Abstract:Objective To investigate the efficacy of high-intensity interval training（HIIT）and live Bifidobacteriumcapsules combined with 5-aminosalicylic acid in the treatment of ulcerative colitis（UC），and its impact on immunefunction，intestinal flora，intestinal mucosal function and inflammatory factors. Methods A total of 80 patients with mild to moderate active UC who were admitted to Jiangsu Province（Suqian）Hospital from March 2022 to March2024 were retrospectively enrolled as the research subjects. All patients received standard treatment based on 5 -aminosalicylic acid preparations. On this basis，40 patients treated with live Bifidobacterium capsules were assigned to the control group，and 40 patients treated with HIIT combined with live Bifidobacterium capsules were assigned to the combination group. Both groups were treated continuously for one month，with colonoscopy performed before and after treatment to evaluate mucosal healing. The curative effect，as well as the levels of peripheral blood T lymphocyte subsets，intestinal flora，intestinal mucosal function indicators ［diamine oxidase （DAO），D-lactic acid］ and inflammatory factors［interleukin（IL）-1β，tumor necrosis factor（TNF）-α，IL-8］of the two groups were compared.Results After one month of treatment，the overall effective rate of the combination group was higher than that of the control group（97.50% vs 80.00%，χ2=4.507，P=0.034）. In both groups，the patients' fecal Escherichia coli colonycounts，peripheral blood CD8 +，serum DAO，D-lactic acid，IL-1β，TNF-α，and IL-8 levels decreased compared to before treatment，while CD4 +，CD3 +，CD4 +/CD8 +，and Bifidobacterium and Lactobacillus colony counts increased compared to before treatment（P<0.05），and all indicators in the combination group were better than those in the control group（P<0.05）. Conclusion Based on standard treatment with 5-aminosalicylic acid，combining HIIT with live Bifidobacterium capsules can effectively enhance patients ' immune function，optimize intestinal microbiota，improve intestinal mucosal function，reduce UC inflammatory response，and significantly increase the efficacy of UC treatment.