Journal of Applied Sports Sciences 9(1): 12-23, doi: 10.37393/JASS.2025.09.01.2
The increase in plasma IL-6 following sprint interval training does not depend on total sprint volume
Jie Zhang‡, Johnny LM Blaschek§, Matthew Hutchinson§, Daniel Kinghorn§, Richard S. Metcalfe|, Elliott C.R. Hall§, Kerry L Bartie§, Niels B.J. Vollaard§‡ Donghua university, Shanghai, China§ University of Stirling, Stirling, United Kingdom| Swansea University, Swansea, United Kingdom
Corresponding author: Niels B.J. Vollaard ( n.vollaard@stir.ac.uk ) © Jie Zhang, Johnny LM Blaschek, Matthew Hutchinson, Daniel Kinghorn, Richard S. Metcalfe, Elliott C.R. Hall, Kerry L Bartie, Niels B.J. Vollaard. This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY-NC-SA 4.0), which permits to copy and distribute the article for non-commercial purposes, and the original author and source are credited. Adapted content must be distributed under the same license Citation:
Zhang J, Blaschek JL, Hutchinson M, Kinghorn D, Metcalfe RS, Hall ECR, Bartie KL, Vollaard NBJ (2025) The increase in plasma IL-6 following sprint interval training does not depend on total sprint volume. Journal of Applied Sports Sciences 9(1): 12-23. https://doi.org/10.37393/JASS.2025.09.01.2 |  |
Abstract
The magnitude of the benefi cial increase in plasma interleukin-6 (IL-6) with exercise is greater with continuous exercise of higher intensity and longer duration. However, it is unknown whether a greater volume of supramaximal interval exercise also enhances the IL-6 response. Therefore, the aim of this study was to compare the eff ects of two sprint interval training (SIT) protocols involving different volumes of sprint exercise on plasma IL-6 levels. Nine healthy young men (age: 24±4 y, BMI: 23.3±3.1 kg·m-2, V̇ O2max: 42±6 mL·kg-1·min-1) completed three experimental trials in randomised order, including ‘classic’ SIT (4x30-s ‘all-out’ cycle sprints within a 22-min session), reduced-exertion high-intensity interval training (REHIT; 2x20-s ‘all-out’ cycle sprints within a 10-min session), and a control condition (seated rest). Blood samples were collected before exercise and at 0-, 30-, and 90-min post-exercise, and analyzed for lactate and IL-6. Blood lactate levels peaked directly post-SIT (1.5±0.2 mM to 11.9±2.5 mM; p<.001) and REHIT (1.7±0.4 to 9.1±3.1 mM; p<.001). Plasma IL-6 levels peaked 30-min post-exercise (0.84±0.12 to 1.31±0.17 pg·mL-1 for SIT, p=.003; 0.75±0.09 to 1.18±0.36 pg·mL-1 for REHIT, p=.028). Compared to the con-trol trial, IL-6 iAUC was signifi cantly higher for both SIT (p=.002) and REHIT (p=.013), with no signifi cant diff erence between SIT and REHIT. In conclusion, we demonstrate that the increase in plasma IL-6 levels is similar for the two SIT protocols involving a 3-fold diff erence in sprint exercise volume (120 s vs. 40 s). Our data provide support for a possible role of glycogenolysis in the IL-6 response to SIT.
Keywords
interleukin-6, lactate, Reduced-exertion high-intensity interval training, REHIT, SIT