Effects of exercise based on ACSM recommendations on individuals with a prediabetic state: a systematic review and meta-analysis of randomised controlled trials

Subgroup analyses were conducted to evaluate whether intervention adherence modifies the metabolic benefits of exercise. Mean reductions in FBG, 2hPG, and HOMA-IR were numerically larger in participants with high, compared with low or uncertain, adherence, suggesting a possible dose-response relationship between adherence and glycaemic improvement. Conversely, HbA1c displayed a marginally greater reduction in the low-adherence stratum - an observation that contrasts with the pattern seen for the other glucose/insulin indices. This discrepancy may reflect greater analytical variability of HbA1c, differences in intervention duration, baseline imbalance, or heterogeneity in programme content and individual responsivity across adherence categories. Large-scale, long-term trials that standardise the measurement of adherence and the delivery of exercise interventions are needed to definitively clarify the association between adherence and metabolic outcome.