Impact of acute partial-body cryostimulation on cognitive performance, cerebral oxygenation, and cardiac autonomic activity
Authors: Paul Guitet
Julien Louis
Dimitri Theurot
Benoit Dugué
Wafa Douzi
Olivier Dupuy
Journal: Scientific Reports (2021)
Discipline: Multidisciplinary
Keywords: Cryostimulation; Cognitive performance; Parasympathetic control; Cerebral oxygenation; Heart rate variability
Affiliations: Laboratory MOVE (EA 6314), Faculty of Sport Sciences, University of Poitiers, 8 allée Jean Monnet, 86000, Poitiers, France., Research Institute for Sport and Exercise Sciences (RISES), Liverpool John Moores University, Byrom Street, Liverpool, L3 3AF, UK., Laboratory MOVE (EA 6314), Faculty of Sport Sciences, University of Poitiers, 8 allée Jean Monnet, 86000, Poitiers, France. ., Ecole de Kinésiologie et des Sciences de l'Actvivité Physique (EKSAP), Faculté de Medecine, Université de Montreal, Montreal, Canada. .

Abstract:  We assessed the effects of a 3-min partial-body cryostimulation (PBC) exposure-where the whole body is exposed to extreme cold, except the head-on cognitive inhibition performance and the possible implications of parasympathetic cardiac control and cerebral oxygenation. In a randomized controlled counterbalanced cross-over design, eighteen healthy young adults (nine males and nine females) completed a cognitive Stroop task before and after one single session of PBC (3-min exposure at - 150 °C cold air) and a control condition (3 min at room temperature, 20 °C). During the cognitive task, heart rate variability (HRV) and cerebral oxygenation of the prefrontal cortex were measured using heart rate monitoring and near-infrared spectroscopy methods. We also recorded the cerebral oxygenation during the PBC session. Stroop performance after PBC exposure was enhanced (562.0 ± 40.2 ms) compared to pre-PBC (602.0 ± 56.4 ms; P &lt; 0.042) in males only, accompanied by an increase (P &lt; 0.05) in HRV indices of parasympathetic tone, in greater proportion in males compared to females. During PBC, cerebral oxygenation decreased in a similar proportion in males and females but the cerebral extraction (deoxyhemoglobin: ΔHHb) remained higher after exposure in males, only. These data demonstrate that a single PBC session enhances the cognitive inhibition performance on a Stroop task in males, partly mediated by a greater parasympathetic cardiac control and greater cerebral oxygenation. The effects of PBC on cognitive function seem different in females, possibly explained by a different sensitivity to cold stimulation. 

Retracted: No

PubPeer comments:
 Recently, a [study] was retracted by authors because they did not obtain an approval from a Comitu00e9 de Protection des Personnes (CPP) for a study related to cryotherapy. In France, prospective studies on cryotherapy are considered as researches in humans and must obtain an approval from a CPP before to start. In this article, the description of the study highlights a prospective research in human. * In a randomized controlled counterbalanced cross-over design, eighteen healthy young adults (nine males and nine females) completed a cognitive Stroop task before and after one single session of PBC (3-min exposure at u2212u2009150 u00b0C cold air) and a control condition (3 min at room temperature, 20 u00b0C). During the cognitive task, heart rate variability (HRV) and cerebral oxygenation of the prefrontal cortex were measured using heart rate monitoring and near-infrared spectroscopy methods. We also recorded the cerebral oxygenation during the PBC session.  * The study recruited healthy volunteers and performed several interventions. It clearly is a research in humans as described by the French Health Law. This type of study must obtain an approval from a CPP before to start the recruitment of patients. However, the ethics statement do no mention any approval from a CPP. Instead, it mentions an approval from a local committee. * All participants were volunteers and received an information leaflet explaining the protocol and measures. They were also informed about the risks and benefits of their participation as well as their rights according to the declaration of Helsinki and signed a written informed consent. This protocol and all the methods and measures used in this study were in accordance with the recommendations and guidelines provided by the declaration of Helsinki. The study was approved by the local Ethics Committee (Comitu00e9 du2019Ethique pour la Recherche en STAPS number: 2019-26-05-34) * The Comitu00e9 du2019Ethique pour la Recherche en STAPS is not on the list of the registered CPP. It is not an appropriate approval for a research in humans in France and it can not replace an approval from a CPP. On the [CERSTAPS website] , It is mentioned the following: * Please note: the opinion issued by CERSTAPS does not dispense with a submission to a CPP, or a declaration to the CNIL when these procedures are necessary. * Considering this point, can the authors clarify and mention if they obtain an approval from a CPP before to obtain the approval? If not, do they seek an approval from a CPP ? In this case, what was the answer of the CPP and what was the reasons the CPP provided to waive the CPP approval ? Providing a copy of the CPP waiver in the supplementary material could help to raise any ethical concerns. ,