Cold Stress Protocol in Brown Adipose Tissue Activation in Obese Men

PURPOSE: To measure the activation of brown adipose tissue by cold stress protocol in obese men. METHODS: 24 male military from Brazilian Army were evaluated (38.5 ± 1.8 years, BMI:30.7 ± 2.9 kg/m2,body fat:31.0 ± .2%). The maximum and medium supraclavicular temperature (TScvMax/TScvMed) from right/left sides and the maximum and medium sternum temperature (TStrMax/TStrMed) were register using the infrared camera E75 FLIR®, in two moments. First, volunteers remain 30 min in a thermoneutral environment (22.6 ± 0.2 °C) for thermalization. Second, hands were submerged in a container with ice water at the temperature of 13.0 ± 0.4 °C, during 5 min after. The body composition was evaluated using double X-ray absorptiometry. Kolmogorov-Smirnov normality test applied and confirmed parametric approach. The data were analyzed by SPSS® 25.0, running Student’s t-test two paired samples. The effect-size (Cohen's d) was calculated with GPower software. Significance level at p < 0.05. The images were analyzed using FLIR Tools® software. RESULTS: On the TScvMax was observed a significant increase on the right side from 33.6 ± 0.4 °C to 34.1 ± 0.6 °C (p < 0.001;d = 0.787) and on the left side 33.3 ± 0.6 °C to 34.0 ± 06.4 °C (p < 0.001;d = 0.787). On the TScvMed also was observed a significant increase on the right side from 32.8 ± 0.4 °C to 33.4 ± 0.6 °C (p < 0.001;d = 0.787) and on the left side 32.5 ± 0.5 °C to 33.1 ± 0.5 °C (p < 0.001;d = 0.787). But it was not observed in the control region (Sternum) where there was no BAT for TMax and TMed (p = 0.923 and p = 0.869), respectively. CONCLUSIONS: Cold stress protocol proved to be effective in BAT activation, increasing the temperature in the supraclavicular region for the obesity men group. This protocol ican be used in the clinical evaluation. It is suggested that in future studies other protocols with less time of exposure to the cold be studied, thus reducing the discomfort of the evaluated individual.