THE SCIENCE BEHIND COLD EXPOSURE THERAPY

In recent years, cold exposure therapy has made waves among athletes and health enthusiasts as an effective means of enhancing recovery, improving metabolic health, and boosting mental resilience.

This therapy, primarily through cold-water immersion and cryotherapy, promises benefits that extend well beyond traditional recovery techniques.

So, what is the science behind the effects of cold exposure therapy, the subsequent physiology, its benefits for active individuals, and practical considerations to keep in mind?

What is Cold Exposure Therapy?

Cold exposure therapy includes methods like cold-water immersion and whole or partial-body cryostimulation, which are designed to expose the body to low temperatures.

Cold water immersion involves submerging parts or the entire body in cold water, usually below 15°C, and is commonly used post-exercise for recovery.

Cryotherapy, by contrast, uses extremely cold air ranging from -50°C to -160°C over brief exposures, typically lasting between two to five minutes (Jdidi et al., 2024).

Both of these methods activate the body’s natural responses to cold, inducing a range of physiological changes aimed at protecting core temperature and stimulating metabolic and cardiovascular adaptations.

How Does Cold Exposure Therapy Work?

The physiological effects of cold exposure are rooted in the body’s natural thermoregulatory mechanisms (what helps maintain a stable body temperature), which are activated when the body senses a drop in temperature.

This triggers a cascade of responses, starting with blood vessel constriction to preserve core warmth and a decrease in heart rate.

As the body responds to the cold environment, blood vessels constrict, and the sympathetic nervous system triggers the release of hormones like adrenaline, which mobilise energy stores and can aid in both physical recovery and mental alertness (Espeland et al., 2022).

Are There Any Benefits for Athletes? 

1. Enhanced Muscle Recovery

The primary reason athletes turn to cold exposure therapy is to improve muscle recovery.

Studies show that cold exposure can help reduce muscle soreness and accelerate the recovery process by decreasing inflammation and clearing metabolic waste products like lactate, which builds up post-exercise (Moore et al., 2023).

This decreases in lactate levels enables athletes to recover faster and perform better in subsequent training sessions (Fujita et al., 2022).

A systematic review found that cold-water immersion was more effective than other recovery methods, such as active recovery and contrast water therapy, at reducing muscle soreness following intense workouts.

By constricting blood vessels and lowering tissue temperature, cold exposure reduces the inflammatory response, which is a key source of muscle soreness.

2. Improved Metabolic Health and Fat Loss

Cold exposure therapy has also shown promising results in enhancing metabolic health by activating brown adipose tissue (BAT).

Unlike white adipose tissue, which stores energy, BAT burns calories to generate heat through non-shivering thermogenesis (when the body produces heat without shivering), which not only aids in warming the body but also increases calorie expenditure.

Importantly, BAT activation has been linked to improved glucose metabolism, which can have significant benefits for individuals with metabolic health concerns like obesity and type 2 diabetes (Ivanova & Blondin, 2021).

Additionally, the thermogenic effect of BAT activation contributes to fat oxidation, pointing to cold exposure serving as a complementary strategy for weight loss.

3. Mental Resilience and Stress Adaptation

The process of exposing the body to controlled, brief cold stress can enhance mental resilience by promoting adaptation to stress.

Cold exposure induces a “hormetic effect,” a mild stressor that prompts the body to adapt and build resilience to both physical and mental stressors over time.

This can have profound effects on mental well-being, as studies have found that winter swimmers report greater mental clarity, lower stress, and even reductions in symptoms of depression (Teległów et al., 2024).

This is due to the fact cold exposure stimulates the release of endorphins and other “feel-good” hormones, which can improve mood and contribute to mental resilience.

Moreover, these physiological changes may be beneficial for stress tolerance both in athletic performance and in daily life.

4. Cardiovascular Health

The cardiovascular benefits of cold exposure therapy are particularly relevant for athletes and active individuals.

When exposed to cold, the body initiates vasoconstriction to preserve core body temperature.

This response improves vascular function by promoting “vascular training,” whereby blood vessels contract and relax in response to the stimulus, strengthening the cardiovascular system over time.

