The response of meteorin-like hormone and interleukin-4 in overweight women during exercise in temperate, warm and cold water.

Background Meteorin-like hormone (Metrnl) and interleukin-4 (IL-4) are protein molecules that stimulate the production of brown adipose tissue to improve diseases such as type 2 diabetes and obesity. The aim of this study was to investigate the response of Metrnl protein and IL-4 in overweight women during exercise in temperate, warm and cold water. Materials and methods Thirteen overweight young women (mean age 25.21 ± 3.27 years, body mass index 26.43 ± 1.34 kg/m2) were selected randomly and performed three sessions of interval exercise (40 min per session, 65% of maximum oxygen consumption) in non-consecutive days in temperate (24-25 °C), warm (36.5-37.5 °C) and cold (16.5-17.5 °C) water. Blood sampling was done immediately before and after exercise. Results The Metrnl level significantly increased after exercise in temperate and warm water (p = 0.0001) and significantly decreased in cold water (p = 0.0001). IL-4 level significantly increased after exercise in warm water (p = 0.003), while there was no significant change after exercise in temperate and cold water. Conclusions Exercise in warm water appears to stimulate and accumulate immune cells compared to temperate and cold water. This feature can be used to stimulate the production of hormones such as Metrnl and IL-4 to enhance brown fat, although more studies are needed in this regard.