Intestinal permeability may contribute to low-grade inflammation and cardiovascular disease (CVD). Despite health benefits, aerobic exercise acutely increases intestinal permeability, even in healthy populations. The possibility that at-risk groups display exaggerated intestinal permeability and inflammatory responses to exercise compared to healthy individuals is largely unexamined. Those with a normal body mass index (BMI) and high body fat percent (normal-weight obesity or NWO) are at increased CVD risk. Subclinical inflammation is one suggested mechanism promoting CVD in NWO; yet underlying drivers remain unclear. The objective of this study was to examine intestinal permeability and inflammatory biomarkers in NWO pre/post incremental peak and submaximal steady-state exercise relative to normal-weight lean (normal BMI, low body fat; NWL) and obese BMI, high body fat (OB) participants. We hypothesized that NWO and OB would display a more pronounced increase in intestinal permeability and inflammatory biomarkers compared to NWL following both exercise bouts. Participants (N=31; n=10-11/group; 52% female) were grouped using standard BMI cutoffs (i.e., 18.5-24.9 kg/m 2 or ≥ 30.0 kg/m 2 ). High body fat percent was defined as ≥ 25% in males and ≥ 35% females and low body fat percent was below these thresholds. Each participant completed a Formula: see textO 2 peak test (T1) and 45 minutes at 65% Formula: see textO 2 peak (T2) on a cycle ergometer. Serum samples were obtained before and immediately following exercise. At T1, circulating soluble CD14 (sCD14), lipopolysaccharide binding protein (LBP), and fatty acid binding protein 2 (FABP2) were measured as indicators of intestinal permeability. At T2, FABP2 and interleukin (IL)-6 were assayed. Full sample and within group changes pre/post exercise were assessed (paired t tests) and absolute change scores across groups compared (one-way ANOVAs). Following T1, sCD14 increased in the full sample, NWL, and OB (p’s≤0.05). FABP2 increased in NWO at T1 (p˂0.05), but not in other pre/post comparisons. At T2, FABP2 increased in the full sample and OB (p’s≤0.05). IL-6 also increased at T2 in all participants, NWL, NWO (p’s≤0.05), and nearly OB (p=0.06). When comparing absolute changes in intestinal permeability and inflammatory markers across groups, no differences were noted at T1 or T2. Exploratory correlation analysis revealed that body fat percent was positively associated with T1 change in sCD14 in the full sample (r=0.36;p˂0.05). In summary, NWO’s intestinal barrier response to exercise was largely similar to other groups, with some preliminary exceptions. The influence of relative adiposity on exercise-induced intestinal permeability warrants further examination. This abstract was presented at the American Physiology Summit 2026 and is only available in HTML format. There is no downloadable file or PDF version. The Physiology editorial board was not involved in the peer review process.
Keirns et al. (Fri,) studied this question.