Low-volume High-intensity Interval Training Research Articles

High-intensity interval training and cardiorespiratory fitness in adults: An umbrella review of systematic reviews and meta-analyses.

High-intensity interval training (HIIT) is characterized by repeated bouts of relatively intense exercise interspersed with recovery periods. Previous studies have evaluated this exercise strategy with various population subgroups, regimens, and comparator groups, limiting the generalizability of findings. We performed a novel umbrella review to generate an up-to-date synthesis of the available evidence regarding the effect of HIIT on cardiorespiratory fitness (CRF) in adults as compared to non-exercise control and traditional continuous forms of exercise such as moderate-intensity continuous training (MICT). An umbrella review was conducted in accordance with the Preferred Reporting Items for Overviews of Reviews guideline. Seven databases (MEDLINE, EMBASE, Cochrane Database, CINAHL, Scopus, SPORTDiscus, and Web of Science) were searched until February 2024. Systematic reviews with meta-analyses comparing HIIT and active/non-active control conditions were included. Literature search, data extraction, and methodological quality assessment (AMSTAR-2) were conducted independently by two reviewers. Twenty-four systematic reviews with meta-analyses, representing 429 primary studies and 12 967 unique participants, met the inclusion criteria. Most of the systematic reviews received moderate-to-critically low AMSTAR-2 scores. The data showed that HIIT, including the particularly intense variant "sprint interval training" (SIT), significantly increases CRF in adults compared to non-exercise control (standardized mean difference [SMD]: 0.28 to 4.31; weighted mean difference [WMD]: 3.25 to 5.5 mL/kg/min) and MICT (SMD: 0.18 to 0.99; WMD: 0.52 to 3.76 mL/kg/min). This effect was consistently observed across specific groups of individuals (e.g., apparently healthy adults, individuals with overweight/obesity, older adults, and high-level athletes) and HIIT modalities (e.g., low-volume HIIT, whole-body HIIT, home-based HIIT, aquatic HIIT, and short SIT). Existing evidence from systematic reviews consistently supports the effect of HIIT on enhancing CRF in adults when compared to non-exercise control and MICT. Our findings offer a comprehensive basis that may potentially contribute to informing physical activity guidelines aimed at improving CRF in the general population.

Effect of 5:2 Regimens: Energy-Restricted Diet or Low-Volume High-Intensity Interval Training Combined With Resistance Exercise on Glycemic Control and Cardiometabolic Health in Adults With Overweight/Obesity and Type 2 Diabetes: A Three-Arm Randomized Controlled Trial.

We aimed to examine the effects of a 5:2 diet (2 days per week of energy restriction by formula diet) or an exercise (2 days per week of high-intensity interval training and resistance training) intervention compared with routine lifestyle education (control) on glycemic control and cardiometabolic health among adults with overweight/obesity and type 2 diabetes. This two-center, open-label, three-arm, parallel-group, randomized controlled trial recruited 326 participants with overweight/obesity and type 2 diabetes and randomized them into 12 weeks of diet intervention (n = 109), exercise intervention (n = 108), or lifestyle education (control) (n = 109). The primary outcome was the change of glycemic control measured as glycated hemoglobin (HbA1c) between the diet or exercise intervention groups and the control group after the 12-week intervention. The diet intervention significantly reduced HbA1c level (%) after the 12-week intervention (-0.72, 95% CI -0.95 to -0.48) compared with the control group (-0.37, 95% CI -0.60 to -0.15) (diet vs. control -0.34, 95% CI -0.58 to -0.11, P = 0.007). The reduction in HbA1c level in the exercise intervention group (-0.46, 95% CI -0.70 to -0.23) did not significantly differ from the control group (exercise vs. control -0.09, 95% CI -0.32 to 0.15, P = 0.47). The exercise intervention group was superior in maintaining lean body mass. Both diet and exercise interventions induced improvements in adiposity and hepatic steatosis. These findings suggest that the medically supervised 5:2 energy-restricted diet could provide an alternative strategy for improving glycemic control and that the exercise regimen could improve body composition, although it inadequately improved glycemic control.

