Head Exposure to Cold during Whole-Body Cryostimulation: Influence on Thermal Response and Autonomic Modulation

Recent research on whole-body cryotherapy has hypothesized a major responsibility of head cooling in the physiological changes classically reported after a cryostimulation session. The aim of this experiment was to verify this hypothesis by studying the influence of exposing the head to cold during whole-body cryostimulation sessions, on the thermal response and the autonomic nervous system (ANS). Over five consecutive days, two groups of 10 participants performed one whole-body cryostimulation session daily, in one of two different systems; one exposing the whole-body to cold (whole-body cryostimulation, WBC), and the other exposing the whole-body except the head (partial-body cryostimulation, PBC).10 participants constituted a control group (CON) not receiving any cryostimulation. In order to isolate the head-cooling effect on recorded variables, it was ensured that the WBC and PBC systems induced the same decrease in skin temperature for all body regions (mean decrease over the 5 exposures: -8.6°C±1.3°C and -8.3±0.7°C for WBC and PBC, respectively), which persisted up to 20-min after the sessions (P20). The WBC sessions caused an almost certain decrease in tympanic temperature from Pre to P20 (-0.28 ±0.11°C), while it only decreased at P20 (-0.14±0.05°C) after PBC sessions. Heart rate almost certainly decreased after PBC (-8.6%) and WBC (-12.3%) sessions. Resting vagal-related heart rate variability indices (the root-mean square difference of successive normal R-R intervals, RMSSD, and high frequency band, HF) were very likely to almost certainly increased after PBC (RMSSD:+49.1%, HF: +123.3%) and WBC (RMSSD: +38.8%, HF:+70.3%). Plasma norepinephrine concentration was likely increased in similar proportions after PBC and WBC, but only after the first session. Both cryostimulation techniques stimulated the ANS with a predominance of parasympathetic tone activation from the first to the fifth session and in slightly greater proportion with WBC than PBC. The main result of this study indicates that the head exposure to cold during whole-body cryostimulation may not be the main factor responsible for the effects of cryostimulation on the ANS

Parasympathetic Activity and Blood Catecholamine Responses Following a Single Partial-Body Cryostimulation and a Whole-Body Cryostimulation

The aim of this study was to compare the effects of a single whole-body cryostimulation (WBC) and a partial-body cryostimulation (PBC) (i.e., not exposing the head to cold) on indices of parasympathetic activity and blood catecholamines. Two groups of 15 participants were assigned either to a 3-min WBC or PBC session, while 10 participants constituted a control group (CON) not receiving any cryostimulation. Changes in thermal, physiological and subjective variables were recorded before and during the 20-min after each cryostimulation. According to a qualitative statistical analysis, an almost certain decrease in skin temperature was reported for all body regions immediately after the WBC (mean decrease±90% CL, -13.7±0.7°C) and PBC (-8.3±0.3°C), which persisted up to 20-min after the session. The tympanic temperature almost certainly decreased only after the WBC session (-0.32±0.04°C). Systolic and diastolic blood pressures were very likely increased after the WBC session, whereas these changes were trivial in the other groups. In addition, heart rate almost certainly decreased after PBC (-10.9%) and WBC (-15.2%) sessions, in a likely greater proportion for WBC compared to PBC. Resting vagal-related heart rate variability indices (the root-mean square difference of successive normal R-R intervals, RMSSD, and high frequency band, HF) were very likely increased after PBC (RMSSD: +54.4%, HF: +138%) and WBC (RMSSD: +85.2%, HF: +632%) sessions without any marked difference between groups. Plasma norepinephrine concentrations were likely to very likely increased after PBC (+57.4%) and WBC (+76.2%), respectively. Finally, cold and comfort sensations were almost certainly altered after WBC and PBC, sensation of discomfort being likely more pronounced after WBC than PBC. Both acute cryostimulation techniques effectively stimulated the autonomic nervous system (ANS), with a predominance of parasympathetic tone activation. The results of this study also suggest that a whole-body cold exposure induced a larger stimulation of the ANS compared to partial-body cold exposure

