Regional and time course differences in sweat cortisol, glucose, and select cytokine concentrations during exercise

Abstract

Introduction The use of sweat as a biofluid for non-invasive sampling and diagnostics is a popular area of research. However, concentrations of cortisol, glucose, and cytokines have not been described across anatomical regions or as time progresses throughout exercise. Purpose To determine regional and time course differences in sweat cortisol, glucose, and select cytokines (EGF, IFN-γ, IL-1β, IL-1α, IL-1ra, TNF-α, IL-6, IL-8, and IL-10). Methods Sweat was collected with absorbent patches from eight subjects (24–44 y; 80.2 ± 10.2 kg) on the forehead (FH), right dorsal forearm (RDF), right scapula (RS), and right triceps (RT) at 0–25 min, 30–55 min, and 60–85 min during 90 min of cycling (~ 82% HRmax) in a heated chamber (32 °C, 50% rh). ANOVA was used to determine the effect of site and time on outcomes. Data are reported as LS means ± SE. Results There was a significant effect of location on sweat analyte concentrations with FH having higher values than most other regions for cortisol (FH: 1.15 ± 0.08 ng/mL > RDF: 0.62 ± 0.09 ng/mL and RT: 0.65 ± 0.12 ng/mL, P = 0.02), IL-1ra (P < 0.0001), and IL-8 (P < 0.0001), but lower concentrations for glucose (P = 0.01), IL-1α (P < 0.0001), and IL-10 (P = 0.02). Sweat IL-1β concentration was higher on the RS than RT (P < 0.0001). Sweat cortisol concentration increased (25 min: 0.34 ± 0.10 ng/mL < 55 min: 0.89 ± 0.07 ng/mL < 85 min: 1.27 ± 0.07 ng/mL; P < 0.0001), while EGF (P < 0.0001), IL-1ra (P < 0.0001), and IL-6 (P = 0.02) concentrations decreased over time. Conclusion Sweat analyte concentrations varied with time of sampling and anatomical region, which is essential information to consider when conducting future work in this area. Clinical trial identifier NCT04240951 registered January 27, 2020.

No effect of tattoos on local sweat concentrations of select cytokines, cortisol, glucose, blood urea nitrogen, or lactate during exercise

“…Additionally, previous studies have reported similar local sweat lactate concentrations 34,35 and local sweat cytokine concentrations and excretion rates for EGF and IL-8 36 as our study. Further, local sweat cortisol concentration reported in our study is in line with previously reported values following exercise 36,37 and passive heating 38 . There were differences in local sweat concentrations in the present study versus previous studies for IL-8 2,5 , IL-1α 3 , and BUN 39 .…”

No Effect of Tattoos on Local Sweat Concentrations of Select Cytokines, Cortisol, Glucose, Blood Urea Nitrogen, or Lactate During Exercise

“…Previous studies have reported similar local sweat cytokine concentrations and excretion rates for EGF and IL-8 33 , local sweat lactate concentrations 34,35 , and local sweat BUN and glucose concentrations 1 as our study. Further, local sweat cortisol concentration reported in our study is in line with previously reported values following exercise 33,36 and passive heating 37 . There were differences in local sweat concentrations for IL-8, TNF-α 2,5 , IL-1α 3 IL-1β 2,3,5 and BUN 38 .…”