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The Impact of High-Intensity Interval Training Versus Moderate-Intensity Continuous Training on Vascular Function: a Systematic Review and Meta-Analysis

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Vascular dysfunction is a precursor to the atherosclerotic cascade, significantly increasing susceptibility to cardiovascular events such as myocardial infarction or stroke. Previous studies have revealed a strong relationship between vascular function and cardiorespiratory fitness (CRF). Thus, since high-intensity interval training (HIIT) is a potent method of improving CRF, several small randomized trials have investigated the impact on vascular function of HIIT relative to moderate-intensity continuous training (MICT). The aim of this study was to systematically review the evidence and quantify the impact on vascular function of HIIT compared with MICT. Three electronic databases (PubMed, Embase, and MEDLINE) were searched (until May 2014) for randomized trials comparing the effect of at least 2 weeks of HIIT and MICT on vascular function. HIIT protocols involved predominantly aerobic exercise at a high intensity, interspersed with active or passive recovery periods. We performed a meta-analysis to compare the mean difference in the change in vascular function assessed via brachial artery flow-mediated dilation (FMD) from baseline to post-intervention between HIIT and MICT. The impact of HIIT versus MICT on CRF, traditional cardiovascular disease (CVD) risk factors, and biomarkers associated with vascular function (oxidative stress, inflammation, and insulin resistance) was also reviewed across included studies. Seven randomized trials, including 182 patients, met the eligibility criteria and were included in the meta-analysis. A commonly used HIIT prescription was four intervals of 4 min (4 × 4 HIIT) at 85-95 % of maximum or peak heart rate (HRmax/peak), interspersed with 3 min of active recovery at 60-70 % HRmax/peak, three times per week for 12-16 weeks. Brachial artery FMD improved by 4.31 and 2.15 % following HIIT and MICT, respectively. This resulted in a significant (p < 0.05) mean difference of 2.26 %. HIIT also had a greater tendency than MICT to induce positive effects on secondary outcome measures, including CRF, traditional CVD risk factors, oxidative stress, inflammation, and insulin sensitivity. HIIT is more effective at improving brachial artery vascular function than MICT, perhaps due to its tendency to positively influence CRF, traditional CVD risk factors, oxidative stress, inflammation, and insulin sensitivity. However, the variability in the secondary outcome measures, coupled with the small sample sizes in these studies, limits this finding. Nonetheless, this review suggests that 4 × 4 HIIT, three times per week for at least 12 weeks, is a powerful form of exercise to enhance vascular function.
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... Previous research has explored the comparison between HIIT and MICT in terms of improving vascular function, with HIIT showing greater enhancement in flow-mediated dilation compared to MICT. However, these findings were typically observed over extended training periods and in people who did not necessarily follow a CR program [53]. ...
... HIIT showed a more significant improvement in flow-mediated dilation than MICT after 4 weeks, but not 12 months. A possible explanation for this effect is that exercise of higher intensity leads to greater blood flow and shear stress, which increases the availability of nitric oxide [51,53]. After 4 weeks and over a span of 12 months, there were no notable differences in changes in pulse wave velocity and peripheral or central blood pressure between the two training methods. ...
... Their findings showed that, when left unsupervised, people who were initially advised to follow a HIIT program tend to lower the intensity of the recommended exercises. In the long run, HIIT groups did not demonstrate better adherence compared to others [53]. ...
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Exercise-based cardiac rehabilitation (ExCR) programs are essential for patients diagnosed with cardiac diseases. Studies have shown that they aid in the rehabilitation process and may even facilitate a return to previous cardiorespiratory fitness. Also, patients who enroll and follow such programs have shown a lower rate of complications and mortality in the long run. The results vary depending on the type of program followed and the degree of debilitation the disease has caused. Therefore, in order to obtain optimal results, it is ideal to tailor each ExCR program to the individual profile of each patient. At the moment, the two most studied and employed training types are medium-intensity continuous training (MICT) and high-intensity interval training (HIIT). For most of the time, MICT was the first-choice program for patients with cardiovascular disease. In recent years, however, more and more studies have pointed towards the benefits of HIIT and how it better aids patients in recovering their cardiovascular fitness. Generally, MICT is more suited for patients with a severe degradation in functional capacity and who require a higher degree of safety (e.g., elderly, with a high number of comorbidities). On the other hand, while HIIT is more demanding, it appears to offer better outcomes. Therefore, this review aimed to summarize information from different publications on both types of training regimens in ExCR and assess their utility in current clinical practice.
... 12 In recent years, empirical studies on the effects of HIIE and MICE on endothelial function have been inconclusive, with some studies suggesting that long-term HIIE has yielded more favorable outcomes than MICE in enhancing vascular function. [13][14][15] However, some studies have found no significant difference in the improvement of endothelial function between HIIE and MICE. [16][17] This discrepancy may be due to a number of factors, including different exercise protocols, study populations, measuring methods, etc. ...