Enfant : sport et dos

Au moment de la croissance de l'enfant, il est nécessaire de choisir le bon sport et une préparation physique adéquate pour éviter les traumatismes du dos

Chapitre 15. Les variations des ambiances thermiques

Introduction Le stress lié à l'exercice est souvent accru en raison des conditions environnementales, en particulier lors de la modification des contraintes thermiques. Pour tout effort sportif, il existe une « ambiance thermique » avec une température idéale. Tout écart à cette référence aura des répercussions négatives sur la performance. L'activité physique, en ambiance chaude ou froide, représente en effet une lourde charge pour l'organisme ainsi que pour les mécanismes impliqués dans la ..

Changes (Cohen’s <i>d</i> or effect size) in plasma concentrations in catecholamines from pre to post whole-body cryostimulation (WBC), and partial-body cryostimulation (PBC) sessions, and for the control (CON) condition.

<div><p>Circles around the plots highlight <i>likely</i> to <i>almost certain</i> differences in the change. The shaded area represents the smallest worthwhile change.</p> <p>Between-group (vs. CON) difference in the change: # likely; ## very likely; ### almost certain.</p> <p>Between-group (PBC vs. WBC) difference in the change: § likely; §§ very likely; §§§ almost certain.</p></div

Changes in tympanic temperature.

<div><p>Values were recorded before (Pre), immediately (Post), 5-min (P5), and 20-min (P20) after whole-body cryostimulation (WBC), and partial-body cryostimulation (PBC) sessions, and the control (CON) condition.</p> <p>Within-group change (Post conditions vs. Pre): * likely; ** very likely; *** almost certain.</p> <p>Between-group (vs. CON) difference in the change: # likely; ## very likely; ### almost certain.</p> <p>Between-group (PBC vs. WBC) difference in the change: § likely; §§ very likely; §§§ almost certain.</p></div

Schematic representation of the experimental protocol.

<p>Each subject experienced five consecutive (one session per day over five consecutive days) whole-body cryostimulation (WBC) or partial-body cryostimulation (PBC) sessions or no session (CON) for 3-min, immediately preceded and followed by the same measurements. Blood, and camera recordings were performed only on the first and fifth session. <i>HRV + BP</i>, measurements of heart rate variability and blood pressure.</p

Changes in the mean skin temperature of the whole body (except the head) and the head alone.

<p>Values were recorded before (Pre), immediately after (Post) and for 20-min (P1 to P20) after the first and the fifth whole-body cryostimulation (WBC), and partial-body cryostimulation (PBC) sessions, and in the control (CON) condition. Within-group change (Post conditions vs. Pre): * likely; ** very likely; *** almost certain. Between-group (vs. CON) difference in the change: # likely; ## very likely; ### almost certain. Between-group (PBC vs. WBC) difference in the change: ¤ likely; ¤¤ very likely; ¤¤¤ almost certain.</p

Changes (% of pre values) in systolic and diastolic blood pressures from pre to post whole-body cryostimulation (WBC), and partial-body cryostimulation (PBC) sessions, and in the control (CON) condition.

<p>The shaded area represents trivial changes. Values were recorded daily on five consecutive days before and after each cryostimulation sessions. Between-group (PBC or WBC vs. CON) difference in the change: * likely; ** very likely; *** almost certain. Between-group (PBC vs. WBC) difference in the change: # likely; ## very likely; ### almost certain.</p

Changes (% of pre values) in heart rate and HRV indices of parasympathetic activity from pre to post whole-body cryostimulation (WBC), and partial-body cryostimulation (PBC) sessions, and in the control (CON) condition.

<p>The shaded area represents trivial changes. Values were recorded daily on five consecutive days before and after each cryostimulation session. Between-group (PBC and WBC vs. CON) difference in the change: * likely; ** very likely; *** almost certain. Between-group (PBC vs. WBC) difference in the change: # likely; ## very likely; ### almost certain.</p