Feasibility and preliminary effects of high-intensity interval training vs. moderate-intensity continuous training on...

Elevated plasma calprotectin, an inflammatory biomarker, is linked to higher cardiovascular risk in type 2 diabetes (T2DM), suggesting lifestyle interventions like exercise may help regulate it. This pilot study evaluated the feasibility of future full-scale trial for comparing the effect of high-intensity interval training (HIIT) vs. moderate-intensity continuous training (MICT) on calprotectin in T2DM patients without cardiovascular disease.

This open-label, randomized controlled pilot trial was conducted from December 2018 to March 2019 at the Rajaie Cardiovascular Institute, Tehran, Iran. Participants over 18 years of age with T2DM, an HbA1c between 6.5% and 10%, a BMI between 24 and 35 kg/m², and stable medication use for at least four weeks before enrollment, were randomly assigned at a 1:1 ratio to HIIT or MICT group for eight weeks. Primary endpoints included recruitment and retention rates, whereas changes in biomarkers after training were secondary endpoints.

Out of 58 T2DM patients assessed for eligibility, 18 were recruited (9 females, 9 males; mean age: 52 ± 6.0 years; mean BMI: 28.7 ± 3.8 kg/m²), resulting in a recruitment rate of 32%. All participants completed the study, and no adverse events occurred. The calprotectin level decreased in the HIIT group but increased in the MICT group [mean difference (CI95%): 73.4(-337.1, 483.9) vs. -15.4(-553.9, 523.2)].

This study demonstrated efficient participant recruitment, complete retention, and safety, indicating that a full-scale trial is feasible. The reduction in calprotectin levels in the HIIT group supports further investigation in the full-scale trial.

Iranian Registry of Clinical Trials (IRCT), IRCT20181129041797N1, Registered 25 Dec 2018, https://irct.behdasht.gov.ir/trial/35598.

The online version contains supplementary material available at 10.1007/s40200-025-01713-6.