AUTHOR=Mu Shuai , Ding Ding , Ji Chao , Wu Qijun , Xia Yang , Zhou Long , Yang Liyu , Ba Gen , Chang Qing , Fu Qin , Zhao Yuhong 

TITLE=Relationships Between Circulating Irisin Response to Ice Swimming and Body Composition in People With Regular Exercise Experience

JOURNAL=Frontiers in Physiology

VOLUME=Volume 11 - 2020

YEAR=2021

URL=https://www.frontiersin.org/journals/physiology/articles/10.3389/fphys.2020.596896

DOI=10.3389/fphys.2020.596896

ISSN=1664-042X

ABSTRACT=Austere cold exercise involve irisin responses, and may be related to body composition. We aim to investigate changes in circulating irisin after ice swimming (IS), as well as evaluate the correlation between body composition and the change of irisin caused by IS (Δirisin). Eighty-one ice swimmers were recruited to perform IS activities. Blood samples were drawn 30 min before and 30 min after IS, and the serum levels of irisin and the ice swimmers’ body composition were measured. As a result, the circulating irisin declined significantly during the recovery period following IS exercise (P < 0.001). The afternoon baseline circulation irisin level and Δirisin in response to IS were correlated with body fat characteristics rather than muscle parameters in ice swimmers. Δirisin subgroup analyses shown the Δirisin ascending group (Δirisin+) subjects had a higher fat composition and higher basal irisin level compared with the Δirisin descending group (Δirisin-). Furthermore, the decrease in irisin was negatively correlated with fat components in Δirisin- subjects, whereas no correlation was observed between the increase in irisin and body composition in Δirisin+ subjects. Finally, nonlinear associations analysis suggested body fat indicators have obvious curvilinear relationships with Δirisin. In conclusion, IS caused significant reduction in irisin. Statistical and curvilinear associations suggested the correlation between fat tissue and Δirisin caused by IS is dimorphic and the underlying mechanisms may be due to the different metabolic states of subjects.