Effects of high-intensity interval and continuous moderate aerobic training on fitness and health markers of older adults: A systematic review and meta-analysis.

High-intensity interval training (HIIT) promotes similar or superior gains in physical fitness and health compared to continuous moderate-intensity training (MICT) in young individuals. However, the effectiveness of HIIT in older adults is uncertain. This meta-analysis compared the effects of HIIT and MICT on cardiorespiratory fitness, body composition, vascular, metabolic, and hormonal variables, cognitive function, and quality of life in older adults. PubMed, Embase, Cochrane, Web of Science, Scopus, and SportDiscus databases were searched from inception until December 2023. Trials included adults ≥ 60 y. Hedge's effect sizes (g) were calculated and study quality and features of training interventions were tested as moderators. Twenty-nine trials including 1,227 subjects (65.4 ± 3.3 y). HIIT and MICT elicited significant (p < 0.021) and similar (p > 0.156) 'gs' for VO2max (0.722 vs. 0.490), maximal workload/peak power output ratio (0.290 vs. 0.372),% fat (-0.297 vs. -0.262), glycemia (-0.273 vs. -0.334), systolic (-0.465 vs. -0.341), and diastolic blood pressure (-0.566 vs. -2.311). HIIT (p < 0.04) but not MICT (p > 0.170) produced significant 'gs' for fat mass (-0.245 vs. -0.103), waist circumference (-0.239 vs. -0.116), testosterone (0.339 vs. 0.170), and complex Stroop test (-0.595 vs. -0.250). Increases in the VO2max occurred only in controlled trials after HIIT but not MICT (Q = 6.286, p = 0.012; HITT-g = 1.068, p < 0.0001 vs. MICT-g = 0.109, p= 0.596). HIIT and MICT produced similar changes in most of the investigated variables. In trials with greater quality (controlled vs. non-controlled trials), cardiorespiratory gains were higher in HIIT vs. MICT. These findings suggest that HIIT might be suitable for improving fitness and health in older adults.

Oliveira A ，Fidalgo A ，Farinatti P ，Monteiro W ... -  《-》

High-Intensity Interval Training Programs Versus Moderate-Intensity Continuous Training for Individuals With Heart Failure: A Systematic Review and Meta-analysis.

To explore the effect sizes of different high-intensity interval training (HIIT) protocols on cardiorespiratory parameters when compared with moderate-intensity continuous training (MICT) in different heart failure (HF) subtypes. Electronic databases were searched from their inception date until January 23, 2023. Randomized controlled trials (RCTs) were included if they compared HIIT with MICT in patients with HF. The primary outcome was peak oxygen consumption (Vo2peak). Two reviewers independently evaluated 99 initially identified studies, resulting in the selection of 15 RCTs that met the eligibility criteria. Data were extracted independently by 2 observers using a data extraction form drafted based on the CONSORT statement and the Template for Intervention Description and Replication; the methodological quality of the studies was analyzed individually based on the Tool for the Assessment of Study Quality in Exercise scale. Fifteen RCTs with 553 patients with HF were included in the systematic review. The included studies had moderate to good overall methodological quality. The results showed that HIIT was generally more effective than MICT at improving Vo2peak in patients with HF (n=541, 15 RCTs; MD: 1.49 mL/kg/min; I2=66%; P<.001). However, the effect size varied depending on the HF subtype and HIIT protocol used. For patients with HF with reduced ejection fraction (HFrEF), the long-interval (high-intensity interval lasting ≥4 min) and high-volume HIIT (high-intensity efforts in total ≥15 min) showed the largest benefits over the MICT (n=261, 6 RCTs; MD: 2.11 mL/kg/min; P<.001); followed by the short-interval (≤1 min) and high-volume HIIT (≥15 min; n=71, 3 RCTs; MD: 0.91 mL/kg/min; P=.12), and the short-interval and low-volume HIIT showed the least superiority over MICT (n=68, 3 RCTs; MD: 0.54 mL/kg/min; P=.05). For patients with HF with perceived ejection fraction, there was a modest beneficial effect from HIIT over MICT (n=141, 3 RCTs; MD: 0.55 mL/kg/min; P=.32). The long-interval and high-volume HIIT protocol may produce greater benefits than MICT for improving cardiopulmonary fitness in patients with HFrEF. Further research is needed to determine the optimal HIIT protocol for different HF subtypes and to provide definitive recommendations for clinical practice.

