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7-Day Cold Challenge

If you were to take a time machine back to the days when your ancient ancestors roamed the earth, daily life would look a lot different. 

While modern technology has allowed for many advances in society, it hasn't necessarily set our bodies up for physical and emotional health. 

In this article, you'll learn:

  • How our ancestors exposed themselves to stress in a good way
  • The benefits of cold-water exposure
  • The best way to start living in alignment with your biology
  • Tips for getting your body back into harmony

What's A Cold Plunge?

Put simply, a cold plunge involves immersing yourself in cold water for specific intervals of time to generate a hit of physical stress to your body. 

Now, you may be thinking, why would I inflict such pain on myself? If you're someone who enjoys the comforts of a modern world, the idea of putting your body through the discomfort of cold water probably sounds like a masochistic experiment that you gladly pass on. 

However, from an ancestral perspective, there are some pretty compelling reasons to push your physical limits and induce a little bit of "unwanted" stress. 

If you imagine how your ancient relatives lived, they would constantly be pushing their physical limits and testing their emotional strength against their immediate environment. They would expose themselves to all sorts of stressors, from extreme heat and cold to prolonged fasting, not to mention the discomfort of sleeping on the earth instead of a warm, cozy bed. 

Although it may not seem ideal to us modern folk, what this gave our native ancestors is something that we gravely lack today -- and that's resilience. 

Research shows that today our lifestyles lack certain physiological stresses that were experienced for millions of years of evolution by those who came before us. As a result, we have lost the capacity to bounce back, withstand pressure, and be resilient in the way our ancestors would be[1]

However, when you take a cold plunge, it activates ancient mechanisms in your body that signal an acute and very helpful stress response. While you may be used to a comfortable temperature that ranges anywhere between 65 and 75 degrees, immersing yourself in cold water sets off a cascade of processes that tells your body it's time to toughen up. 

In this way, frequently doing a cold plunge or a cold shower starts to build your "anti-stress muscles." 

On a genetic level, your body wants you to eat, move, and live in harmony with your biology, and engaging in a cold plunge or shower is an excellent way to start.

7-Day Cold Challenge

A 7-day cold challenge is an excellent way to introduce yourself to the benefits of cold-induced stress. 

While cold plunging is traditionally done in an ice bath, for most people, the place to start is in the comfort of your own shower. Simply turn the dial to the coldest temperature you can, and allow the water to rush over you for 30 seconds, switch it back to warm water, then repeat.

If you want to reap the physical benefits of a cold plunge, all you need to do is expose yourself to the cold water. However, if you want to optimize the physiological benefits, use your breath to relax into it. 

Your first instinct will be to resist the discomfort, but as you allow yourself to relax and breathe into it builds mental strength and resilience that will have a ripple effect on your everyday life. 

You'll quickly learn that the resistance you have to cold water is really all in your head. Once you understand this and experience the ability to allow yourself to be in the cold water, you'll see that the same thing applies in real-life situations when stressful things happen. When you can learn to relax your body, you will think more clearly and become more alert instead of fighting and resisting whatever is coming your way. 

The Benefits Of A Cold Plunge

Aside from the internal emotional strength you build from withstanding cold temperatures; there are several research-backed health benefits to further motivate you to take the plunge. 

These include:

#1 Enhanced Fat Burning

Your body is always working hard to maintain homeostasis in specific areas -- pH, weight, immunity, and of course, temperature. Therefore, when you put your body into a situation that shocks the system out of its comfort zone, it responds rapidly.

In the case of cold temperature, something called cold-induced thermogenesis (CIT) kicks on. CIT is your body's ability to generate heat by increasing your metabolism in response to cold temperatures. This allows your core temperature to remain stable[2].

Research shows that when you expose yourself to cold temperatures, this elevation in metabolism can improve your body's ability to burn fat. In fact, cold temperatures increase the amount of brown fat in your body, which is a type of adipose tissue that's activated when you get cold.

Weight loss results from burning more calories than you take in, and brown fat has a primary job of burning calories from glucose and fat to help you maintain your core temperature. In fact, brown fat is "brown" due to the abundance of energy-burning mitochondria it contains[3][4]

#2 Improved Circulation

Another adaptive strategy by your body to maintain core temperature is to enhance internal circulation. 

When your body senses cold temperatures on your skin, it activates compensatory vasodilation (blood vessel dilation) in the deeper tissues of your vascular system, as a result, you get increased blood flow, blood pressure, and heart rate[3][5].

#3 Elevated Mood

While stress is often thought of as a bad thing, research shows that a certain amount of stress, referred to as eustress, is actually normal and even beneficial for you. We're not talking about the stress you experience from a heated argument or hours of sitting in traffic, but the physiological stressors that your ancestors would have dealt with, like changes in body temperature. 