Impact of Low-Volume High-Intensity Interval Training and Moderate-Intensity Continuous Training on Physical Performance and Quality of Life among Postmenopausal Women

Background: Menopause is one of the life stages for women that marks the end of reproductive years. Physical, emotional, mental, and social well-being can all be impacted by the hormonal changes brought on by menopause. Hence, the study aims to determine the effect of Moderate-Intensity Continuous Training (MICT) and High-Intensity Interval Training (HIIT) on cardiovascular parameters and quality of life in postmenopausal females. Methods: A two-arm, randomized controlled trial was conducted on 40 postmenopausal females, recruited via envelop method of simple random sampling technique into Group-A, who received HIIT and Group-B, who received MICT. Firstly, informed consent was taken from the participants by explaining all the protocols and procedures. Following the assessment, both groups received six weeks of exercise training thrice a week with 40 minutes of HIIT and 50 minutes of MICT, respectively. Results: Predicted VO2max increased statistically and practically significantly in response to the HIIT intervention (6.92 ml/kg/min; p=0.01), while it changed marginally and practically in the MICT group (2.8 ml/kg/min; p>0.05). Conclusion: The results indicate that the HIIT groupexperienced a statistically and clinically significant improvement in predicted VO2max compared to a slight significant change observed in the MICT group. Keywords: Cardiorespiratory Fitness, Exercise, Obesity, Quality of Life.

Is low-volume high-intensity interval training a time-efficient strategy to improve cardiometabolic health and body composition? A meta-analysis.

The present meta-analysis aimed to assess the effects of low-volume high-intensity interval training (LV-HIIT; i.e., ≤5min high-intensity exercise within a≤15 min session) on cardiometabolic health and body composition. A systematic search was performed in accordance with PRISMA guidelines to assess the effect of LV-HIIT on cardiometabolic health and body composition. Twenty-one studies (moderate to high quality) with a total of 849 participants were included in this meta-analysis. LV-HIIT increased cardiorespiratory fitness (CRF, SMD=1.19 [0.87, 1.50]) while lowering systolic blood pressure (SMD = -1.44 [-1.68, -1.20]), diastolic blood pressure (SMD = -1.51 [-1.75, -1.27]), mean arterial pressure (SMD = -1.55 [-1.80, -1.30]), MetS z-score (SMD = -0.76 [-1.02, -0.49]), fat mass (kg) (SMD = -0.22 [-0.44, 0.00]), fat mass (%) (SMD = -0.22 [-0.41, -0.02]), and waist circumference (SMD = -0.53 [-0.75, -0.31]) compared to untrained control (CONTROL). Despite a total time-commitment of LV-HIIT of only 14%-47% and 45%-94% compared to moderate-intensity continuous training and HV-HIIT, respectively, there were no statistically significant differences observed for any outcomes in comparisons between LV-HIIT and moderate-intensity continuous training (MICT) or high-volume HIIT. Significant inverse dose-responses were observed between the change in CRF with LV-HIIT and sprint repetitions (β = -0.52 [-0.76, -0.28]), high-intensity duration (β = -0.21 [-0.39, -0.02]), and total duration (β = -0.19 [-0.36, -0.02]), while higher intensity significantly improved CRF gains. LV-HIIT can improve cardiometabolic health and body composition and represent a time-efficient alternative to MICT and HV-HIIT. Performing LV-HIIT at a higher intensity drives higher CRF gains. More repetitions, longer time at high intensity, and total session duration did not augment gains in CRF.

Enhanced Gait Recovery in Chronic Post-COVID-19 Stroke: The Role of Combined Physical Rehabilitation

Background: Rehabilitation programs applied in cases of COVID-19-related stroke should counteract not only the effects of the stroke but also the effects of long-term COVID-19. As the molecular processes underlying these cases are still not fully understood, and evidence-based clinical outcomes are scarcely documented, there is a valid need to gather information and develop rehabilitation strategies for these patients. The risks, already clarified in the case of stroke, need to be assessed taking into account the coincidence of the two diseases. Endothelial injuries and emboli that develop after the hypercoagulable state of COVID-19 may take longer to heal, and complications may occur during exercise. This case study attempts to determine what the rehabilitation of a COVID-19-related stroke patient should include. The participant was a 64-year-old male with ischemic right middle cerebral artery stroke, left-side hemiplegia, and middle cerebral artery stenosis, and the CT showed a well-defined area of hypoattenuation in the basal ganglia territory involving the right lentiform nucleus, the anterior and posterior limbs of the internal capsule, and the dorsal part of the external capsule. His NIHSS score was 14, and he registered 15 points on the Barthel index. The patient had a COVID-19 infection two weeks before the stroke event. Methods: Conventional physical therapy was combined with adaptive ballistic strength training, a high-intensity interval training regimen, and manual treatment for myofascial release throughout the chronic recovery phase. Our primary goals were gait rehabilitation, muscle strengthening, weakness management, as well as spasticity reduction, while three different rehabilitation approaches were adopted in a single rehabilitation program to improve the outcome and long-term functional recovery of the patient. Results: The patient progressed in almost every aspect of the assessment criteria. This combined approach’s main success was improved gait speed, gait quality, and improved cardiovascular fitness. Take-away message: In the case of a stroke caused by COVID-19, where the endothelium cells are compromised, HIIT may be questionable due to the poor vascular condition. Based on our results, the low-volume HIIT approach proved appropriate and effective.

