However, in contrast to this, one of the studies used in this systematic review showed a significant reduction in the values of weight and abdominal fat within the HIIT group and T2D, but it did not show changes in any of the inflammatory biomarkers [54], and another study showed a significant increase in irisin within the HIIT group, but not in the values of body composition [53]. This evidence concerns the gene FNDC5 and type 2 diabetes mellitus.