I’m sure you’ve noticed that cold sponges and showers are gaining popularity these days, but this isn’t just a passing trend; it’s here to stay.

In the wonderful world of biohacking and human optimization aimed at unlocking our fullest potential, the concept of hormetic stressors has garnered significant attention. These stressors, including cold plunges, saunas, and HIIT workouts, are potent tools that condition our physiology to thrive when faced with challenging circumstances.

If I were to pick one biohack, cold immersion therapy would be at the top of my list, even surpassing saunas. In this article, we’ll go on an in-depth journey into the world of cold exposure, exploring how it can enhance your resilience, longevity, and overall well-being.

Benefits of Cold Showers & Ice Baths

Cold showers and ice baths reduce anxiety, boost energy and immunity, improve mood, and foster longevity.

1. Increased Dopamine: Cold showers can lead to a significant increase in dopamine concentrations in the brain, impacting cognitive function and memory. Cold therapy releases norepinephrine from our adrenal glands which activates the brain’s energizing dopamine system. One study found a 530% increase in norepinephrine and a 250% increase in dopamine in subjects who were immersed in chilly water for just a few minutes.
2. Reduction of Cortisol: Cortisol, the stress hormone, is reduced with cold shower therapy. Lower cortisol levels can help with metabolism, inflammation reduction, blood pressure regulation, and memory formation.
3. Analgesic Effects: Cold showers have been reported to provide pain-relieving effects, making them a potential natural remedy for pain management.
4. Improved Sleep Patterns: Cold showers may contribute to better sleep quality, promoting restful and rejuvenating sleep. Better sleep means higher quality of life.
5. Enhanced Energy Levels: Participants in a study reported increased perceived energy levels, akin to the effects of caffeine, after consistently incorporating cold showers into their routine.
6. Better Mood. Your skin, the body’s largest organ, is equipped with cold receptors. When exposed to cold water, the skin sends numerous electrical signals from its peripheral nerve endings to the brain. This process has been demonstrated to alleviate symptoms of depression and anxiety.
7. Happier Human Beings. A study conducted in the Netherlands with more than 3,000 participants which revealed that consistently ending a shower with 30 seconds of cold water resulted in a 29% reduction in self-reported sick leave from work.

The Rules Of Cold Immersion Therapy

1. Stress Up to Stress Down

The fundamental principle of exposure therapy is simple – stress your body to build resilience. Cold plunges follow this principle by subjecting your body to extreme cold, triggering a cascade of physiological responses.

2. Efficient Heating and Cooling

The ultimate goal of cold therapy is to turn your body into an efficient heating and cooling system. It’s about training your body to adapt swiftly to temperature changes, a crucial skill for survival.

3. Avoid Adaptation

Keep the stimulus of cold exposure fresh by avoiding adaptation. Changing the intensity and duration of cold sessions can help maintain their effectiveness.

How Cold Immersion Lights Our Metabolic Furnace

Cold showers and ice baths stimulate the growth of brown fat.

Brown adipose tissue (brown fat) is a unique type of fat in our bodies with a special job: it helps generate heat to keep us warm. Think of it as our internal heater. Unlike regular white fat that stores energy (and gets us literally, fat), brown fat burns calories to produce heat.

This is especially important when we’re exposed to cold temperatures. When it’s cold, our brain signals brown fat to kick into action, and it starts burning fat to create warmth. This not only helps us stay cozy but also has some extraordinary health benefits.

Brown fat gets its name from its appearance, which is due to a high density of iron-containing mitochondria—the cell’s powerhouse responsible for energy production. These mitochondria give brown fat a brownish color, in contrast to the whitish appearance of white adipose tissue.

Now, here’s where it connects to cold immersion therapy: exposing ourselves to cold, like taking cold showers or swims, can activate our brown fat. It’s like giving it a workout, making it more efficient at burning calories and improving our metabolic health.

Brown Fat Activation With ‘The Drop’

One of the central mechanisms of cold exposure is “the drop.” When you enter cold water, your core temperature decreases kickstarting a process called peripheral vasoconstriction. This prompts blood vessels to constrict, reducing blood flow to the skin and limbs to preserve warmth in your core to protect vital organs.

Once you exit the cold, peripheral vasoconstriction ends and the cold blood from your limbs and skin starts to return to your core, mingling with warmer blood. This cycle of temperature change, known as “the drop,” is the key to the magic of cold plunges.

It’s during this phase that your body starts to shiver, a mechanism that helps generate heat to warm up your body often activates brown fat.

Shiverrrrring In Thermogensis

As your core temperature decreases during the ‘after-drop,’ the body relies on various mechanisms to restore warmth. Brown fat generates heat through a process called thermogenesis, which consumes calories and, in turn, enhances your metabolic rate.

