The power of hot and cold - how cold exposure supports well-being
Cold water awakens both body and mind, bringing with it a deep sense of well-being. Dr. Emilia - a Finnish medical doctor, bestselling author, and pioneer in hormonal health and well-being - explains how cold exposure affects the nervous system, energy levels, and recovery, and what happens when cold water is combined with the warmth of a sauna.
More and more people are drawn to ice swimming
Your breath catches. Your skin tingles. A moment later, your mind feels exceptionally clear.
Ice swimming has grown rapidly in popularity in recent years, capturing the interest of more and more people seeking new ways to support their well-being. At the same time, it’s important to remember that ice swimming is just one way to expose yourself to the cold, and there are many alternatives. The wellbeing benefits are linked more broadly to cold as a stimulus — not just to icy water.
Ice swimming means swimming in freezing water, often through a hole cut into the ice. While especially popular in Nordic countries, interest continues to grow worldwide. Beyond the thrill of the experience, many are drawn to ice swimming for the positive health effects associated with cold exposure.
How the body responds to cold
When you step into cold water, the body reacts immediately. Adrenaline and noradrenaline rise, your breathing quickens, and the first sensation may feel uncomfortable. As the breath settles, however, the nervous system begins to regain balance. The parasympathetic system activates, and the initial intensity gradually transforms into a sense of control.
Dr. Emilia describes cold exposure as a powerful tool for regulating the nervous system. It can quickly elevate alertness, yet it can also calm the body when it is running on overdrive. In this way, cold exposure serves as an effective way to rebalance your nervous system.
Why does cold feel so good?
"At first, it feels uncomfortable — and then it feels incredibly good”, says Dr. Emilia.
She describes how she herself once became almost “hooked” on cold exposure because of its powerful balancing effect on the nervous system. Cold can be especially helpful during periods of stress: thoughts become clearer, and the body begins to settle.
Cold exposure can also be used before demanding situations that require focus. Dr. Emilia shares that she sometimes uses cold before important meetings or podcast recordings. The surge of noradrenaline and dopamine sharpens concentration and supports cognitive performance.
That initial “comfortably uncomfortable” sensation is linked to dynorphins, which intensify the experience. As the body adapts, endorphins are released, amplifying the feeling of well-being. When we briefly approach our limits and then return to warmth, the result can feel like a reset, as if body and mind have been recalibrated.
How alternating hot and cold complement each other
Especially ice swimming is often paired with sauna bathing, which makes the experience more accessible and enjoyable. Warmth and cold complement one another: alternating between them supports recovery and strengthens nervous system resilience.
In the sauna, blood vessels dilate and circulation increases. When moving into cold water, blood vessels constrict rapidly. This creates a pumping effect that supports vascular elasticity and enhances recovery, including aiding the removal of metabolic byproducts such as lactic acid.
Alternating between heat and cold also trains the autonomic nervous system. Cold activates the sympathetic system, temporarily increasing blood pressure and adrenaline levels, while stepping out of the sauna reactivates the parasympathetic system. This repeated adjustment strengthens the body’s adaptability and improves stress resilience over time.
Read more about the many physical and mental benefits of sauna here
When we alternate between the heat of the sauna and cold water, we train our autonomic nervous system. Our body learns to recover more efficiently and tolerate stress more effectively.
Alternatives to cold exposure
Cold exposure does not have to mean jumping into an icy lake. In addition to ice swimming, cold pools or cool showers can offer similar benefits.
A cold plunge allows for regular cold exposure throughout the year, making the benefits of ice swimming accessible beyond the colder months.
Dr. Emilia emphasizes that the cold does not need to be extreme to be effective. Water around 10–15°C (50–59°F) is already sufficient to activate brown fat and increase the production of noradrenaline and dopamine. For many people, this temperature range offers a gentle yet effective way to begin, and staying in for 1–3 minutes is often enough to experience the benefits.
In icy water, the effects occur much faster, often within 30 seconds. Staying too long in freezing water is not recommended, as it can place unnecessary strain on the body. Moderation and listening to your body are essential.
Why might gentler cold exposure be a better option?
The effects of cold exposure are highly individual. In women, the body protects vital organs efficiently, which means blood vessels constrict more readily and the cold can feel more intense. Muscle mass, body fat percentage, age, hormonal function, and overall life stress also influence how the body responds. If life already involves significant stress, very intense exposure may add to the overall load rather than support recovery.
Emilia emphasizes that less is often more and that the most important thing is to find an approach that works for you. That’s why she chooses cool showers and swims in the sea after the ice has melted, finding that more moderate cold exposure suits her best.
How to start safely
The body gradually adapts to cold. With repeated exposure, tolerance improves and the experience often becomes more comfortable over time.
Adaptation should begin gradually, with careful attention to your body’s signals.
When heading out for ice swimming, simple clothing can make the experience more pleasant. Gloves and neoprene shoes help protect hands and feet, while the warmth of the sauna provides a supportive contrast to cold exposure.
Start slowly. Breathe deeply and steadily. Keep your shoulders relaxed and allow your body to settle into the sensation. In the beginning, a brief dip of just a few seconds is enough. Over time, you can extend your exposure as your body adapts.
Regular cold exposure may:
Reduce stress
Balance energy levels
Support nervous system flexibility
Improve stress resilience
Enhance mental clarity
Support recovery
Increase feelings of well-being
Ice swimming may not be safe for everyone. Consult your doctor before trying cold-water immersion, especially if you have heart conditions, high blood pressure, or other health concerns.
Every day is different, and your stress levels influence how your body tolerates the cold. It’s not about performance. Listen to your body. It will tell you what feels right.
Finnish doctor and bestselling author Dr. Emilia Vuorisalmi
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