Eight-week flexi-bar vibration exercise improves cardiovascular function accompanied by altered gut microbiota and metabolites in middle-aged and elderly women: a randomized controlled trial

Aims This study aimed to investigate the impact of 8-week FE on cardiovascular health in middle-aged and elderly women and explore correlational associations involving gut microbiota and its metabolites. Methods Thirty middle-aged and elderly women were randomly divided into FE group and control group. Body composition parameters were assessed using a body composition analyzer. cfPWV and baPWV were detected to assess central and systemic arterial stiffness, respectively. To evaluate central hemodynamic parameters and cardiac autonomic function, HR, augmentation index, SEVR, and HRV were measured. Biochemical factors in serum were detected by ELISA. Gut microbiota and SCFAs levels in Fecal samples were assessed by 16S rRNA gene sequencing and GC-MS. Results FE helped preserve water, inorganic salts, muscle mass, and fat-free mass, while prevented the accumulation of body weight and body fat. FE also significantly decreased HR, central systolic and diastolic blood pressure, cfPWV and R-baPWV. The HRV analysis demonstrated that FE increased SDNN and NN50 (time-domain indices) and high-frequency band, while decreasing low-frequency band. Moreover, FE significantly up-regulated the serum eNOS level and down-regulated ICAM1 level. Meanwhile, FE increased Bacteroidota abundance and decreased Firmicutes abundance, alongside elevated fecal acetic acid, propionic acid, and caproic acid in fecal samples. Conclusions 8-week FE improves cardiovascular function in middle-aged and elderly women by enhancing parasympathetic activity, reducing sympathetic overactivity, and mitigating arterial stiffness. Parallel shifts in gut microbiota composition and elevated SCFAs were observed following FE intervention, highlighting FE as an effective intervention for cardiovascular health in this population. Clinical Trial Registration http://www.chictr.org.cn/ , identifier ChiCTR2000041245.