Two Weekly Sessions of High-Intensity Interval Training Improve Metabolic Syndrome and Hypertriglyceridemic Waist Phenotype in Older Adults: A Randomized Controlled Trial

Background: Exercise training provides physiological benefits for maintaining good health. A common exercise strategy is high-intensity interval training (HIIT). HIIT may alleviate metabolic syndrome (MetS) and hypertriglyceridemic waist (HTGW) phenotype, but remains largely unstudied in ageing participants. The aim of this research was to investigate the impact of 2 weekly HIIT sessions on MetS markers and HTGW-related factors in older adults. Methods: In this randomized controlled trial, 140 older men and women were randomized into two groups, the experimental group (EG), and the control group (CG). The EG performed 2 weekly sessions of HIIT during 12 weeks. HIIT sessions consisted of 40 min treadmill running/walking: a 10 min warm-up at 50%-60% of maximum heart rate (HRmax), followed by 10 sets of 1 min bouts at 85%-90% of HRmax interspersed with 1 min walking at self-selected pace (totaling 20 min), and 10 min cool-down walking at self-selected pace. The CG did not perform any type of intense exercise during the intervention period. Results: Participants in the EG of both sexes decreased MetS, HTGW, blood pressure, cholesterol, and glycemia (P < 0.05). After training, the number of hypertensive men decreased by 100% and women by 70%. There was a 75% reduction in women with diabetes, a 100% reduction in MetS indicators and over 80% reduction in HTGW in participants of both sexes. Conclusion: Two weekly sessions of HIIT proved to be feasible and effective to induce clinically relevant improvements in MetS and HTGW indicators.