Effect of Tai Chi Versus Moderate-intensity Combined Exercise Training on Cardiovascular Health and Physical Functional Performance in Older Men and Women With T2DM: the Tai Chi Intervention for Diabetes Management During Aging (TIDA) Study

This randomized, single-blind, controlled clinical trial compares the effects of a 12-week Tai Chi program versus moderate-intensity combined exercise (MICE) training on cardiovascular health, glycemic control, and physical function in older adults with type 2 diabetes (T2DM). Sixty-six participants (33 men and 33 women) will be randomized 1:1:1 to Tai Chi (n = 22), MICE (n = 22), or a non-exercise control group (CON, n = 22). The Tai Chi intervention involves three weekly Yang-style sessions, progressively increasing in duration and complexity while maintaining perceived exertion (PSE) below 12 (6-20 scale). The MICE program combines moderate-intensity walking (PSE 12-13) with six strengthening exercises (PSE 12-14), gradually increasing from 15 to 30 minutes/session and 1 to 3 sets over 12 weeks. Primary outcomes include cardiovascular health (Life's Essential 8 index: diet, physical activity, nicotine exposure, sleep, BMI, lipids, blood glucose, and blood pressure) and glycemic control (fasting glucose, HbA1c). Secondary outcomes assess physiological mechanisms (heart rate variability, pulse wave velocity, flow-mediated dilation, carotid intima-media thickness), physical performance (6-minute walk test, grip strength, timed up-and-go), and quality of life (WHOQOL-BREF/OLD). All evaluations will be conducted by blinded assessors under standardized conditions (21-24°C, morning fasting), except the 6MWT. Statistical analysis includes intention-to-treat repeated-measures ANOVA, ANCOVA for baseline adjustments, and per-protocol/adherence-adjusted analyses. Sample size (GPower) was calculated to detect a 0.8% HbA1c reduction with 90% power (30% attrition accounted for). An interim analysis at 50% completion will evaluate effect sizes/variability, with potential sample-size recalibration by an independent committee. The study employs rigorous quality controls: standardized protocols, blinded assessments, and monitoring of confounders (medication changes, acute exercise effects). Ethical approval (CAAE: 88582225.1.0000.5398) ensures adherence to informed consent and privacy. By determining whether Tai Chi offers comparable or superior benefits to MICE for cardio metabolic health and functional capacity, this trial aims to inform evidence-based exercise prescriptions for older T2DM patients.