Available online 10 April 2024

A single bout of exercise is likely to induce small to large increases in myokine expression immediately after and up to 60 min post-exercise, while myokine responses typically revert to baseline levels from 180 min to 24 h post-exercise.

Both aerobic exercise and resistance exercise lead to notable changes in the expression of myokines; however, the magnitude of these changes varies according to the specific myokine type.

This meta-analysis expands our knowledge of the overall effects of myokine expression in relation to exercise modes; however, substantial variation is evident, indicating that the response to exercise mode is myokine-specific.

Some exercise modes and time points have not been investigated for certain myokines and, thus, should be considered for future research.

The benefits of exercise are well known; however, many of the underlying molecular mechanisms are not fully understood. Skeletal muscle secretes myokines, which mediate muscle–organ crosstalk. Myokines regulate satellite-cell proliferation and migration, inflammatory cascade, insulin secretion, angiogenesis, fatty oxidation, and cancer suppression. To date, the effects of different exercise modes (namely, aerobic and resistance exercise) on myokine response remain to be elucidated. This is crucial considering the clinical implementation of exercise to enhance general health and wellbeing and as a medical treatment.

A systematic search was undertaken in PubMed, Medline, CINAHL, Embase, SPORTDiscus, and Web of Science in April 2023. Eligible studies examining the effects of a single bout of exercise on IL-15, irisin, SPARC, OSM, and decorin were included. A random-effects meta-analysis was also undertaken to quantify the magnitude of change.

Sixty-two studies were included (n = 1193). Overall, exercise appeared to induce small to large increases in myokine expression, with effects observed immediately after to 60 min post-exercise, although these were mostly not statistically significant. Both aerobic and resistance exercise resulted in changes in myokine levels, without any significant difference between training modes, and with the magnitude of change differing across myokines. Myokine levels returned to baseline levels within 180 min to 24 h post-exercise. However, owing to potential sources of heterogeneity, most changes were not statistically significant, indicating that precise conclusions cannot be drawn.

Knowledge is limited but expanding with respect to the impact of overall and specific effects of exercise on myokine expression at different time points in the systemic circulation. Further research is required to investigate the effects of different exercise modes at multiple time points on myokine response.

Myokine

Resistance exercise

Aerobic exercise

Cytokine

Systemic circulation

© 2024 Published by Elsevier B.V. on behalf of Shanghai University of Sport.