Research shows that when we remove these types of stressors, it results in inadequate brain function and can lead to issues like depression and other psychological conditions. 

In studies evaluating the impact of cold water immersion on mood and psychological health, scientists have discovered that experiencing cold temperatures activates the sympathetic nervous system and increases levels of the feel-good endorphin hormones. 

What's more, due to the high intensity of cold temperatures on the skin, a cold shower may send an overwhelming amount of electrical impulses to the brain, which could crowd out neurotransmitters involved in psychological disorders. Some researchers even suggest that the results may be similar to electroconvulsive therapy -- although much less invasive[1][5].

#4 Enhanced Alertness

When you take a cold shower, the first thing you'll notice is an instant jolt of energy. There's nothing to wake you up quite like a hit of cold water to the body. 

Research shows that cold immersion engages parts of your brain associated with self-reflection and facilitates internal focus, along with sustained attention. What makes this neuro-mechanism so fascinating is that these areas of attention and alertness are not just activated in waking states but are able to stay sustained in the presence of averse external stimuli (such as an ice bath)[6]

#5 Improved Immune Function

The impact of cold-induced stress on your immune system is truly astounding. 

Your immune system's number one function is to stay alert and jump into action when something out of the normal happens. Of course, a rapid change in body temperature is certainly something out of the normal.

Research shows that daily cold stress can increase the numbers and activity of immune cells and messengers involved in innate and adaptive immunity, such as cytotoxic T-lymphocytes, tumor necrosis factor-α, IL-2 IL-6, and NK cells[5].

#6 Reduced Inflammation

Studies in healthy individuals show that cold exposure can decrease systemic inflammation, which would make sense due to the influx of immune cell activation that comes with cold stress. 

However, evidence also suggests that even those with chronic inflammatory conditions can benefit from the anti-inflammatory effect of a cold plunge. 

In one study, a group of patients with axial spondyloarthritis (inflammatory arthritis that primarily impacts the spine) underwent a cold plunge trial for eight weeks to assess the impact on inflammatory markers. The researchers reported that after the 8-week trial, inflammatory markers for the disease (C-reactive protein and ESR) had significantly decreased. This study has paved the way for future research into the anti-inflammatory impact of cold-induced stress[7]

Other Ways To Get Your Body Back Into Harmony 

While your native ancestors may have had to go without some of the modern comforts you're used to (a comfortable bed, thermostat, an abundance of food), one thing they didn't have to worry about is actively keeping their bodies in homeostasis. 

As you can imagine, your ancestors wouldn't have to weigh the decision as to whether or not they were going to turn the dial on the shower to experience a hit of cold. For them, cold water may have been the only option. As such, life presented stressors for them, and their body had no choice but to plow through them and reap the benefits. 

They also never had to worry about eating too much sugar, processed foods, or trans fat -- they ate what they could forage, kill, or capture, and that was the end of the story. 

Today, things are a little different. That's why it's crucial that you actively keep your body in homeostasis by engaging in lifestyle habits that support your health and help you to break the mold of modern comforts here and there. 

Some simple ways that can help your body get back into harmony include:

#1 Collagen Supplements

When your ancestors made a kill, they didn't parse out the best "cuts" of meat and throw the rest away. With food being a scarce commodity, you can bet that they ate every part of that animal -- head to toe. 

Today, we skip the tendons, organs, cartilage, and connective tissue and enjoy only the meatiest cuts of the animal. Although our meals are undoubtedly more delicious, we lose out on crucial nutrients found in other parts of the animal. 

Collagen is one such nutrient that research shows can enhance bone mineral density, support the health of your joints, and improve skin elasticity and hydration[8][9][10]

By incorporating collagen into your diet, you're bringing yourself a step closer to a diet that resembles what your ancestors would have consumed. 

#2 Extended Cold Water Immersion

Once you've got yourself used to your 30 seconds on, 30 seconds off cold shower, it's time to kick it up a notch. 

You can enhance the benefits of cold-induced stress by slowly ramping up your time in the cold by 15-second increments. You can eventually bump up your cold shower from 30 seconds to 60 seconds, to 90 seconds, and until you reach a full three minutes of cold water immersion. 

#3 Nutrition

Aside from collagen supplementation, there are many ways to keep your diet clean and enhance your body's ability to maintain harmony. 

First, as much as possible, if you're able to eat foods that are local and in season, you will be receiving nutrients that are meant to support your body in the climate you're in. Shopping at a farmers market is ideal as you can meet the farmers and talk about their quality standards -- non-GMO and organic is always best for produce. 

However, even in your local supermarket, you can pick up organic fruits and vegetables and, when possible, look for a sign that says "local."

Regarding animal products, quality is vital. When you see an organic label, it means that the animal was fed organic feed, but it also means they were not given antibiotics or hormones. 

