Author(s): RELJIC, D., HERRMANN, H.J., NEURATH, M.F., ZOPF, Y., Institution: UNIVERSITY HOSPITAL ERLANGEN, Country: GERMANY, Abstract-ID: 2307

INTRODUCTION:
Obesity and the metabolic syndrome (MetS) are major global health concerns, increasing the risk for morbidity and mortality. Recent research highlights the gut microbiome as a key regulator of metabolic health, with short-chain fatty acids (SCFAs) produced in the intestinal tract playing a crucial role in cardiometabolic health [1]. There is evidence that exercise may alter gut metabolites [2], but findings of previous studies remain inconsistent. We hypothesized that these discrepancies stem from differences in exercise intensity, with higher-intensity exercise leading to more pronounced microbial adaptations. This study examined the effects of a low-volume interval training plus single-set resistance training (RT) program, performed at either high intensity (HIGH-EX) or moderate intensity (MOD-EX), on gut SCFAs and cardiometabolic health indices in obese individuals with MetS.
METHODS:
A total of 113 subjects (53±12 yrs, BMI: 39±5) were randomized into three groups: HIGH-EX (5×1 min cycling at 80–95% HRmax, followed by progressive RT, 5 exercises, 50–80% 1-RM), MOD-EX (5×1 min cycling at <80% HRmax, followed by moderate RT, 50–60% 1-RM), and a non-exercising control group (CON). Training was performed twice weekly for 12 weeks. Stool samples were collected pre- and post-intervention to analyze SCFA concentrations. Additionally, VO2max, muscle strength, cardiometabolic risk markers, and MetS severity (MetS Z-score) were assessed.
RESULTS:
HIGH-EX and MOD-EX improved MetS-Z-Score (–1.1 units, p<0.01; and –0.5 units, p<0.05, respectively), VO2max (+4.2 mL/kg/min, p<0.01; and +2.7 mL/kg/min, p<0.05, respectively) and 1-RM strength values in major muscle groups (19–26%, all p<0.001; and 22–29%, all p<0.001, respectively). Both exercise groups also significantly reduced inflammation (hs-CRP, HIGH-EX: –2.2 mg/L, p=0.013; MOD-EX: –1.3 mg/L, p=0.01). Only HIGH-EX significantly increased total fecal SCFA concentration (+29%, p<0.001), including acetate (+27%, p<0.001), propionate (+24 %, p<0.001), and butyrate (+39%, p<0.001). None of the parameters changed in CON.
CONCLUSION:
This study indicates that low-volume interval training combined with single-set RT (70 min/week) improves physical fitness and cardiometabolic health in obese MetS patients at both high and moderate intensities. However, improvements in SCFA production were only observed in HIGH-EX. This suggests that exercise intensity plays a critical role in gut microbial adaptations, potentially mediated by higher lactate production, which has been linked to increased SCFA production [3]. Future research should further explore the mechanistic links between exercise intensity and gut microbiota metabolism to optimize exercise prescriptions for metabolic health improvements.

References:
1) Koh A et al. (2016) Cell 165: 1332-1345.
2) Sales KM, Reimer RA (2023) J Sport Health Sci 12: 36-44.
3) Scheiman J et al. (2019) Nat Med 25:1104-1109.