Effects of a Cycling versus Running HIIT Program on Fat Mass Loss and Gut Microbiota Composition in Men with Overweight/Obesity

Abstract

Purpose High-intensity interval training (HIIT) can efficiently decrease total and (intra-) abdominal fat mass (FM); however, the effects of running versus cycling HIIT programs on FM reduction have not been compared yet. Additionally, the link between HIIT-induced FM reduction and gut microbiota must be better investigated. The aim of this study was to compare the effects of two 12-week HIIT isoenergetic programs (cycling vs. running) on body composition and fecal microbiota composition in nondieting men with overweight or obesity. Methods Sixteen men (age: 54.2 ± 9.6 years; BMI: 29.9 ± 2.3 kg.m-2) were randomly assigned to the HIIT-BIKE (10x45s at 80-85% of HRmax, 90s active recovery) or HIIT-RUN (9x45s at 80-85% of HRmax, 90s active recovery) group (3 times per week). DXA was used to determine body composition. Pre- and post-intervention fecal microbiota composition was analyzed by 16S rRNA gene sequencing, and diet was controlled. Results Overall, body weight, abdominal and visceral FM decreased over time (p < 0.05). No difference was observed for weight, total body FM and visceral FM between groups (% change). Conversely, abdominal FM loss was greater in the HIIT-RUN group (-16.1% vs -8.3%; p = 0.050). The α-diversity of gut microbiota did not vary between baseline and intervention end and between groups, but was associated with abdominal FM change (r = -0.6; p = 0.02). The baseline microbiota profile and composition changes were correlated with total and abdominal/visceral FM losses. Conclusions Both cycling and running isoenergetic HIIT programs improved body composition in men with overweight/obesity. Baseline intestinal microbiota composition and its post-intervention variations were correlated with FM reduction, strengthening the possible link between these parameters. The mechanisms underlying the greater abdominal FM loss in the HIIT-RUN group require additional investigations.