Your ancestors would have never had to worry about the quality of their meat for obvious reasons, but today this can be an immense issue. When possible, always go for 100% grass-fed beef and free-range chicken and eggs.

#4 Stress Management

While on the one hand, this whole article is recommending that you find ways to increase your tolerance to physical stress, on the other hand, finding ways to minimize psychological stress is vital. 

Coldwater immersion can enhance your body's defenses and make you stronger, a fantastic example of the benefits of physical stress. Emotional stress, however, is known to exacerbate health issues like hypertension, cardiovascular disease, diabetes, and mental illnesses like depression and anxiety. 

Side effects of emotional stress can also include insomnia, digestive disturbances, hormonal imbalances, and immunological issues[11].

Therefore, while pushing your physical limits may benefit your health, pushing your emotional limits can be quite detrimental. 

If emotional stress is an issue for you, try stress management techniques like breathwork, yoga, meditation, or journaling. Even talking with a friend or finding ways to incorporate more laughter into your life can produce beneficial outcomes when it comes to stress management. 

#5 Sleep

One of the essential steps in keeping your body within its natural rhythm is to dial in your sleep schedule. 

Getting enough sleep is vital for the health of both your mind and your body. While you sleep, your body gets a chance to clean up shop and support healthy brain function, enhancing your problem-solving skills, memory, learning, emotional control, and mood. 

From a physical perspective, sleep allows for the healing and repair of your body tissues; it assists in balancing your hormones, supports growth and development, and much more. 

Research suggests that adults should aim for seven to eight hours of sleep per day, although this can vary slightly[12]


While there are many reasons to be grateful for the comforts of modern living, it's essential that we always remember our biological roots. Our ancestors had to weather the storm of the unknown and brave unexpected stressors like extreme temperatures and famine for millennia.

Today, we can get the best of both worlds by incorporating a little ancient wisdom into our daily lives. Although it may have to be an intentional act, giving your body a little positive stress (eustress) can provide immense benefits to both your physical and psychological health. 

I invite you to start with a 7-day cold challenge. Get in your shower and alternate between extreme cold and warm water for about 30 seconds, and prime your body for enhanced immunity, fat-burning, mood regulation, and decreased inflammation.


  1. Shevchuk, Nikolai A. "Adapted cold shower as a potential treatment for depression." Medical hypotheses 70.5 (2008): 995-1001.
  2. Brychta, R. J., and K. Y. Chen. "Cold-induced thermogenesis in humans." European journal of clinical nutrition 71.3 (2017): 345-352.
  3. Bleakley, Chris M., and Gareth W. Davison. "What is the biochemical and physiological rationale for using cold-water immersion in sports recovery? A systematic review." British journal of sports medicine 44.3 (2010): 179-187.
  4. https://www.nih.gov/news-events/nih-research-matters/cool-temperature-alters-human-fat-metabolism
  5. Mooventhan, A., and L. Nivethitha. "Scientific evidence-based effects of hydrotherapy on various systems of the body." North American journal of medical sciences 6.5 (2014): 199.
  6. Muzik, Otto, Kaice T. Reilly, and Vaibhav A. Diwadkar. "“Brain over body”–A study on the willful regulation of autonomic function during cold exposure." NeuroImage 172 (2018): 632-641.
  7. Buijze, G. A., et al. "An add-on training program involving breathing exercises, cold exposure, and meditation attenuates inflammation and disease activity in axial spondyloarthritis–A proof of concept trial." PloS one 14.12 (2019): e0225749.
  8. König, Daniel, et al. "Specific collagen peptides improve bone mineral density and bone markers in postmenopausal women—A randomized controlled study." Nutrients 10.1 (2018): 97.
  9. Bolke, Liane, et al. "A collagen supplement improves skin hydration, elasticity, roughness, and density: Results of a randomized, placebo-controlled, blind study." Nutrients 11.10 (2019): 2494.
  10. Bello, Alfonso E., and Steffen Oesser. "Collagen hydrolysate for the treatment of osteoarthritis and other joint disorders: a review of the literature." Current medical research and opinion 22.11 (2006): 2221-2232.
  11. https://www.nimh.nih.gov/health/publications/stress/
  12. https://www.nhlbi.nih.gov/health-topics/sleep-deprivation-and-deficiency

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Medical Disclaimer
This content is for informational and educational purposes only. It is not intended to provide medical advice or to take the place of such advice or treatment from a personal physician. All readers/viewers of this content are advised to consult their doctors or qualified health professionals regarding specific health questions. Neither Dr. Chad Walding nor the publisher of this content takes responsibility for possible health consequences of any person or persons reading or following the information in this educational content. All viewers of this content, especially those taking prescription or over-the-counter medications, should consult their physicians before beginning any nutrition, supplement, or lifestyle program.

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