Author(s): NUZUM, N., VALDERRAMA, B., KANON, A.P., GRABRUCKER, S., MUNUSWAMY, R., OSULLIVAN, O., CRYAN, J.F., CLARKE, G., Institution: UNIVERSITY COLLEGE CORK, Country: IRELAND, Abstract-ID: 1772

INTRODUCTION:
The brain health benefits of exercise are increasingly appreciated as are the implications of the gut microbiome for the regulation of brain function and behaviour. While research has investigated relationships between exercise and the gut microbiome, results are variable and the interface between aerobic fitness, the gut microbiome (and its neuroactive potential) and brain health remain poorly understood. By systematically re-analysing prior exercise and gut microbiome research via in silico pipelines, we aimed to explore the relationship between the functions of the gut microbiome and aerobic fitness. Elucidating the details of the relationship between exercise and the gut microbiome can help uncover mechanisms of action and pave the way for increased uptake of exercise to support gut and brain health.
METHODS:
This review (PROSPERO CRD42024480951) included human studies with gut bacterial data, VO2max, or studies implementing an aerobic exercise intervention with pre-post data. 16 studies were included with 1,230 individual samples (473 females and 433 males; 27.8±10 y, 24.1±3.9 kg/m2, VO2max 40.4±11.5 ml/kg/min). Study data was downloaded and assessed via bioinformatics pipelines, with statistical analysis conducted in R covering bacterial diversity, abundance and functionality assessed via the gut-metabolic and gut-brain modules (predicted via PICRUSt2 on 16S samples).
RESULTS:
While alpha-diversity was not related to VO2max (all p>0.05), significant associations were observed between five gut brain modules and VO2max (all q<0.05), including a positive association of ‘Propionate Synthesis III’, a short chain fatty acid of importance for gut-brain axis signalling [1]. 10 bacterial genera were also associated with VO2max (all q<0.05).
CONCLUSION:
This research indicates that VO2max and functional gut bacterial measures, or relative abundance of specific genera, are related. Positive associations between VO2max and propionate synthesis is consistent with prior research showing exercise induced lactate is converted by Veillonella bacteria to propionate, a feature associated with endurance performance in mice [2]. These data show that aerobic fitness may be associated with the metabolic and neuroactive potential of the gut microbiome. Further analyses of studies reporting the impact of aerobic interventions on gut bacterial composition and function over time are underway. Together, this information may be used to better inform the prescription of physical activity interventions towards enhancing performance and brain health.

1. O’Riordan KJ, Collins MK, Moloney GM, Knox EG, Aburto MR, Fülling C, et al. Short chain fatty acids: Microbial metabolites for gut-brain axis signalling. Molecular and Cellular Endocrinology. 2022 Apr 15;546:111572.
2. Scheiman J, Luber JM, Chavkin TA, MacDonald T, Tung A, Pham LD, et al. Meta-omic analysis of elite athletes identifies a performance-enhancing microbe that functions via lactate metabolism. Nature medicine. 2019 Jul;25(7):1104.