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The New Science of Cold Exposure: Reduce Stress, Boost Immunity & Increase Resilience with Dr Susanna Søberg #322

Jan 4, 2023 2h 22m 15 insights
Cold showers, icy plunge pools, outdoor swimming – are you a fan, or does the very idea make you shiver? Today’s podcast is all about one of the biggest wellness trends of the past few years: cold water immersion therapy. My guest is Dr Susanna Søberg who is arguably one of the leading researchers on the topic. Susanna studied at the University of Copenhagen, looking at metabolism and the role of brown fat. Her research on the physiology of deliberate cold and heat exposure is helping to back up what many cultures have known instinctively for thousands of years – changing our temperature is good for us. Her new book Winter Swimming: The Nordic Way Towards a Healthier and Happier Life is a beautifully illustrated volume, which looks at cold-water traditions around the world and shares what incredible benefits they can provide for our health and wellbeing. In this conversation, Susanna talks us through the many physical benefits, from increased metabolism, immunity and lowered insulin resistance, to the potential to reduce excess weight and ease muscle and joint pain. The key player in all these benefits? Brown fat, a type of healthy fat stored around the spine that acts as our body’s temperature regulator, boosts metabolism and can even aid blood-sugar response and weight control. The more we expose ourselves to the cold, the more brown fat cells we have. So it’s a case of use it or lose it. There are also incredible mental health benefits from engaging with the cold. The very act of pushing out of your comfort zone and braving the cold can give you a sense of confidence. It releases mood-boosting hormones and exposes us to a form of ‘healthy stress’, building our resilience to modern life. It’s also the ultimate in mindfulness – a sensory experience that takes you out of your head and into your body. In 2021 Susanna published research setting out the minimum amount of time that we need to spend in the cold to receive all these incredible health benefits. It’s now been dubbed the Søberg Principle and it’s not nearly as extreme as you might think. Even just a cooler blast at the end of your shower is a very effective place to start.   I really was delighted and honoured that Susanna came over from Denmark to record her first ever long form podcast. Whatever your view on the cold – whether you embrace it fully or whether you think this is a trend that is not for you – I really think you are going to enjoy listening and I’m pretty sure that after listening, you may well be tempted to give the cold a go. CAUTION: If you have uncontrolled hypertension or heart disease it is not advised that you start practising cold water immersion. If you have any doubt at all as to whether you are fit enough to give this practice a go, please consult a qualified healthcare professional. Thanks to our
Actionable Insights

1. Activate Brown Fat Metabolism

Expose yourself to cold temperatures (e.g., cold showers, cold plunges, cooler rooms) to activate healthy brown fat, which boosts metabolism by using glucose and fat as fuel, potentially preventing obesity, type 2 diabetes, high cholesterol, and high blood pressure. Sleeping in a room at 19 degrees Celsius for a month has been shown to increase brown fat and insulin sensitivity.

2. Boost Resilience, Mood, Focus

Deliberately expose yourself to cold to increase self-confidence, resilience, and stress tolerance, as it acts as a mental workout that strengthens both mind and body. This practice immediately shifts focus from mental anxieties to physical sensations, releasing neurotransmitters like noradrenaline and dopamine that improve mood, drive, and motivation for hours.

3. 30-Second Cold Shower Immunity

Finish your warm shower with a cold blast for at least 30 seconds to potentially boost your immune system and reduce sick days, as shown in a randomized controlled trial.

4. Soberg Principle: Cold Exposure

For adapted individuals, aim for a total of 11 minutes of cold water exposure per week, divided into 2-3 days with up to three dips per session, to achieve significant health benefits. Beginners will still gain benefits from shorter exposures, even 30 seconds.

5. Optimal Sauna Use Protocol

For heat exposure, aim for 57 minutes per week in the sauna, divided into 2-3 sessions, with each session lasting between 19-29 minutes, to achieve profound health benefits including a reduced risk of mortality.

6. Progressive Cold Adaptation

Start with short durations of cold exposure (e.g., 5 seconds in a cold shower) and gradually increase the time as your body adapts, understanding that initial discomfort will lessen with consistent practice. Do not start with extreme durations.

7. Mindful Cold Exposure

Practice cold exposure mindfully, listening to your body’s signals to avoid over-stressing cells or risking hypothermia; focus on acute, micro-stress doses rather than prolonged exposure, as excessive time can flatten benefits and pose real risks. Avoid competition and be aware of the ‘after drop’ effect.

8. Vary Cold Temperature

To continuously challenge your body and mind, vary the temperature of your cold exposure, either by decreasing the temperature or slightly increasing it, rather than sticking to the same temperature once adapted. Nature provides this variation through seasons.

9. Cold for Pain Relief

Use cold exposure as a modality to reduce physical pain, as it can provide relief that lasts for the day.

10. Supervised Cold for Kids

When introducing children to cold water, ensure adult supervision and limit their exposure to quick dips, as their smaller mass and larger surface area mean they cool down faster and are at higher risk of hypothermia if they stay in too long. Teach them to listen to their body’s signals.

11. Embrace Year-Round Temperature Change

Integrate temperature changes (cold and heat) into your daily health practices year-round, as it’s a natural, healthy, and often free way to enhance overall well-being and complement other health routines.

12. Protect Head, Hands in Cold

If you find yourself getting too cold easily or experiencing discomfort in your ears or hands during cold immersion, wear a hat to retain heat and protect your ears, and keep your hands out of the water or wear gloves, as you can still reap benefits without full submersion.

13. Partial Cold Exposure Benefits

You can achieve cold adaptation and benefits even without full body or head submersion; simply exposing parts of your body, like hands or feet, to cold water can contribute to overall cold tolerance.

14. Bring a Swim Buddy

Always engage in cold water activities with a ‘swim buddy’ for safety and social support.

15. Enroll in Thermalist Course

For structured guidance on safe cold and heat exposure, consider enrolling in Dr. Soberg’s online thermalist course (soberginstitute.com), which includes breathing practices and is suitable for all experience levels, with a 10% discount using code RONGAN.