Research

Hormonal

Endurance training adaptations, including visceral fat reduction and cardiac remodeling, are mediated by muscle-secreted IL-6, as blocking IL-6 receptors impairs these specific structural adaptations without affecting peak endurance capacity (VO2peak).

If you are doing endurance training to lose visceral fat or improve heart structure, your body's natural IL-6 response is likely helping you achieve those specific structural goals. However, you do not need to worry about 'blocking' this pathway if you are just trying to improve your overall aerobic fitness (VO2max), as that improvement can still occur even if IL-6 signaling is impaired. Focus on consistent training; the structural benefits are tied to this specific inflammatory-like signaling, but peak capacity is not.

ModerateSupportsMEDIUM confidence
the reduction of visceral and epicardial fat tissue in response to 12 weeks of high-intensity endurance training was dependent on intact IL-6 signaling... intact IL-6 signaling was required for training-linked left ventricle hypertrophy... VO2peak... was similarly ameliorated after endurance training in participants treated with the IL-6 receptor (IL-6R) antagonist tocilizumab or placebo
Aurel B. Leuchtmann et al. · Frontiers in Physiology · 2021

Why this rating

Based on human clinical trials using IL-6R antagonists, but the paper notes caveats regarding the source of IL-6 (muscle vs. other organs).

Source

The Role of the Skeletal Muscle Secretome in Mediating Endurance and Resistance Training Adaptations

Aurel B. Leuchtmann et al. · Frontiers in Physiology · 2021

DOI 10.3389/fphys.2021.709807

narrative_reviewCited 77×
Read the paper
DOI resolved against Crossref · corpus check 2026-06-10

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