Chen X ，Zhang T ，Hu X ，Wen Z ，Lu W ，Jiang W ... -  《-》

Characteristics of High-Intensity Interval Training Influence Anthropometrics, Glycemic Control, and Cardiorespiratory Fitness in Type 2 Diabetes Mellitus: A Systematic Review and Meta-Analysis of Randomized Controlled Trials.

Exercise is a non-pharmacological intervention for type 2 diabetes mellitus (T2DM), including moderate-intensity continuous training (MICT) and high-intensity interval training (HIIT). Despite diverse exercise protocol variations, the impact of these variations in HIIT on T2DM anthropometrics, glycemic control, and cardiorespiratory fitness (CRF) remains unclear. The aim was to examine the influence of HIIT protocol characteristics on anthropometrics, glycemic control, and CRF in T2DM patients and compare it to control (without exercise) and MICT. This review is registered in PROSPERO (CRD42021281398) and follows Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. The search, employing "high-intensity interval training" and "diabetes mellitus" in PubMed and Web of Science databases, with a "randomized controlled trial" filter, spanned articles up to January 2023. Of 190 records, 29 trials were included, categorized by HIIT interval duration, training volume, and intervention period. Long-duration, high-volume, and long-term HIIT yields superior outcomes compared to control conditions for body mass, waist circumference, fasting plasma glucose, Homeostatic Model Assessment for Insulin Resistance (HOMA-IR), glycosylated hemoglobin (%HbA1c), and CRF. The findings favored HIIT over MICT for body mass in long-duration, high-volume, and short-term intervals (mean difference [MD] - 3.45, - 3.13, and - 5.42, respectively, all p < 0.05) and for CRF in long and medium work intervals and high volume (MD 1.91, 2.55, and 2.43, respectively, all p < 0.05), as well as in medium and long-term intervention (MD 2.66 and 2.21, respectively, all p < 0.05). Regardless of specific HIIT characteristics, no differences were found in the HIIT versus MICT comparison for glycemic control. Specific HIIT protocol characteristics influence changes in anthropometrics, glycemic control, and CRF compared to control groups. However, compared to MICT, only longer duration, higher volume, and short-term HIIT improved body mass, waist circumference, and CRF in individuals with T2DM.

Opazo-Díaz E ，Montes-de-Oca-García A ，Galán-Mercant A ，Marín-Galindo A ，Corral-Pérez J ，Ponce-González JG ... -  《-》

Effects of high-intensity interval training on selected indicators of physical fitness among male team-sport athletes: A systematic review and meta-analysis.

