HIIT discontinuation may be detrimental to diabesity parameters whereas retraining enhances intestinal health and gut microbiota diversity 

AbstractBackground The term "diabesity," which refers to the simultaneous presence of diabetes and obesity, is associated with a significant mortality rate globally. However, there is a lack of comprehensive literature on the effects of stopping high-intensity interval training (HIIT) and then resuming it. This study sought to examine how the interruption and subsequent resumption of HIIT impacted the physiological changes in mice with diabesity. Seventy-five C57BL6 mice were used in this study, divided into five stages: baseline, diabesity induction, training, detraining, and retraining. Diabesity was induced in two groups of mice (obese - Western Diet, and control - diet AIN) over 10 weeks. Both groups were further divided into control and trained animals, with each stage (training, detraining, and retraining) lasting 6 weeks. HIIT was performed three times a week, consisting of five sets at 90% of maximum speed (Vmax). This study also analyzed various parameters, including lipid profile, glycemic kinetics, blood glucose, adiposity index, intestinal histology, and gut microbiota profile. Results HIIT resulted in metabolic enhancements and a fat loss, whereas the detraining led to a decline in these alterations. Although retraining exhibits a degree of blood glucose regulation, it was not effective in generating fat loss and weight loss. Conversely, HIIT retraining seems to enhance goblet cell populations and increase gut crypt depth, concurrently causing modifications in the gut microbiota composition. While both the initial training and subsequent retraining exerted an effect on the composition of the gut microbiota, the impact of a Western diet demonstrates a more substantial potency compared to that of physical training concerning intestinal health and microbial composition. Conclusions These findings may contribute to a broader understanding of diabesity management and introduce novel perspectives for the use of physical training to enhance patient outcomes in gut microbiota composition.