Cold water immersion and thermal response.

The practice of physical exercise triggers an inflammatory response in the musculoskeletal tissue. That’s why recovery is essential.

Use of Cryotherapy

Recovery is crucial, especially for athletes with frequent training sessions or competitions. Different techniques have been used to improve and optimize recovery, but undoubtedly one of the most commonly used is cryotherapy. Cryotherapy is a treatment that uses cold temperatures to influence physiological processes and promote tissue recovery. Initially used for the treatment of chronic diseases, it is currently applied for the immediate treatment of soft tissues by medical professionals, physiotherapists, trainers, etc.

There are various ways to apply cryotherapy, such as cold water immersion, ice, whole-body cryotherapy, cooling gel, etc. Of all these, one of the most common is cold water immersion (due to its easy accessibility), and although it has been widely used, scientific debate about its use and protocols still persists.

The effectiveness of cryotherapy is based on reducing skin temperature through contact with cold water or ice. The skin, as the main thermoregulatory organ, is crucial for maintaining body thermal balance. During cryotherapy, peripheral vasoconstriction responds to the decrease in skin temperature, redirecting blood flow to internal organs and minimizing heat loss.

This vasoconstriction causes a hyperemic reaction, with an increase in blood volume in internal organs and regulation of blood pressure through negative feedback mechanisms. The complex cutaneous microcirculation, essential for material exchange, requires further clinical studies. According to PRICE guidelines, a reduction in skin temperature of 5 to 15 °C is needed to achieve analgesia, avoiding drops below 5 °C due to possible adverse effects.

Thermography and Cryotherapy

In this context, infrared thermography has been presented as a valuable tool for analyzing temperature variations in the skin after cryotherapy. It stands out as a safe and reliable method for monitoring thermal responses. Thermography is presented as a safe, painless, and radiation-free option, without contact or contrast. By detecting the infrared radiation emitted by the skin, this approach provides a detailed analysis of physiological functions related to skin temperature.

An example of thermography and its use in cryotherapy can be found in one of the articles from the doctoral thesis of one of our co-founders, Javier Arnaiz. This article studied the acute effects of whole-body cryotherapy on the skin temperature of professional football players. Thermography was used, focusing on the cooling and reheating processes as well as the differences between the dominant and non-dominant sides.

It is important to mention from this study that:

• It was carried out using a dynamic thermography protocol. Although this protocol is valid and correct, we do not recommend using it with our Thermohuman software due to time, logistics, and interpretation of results. However, as this is a research study, it is interesting to present some of the most prominent findings.
• An immersion in water at 5º was performed for 10 minutes. Following this, images were captured after 10, 15, and 20 minutes to study the skin temperature response. Following this scheme:

Our Co-founder’s article concludes that:

• After a whole-body cryotherapy protocol: Dominant (D) vs. Non-Dominant (ND) provides different information than the analysis of Right (R) vs. Left (L) ROI.
• Following the protocol, absolute skin temperature differed significantly only at one moment, but not in the subsequent ones when comparing D vs. ND sides on the anterior thigh, anterior knee, and posterior thigh. In contrast, when comparing R vs. L sides, significant changes occurred in the anterior thigh, anterior knee, and posterior leg.
• Professional football players exhibit the same cooling skin temperature on both sides for all ROIs except for the posterior leg when comparing R vs. L limbs.
• Professional football players experience significantly faster reheating of the dominant posterior thigh when comparing D vs. ND limbs.

Bibliography:

Arnaiz Lastras, J. (2017). Monitoring the acute effects of recovery, training and competition on football player’s skin temperature with infrared thermography (Doctoral dissertation, Ciencias).

Matos, F., Neves, E. B., Norte, M., Rosa, C., Reis, V. M., & Vilaça-Alves, J. (2015). The use of thermal imaging to monitoring skin temperature during cryotherapy: a systematic review. Infrared Physics & Technology, 73, 194-203.