Comparison of Sweat versus Serum IL‐1α and IL‐1β Concentrations during Exercise

Abstract

Interleukin (IL) 1 cytokines, IL‐1α and IL‐1β, are well known for their immunological responses as blood biomarkers; however, it is unclear if sweat cytokine concentrations can be used to predict that of blood. The purpose of this study was to determine the correlations between sweat and serum for IL‐1α and IL‐1β concentrations measured during exercise. Nine moderately‐trained recreational athletes (35±7 y, 73.9±14.4 kg, VO2max 46.2±8.0 ml/kg/min) completed 90 min of cycling at 80±5% HRmax in the heat (31°C, 50% RH). Preceding exercise, left ventral forearm (LVF) was cleaned with alcohol and deionized water, and an absorbent patch (10 cm2 absorbent pad, 3M Tegaderm™ + Pad) was applied 10 min into exercise. The patch was removed at the end of 90 min of exercise alongside a synchronous blood draw. Sweat and serum IL‐1α and IL‐1β were measured using Multiplex (EMD Millipore, MagPix) IL‐1α and IL‐1β kits. Spearman correlation was performed to determine the relation between sweat and serum for IL‐1α and IL‐1β. Non parametric sign test was used to determine mean differences between sweat and serum. Cytokine measurements are shown as mean ± SD. There were no significant correlations between sweat and serum for IL‐1α (r=−0.19, p=0.61) or IL‐1β (r=0.20, p=0.61). There were significant mean differences in IL‐1α expression between sweat (1004.5±613.8 pg/mL) and serum (24.9±58.1 pg/mL) (p=0.004), and non‐significant mean differences in IL‐1β between sweat (2.3±1.9 pg/mL) and serum (1.3±1.3 pg/mL) (p=0.45). These results suggest that there were no significant correlations between sweat and serum IL‐1 cytokine concentrations. Unlike IL‐1β, IL‐1α expression in sweat was significantly different between sweat and serum. Therefore, it seems that IL‐1 expression in sweat may have limited utility in predicting blood IL‐1 concentrations.Support or Funding InformationThis study was funded by the Gatorade Sports Science Institute, a division of PepsiCo, Inc. The views expressed in this abstract are those of the authors and do not necessarily reflect the position or policy of PepsiCo, Inc.