Influence of body position on skin temperature, heart rate, and blood pressure in active men

The use of thermography to measure skin temperature (Tsk) is typically assessed in a standing position; however, the differences of Tsk in different body positions have not been adequately studied. This study aimed to analyze the influence of body position (sitting, standing, and supine) on Tsk. Twenty-nine trained men (age 23.52 ± 0.34 years) spent 10 minutes in each of the three positions in random order. During these postures, the heart rate (HR) response and systolic and diastolic blood pressure were measured as influential cardiovascular variables. Tsk was measured in the trapezius, shoulder, chest, biceps, costal, elbow, abdomen, and forearm. Covariance analysis (ANCOVA), intraclass correlation (ICC), typical error, and effect size (ES) were applied. When comparing the three positions, greater variations in Tsk were observed in the shoulder (0.74–1.31 %), biceps (−0.36 - 1.33 %), elbow (0.46–1.20%) and forearm (0.58–1.41%). HR varied significantly between the different positions (p < 0.05), influencing Tsk in the chest (ES = 0.71), the biceps (ES = 0.56) and abdominal regions (ES = 0.91) in the sitting position compared to the supine position, and in the abdominal region (ES = 1.12) in the standing position compared to the supine position. The reliability of the measurement was excellent in the chest (ICC = 0.91), costal (ICC = 0.91), and abdominal (ICC = 0.89) regions. Although many studies traditionally measure Tsk in a standing position, the results of this study support that the Tsk distribution varies with body position, and this factor should be considered in any study using thermography.