Protective Effect of Low-Volume High-Intensity Interval Training on Aspirin-Induced Reproductive Impairments in Adult Male Wistar Rats.

Lifestyle factors such as sedentary behavior and consumption of certain medications can disturb the function of the male reproductive system. In the present study, we investigated the potential co-treatment effects of low-volume high-intensity interval training (HIIT) on markers of reproductive function in adult male Wistar rats under aspirin (ASA) treatment. Eighteen adult male Wistar rats were randomized into three groups: control (C), aspirin treatment (AT), and aspirin treatment + exercise (ATE). Animals in the AT and ATE groups received an oral subchronic dose of aspirin (12.5 mg/kg body mass). The exercise was performed three times per week for 6 weeks (4-6 reps of 10-s sprints). Serum testosterone level, sperm parameters (sperm count, viability, maturity, and DNA fragmentation), histomorphometric (Leydig cell, tubule diameter, thickness of tubular epithelium, and indices of spermatogenesis and spermiogenesis), and histochemical parameter (testicular fat density) were assessed. Results revealed that compared to the C group, ASA consumption led to a negative alteration in serum testosterone levels, sperm parameters, and histomorphometric and histochemical parameters (P < 0.05). However, there were no significant differences between the C and ATE groups in terms of serum testosterone level, number of Leydig cells, epididymal fat density, tubule diameter, epithelium height, immature-to-mature sperm ratio, and DNA breakage (P > 0.05). These findings suggest that ASA treatment is associated with deleterious changes in male reproductive parameters. However, low-volume HIIT may prevent ASA-induced male reproductive impairments and could be considered a potential prophylactic measure in subjects under ASA treatment.

Retracted: A Study Using Power Cycling on the Affective Responses of a Low-Volume High-Intensity Interval Training to Male Subjects with Type 2 Diabetes in Different Physical Activity Status.

[This retracts the article DOI: 10.1155/2021/1255943.].

Effects of the menstrual cycle on EPOC and fat oxidation after low-volume high-intensity interval training.

Low-volume high-intensity interval training (HIIT) for weight loss has become prevalent in recent years, with increased excess post-exercise oxygen consumption (EPOC) as the mechanism. However, the influence of the menstrual cycle on EPOC and fat oxidation following low-volume HIIT is unclear. This study aimed to investigate the effect of the menstrual cycle on the increase in EPOC and fat oxidation after low-volume HIIT. Twelve eumenorrheic women participated during their early follicular and luteal phases. On each experimental day, they performed low-volume HIIT comprising fifteen repeated 8 s sprint cycling tests with 12 s rests, for 5 min. Expired gas samples were collected before and every 60 min until 180 min post-exercise. EPOC was defined as the increase in oxygen consumption from the resting state, and the total EPOC and fat oxidation were calculated from the total time of each measurement. Blood samples for serum estradiol, progesterone, free fatty acids, blood glucose, lactate, and plasma noradrenaline were collected and assessed before immediately after, and at 180 min post-exercise and were assessed. Serum estradiol and progesterone were significantly higher in the luteal phase than the follicular phase (P<0.01 for both). No significant differences in total EPOC and fat oxidation were found between the menstrual phases. Serum free fatty acid, blood glucose, lactate, and plasma noradrenaline concentrations were not affected by the menstrual cycle. These results suggest that the menstrual cycle does not affect the increase in EPOC or fat oxidation after low-volume HIIT.