Superior physical fitness and performance are essential in male team sports. Among a myriad of training methodologies, high-intensity interval training (HIIT) has gained popularity owing to its unparalleled efficiency and effectiveness. Previous studies have established that HIIT is a proven and effective approach for enhancing various physiological performance outcomes, particularly oxygen consumption capacity, in individual sports. Despite potential differences in training practices between male and female athletes, HIIT is recognized as an anaerobic training approach for team-sport athletes. This systematic review aimed to comprehensively and innovatively analyze the existing literature to examine the effectiveness of HIIT on oxygen consumption performance among male team-sport athletes. A comprehensive literature search was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines across the PubMed, SCOPUS, Web of Science, and SPORTDiscus databases until December 31, 2023. The inclusion criteria for this review encompassed research articles published in peer-reviewed journals that specifically focused on the impact of HIIT on the oxygen consumption performance of male players engaged in team sports. The study population exclusively consisted of male participants. The collected data included study characteristics, participant demographics, intervention details, and outcomes. Methodological quality assessment was performed using standardized criteria. The effect sizes (ESs) were calculated, and a meta-analysis was conducted using a random-effects model. The literature search yielded 13 eligible studies encompassing 286 athletes aged 14-26 years. The meta-analysis showed statistically significant enhancements in maximal oxygen uptake (VO2max) in six studies (ES, 0.19-0.74; p < 0.005), Yo-Yo Intermittent Recovery Test (YYIRT) performance in six studies (ES, 0.20-2.07; p = 0.009), repeated-sprint ability total time (RSAtotal) in five studies (ES, 0.18-1.33; p < 0.001), and the best and average times for repeated-sprint ability (RSAbest and RSAmean, respectively) in four studies (ES, 0.47-1.50; p < 0.001). However, two studies did not report any significant differences in the outcomes of the Velocity in 30-15 Intermittent Fitness Test (VIFT) between the experimental and control groups (ES, -0.08 and -0.27; p = 0.87 and 0.443, respectively). Moreover, one study did not report any significant differences in the maximal aerobic speed (MAS) (ES, 0.41, p = 0.403). HIIT significantly improved VO2max, YYIRT, and RSA; however, it did not appear to enhance VIFT and MAS performance, irrespective of age or competition level. These findings indicate that HIIT could serve as a valuable method for improving oxygen consumption performance (VO2max, YYIRT, and RSA) in male team-sport athletes, offering a time-efficient alternative to the traditional training methods. Further research is warranted to investigate its impact on performance outcomes in competitive settings and identify optimal HIIT protocols tailored to specific team sports.

Yuan Y ，Soh KG ，Qi F ，Bashir M ，Zhao N ... -  《PLoS One》

Efficacy of Interval Training in Improving Body Composition and Adiposity in Apparently Healthy Adults: An Umbrella Review with Meta-Analysis.

Although the efficacy of interval training for improving body composition has been summarized in an increasing number of systematic reviews in recent years, discrepancies in review findings and conclusions have been observed. This study aims to synthesize the available evidence on the efficacy of interval training compared with moderate-intensity continuous training (MICT) and nonexercise control (CON) in reducing body adiposity in apparently healthy adults. An umbrella review with meta-analysis was performed. A systematic search was conducted in seven databases (MEDLINE, EMBASE, Cochrane Database, CINAHL, Scopus, SPORTDiscus, and Web of Science) up to October 2023. Systematic reviews with meta-analyses of randomized controlled trials (RCTs) comparing interval training and MICT/CON were included. Literature selection, data extraction, and methodological quality assessment (AMSTAR-2) were conducted independently by two reviewers. Meta-analyses were performed using a random-effects model. Subgroup analyses were conducted based on the type of interval training [high-intensity interval training (HIIT) and sprint interval training (SIT)], intervention duration, body mass index, exercise modality, and volume of HIIT protocols. Sixteen systematic reviews, including 79 RCTs and 2474 unique participants, met the inclusion criteria. Most systematic reviews had a critically low (n = 6) or low (n = 6) AMSTAR-2 score. Interval training demonstrated significantly greater reductions in total body fat percent (BF%) compared with MICT [weighted mean difference (WMD) of - 0.77%; 95% confidence interval (CI) - 1.12 to - 0.32%] and CON (WMD of - 1.50%; 95% CI - 2.40 to - 0.58%). Significant reductions in fat mass, visceral adipose tissue, subcutaneous abdominal fat, and android abdominal fat were also observed following interval training compared to CON. Subgroup analyses indicated that both HIIT and SIT resulted in superior BF% loss than MICT. These benefits appeared to be more prominent in individuals with overweight/obesity and longer duration interventions (≥ 12 weeks), as well as in protocols using cycling as a modality and low-volume HIIT (i.e., < 15 min of high-intensity exercise per session). This novel umbrella review with large-scale meta-analysis provides an updated synthesis of evidence with implications for physical activity guideline recommendations. The findings support interval training as a viable exercise strategy for reducing adiposity in the general population.

Poon ET ，Li HY ，Little JP ，Wong SH ，Ho RS ... -  《-》