Is high-intensity interval training better than steady cardio?

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1. 1

   Optimising Exercise Prescription: A Meta-Analysis Examining the Dose Response of Exercise Duration on Cardiorespiratory Fitness Following HIIT and MICT.

   Sports medicine (Auckland, N.Z.) (Mattioni et al.)Published Sep 12, 2026Checked Oct 4, 2026

   “High-intensity interval training elicited greater improvements in VO2max than MICT (d = 0.38, 95% confidence interval 0.27-0.49, p 2max, with 80% of maximal effect (changes in VO2max = 3.45 mL/kg/min) achieved with only ~11 min/session (95% confidence interval 9.5-40.2). Moderate-intensity interval training showed a linear dose-response relationship between exercise session duration and VO2max, requiring ~52 min/session to achieve 80% of the maximal observed effect (95% confidence interval 30.4-55.8). The dose-response relationship was consistent across populations. High-intensity interval training and MICT had comparable effects in improving cardiometabolic risk factors.ConclusionsHigh-intensity interval training demonstrated a non-linear dose response, with 80% of maximal effect on VO2max in ~11 min/session, whilst MICT required four to five times longer to reach similar responses. The different types of training had comparable effects on cardiometabolic risk factors.”

2. 2

   Impact of High-Intensity Interval Training on Cardiometabolic Risk Factors in Youth With Overweight/Obesity: A Systematic Review and Meta-Analysis.

   Pediatric exercise science (Paahoo et al.)Published Jul 10, 2026Checked Oct 4, 2026

   “Subgroup analyses showed a higher superiority of HIIT on most outcomes compared with moderate-intensity continuous training, but not versus moderate-intensity interval training or school-based exercise. However, comparisons with moderate-intensity interval training and school-based exercise were based on a limited number of studies. Moderate heterogeneity (I2 = 48%-73%) was observed across outcomes.ConclusionOur data show that HIIT is an effective strategy for improving cardiometabolic health in children and adolescents with overweight/obesity as it significantly reduces blood lipids and improves body composition, glycemic control, and cardiorespiratory fitness, with this effect often surpassing that of traditional moderate-intensity continuous training protocols. Further studies should identify optimal HIIT protocols and explore long-term benefits to develop clinical guidelines.”

3. 3

   High-Intensity Interval Training Versus Moderate Continuous Training in Patients With Heart Failure With Preserved Ejection Fraction: A Systematic Review and Meta-analysis.

   Current problems in cardiology (Siddiqi et al.)Published Mar 24, 2023Checked Oct 4, 2026

   “A random-effects model was applied, and the weighted mean difference (WMD) of each outcome was reported with 95% confidence intervals (CI). Three RCTs (total N = 150 patients with HFpEF), with a follow-up of 4 to 52 weeks were included in our analysis. Our pooled analysis demonstrated that HIIT significantly improved peak VO2 (WMD = 1.46 mL/kg/min (0.88, 2.05); P 2 = 0%), as compared to MCT. However, no statistically significant change was demonstrated for LAVI (WMD = -1.71 mL/m2 (-5.58, 2.17); P = 0.39; I2 = 22%), RER (WMD = -0.10 (-0.32, 0.12); P = 0.38; I2 = 0%), and VE/CO2 slope (WMD = 0.62 (-1.99, 3.24); P = 0.64; I2 = 67%) in patients with HFpEF. Across current RCT data, HIIT, compared to MCT, had a significant impact on improving peak VO2. Conversely, there was no significant change in LAVI, RER, and VE/CO2 slope between HFpEF patients undertaking HIIT as opposed to MCT.”

4. 4

   Effects of High-Intensity Interval Training in Older Adults: A Systematic Review of Randomized and Non-Randomized Intervention Studies.

   Journal of clinical medicine (Moreira et al.)Published Aug 29, 2026Checked Oct 4, 2026

   “Twenty-five eligible reports were included, representing approximately 2818 unique participants. The most consistent findings concerned cardiorespiratory fitness, with improvements in VO2peak and exercise tolerance reported across several populations. Selected functional and metabolic benefits were also observed, whereas cognitive, psychological, and quality-of-life findings were more limited and heterogeneous. HIIT produced comparable or greater improvements than moderate-intensity continuous training in some studies, but overall superiority was not established. Feasibility and adherence were generally favourable, although adverse-event reporting was inconsistent. HIIT/AIT may improve cardiorespiratory fitness and selected functional outcomes in older adults. However, confidence in these findings is limited by heterogeneity in populations, protocols, and outcomes, together with the predominance of risk-of-bias concerns across the included evidence. The available findings do not establish overall superiority, comparative safety, or an optimal HIIT/AIT prescription.”

5. 5

   Comparing four training modalities on body composition, cardiorespiratory fitness and cardiovascular responses in sedentary young men: a randomized trial.

   BMC sports science, medicine & rehabilitation (Zheng et al.)Published Aug 27, 2026Checked Oct 4, 2026

   “Secondary outcomes included total exercise duration to volitional exhaustion during the Bruce graded exercise test (Bruce test duration) and body-composition measures. Group-by-time interactions were examined using linear mixed-effects models, followed, where appropriate, by Bonferroni-adjusted post hoc comparisons.ResultsSignificant group-by-time interactions were observed for VO2peak (P = 0.040, η2 = 0.21), Bruce test duration (P = 0.016, η2 = 0.26), resting systolic blood pressure (P ConclusionsThese preliminary findings suggest outcome-specific differences among the training protocols. HIIT improved VO2peak more than MIIT, while high-intensity protocols showed greater improvements in selected cardiovascular responses. No adjusted between-group differences were detected for Bruce test duration, and no differential effects were observed for body composition. Larger controlled trials are needed to confirm these findings.Trial registrationChinese Clinical Trial Registry ChiCTR2500106395. Registered 23 July 2025.”

6. 6

   High-intensity interval training (Wikipedia)

   WikipediaPublished Oct 3, 2026Checked Oct 4, 2026

   “High-intensity interval training (HIIT) is a training protocol alternating short periods of intense or explosive anaerobic exercise with brief recovery periods until the point of exhaustion. HIIT involves exercises performed in repeated quick bursts at maximum or near maximal effort with periods of rest or low activity between bouts. The very high level of intensity, the interval duration, and number of bouts distinguish it from aerobic (cardiovascular) activity, because the body significantly recruits anaerobic energy systems (although not completely to the exclusion of aerobic pathways). The method thereby relies on "the anaerobic energy releasing system almost maximally". Although there are varying forms of HIIT-style workouts which may involve exercises associated with both cardiovascular activity and also resistance training, HIIT's crucial features of maximal effort, duration, and short rest periods (thereby triggering the anaerobic pathways of energy production) materially differentiate it from being considered a form of cardiovascular exercise.”