The effects of high intensity interval training (HIIT) on insulin sensitivity and metabolic health in adults with prediabetes

Abstract

Background. Prediabetes elevates lifetime risk of type 2 diabetes and cardiovascular disease. Moderate-intensity continuous training (MICT) improves metabolic health but is limited by time demands. High-intensity interval training (HIIT) is a time-efficient alternative that can match or exceed MICT benefits for insulin sensitivity and glycemic control, yet optimal protocols remain unclear.  Aim. To evaluate the effects of HIIT on insulin sensitivity and metabolic health in adults with prediabetes.  Material and methods.  PubMed, Scopus and Google Scholar were searched for English-language peer-reviewed studies (2015–2026) on HIIT and insulin sensitivity or metabolic outcomes in adults with prediabetes. Eligible randomised controlled trials, controlled trials, observational studies and reviews were screened by title/abstract and full text after duplicate removal; reference lists were also hand-searched.  Results. HIIT improved muscle and whole-body insulin sensitivity, reduced fasting glucose and HbA1c, and increased VO₂max, often comparably to MICT despite lower time commitment. Higher-volume protocols yielded greater HbA1c reductions; greater volume also strengthened benefits for fasting glucose, insulin and HOMA-IR. Combined HIIT plus diet produced the best BMI outcomes, while clamp-derived insulin sensitivity improvements partly depended on ≥3 % weight loss. Superiority over MICT varied by outcome and protocol.  Conclusions. HIIT delivers meaningful gains in insulin sensitivity and metabolic health that are frequently comparable to MICT with substantially less time. Larger standardised trials are needed to define optimal, individualised prescriptions for type 2 diabetes prevention.