Effects of low-versus high-volume high-intensity interval training on glycemic control and quality of life in obese women with type 2 diabetes: A randomized controlled trial

Background/objectiveComparison between different training volumes of high-intensity interval training (HIIT) is understudied in type 2 diabetes. This study aimed to compare the effects of low- and high-volume HIIT on glycemic control, blood lipids, blood pressure, anthropometric adiposity measures, cardiorespiratory fitness, and health-related quality of life (HRQoL) in women with type 2 diabetes. MethodsSeventy-two obese women with type 2 diabetes aged 36–55 were randomly assigned to a low-volume HIIT group (i.e., 2 × 4-min high-intensity treadmill exercise at 85%–90% of peak heart rate, with a 3-min active recovery interval in between), a high-volume HIIT group (i.e., 4 × 4-min high-intensity treadmill exercise at 85%–90% of peak heart rate, with three 3-min active recovery intervals in between), and a non-exercising control group. Patients in HIIT groups exercised three days a week for 12 weeks. All patients received oral hypoglycemic medications with no calorie restrictions. The outcome measures were glycosylated hemoglobin (HbA1c), fasting blood glucose (FBG), 2-hour postprandial blood glucose (2-hr PPBG), total cholesterol (TC), triglyceride (TG), low-density lipoprotein (LDL), high-density lipoprotein (HDL), systolic blood pressure (SBP), diastolic blood pressure (DBP), body mass index (BMI), waist circumference (WC), waist-to-hip ratio, time to maximal exhaustion determined from a maximal treadmill exercise test (i.e., a measure of cardiorespiratory fitness), and HRQoL assessed by the 12-item Short Form (SF-12) Health Survey. ResultsThe low- and high-volume HIIT groups showed significant improvements in all outcome measures compared to the baseline and the non-exercising group (P < 0.05), except for DBP in the low-volume HIIT group (p > 0.05). Also, both low- and high-volume HIIT groups showed similar improvements in TC, HDL, SBP, DBP, BMI, WC, waist-to-hip ratio, and the SF-12 scores, with no significant between-groups difference (p > 0.05). The high-volume HIIT group, however, showed more significant improvements in HbA1c, FBG, 2-hr PPBG, TG, LDL, and treadmill time to maximal exhaustion than the low-volume HIIT group (p < 0.05). The non-exercising group showed non-significant changes in all outcome measures (p > 0.05). ConclusionLow-volume HIIT could be equally effective as high-volume HIIT for improving TC, HDL, blood pressure, anthropometric adiposity measures, and HRQoL in obese women with type 2 diabetes. Nevertheless, high-volume HIIT could have a greater impact on glycemic control, TG, LDL, and cardiorespiratory fitness in these patients. Trial registrationClinicalTrials.gov, NCT05110404.

As we were and as we Should Be, Combined Exercise Training in Adults with Schizophrenia: CORTEX-SP Study Part I.

Given the health benefits and the role of exercise as an anti-inflammatory adjuvant program, this study aimed to determine the effectiveness of a combined exercise program on cardiorespiratory fitness (CRF), body composition, and biochemical levels in adults with schizophrenia (SZ) characterized at baseline as metabolically unhealthy overweight with low CRF. Participants diagnosed with SZ (n = 112, 41.3 ± 10.4 yr, 28.7% women) were randomly assigned into a Treatment-As-Usual (TAU) control group (n = 53) or a supervised exercise group (n = 59, 3 days/week). Each combined exercise session consisted of both a low-volume high-intensity interval training (less than 10 min of high-intensity time per session) and a resistance circuit-training program. All variables were assessed pre-and post-intervention (20 weeks). For the assessment of CRF, a peak cardiopulmonary exercise test on a cycle ergometer was used. Following the intervention, participants from the exercise group (n = 51) showed increases in CRF (P < 0.001) through peak oxygen uptake (L·min-1; Δ = 17.6%; mL·kg.1·min-1, Δ = 19.6%) and the metabolic equivalent of task (Δ = 19%), with no significant changes (P > 0.05) in body composition and biochemical variables. However, the TAU group (n = 38) did not show any significant change in the study variables (P > 0.05). Between-group significant differences (P ≤ 0.05) were observed in CRF, first ventilatory threshold, and heart rate peak after the intervention period favoring the exercise group. This study demonstrated that a supervised combined exercise program in people with SZ helps to maintain body composition values and improve CRF levels. This could lead to an important clinical change in the characterization from metabolically unhealthy overweight to a metabolically healthy overweight population. Hence, exercise should be considered a co-adjuvant program in the treatment of the SZ population.

