Understanding the Context of Research is Essential

Research can provide valuable insights, but its reliability depends on study quality, methodology, sample size, controls, equipment and measurement accuracy. A notable example that I see often cited on social media is Hausswirth et al. (2013), “Parasympathetic Activity and Blood Catecholamine Responses Following a Single Partial-Body Cryostimulation and a Whole-Body Cryostimulation.”

This study compared a single 3 minute session of Whole Body Cryostimulation (WBC) and Partial Body Cryostimulation (PBC, excluding the head) in 30 participants, assessing parasympathetic activity, blood catecholamines, and thermal and subjective responses up to 20 minutes post-exposure. The reported mean skin temperature drops were -13.7 ± 0.7 °C for WBC and -8.3 ± 0.3 °C for PBC. Assuming a baseline of ~32 °C, this corresponds to ~18.3 °C and ~23.7 °C post-exposure, respectively. Based on Cryostimulation research and practical experience, these temperature reductions are insufficient to induce a true thermal shock response, which is consistent with the cooling rates typically observed in -60 °C Cryochambers.

Methodologically, the study used a Cryosauna by Cryotechno® (TEC4H, France). Very little is known about this unit, and the reported −160 °C appears to reflect the entry-point temperature rather than the internal cabin temperature. Thermovision data indicated uneven cooling, particularly greater in the lower back and legs, suggesting suboptimal circulation. Modern Cryosaunas address this with nitrogen vapour delivery higher up and internal fans to optimise even cooling. Additionally, the open cabin design used in the study lacks a hood, which reduces cooling efficiency and safety.

Although nitrogen vapour at -110 °C has a higher density than cooled air (~8.3 vs. ~4.4 kg/m³), thermal conduction to the skin is driven primarily by the temperature gradient and energy output, not the medium. Consistent evidence shows that WBC at −110 °C for 2–3 minutes can reduce peripheral skin temperatures to 10 – 15 °C or lower, while maintaining core temperature. For instance, Savic et al. (2003) reported skin temperatures as low as ~12 °C in the lower abdomen after WBC at -135 °C, and Louis et al. (2020) found that -110 °C significantly increased HRV and norepinephrine, whereas -60 °C did not.

The key takeaway is that understanding the context of research is essential. Hausswirth et al. show that both WBC and PBC activate the autonomic nervous system, with whole-body exposure producing a stronger parasympathetic response. However, the skin cooling reported in the study is modest and does not reach true thermal shock for either modality. While the findings are useful for moderate WBC at -60 °C, they offer limited value as a benchmark for current PBC protocols at lower temperatures.

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