is over, we can return to being fully relaxed, which allows our parasympathetic mode to take over and we recover quickly. As we recover, our body becomes stronger so that next time this same stress is easier for us to handle.

Both chronic and acute stress can be overdone, but it is almost always the chronic stress that harms us since acute stress usually takes a lot more effort to overdo. Occasionally, we find someone who overtrains in their workouts generating too much acute stress, but that usually only applies to extreme cases like Olympic athletes. Long bouts of cardio can also overtax our bodies, and similarities can be drawn between excessive cardio (think marathons), and chronic stress in that it lasts too long and overall is too much volume of stress burden for us. Some call this chronic cardio.

Optimal Stress Training

To make things simple, good stress causes you to build back stronger after, and bad stress – too much or for too long – causes you to break down and get weaker.

So we don’t want to be WALL-E blob people with no stress, and we don’t want to be pulling our hair out with chronic stress or overtraining ourselves. We want to train ourselves in the eustress zone with exercise, heat exposure like saunas, sunlight exposure, difficult mental problems, and…THE COLD.

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Just like when we lift weights, rip our muscle fibers, and then let them rebuild stronger, we also have an equivalent “cold muscle” that we can train. Cold exposure usually lasts for only a few minutes, but is very intense and can cause deep changes within our brain and physiology.

Read on to see what these effects are.

“Come inside before you catch a cold!”

Your mother yells out the door as you run around playing basketball with your brothers in jeans and a t- shirt while it’s just above freezing out. How many of us have heard of the idea that being in the cold makes us more likely to get sick? Is it true, or just a correlation?

Do ice cream sales cause shark attacks, or are both correlated with sunny days? [f]

Firstly, viruses like the common cold and flu seem to spread more easily in cold and dry weather. In fact, the flu seems to spread best in about 5^oC weather. We also tend to spend more time indoors, increasing our contact with each other and breathing of recirculated air. These could be factors to the old wives tale and it would make sense as colds and flus are more common in winter months.

Another factor would be how the cold affects your immune system itself. With the cold weather usually comes overcast skies, and a lower amount of vitamin D being made in the skin. Vitamin D is a key nutrient and hormone for our immune system. Another factor is that our blood vessels constrict when in the cold meaning less blood makes it to mucus membranes to fend off infection. All of these factors play into the link between cold weather and getting sick. [3]

When it comes to the cold itself though, it’s hard to find evidence that it weakens your immune system making you more susceptible to infections. Quite the opposite in fact, as it appears to strengthen the immune system substantially as your body builds up defenses to the cold.

What Are the Benefits of Cold Exposure?

The benefits of cold exposure stem from a term called hormesis. This is where exposure to stress yields benefits, like in the case of exercise and heat exposure. It does this by “waking up”, or activating a series of genes related to helping regulate stress. In other words, cold exposure changes our epigenetics just like exercise and other hormetic stressors. The benefits are not as well understood as other hormetic stressors like exercise and heat exposure, but we do have some insights, as you’ll see below.

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The beneficial effects of cold exposure include:

An increase in norepinephrine (similar to adrenaline) release, triggering many effects including creating mitochondria in fat cells
An increase in creation of new mitochondria in our muscle and fat cells which keep us warm and generate ATP, including changing our white fat into brown fat
A decrease in inflammation
A decrease in recovery time
An improvement in athletic performance
An activation of deep areas of the brain like the brain stem, which releases endocannabinoids, natural opioids, and endorphins – all pain relievers
Strengthens the immune system, including an increase in white blood cells and glutathione levels
An exercising of the cardiovascular system by constricting blood vessels to conserve heat

And perhaps most importantly, we learn to control our minds in the face of great stress which gives us much better control over ourselves day to day.

Norepinephrine and More Mitochondria

According to Rhonda Patrick who made a presentation at the Biohacking Convention, the most robust finding of cold exposure is the release of norepinephrine, which is a neurotransmitter important for mood and focus. It keeps us vigilant. This release of norepinephrine causes many changes in the body, including an increase in mitochondrial biogenesis – creation of new mitochondria in cells. This includes the well known effect of turning white fat into brown fat, which is just fat with so much mitochondria it looks light brown under a microscope. Norepinephrine also acts as a hormone and helps with vasoconstriction – making the blood vessels smaller so less blood makes it to our extremities. This helps us resist the cold.

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Here are a few cases to give you an idea of the changes happening in your body:

Participants exposed to 16 degree celsius air for 6 hours had an average of 260% increase in norepinephrine, and a 37% increase in browning of their adipose tissue
Participants exposed to 4.4 celsius water for only 20 seconds had an increase in norepinephrine of 200-300%
Men who put their legs in 10 degree celsius water for 10 minutes showed a large amount of mitochondrial biogenesis in their muscle cells

Your body creates large amounts of mitochondria to help generate heat and keep you alive in the cold. However, mitochondria don’t just make heat, they also make ATP, which you can use for a limitless amount of other activities including helping with athletic performance. This is especially true of mitochondria in muscle cells. There is evidence that mitochondrial biogenesis improves aerobic performance and cold exposure shows some evidence of improving sports performance and recovery.

However, cold exposure after lifting for hypertrophy (within an hour) does not benefit performance. This is because after you lift for hypertrophy, your body activates anti-inflammatory pathways and immune cells that help make Insulin-like Growth Factor (IGF) in muscle tissue, which is necessary for the anabolic effects. Cold exposure itself though is anti-inflammatory, and blunts this natural response by your body if done too soon after hypertrophy training.

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Brain Training & Stress Response Control

Perhaps the best part about cold exposure is training our minds. When we are exposed to cold, instinctively we go into fight or flight mode, however with training we can shift ourselves into a calm parasympathetic state. We can then bring this control into our everyday lives and drastically lower our stress.

