• Impact of Exercise on Gut Microbiome: Age and BMI-Dependent Variations in Interventional Studies
  • Raziye Tahmasebi,1,*
    1. Department of Nutrition, School of Allied Medical Sciences, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran


  • Introduction: The gut microbiota, comprising a diverse community of microorganisms in the digestive system, plays a pivotal role in maintaining health. Emerging evidence suggests that exercise training programs can modify the composition and function of the gut microbiota, potentially countering dysbiosis and the effects of chronic metabolic conditions, and even aging. This review study investigates the impact of exercise on the gut microbiome, taking into account age and body mass index (BMI) variations among participants.
  • Methods: Since active individuals and professional athletes tend to eat differently from sedentary individuals and have altered gut microbial metabolic pathways, only longitudinal studies on sedentary individuals were included to investigate the causality of this association. Moreover, exercise effect on gut microbiota can be immediate (acute physiological response) or delayed; the later which is referred to as training-effect was explored in this review. Articles were excluded if the participants were receiving medications, supplements, or specific diets designed to, or with the potential to alter the gut microbiota community. A systematic search of published peer-reviewed articles on PubMed and Google Scholar were conducted. Data from selected studies were meticulously extracted and recorded in an Excel file.
  • Results: The current review included 18 original studies meeting the inclusion criteria, revealing diverse efficacy levels and considerable inter-individual variations. Notable findings include: In obese children, exercise significantly improved gut microbiome composition toward a healthier composition. However, exercise did not induce significant changes in the gut microbiome of normal-weight adolescents. In obese or insulin resistant adults, Bacteriodetes phylum increased significantly after exercise interventions. Lean adults exhibited an increase in the Firmicutes to Bacteroidetes (F/B) ratio, while obese subjects displayed the opposite trend. In the elderly group, studies with lean subjects reported a significant decrease in Clostridium abundance after exercise intervention. Studies with a wide range of BMI in both adults and elderly, as well as one study in adolescents who recruited participants with different baseline physical activity levels, did not report significant alterations in gut microbiome composition.
  • Conclusion: The observed differences in baseline gut microbiome composition among lean, overweight, and obese individuals highlight the need for targeted interventions. This review underscores the importance of considering participants' baseline BMI, physical activity levels, and metabolic condition when investigating the impact of exercise on the gut microbiome. Future studies should address baseline microbiota heterogeneity and strive to minimize it, either by focusing on a narrow range of BMI or by adjusting results for influential factors.
  • Keywords: Gut microbiome, Exercise, Body mass index, age