Systemic Lupus, Metabolic Syndrome, Cardiac Disease, and Peripheral Artery Disease

Systemic Lupus, Metabolic Syndrome, Cardiac Disease, and Peripheral Artery Disease

Post-Exercise Protein Supplementation Does Not Maximize Adaptations To Low-Volume High-Intensity Interval Training In Previously Sedentary Adults

Post-Exercise Protein Supplementation Does Not Maximize Adaptations To Low-Volume High-Intensity Interval Training In Previously Sedentary Adults

Maximum Heart Rate- and Lactate Threshold-Based Low-Volume High-Intensity Interval Training Prescriptions Provide Similar Health Benefits in Metabolic Syndrome Patients

Exercise is an integral part of metabolic syndrome (MetS) treatment. Recently, low-volume high-intensity interval training (LOW-HIIT) has emerged as a time-efficient approach to improving cardiometabolic health. Intensity prescriptions for LOW-HIIT are typically based on maximum heart rate (HRmax) percentages. However, HRmax determination requires maximal effort during exercise testing, which may not always be feasible/safe for MetS patients. This trial compared the effects of a 12-week LOW-HIIT program based on: (a) HRmax (HIIT-HR), or (b) submaximal lactate threshold (HIIT-LT), on cardiometabolic health and quality of life (QoL) in MetS patients. Seventy-five patients were randomized to HIIT-HR (5 × 1 min at 80-95% HRmax), HIIT-LT (5 × 1 min at 95-105% LT) groups, both performed twice weekly on cycle ergometers, or a control group (CON). All patients received nutritional weight loss consultation. All groups reduced their body weight (HIIT-HR: -3.9 kg, p < 0.001; HTT-LT: -5.6 kg, p < 0.001; CON: -2.6 kg, p = 0.003). The HIIT-HR and HIIT-LT groups similarly, improved their maximal oxygen uptake (+3.6 and +3.7 mL/kg/min, p < 0.001), glycohemoglobin (-0.2%, p = 0.005, and -0.3%, p < 0.001), homeostasis model assessment index (-1.3 units, p = 0.005, and -1.0 units, p = 0.014), MetS z-score (-1.9 and -2.5 units, p < 0.001) and QoL (+10 points, p = 0.029, and +11 points, p = 0.002), while the CON did not experience changes in these variables. We conclude that HIIT-LT is a viable alternative to HIIT-HR for patients who are not able/willing to undergo maximal exercise testing.

The effect of Tabata-style functional high-intensity interval training on cardiometabolic health and physical activity in female university students.

Introduction: The increasing prevalence of metabolic syndrome and physical inactivity enhances exposure to cardiometabolic risk factors in university students. High-intensity interval training (HIIT) improved cardiometabolic health in clinical adults but the evidence in the university setting is limited. Furthermore, few studies examined the effect of low-volume HIIT on habitual physical activity (PA). Therefore, the primary aim of this study was to evaluate the efficacy of 12-week Tabata-style functional HIIT for improving multiple cardiometabolic health outcomes and habitual PA. We also investigated whether changes in habitual PA over the intervention period had an impact on exercise-induced health outcomes. Methods: 122 female freshmen were randomized into the Tabata group (n = 60) and the control (n = 62). The Tabata training protocol involved 8 × 20s maximal repeated functional exercises followed by 10s rest with a frequency of 3 times per week for 12 weeks. Body composition, maximal oxygen uptake (VO2max), blood pressure (BP), blood lipids, fasting glucose and insulin, C-reactive protein and PA were objectively measured using standardized methods. Dietary intake was measured using a valid food frequency questionnaire. All variables were measured pre- and post-intervention. Results: Mixed linear modelling results showed that there were large intervention effects on VO2max (p < 0.001, d = 2.53, 95% CI: 2.03 to 3.00 for relative VO2max; p < 0.001, d = 2.24, 95% CI: 1.76 to 2.68 for absolute VO2max), resting heart rate (p < 0.001, d = -1.82, 95% CI: -2.23 to -1.37), systolic BP (p < 0.001, d = -1.24, 95% CI: -1.63 to -0.84), moderate-to-vigorous intensity physical activity (MVPA) (p < 0.001, d = 2.31, 95% CI: 1.83 to 2.77), total PA (p < 0.001, d = 1.98, 95% CI: 1.53 to 2.41); moderate effects on %BF (p < 0.001, d = -1.15, 95% CI: -1.53 to -0.75), FM (p < 0.001, d = -1.08, 95% CI: -1.46 to -0.69), high-density lipoprotein (HDL) (p < 0.001, d = 1.04, 95% CI: 0.65 to 1.42), total cholesterol (p = 0.001, d = -0.64, 95% CI: -1.00 to -0.26); small effects on BMI (p = 0.011, d = -0.48, 95% CI: -0.84 to 0.11), WC (p = 0.043, d = -0.37, 95% CI: -0.74 to -0.01), low-density lipoprotein (p = 0.003, d = -0.57, 95% CI: -0.93 to -0.19), HOMA-IR (p = 0.026, d = -0.42, 95% CI: -0.78 to -0.05) and fasting insulin (p = 0.035, d = -0.40, 95% CI: -0.76 to -0.03). Regression analysis showed that only the percentage change of HDL was associated with the change of MVPA (b = 0.326, p = 0.015) and TPA (b = 0.480, p = 0.001). Conclusion: From the findings of the study we can conclude that 12-week low-volume Tabata-style functional HIIT was highly effective for university female students to improve cardiorespiratory fitness, body fat, some cardiometabolic health outcomes and habitual PA.