In essence, the ‘after-drop’ stimulates brown fat activation, which helps raise your metabolism and burn more calories to compensate for the drop in core temperature. This metabolic boost not only aids in rewarming your body but also contributes to improved insulin sensitivity and overall metabolic health.

Insulin Resistance: A Global Epidemic

Insulin resistance, or reduced insulin sensitivity, is indeed a global health concern, and a root cause of many diseases. It’s a condition where your body’s cells don’t respond effectively to insulin, leading to elevated blood sugar levels. This condition is a significant contributor to obesity and type 2 diabetes, which are major health problems worldwide.

When brown fat is active, it burns calories, and this can contribute to weight loss. Plus, it improves our body’s sensitivity to insulin and is one of the 3 trifectas of wellness you need to measure, along with hormones and nutrition deficiencies Poor insulin sensitivity is linked to various health issues, including obesity, type 2 diabetes, and heart disease.

The Release of Fat-Burning Hormones

Taking cold showers or ice baths can activate Irisin and FGF21, which work together to promote fat loss and improve your metabolism. Irisin helps convert white fat into energy-burning brown fat, while FGF21 enhances insulin sensitivity and encourages the utilization of stored fat for energy.

1. Irisin: Irisin is a hormone that is primarily produced by your muscle cells during exercise, especially when you engage in intense physical activity. When you expose your body to cold temperatures, such as during an ice bath, it can also trigger the release of Irisin. This hormone has a remarkable ability to convert white adipose tissue (commonly known as white fat) into brown adipose tissue (brown fat) or beige fat. Brown fat is highly metabolically active and is known for its capacity to burn calories to generate heat. So, the more Irisin you produce, the more your body tends to convert energy-storing white fat into energy-burning brown fat.
2. FGF21 (Fibroblast Growth Factor 21): FGF21 is another hormone that is secreted by the liver and adipose tissue (fat cells). It is involved in regulating various metabolic processes, including glucose and lipid metabolism. Ice baths can also lead to an increase in FGF21 levels. This hormone helps improve insulin sensitivity, which means your body becomes more efficient at utilizing glucose (sugar) for energy instead of storing it as fat. Additionally, FGF21 can enhance the breakdown of fatty acids and the oxidation of fat, contributing to weight management.

How Cold & How Long?

While research shows that there are benefits achieved at 32°C (89.6°F), the results are far more substantial at 14°C (57.2°F). As an example, dopamine concentrations increased by 250% at 32°C, but saw a 530% increase at 14°C.

The optimal duration for cold exposure, such as cold showers or cold baths, can vary depending on individual tolerance and specific health goals. Here are some general guidelines:

1. Start Slowly: If you’re new to cold exposure, begin with shorter durations to allow your body to adapt gradually.
2. Beginners: Aim for a minimum of 11 minutes of cold plunge therapy per week, divided into 1-3 sessions. Combine this with 57 minutes of sauna therapy per week for a balanced approach. Work your way up.
3. For The Committed: Aim for 3-6 minutes every morning upon waking, before coffee, and exercise. There seems to be no more added benefits after 6 minutes.
4. Tailor to Goals: The duration can also depend on your goals. For general health benefits, shorter exposures may be sufficient. If you’re specifically targeting increased brown fat activation or cold adaptation, longer exposures may be beneficial.
5. Listen to Your Body: Always pay attention to how your body responds. If you experience excessive shivering, numbness, or discomfort, it’s essential to warm up.
6. Frequency: Consistency is key. Aim for daily or regular cold exposure sessions for the best results.
7. Combine with Heat: Some people practice contrast therapy, alternating between hot and cold exposures. In this case, you can start with shorter cold exposure periods since you’ll be transitioning back to warmth. Combine your ice bath with 57 minutes of sauna therapy per week for a balanced approach.
8. Avoid ice baths right after a workout— it may decrease your gains in strength and muscle growth.

*Cold exposure can be extremely uncomfortable in the initial 20-30 seconds as your brain adapts. Push through this phase to reap the rewards.

It’s important to emphasize that individual tolerance varies, and what may be comfortable for one person might be challenging for another. Always prioritize safety and gradually build up your cold exposure duration over time. Consulting with a healthcare professional before starting cold exposure, especially if you have any underlying health conditions, is advisable.

Tip: Use Mantras To Get Into A Cold Shower

One effective trick I rely on involves using mantras—simple words or phrases that act as triggers to program your brain for action. Personally, I tell myself, “just do it” or “now or never,” and with that mental reinforcement, I fearlessly step into a cold shower without hesitation.

In fact, I first started using mantras back in 2007 when I began my fitness journey, right before each CrossFit workout. Over time, “just do it” became hardwired into my brain as the go-to mindset whenever I face something uncomfortable.

