Cold water immersion (CWI) has a long history of usage in (sports) practice. It was Dr. James Currie who undertook the first recorded experiment in 1790 on the effects of CWI on humans. The history of whole body cryotherapy (WBC) is much shorter, Dr. Yamauchi was the first recording experiments using WBC in a group of rheumatic patients in 1979. Both modalities are now widely implemented though often either CWI or WBC is used while excluding the other. Why? Do CWI and WBC indeed have similar effects following exposure or is there room for both?
CWI involves immersing the body or parts of the body (for instance the legs only) in cold water at a temperature lower than 68°F / 19°C. WBC involves a short exposure (2-4 minutes) to frigid air (-166°F/-110°C to -220°F/-140°C) in an environmentally controlled chamber for short periods of time (2-4 minutes). CWI and WBC can both be regarded as therapeutic modalities, a form of stress applied to the body to elicit an involuntary physiological response. If the intensity of the modality application is too low or the treatment duration too short, little or no benefit will be gained.
Cooling is about extracting energy, and the necessary heat transfer depends on thermal conductivity. This thermal conductivity depends on different factors like length of the application, the temperature differential between the body and the modality but also on the heat transfer coefficient. This coefficient is much smaller for air-WBC (0.0024) compared to water-CWI (0.58) and allows CWI to make up the difference in temperature. This is illustrated by a study from Costello and colleagues (2012) who elucidated the reductions in muscle, skin and core temperature following after 4 minutes of exposure to either WBC -110°C or CWI to 46°F/ 8°C. They found comparable effects with the exception that WBC elicited a greater skin temperature decrease compared to CWI directly after the exposure. It is reasonable to expect though that the temperature differences following CWI are more considerable when both are applied according to the guidelines: 2-4 minutes for WBC duration and 10-15 minutes for CWI.
What does the literature tell us when directly comparing the effects following CWI and WBC?
There are only a few studies that compared CWI and WBC within the same study design:
- Costello and colleagues (2014) examined and contrasts the effects following exposure to -110°C (4 minutes) WBC and CWI to 46°F/ 8°C (4 minutes) on knee skin temperature and concluded that none of both protocols achieved a knee skin temperature sufficient to elicit an analgesic effect around the patellar region.
- Abaïdia and colleagues (2016) compared the effects of CWI with WBC on recovery kinetics following exercise-induced muscle damage and concluded that CWI was more beneficial than WBC to improve muscle power recovery 72h after.
- Mawhinney and colleagues (2017) examined the effects of CWI and WBC on blood flow and thermoregulatory responses after a cycling exercise and concluded that more significant reductions in blood flow were observed after CWI.
Many more studies are published on CWI (>450) compared WBC (>150), though WBC studies are catching up (>100 in the last ten years). The main differences in outcomes for CWI and WBC are found for the effects on DOMS and parasympathetic reactivation (see table 1).
Table 1: Overview of differences between cold water immersion (CWI) and whole body cryotherapy (WBC) on different outcomes that are used in the literature
It is important to note that both modalities should be regarded as safe with a minimal chance of developing adverse events. Moreover, while the foundation for CWI is more significant, more easily accessible and cheaper, WBC allows shorter exposure times, dry clients, a more comfortable start of the exposure (compliance!) and more acceptance for a broader range of applications (vitality, beauty, and medical purposes).
Clinical Decision Making
Although WBC and CWI imply severe cold exposure, the physiological principles and thereby fields of application and effects are different (think about the difference in energy extraction!). Clinical decision making is essential when using one of these therapeutic modalities. The usage of either CWI or WBC should be determined by the best available research, clinical expertise of the practitioner and regarded as an adjunct to the global approach. WBC and CWI should be regarded as two different modalities which both have significant potential in the field and could easily be implemented besides each other.
- Holmes, M. & Willoughby, D. S. The Effectiveness of Whole Body Cryotherapy Compared to Cold Water Immersion: Implications for Sport and Exercise Recovery. International Journal of Kinesiology and Sports Science 4, 32–39 (2016).
- Costello, J. T., Donnelly, A. E., Karki, A. & Selfe, J. Effects of whole body cryotherapy and cold water immersion on knee skin temperature. Int J Sports Med 35, 35–40 (2014).
- Costello, J. T., Culligan, K., Selfe, J. & Donnelly, A. E. Muscle, skin and core temperature after -110°c cold air and 8°c water treatment. PLoS ONE 7, e48190 (2012).
- Abaïdia, A.-E. et al. Recovery From Exercise-Induced Muscle Damage: Cold Water Immersion Versus Whole Body Cryotherapy. Int J Sports Physiol Perform 1–23 (2016).
- Mawhinney, C. et al. Cold-Water Mediates Greater Reductions in Limb Blood Flow than Whole Body Cryotherapy. Med Sci Sports Exerc 1252–1260 (2017).