Low-Volume and High-Intensity Aerobic Interval Training May Attenuate Dysfunctional Ventricular Remodeling after Myocardial Infarction: Data from the INTERFARCT Study

Background: Aerobic high-intensity interval training (HIIT) has demonstrated benefits for ventricular remodeling after myocardial infarction (MI) through various mechanisms. Despite this, the optimal training volume is not well known. The present study aimed to assess the effects of different (low vs. high volume) aerobic HIIT compared to an attentional control (AC) group on echocardiographic and biochemical indicators of left ventricular (LV) remodeling in adults after MI. Methods: Randomized clinical trial conducted on post-MI patients with preserved ventricular function. Participants were assigned to three study groups. Two groups performed HIIT 2 d/week, one group with low-volume HIIT (20 min, n = 28) and another with high-volume HIIT (40 min, n = 28). A third group was assigned to AC (n = 24) with recommendations for unsupervised aerobic training. Left ventricular echocardiographic parameters and cardiac biomarker levels (N-terminal pro-b-type natriuretic peptide, NT-proBNP; soluble growth stimulation expressed gene 2, ST2; troponin T; and creatine kinase) were assessed at baseline and after the intervention (16 weeks). Results: Eighty participants (58.4 ± 8.3 yrs, 82.5% male) were included. Both low- and high-volume HIIT showed increases (p &lt; 0.05) in left ventricular end-diastolic diameter (1.2%, 2.6%), and volume (1.1%, 1.3%), respectively. Interventricular septal and posterior walls maintained their thickness (p = 0.36) concerning the AC. Significant (p &lt; 0.05) gain in diastolic function was shown with the improvements in E (–2.1%, –3.3%), e’ waves (2.2%, 5.5%), and the deceleration time (2.1%, 2.9%), and in systolic function with a reduction in global longitudinal strain (–3.2%, –4.7%), respectively. Significant (p &lt; 0.05) reductions of N-terminal pro-B-type natriuretic peptide (NT-proBNP) (–4.8%, –11.1%) and of ST2 (–21.7%, –16.7%)were found in both HIIT groups respectively compared to the AC group. Creatine kinase elevation was shown only in high-volume HIIT (19.3%, p &lt; 0.01). Conclusions: Low-volume HIIT is proposed as a clinically time-efficient and safer strategy to attenuate dysfunctional remodeling by preventing wall thinning and improving LV function in post-MI patients.

The effect of low volume high-intensity interval training on metabolic and cardiorespiratory outcomes in patients with type 2 diabetes mellitus: A systematic review and meta-analysis.