The cold does more than just train our minds, it also activates our brain in a unique way by activating the brain stem – the deepest region related to survival in the “reptile” part of our brain. This is what controls the fight or flight response – aka control between the sympathetic and parasympathetic states. The cold also specifically activates something called periaqueductal gray matter (PAG) in the brain stem, which plays a central role in motivated behaviour and response to threatening stimuli. It also is the primary control centre for suppressing pain through activation of hormones and natural opioids.

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When Wim Hof, “The Ice Man”, put on an EEG while taking an ice bath as he was observed by scientists, his frontal cortex – responsible for everyday consciousness – became much less active and his brain stem and insula became quite active. His brain looked to be similar to those in meditation. This indicates that his brain was shifting from “human” thinking and stress mode into a relaxed state even during his cold exposure.

When Wim was on Impact Theory with Tom Bilyeu, he mentions that he was in a meditative state by doing nothing, “And finally, I began to realize, it is all in your mind. Learning to let go with the breath”. Tom was surprised Wim said it was about letting go, and not about battling through the cold. One key to the benefits of cold exposure is controlling this basic fight or flight response, and we can only do this by letting go, relaxing even in the face of freezing cold. Wim says you feel the cold, but when you learn to let go the endocrine system is strongly activated – releasing noradrenaline, endorphins, cannabinoids, and opioids – which all have very strong effects, including strong pain relief.

Wim says training in the cold trains you for all stress physical, emotional, or otherwise. In the cold, he learned his breathwork techniques, which he says oxygenates the body and goes past the “lymphatic knots”, which usually inhibits the oxygen’s ability to go deeper. As the oxygen gets deeper it alkalizes your blood, usually within a couple minutes. Then, when the blood is at this higher pH, the nervous system can send signals better to all the cells. This can be “stacked” with cold exposure to reap additional benefits.

Cold and Genetics

While on the show, Wim also commented on the genetic-level effects of the cold:

“The cells should be protected by proteins. But, because of our comfort zone behaviour, they are inactive. And thus, the inflammatory impulses through the transcription factors, just little assholes, who go into the cell and they begin to mess up the telomeres. And we live shorter… And we become vulnerable for the wrong genome expressions, and that causes diseases.”

The proteins he is talking about are likely cold shock proteins, which are similar to the heat shock proteins we mention in our article on heat exposure. Cold shock proteins are extremely important in our cells for regulating how our DNA gets transcribed – taking DNA and turning it into RNA instructions for the cell. This is the first step of epigenetics, or how our DNA is expressed. These proteins are found in almost all living things except fungi, and are one of the most conserved proteins in all living things, meaning evolution is saying no living thing wants to go without them.

Cold shock proteins regulate genetic expression related to many diseases, and improper functioning is linked with cancer and inflammation. Purported benefits of activation of these proteins includes protecting against brain cell damage, protecting cells from free radical damage and oxidative stress, muscle recovery and growth and DNA repair [5].

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The cold activates these protective proteins strongly. Taking bacteria and bringing their environment from 37 celsius to 10 celsius increases cold shock protein expression by 200 times within minutes [6].

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Strengthening the Immune System & Cardiovascular System

Cold exposure strengthens our immune system by causing us to increase the amount of white blood cells we have, and by increasing levels of a key antioxidant, glutathione. It does this by stressing our bodies. For example, our glutathione levels drop when we are exposed to the cold, then rise the next day as our body adapts for next time.

The cold also, through hormonal effects like those of norepinephrine, constrics our blood vessels and keeps our internal body warm. We have three times the world’s length in terms of veins, arteries, and capillaries in our bodies, so it is a very complex and intricate system to manage. Until recently, cardiovascular related diseases were the number 1 killer in the developed world. Wim says this is because we wear clothes and protect ourselves from the cold too much, and are never exercising our cardiovascular system. The cold causes us to really constrict blood vessels and adapt to the cold in many ways.

The Cold Is Powerful

Overall, we increase our strength and resilience to stress of all kinds by intentionally exposing ourselves to cold stress.

An Easy Cold Exposure Routine

The best way to do cold exposure is to start with what you can handle, just like in the gym or with any new stress. Your body needs time to adapt and make all those lovely mitochondria to keep you warm and your brain and nervous system also need to adapt to the shock of the cold. Start with 30 seconds or even 10 seconds of cold exposure. The easiest way for most people is to end their regular shower with a cold shower, preferably working up to the coldest setting for at least a couple minutes.

Here are some recommendations from beginner to advanced (practiced daily):

If it’s cold outside, try not to wear a coat or sweater for several minutes
End your regular shower with 30 seconds of cold at halfway to the coldest setting
End your regular shower with 2 minutes of cold on the coldest setting
Take a 5 minute cold shower on the coldest setting
Jump in ice water if available for 5 or more minutes

For the really crazy people, one tip is to buy a chest freezer, fill it with water and submerge yourself daily. See a guide from Ben Greenfield here.

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Tip: Breathe deeply and slowly into your diaphragm! Breathe IN the cold, don’t resist it. Take deep, slow, controlled breaths into your belly and learn to be calm in the freezing cold. This is part of the training. If you can be calm in freezing cold water, you can be calm all day.

Summary

Stress is good and bad. We want to limit chronic stress by engaging our rest and digest mode, and to activate our fight or flight mode in bursts of acute stress such as with exercise, heat exposure, and cold exposure. Cold exposure benefits us by training us to switch from fight or flight mode to rest and digest mode so we can heal and recover, and has many benefits for our brain and bodies.