10 Ways To Activate Brown Fat with Cold Immersion

Don’t let fear of bad weather hold you back. Ironically, staying sheltered in your comfortable home or car could be more detrimental in the long run, as it won’t help you build resilience. Here are some suggestions; choose one and take that first step today!

1. Cold Exposure: Exposure to cold temperatures, such as cold plunges, showers, or swims, can activate brown fat as your body tries to generate heat.
2. Cold Showers: Start with a blast of freezing cold water. Start with 10 seconds and work your way up to a minute. Take your regular warm shower. And end with cold— this is extremely important! People misunderstand cold showers. Your entire shower does not have to be cold— the point is being able to feel comfortable when you switch from hot to cold.
3. Ice Baths or Cold Plunges: Fill a bathtub with cold water (ideally around 57.2°F or 14°C) and immerse your body for 3-6 minutes, gradually increasing the time as you become more accustomed to the cold. After that, there are very little benefits. If you sit in there for too long, you’ll adapted to the cold water which isn’t the point— we want to shock your system.
4. Outdoor Exercise: Instead of hitting the gym, exercise outdoors in bad weather— even in the rain and snow. Jogging or doing calisthenics in the park during the winter can help activate brown fat. As we say, “there’s no such thing as bad weather, only improper gear.” This is the BEST way to build grit.
5. Winter Sports: Engaging in winter sports like skiing, snowboarding, or ice skating exposes you to cold temperatures and activates brown fat.
6. Cold Walks: Go for brisk walks in cold weather, wearing lighter clothing to allow your body to feel the cold. Gradually extend the duration and exposure.
7. Cold Work Environments: Jobs that require working outdoors or in cold conditions, like construction or farming, can promote brown fat activation. Have you noticed that those who have been exposed to manual labor outdoors when they were young are leaner and healthier in their 70s and beyond?
8. Cryotherapy: Visit a cryotherapy chamber, where you’ll be exposed to extremely cold temperatures for a short period. Consult a healthcare professional before trying this.
9. Intermittent Cold Exposure: Incorporate intermittent cold exposures throughout the day, like going outside without a jacket for a few minutes. I personally like to bring my laptop out to the patio to work in the winter time and I’ll stay out there until my fingers freeze. 😛 Be obsessed with the outdoors.
10. Cold Sleeping Environment: Keep your bedroom cool, ideally between 60-67°F (15-20°C), to stimulate brown fat activity during sleep.

Get Out Of Your Comfort Zone

If you’re one of those people whose always cold and instinctively reach for a jacket at the slightest breeze, it’s time to step out of your comfort zone.

Triggered? Good. Listen up. If it wasn’t a problem, you wouldn’t be triggered. Triggers are a good thing— it’s your brain’s way of telling you to PAY ATTENTION.

Continuously seeking warmth may keep you in a state of physiological weakness. To thrive and build resilience, you must expose yourself to intentional stressors like heat therapy and cold immersion. Don’t be scared. It’s not gonna kill you. In fact, your comfort zone will kill you.

TL;DR – Biohacking Resilience: Cold Immersion

1. Cold immersion therapy offers numerous benefits, including increased dopamine, reduced cortisol, analgesic effects, improved sleep, enhanced energy levels, better mood, and reduced sick leave.
2. Cold exposure activates brown fat, a calorie-burning tissue that enhances metabolism and insulin sensitivity.
3. “The drop” during cold exposure stimulates brown fat activation and thermogenesis, resulting in increased metabolism and calorie burn.
4. Irisin and FGF21 hormones, released during cold exposure, help convert white fat into energy-burning brown fat and enhance insulin sensitivity, facilitating fat loss and improved metabolism.
5. Start with short cold exposures and gradually increase the duration for optimal cold immersion therapy.
6. Employ mantras to mentally prepare for cold exposure and overcome discomfort.
7. Activate brown fat through cold showers, ice baths, outdoor exercise in bad weather, winter sports, cold walks, working in cold environments, cryotherapy, intermittent cold exposure, and maintaining a cool sleeping environment.
8. Stepping out of your comfort zone and embracing discomfort is essential for building resilience and overall well-being.
9. Cold exposure helps build physiological resilience, enhancing your ability to thrive under challenging conditions.
10. Cold showers can increase norepinephrine and dopamine concentrations in the brain, impacting cognitive function and memory.
11. Reducing cortisol levels through cold therapy can benefit metabolism, inflammation reduction, blood pressure regulation, and memory formation.
12. Brown fat activation contributes to weight loss and improved insulin sensitivity, addressing global health concerns like obesity and type 2 diabetes.
13. Improved insulin sensitivity is vital for health, as poor insulin sensitivity is linked to obesity, type 2 diabetes, and heart disease.
14. Get out of your comfort zone and incorporate daily cold water immersion into your routine— best if combined with sauna therapy. You won’t regret it!