The present systematic review and meta-analysis of randomized controlled trials (RCTs) was conducted to investigate the effect of low volume high-intensity interval training (LVHIIT) on the metabolic and cardiorespiratory outcomes in patients with type 2 diabetes mellitus (T2DM). Relevant articles were sourced from PubMed, EBSCO, Web of Science, Embase, and the Cochrane Library from inception to October 2022. The study search strategy and all other processes were implemented in accordance with the PRISMA statement. Five randomized controlled trials that satisfied the inclusion criteria were included in this meta-analysis. The LVHIIT group had significantly lower fasting blood glucose levels (RR= -1.21; 95% CI= -2.02- -0.40, p = 0.0032) and HbA1c levels (RR= -0.65; 95% CI= -1.06- -0.23, p = 0.002) and higher levels of insulin resistance indicator HOMA-IR (RR= -1.34; 95% CI = -2.59- -0.10, p = 0.03) than the control group. Moreover, our results show that LVHIIT can reduce body mass (RR = -0.94, 95% CI = -1.37- -0.51, p<0.0001) and body mass index (RR = -0.31, 95% CI = -0.47- -0.16, p<0.0001). LVHIIT had a better therapeutic effect on blood lipid metabolism, such as total cholesterol, high-density lipoprotein, low-density lipoprotein and triglycerides. However, the change in fasting insulin levels was not statistically significant (RR= -1.43; 95% CI = -3.46- 0.60, p =0.17). Furthermore, LVHIIT reduced the systolic blood pressure (RR =-4.01, 95% CI = -4.82 - -3.21, p<0.0001) and improved peak oxygen uptake (VO2peak) compared to the control group (RR= 5.45; 95% CI = 1.38 - 9.52, p =0.009). After a certain period of LVHIIT, glycaemic control, insulin resistance, body weight, lipid profile and cardiorespiratory outcomes were significantly improved in T2DM patients.

Feasibility and impact of whole-body high-intensity interval training in patients with stable coronary artery disease: a randomised controlled trial

Exercise training reduces cardiovascular mortality and improves quality of life in CAD patients. We investigated the feasibility and impact of 12 weeks of low-volume high-intensity interval training (HIIT) in CAD-patients. Patients with stable CAD were randomized 1:1 to supervised HIIT or standard care. HIIT sessions were completed three times weekly for 12 weeks on a rowing ergometer. Before and after the 12-week intervention, patients completed a physiological evaluation of cardiorespiratory performance and quality of life questionnaires. Mixed model analysis was used to evaluate differences between and within groups. A total of 142 patients (67 ± 9 years, nHIIT = 64, nStandard care = 78) completed the trial. Training adherence was 97% (range 86–100%). Six patients dropped out because of non-fatal adverse events. Weekly training duration was 54 min with an average power output of 138 W. HIIT increased peak oxygen uptake by 2.5 mL/kg/min (95% CI 2.1–3.0), whereas no change was observed in standard care (0.2 mL/kg/min, 95% CI − 0.2–0.6, P < 0.001). In addition, HIIT improved markers of quality of life, including physical functioning, limitations due to physical illness, general health and vitality (P < 0.05). Twelve weeks of low-volume whole-body HIIT increased cardiorespiratory capacity and improved quality of life in patients with stable CAD compared to standard care. In addition, our study demonstrates that the applied vigorous training regime is feasible for this patient group.Clinical trial registration:www.clinicaltrials.gov. Identification number: NCT04268992.

Very Low-Volume, High-Intensity Interval Training Mitigates Negative Health Impacts of COVID-19 Pandemic-Induced Physical Inactivity.

Initially, we aimed to investigate the impact of a one-year worksite low-volume, high-intensity interval training (LOW-HIIT) on cardiometabolic health in 114 sedentary office workers. Due to the COVID-19 pandemic outbreak, LOW-HIIT was discontinued after 6 months and participants were followed up for 6 months to analyze physical activity/exercise behavior and outcome changes during lockdown. Health examinations, including cardiopulmonary exercise testing and the assessment of cardiometabolic markers were performed baseline (T-1), after 6 months (T-2, termination of worksite LOW-HIIT) and 12 months (T-3, follow-up). Cycle ergometer LOW-HIIT (5 × 1 min at 85–95% HRmax) was performed 2×/week. For follow-up analyses, participants were classified into three groups: HIIT-group (continued home-based LOW-HIIT), EX-group (continued other home-based exercises), and NO-EX-group (discontinued LOW-HIIT/exercise). At T-2, VO2max (+1.5 mL/kg/min, p = 0.002), mean arterial blood pressure (MAB, −4 mmHg, p < 0.001), HbA1c (−0.2%, p = 0.005) and self-reported quality of life (QoL, +5 points, p < 0.001) were improved. At T-3, HIIT-group maintained VO2max and QoL and further improved MAB. EX-group maintained MAB and QoL but experienced a VO2max decrease. In NON-EX, VO2max, MAB and QoL deteriorated. We conclude that LOW-HIIT can be considered a promising option to improve cardiometabolic health in real-life conditions and to mitigate physical inactivity-related negative health impacts during lockdowns.

