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.
Research Department, Sport Expertise and Performance (SEP) Laboratory, French National Institute of Sport, Expertise and Performance (INSEP), Paris, France.
Julien
J
Louis
Research Department, Sport Expertise and Performance (SEP) Laboratory, French National Institute of Sport, Expertise and Performance (INSEP), Paris, France; Sports Performance Laboratory, Sports Medicine Program, University of California Davis, Sacramento, California, United States of America.
Karine
K
Schaal
Research Department, Sport Expertise and Performance (SEP) Laboratory, French National Institute of Sport, Expertise and Performance (INSEP), Paris, France.
François
F
Bieuzen
Research Department, Sport Expertise and Performance (SEP) Laboratory, French National Institute of Sport, Expertise and Performance (INSEP), Paris, France.
Yann
Y
Le Meur
Medical Department, French National Institute of Sport, Expertise and Performance (INSEP), Paris, France.
Jean-Robert
JR
Filliard
Medical Department, French National Institute of Sport, Expertise and Performance (INSEP), Paris, France.
Marielle
M
Volondat
Laboratory of Human Motricity, Education Sport and Health, University of Nice Sophia Antipolis, Nice, France.
Jeanick
J
Brisswalter
Research Department, Sport Expertise and Performance (SEP) Laboratory, French National Institute of Sport, Expertise and Performance (INSEP), Paris, France.
Christophe
C
Hausswirth
D000328:Adult; D001341:Autonomic Nervous System; D001794:Blood Pressure; D015992:Body Mass Index; D001831:Body Temperature; D001835:Body Weight; D002395:Catecholamines / Q000097:blood; D003080:Cold Temperature; D017679:Cryotherapy; D006257:Head; D006339:Heart Rate; D006801:Humans; D007036:Hypothermia, Induced; D008297:Male; D008875:Middle Aged; D010275:Parasympathetic Nervous System; D055815:Young Adult
D002395:Catecholamines