Video·3 min read·May 2026

Navigating Cold Waters: Understanding the Benefits of Contrast Therapy

Cold Therapy • 3 min read • Based on research by Irena Yermakova, Anastasiia Nikolaienko, Yuliia Solopchuk, Michael Regan (2015)

Many of us have experienced the invigorating jolt of cold water on our skin. Whether it’s a brisk morning shower or a refreshing dip in a cold lake, these moments can awaken our senses and bring clarity to our minds. But what exactly happens to our bodies during these cold exposures? Recent research sheds light on the intricate relationship between cold water immersion and our body’s thermoregulatory responses.

A study conducted by Irena Yermakova and her team offers valuable insights into how immersion levels affect our brain temperature and overall safety during cold exposure. By modeling human cooling in various immersion scenarios, the researchers provide a clearer understanding of how cold water can be harnessed for recovery, resilience, and longevity.

The Science of Cooling

When we immerse our bodies in cold water, our brain temperature begins to drop significantly. According to Yermakova's research, full immersion leads to a quicker decrease in brain temperature compared to partial immersion. Specifically, the study found that it takes about 25 minutes for the brain temperature to reach 35°C during whole body immersion in 10°C water.

This rapid cooling can stimulate various physiological responses, enhancing our ability to recover from physical exertion and promoting mental clarity. Cold water immersion, therefore, serves as a powerful tool in our wellness rituals, allowing us to reset our systems and restore equilibrium.

The Role of Immersion Level

The research also highlights the importance of immersion level in determining how quickly our bodies cool. For example, if only the head is kept out of the water, it takes nearly twice as long—about 49 minutes—for brain temperature to reach the same level as when fully immersed. This indicates that the surface area exposed to air plays a crucial role in regulating our core temperature.

Understanding this dynamic can inform our practices around cold exposure. It encourages us to consider not just the temperature of the water, but also the extent of our immersion, allowing us to create safer and more effective protocols for recovery.

Practical Applications for Wellness

So, how can we apply these findings to our wellness routines? First, it's essential to recognize the potential risks of cold water immersion. The study suggests that as we expose more of our body to cold water, the time it takes for our core temperatures to reach critical levels increases, enhancing safety. For instance, immersing only the head, arms, and hands takes 74 minutes to achieve a significant drop in brain temperature, compared to full immersion.

This knowledge can guide us in crafting our contrast therapy rituals. For those new to cold exposure, starting with partial immersion can ease the transition and allow for greater adaptability. Additionally, incorporating brief, intentional cold exposure into recovery protocols can enhance resilience and clarity, particularly after strenuous activities.

Key Takeaways

Cold water immersion can significantly lower brain temperature, enhancing recovery and mental clarity.
The level of immersion affects how quickly our body cools, with full immersion leading to faster temperature drops.
Adjusting the amount of body exposed to cold water can help create safer and more effective recovery protocols.

Based on: Modelling of human cooling in cold water: effect of immersion level
Irena Yermakova, Anastasiia Nikolaienko, Yuliia Solopchuk, Michael Regan (2015). Extreme Physiology & Medicine

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Modelling of human cooling in cold water effect of immersion level

What This Paper Is Actually Saying

Yermakova and her colleagues aren't telling you cold water is good or bad for you. They're asking a more precise question: how does the amount of your body submerged affect how quickly your core cools? And the answer, modeled with careful thermoregulatory mathematics, is more nuanced than most cold exposure practitioners realize.

At 10 degrees Celsius water temperature, full immersion drives brain temperature to 35°C in 25 minutes. Keep your head above water and that same threshold takes 49 minutes. Pull your head, arms, and hands out of the water, and you've bought yourself 74 minutes before reaching the same point. The internal organs lag slightly behind—53, 65, and 120 minutes respectively across those three scenarios. What you expose determines how fast you cool. That's the finding.

How This Compares to What We Know

The broader cold water immersion literature tends to focus on outcomes—muscle soreness recovery, cardiovascular adaptation, hormonal response. The 2015 systematic review on CWI for muscle soreness, also in this knowledge base, is a good example: researchers there were optimizing for efficacy, looking at water temperature and immersion time as variables to tune for recovery benefit. Yermakova's group is doing something different. They're mapping the safety envelope, not the benefit curve.

This matters because most wellness protocols treat cold exposure as a dial you turn up for more benefit. But every dial has a range, and understanding where the range ends—where adaptation becomes danger—is just as important as knowing where the benefit begins.

The head is only 8 percent of your body surface. But it has a disproportionate effect on how fast your core cools. That asymmetry is worth understanding before you design your protocol.

Where the Science Gets Interesting

The arms and hands puzzle me in the best way. They account for 19 percent of total body surface area—more than twice the head's 8 percent. Yet removing them from the water, while helpful, doesn't extend safe immersion time proportionally. The head has outsized influence on core cooling rate, well beyond what its surface area would predict. This aligns with research on head submersion specifically—the brain's thermal sensitivity and proximity to central circulation make the head a uniquely powerful cooling conduit.

The cold adaptation literature reinforces this from another angle. Studies on winter swimmers and whole-body cryotherapy show that repeated cold exposure reshapes thermoregulatory responses over weeks. But those protocols are designed with exit strategies in mind. Yermakova's modeling gives you the physiological clock those exit strategies are built around.

My Practical Recommendation

Know your immersion level before you get in. If you're doing a cold plunge for recovery—three to five minutes in chest-deep water—you're operating well within the safety envelope this model describes. If you're experimenting with longer exposures or colder temperatures, keep your head and arms out. That's not weakness. That's buying yourself time while still getting the thermal stimulus your body needs.

The Surprising Connection

This paper was written to inform rescue operations and protective clothing design, not wellness protocols. That origin matters. The researchers were solving for how long a person can survive in open water before intervention is required. What they built, inadvertently, is a precision tool for anyone designing deliberate cold exposure. The same math that tells a search-and-rescue team how long they have tells you exactly how much of your body to submerge and for how long. Safety research and recovery research are using the same thermoregulatory clock. They just have different reasons to care about it.

Modelling of human cooling in cold water effect of immersion level

Navigating Cold Waters: Understanding the Benefits of Contrast Therapy

The Science of Cooling

The Role of Immersion Level

Practical Applications for Wellness

Key Takeaways

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