Effects of high-intensity interval training on physical morphology, cardiopulmonary function, and metabolic indicators in older adults: A PRISMA-based systematic review and meta-analysis

Abstract

Background Despite the growing attention towards the efficacy of high-intensity interval training (HIIT) on elderly health, a consensus regarding the pleiotropic effects of HIIT in this population is yet to be reached. Previous studies have predominantly focused on specific outcomes or particular groups, lacking comprehensive analysis. Objective We aimed to conduct a systematic evaluation of the impact of HIIT on body composition, cardiopulmonary function, and metabolic parameters in older adults. Methods The databases searched included PubMed, Web of Science, Cochrane Library, Scopus, WanFang, and other relevant sources from the inception of the database until July 2023. We supplemented the randomized controlled trials (RCTs) and retrieved relevant meta-analyses, and found that 5 highly relevant non-RCTs were also included in the supplement to study the effects of high-intensity interval training (HIIT) on body composition, cardiopulmonary function and metabolic parameters in the elderly. Result A total of 92 studies, including 87 RCTs and 5 non-RCTs, involving a sample size of 4355 elderly individuals were included in the analysis. The meta-analysis results demonstrated that HIIT significantly improved body mass index (BMI) [MD: -0.38kg m-2,P = 0.01], body fat percentage (BF%) [MD༚-1.38%, P<0.00001], maximal oxygen uptake (VO2max) [MD:2.23ml min^− 1kg^− 1, P<0.00001], maximal heart rate (HRmax) [MD:2.84 beats min^− 1, P = 0.02], and high-density lipoprotein levels (HDL) [MD:0.04mmol L^− 1, P = 0.0007] among the elderly population. However, no significant improvements were observed for systolic blood pressure (SBP) [MD: -0.28mmHg, P = 0.75], resting heart rate (HRrest) [MD: -0.95time min^− 1, P = 0.24], triglycerides (TG) [MD: -0.04mmol L^− 1, P = 0.27], low-density lipoprotein (LDL) [MD: -0.05mmol L^− 1, P = 0.23]. Sensitivity analysis found that HIIT significantly improved waist circumference (WC) [MD: -2.13cm, P = 0.04], diastolic blood pressure (DBO) [MD: -0.96 mmHg, P = 0.03], respiratory exchange rate (RER) [MD: 0.01, P = 0.04], total cholesterol (TC) [MD: 0.15 mmol L^− 1, P = 0.009], fasting plasma glucose (FPG) [MD: -0.23 mmol L^− 1, P = 0.04]in the elderly, but the results lacked robustness. Conclusions The results of this study provide further support for HIIT to improve the physical health of the elderly, especially in terms of body shape and cardiopulmonary function, more importantly, provide a reference for HIIT in clinical practice and family health management of the elderly and the development of HIIT guidelines.