Protein Supplementation Does Not Maximize Adaptations to Low-Volume High-Intensity Interval Training in Sedentary, Healthy Adults: A Placebo-Controlled Double-Blind Randomized Study.

There is ample evidence that specific nutritional strategies can enhance adaptions to resistance and endurance training. However, it is still unclear whether post-session protein supplementation may increase the effects of low-volume high-intensity interval training (LOW-HIIT). We examined the impact of LOW-HIIT combined with protein vs. placebo supplementation on cardiometabolic health indices in sedentary healthy individuals. Forty-seven participants (31.1 ± 8.0 yrs) performed cycle ergometer LOW-HIIT (5–10x1 min at 80–95% maximum heart rate) for eight weeks and randomly received double-blinded 40 g of whey protein (PRO-HIIT, N = 24) or an isocaloric placebo (maltodextrin, PLA-HIIT, N = 23) after each session. The maximum oxygen uptake (VO2max, primary outcome) and several secondary cardiometabolic outcomes were determined pre-/post-intervention. VO2max increased in PRO-HIIT (+2.8 mL/kg/min, p = 0.003) and PLA-HIIT (+3.5 mL/kg/min, p < 0.001). Systolic and diastolic blood pressure decreased in PRO-HIIT (−7/3 mmHg, p < 0.05) and PLA-HIIT (−8/5 mmHg, p < 0.001). Gamma glutamyl transferase (−2 U/L, p = 0.003) decreased in PRO-HIIT and alanine aminotransferase (−3 U/L, p = 0.014) in PLA-HIIT. There were no significant between-group differences in any of the outcome changes. In conclusion, LOW-HIIT improved VO2max and other cardiometabolic markers irrespective of the supplementation condition. Post-session protein supplementation does not seem to provide any additional benefit to LOW-HIIT in improving cardiometabolic health in sedentary healthy individuals.

High-intensity Interval Training In Patients With Coronary Artery Disease: A Randomized Controlled Trial

PURPOSE: Coronary artery disease (CAD) is the leading cause of mortality worldwide, and the prevalence is increasing. Cardiac rehabilitation is essential after a cardiac event with exercise training having a central role. Exercise training improves quality of life and reduces cardiovascular mortality and hospital admissions in CAD patients. We aimed to investigate the feasibility and efficiency of high-intensity interval training (HIIT) in patients with stable CAD. METHODS: In this randomized controlled trial, 142 patients with stable CAD and a mean age of 66.7 years completed the study, 64 in the HIIT group and 78 in the control group (CON). Patients were randomized 1:1 to supervised HIIT or standard care. HIIT was performed by training on a rowing ergometer 3 x week for 12 weeks. Patients in CON did not change their usual behavior, and all patients continued medications as prescribed before inclusion. Prior to randomization (baseline) and after 12 weeks (post-intervention), maximal oxygen consumption (VO2max), maximal pulmonary ventilation (VEmax) and maximal power output (Wmax) were determined in all patients. During the intervention period, the training load was defined as power output during training in week 3, 6 and 9. The average intensity was quantified and normalized to the average power that patients could sustain during a 5-min-all-out rowing performance test completed at week 5. RESULTS: Adherence to training was 97% (range 86-100%). Three patients dropped out because of non-fatal adverse events, and three patients reported non-severe self-limiting adverse events. The average relative power output was 72 ± 19% during warm-up and 117 ± 11 % during the interval bouts. Weekly training duration was on average 54 min. Compared to standard care, HIIT resulted in a significant (p < 0.001) greater increase in VO2max, VEmax, and Wmax (197 mL/min [160;233], 13 L/min [11;16], and 23 W [19;27]). CONCLUSIONS: Low volume HIIT performed as rowing significantly upregulated cardiorespiratory fitness (VO2max, VEmax, and Wmax) in patients with stable CAD compared to standard care. The exercise training on rowing ergometers was convenient and feasible for this frail patient group.