Accordingly, regular cold exposure has been linked to improved heart rate variability, indicating a healthier balance in the autonomic nervous system (the part of the nervous system which controls involuntary functions) (Jdidi et al., 2024).

In addition to boosting circulation, this process can also lower blood pressure, as the repeated constriction and dilation of blood vessels improve vascular elasticity.

For athletes, this translates to enhanced blood flow during workouts and potentially improved oxygen delivery to muscles during peak performance.

5. Anti-Inflammatory and Antioxidant Effects

Cold exposure’s anti-inflammatory benefits extend beyond the musculoskeletal system, reducing systemic inflammation that can impact overall health and recovery.

Research suggests that cold exposure can help reduce oxidative stress by boosting the body’s antioxidant defences.

Regular exposure to cold, such as through winter swimming, has been linked to higher activity of antioxidant enzymes like catalase and glutathione peroxidase, which help mitigate damage caused by free radicals (which can harm cells, proteins, and DNA) (Selleri et al., 2022).

This effect is crucial for athletes who endure high levels of physical stress and may experience oxidative damage as a result.

By reducing inflammation and enhancing antioxidant defences, cold exposure can help prevent chronic inflammation, support recovery, and improve long-term athletic performance.

How Can I Integrate Cold Exposure Therapy?

Start Gradually

If you’re new to cold exposure, begin with short cold showers and progressively work up to full-body immersion in colder water.

Optimal Temperatures

For cold water immersion, aim for water temperatures between 10°C to 15°C, and for cryotherapy, temperatures range from -110°C to -160°C. Start with brief exposures, such as two to three minutes, and gradually increase your tolerance.

Frequency of Exposure

Studies suggest that one to two sessions per week can deliver noticeable benefits, but those looking for enhanced adaptation may increase the frequency up to several times per week (Moore et al., 2023) 

Listen to Your Body

Cold exposure can be taxing on the body. If you experience intense shivering, dizziness, or pain, exit the cold environment, and warm up gradually.

Individuals with certain health conditions, such as cardiovascular issues, should consult with a healthcare provider before starting cold therapy.

Are There Any Potential Risks?

While the benefits are substantial, it’s essential to approach cold exposure therapy cautiously.

For individuals with cardiovascular conditions, cold exposure can impose undue stress, potentially leading to adverse effects such as hypothermia or cold shock.

Even for healthy individuals, starting with small, controlled doses and gradually building tolerance is critical to prevent injury or shock (Briganti et al., 2023) .

So, Is Cold Exposure Therapy Worth It?

Cold exposure therapy offers a host of benefits for athletes and health-conscious individuals, from faster muscle recovery to enhanced metabolic health, mental resilience, and cardiovascular conditioning.

While it might take some initial discomfort to get started, the results are worth it. With its growing popularity and scientific backing, cold exposure therapy is fast becoming a go-to recovery and wellness tool for those seeking an edge in both performance and health.

References

Briganti, D., et al. (2023). Effects of cold water exposure on stress, cardiovascular, and psychological variables. Acta Physiologica, 239, e14056 .

Espeland, D., et al. (2022). Health effects of voluntary exposure to cold water – a continuing subject of debate. International Journal of Circumpolar Health, 81, 2111789 .

Ivanova, Y. M., & Blondin, D. P. (2021). Examining the benefits of cold exposure as a therapeutic strategy for obesity and type 2 diabetes. Journal of Applied Physiology, 130(3), 1448-1459 .

Jdidi, H., et al. (2024). The effects of cold exposure on cardiovascular and cardiac autonomic control responses. Journal of Thermal Biology, 121, 103857 .

Moore, E., et al. (2023). Effects of Cold-Water Immersion Compared with Other Recovery Modalities. Sports Medicine, 53, 687-705 .

Teległów, A., et al. (2024). Effect of regular winter swimming on blood morphological and biochemical indicators. BMC Sports Science, Medicine and Rehabilitation, 16, 138 .

Selleri, M., et al. (2022). Innate immunity changes in soccer players after whole-body cryotherapy. BMC Sports Science, Medicine and Rehabilitation, 14, 185 .