Acute Cytokine Responses to High-Intensity Intermittent Exercise in Humans: A Systematic Review

Area of Science:

• Exercise Physiology
• Immunology
• Biochemistry

Background:

• High-intensity intermittent exercise (HIIE) acutely affects circulating cytokines.
• Previous findings on cytokine responses to HIIE are inconsistent.
• Understanding these responses is crucial for exercise science and health.

Purpose of the Study:

• To systematically review and synthesize acute blood cytokine changes after a single bout of HIIE in humans.
• To identify consistent patterns and moderators of cytokine responses to HIIE.
• To assess the quality of evidence regarding HIIE and cytokine alterations.

Main Methods:

• Systematic literature search of PubMed, Scopus, and Web of Science.
• Inclusion of human studies measuring serum/plasma cytokines pre- and post-HIIE.
• Narrative synthesis of data, with risk of bias assessment (RoB 2, JBI tool).

Main Results:

• Interleukin 6 (IL-6) was the most consistently elevated cytokine post-HIIE.
• Tumor necrosis factor alpha (TNF-α) and interleukin 10 (IL-10) showed mixed responses.
• Risk of bias was often rated as 'some concerns,' highlighting pre-analytical and reporting limitations.

Conclusions:

• HIIE typically induces a transient, myokine-driven inflammatory response, mainly via IL-6 increase.
• Variability in TNF-α, IL-10, and other mediators is explained by sampling time, exercise dose, and participant characteristics.
• Future research should address pre-analytical standardization and reporting for clearer cytokine response insights.