... mediated VEGF release, attributed to the increase in blood flow shear stress after exercise, are involved in the regulatory mechanisms of improved endothelial function.Although previous studies have investigated the effects of HIIE and MICE on endothelial function and indicated long-term HIIE has yielded more favorable outcomes than MICE in enhancing vascular function,15 few studies compare the acute effects of HIIE with MICE on endothelial function and its associated biomarkers especially in sedentary young individuals and the results are inconsistent.[49][50] Thus, the present study compared the effects of acute HIIE and MICE on brachial artery FMD, the non-invasive gold-standard used to assess endothelial function, in sedentary young people. ...
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Abstracts Objectives Our study investigated the effects of acute high-intensity interval exercise (HIIE) and moderate-intensity continuous exercise (MICE) on endothelial function and its associated biomarkers in sedentary young individuals. Methods Fifteen subjects (10M / 5F; 22 ± 2 years; BMI: 23.07 ± 4.12 kg/m²) participated in a crossover trial including three experimental conditions: HIIE, MICE, and a control session of rest (CON) in random order separated by a 7-day washout period. Endothelial function was assessed using flow-mediated dilation (FMD), mean shear rate (MSR), and circulating levels of blood lactate, VEGF, IGF-1, and irisin. Results Both HIIE and MICE significantly enhanced FMD% (both P < 0.001 and P < 0.01, respectively), lactate (both P < 0.001), VEGF (P < 0.001 and P < 0.01, respectively), IGF-1 (both P < 0.001), and irisin (P < 0.001 and P < 0.05, respectively), with a greater extent after HIIE compared to MICE in FMD% (P < 0.001), MSR (P < 0.05), lactate (P < 0.001), VEGF (P < 0.05), and IGF-1 (P < 0.05). Additionally, change (post-pre) in FMD% was positively correlated with changes in MSR, lactate, and VEGF in both HIIE and MICE conditions. Change in MSR was positively associated with changes in lactate and VEGF in both HIIE and MICE conditions. Furthermore, enhancement in lactate was correlated with enhancements in VEGF in both HIIE and MICE conditions. Conclusions Acute HIIE is a more effective method than MICE at improving endothelial function in sedentary young individuals and increases in lactate and its mediated VEGF release, attributed to increase in shear rate after exercise, are involved in regulatory mechanisms.
... The adaptation of muscles to high-intensity demands contributes to greater strength gains compared to traditional endurance training alone (Gibala & McGee, 2008). Additionally, HIIT has been shown to enhance cardiovascular fitness and functional capacity, which are critical for overall physical performance (Ramos et al., 2015). ...
... Health and Performance Benefits: Beyond fitness improvements, modified HIIT protocols offer broader health benefits such as improved insulin sensitivity, reduced blood pressure, and enhanced lipid profiles (Ramos et al., 2015;Jelleyman et al., 2015). These adaptations are particularly beneficial for individuals with metabolic disorders and cardiovascular risk factors, highlighting HIIT's potential as a therapeutic intervention. ...
... Another study by Ramos et al. (2015) [4] concluded that HIIT interventions improved lung function in adolescent athletes, thus contributing to a higher vital capacity. Given the intense, short-duration demands of handball, these studies support the effectiveness of HIIT protocols, like Tabata, in targeting critical physiological improvements for young female athletes. ...
... Another study by Ramos et al. (2015) [4] concluded that HIIT interventions improved lung function in adolescent athletes, thus contributing to a higher vital capacity. Given the intense, short-duration demands of handball, these studies support the effectiveness of HIIT protocols, like Tabata, in targeting critical physiological improvements for young female athletes. ...
... Many studies have shown the differential physiological adaptations derived from different types of exercise, such as aerobic training, resistance training, and the combination of aerobic and resistance training. 36,37 Furthermore, studies suggested differential effects on physiological outcomes as response to high-intensity interval training (HIIT) and moderate-intensity training (MIT) 38,39 justifying that HIIT and MIT could be considered as two different types of exercise. 40 We categorized the studies into five exercise types based on available literature and the designs of the network plots: HIIT, MIT, HIIT with resistance training (HIIT + R), MIT with resistance training (MIT + R), and stretching-toning-balance training (STBT; Table 1). ...
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Background and Aims Individuals with coronary artery disease have poorer mental health, health-related quality of life (HR-QoL), and cognition compared with (age-matched) controls. Exercise training may attenuate these effects. The aim is to systematically review and meta-analyse the effects of different exercise types and settings on brain structure/function, cognition, HR-QoL, mental health (e.g. depression, anxiety), and sleep in patients with coronary artery disease. Methods A systematic search was conducted and a network meta-analysis compared (i) exercise types, high-intensity interval training (HIIT), HIIT + resistance (HIIT + R), moderate-intensity training (MIT), MIT + R and stretching-toning-balance training, and (ii) exercise settings, in-person and home-based. Results A total of 42 randomized controlled trials with a parallel group design were identified, of which 36 were included in the meta-analysis. Few studies included cognition (n = 2), sleep (n = 2), and none brain structure/function (n = 0). Most studies examined HR-QoL (n = 30), depression (n = 15), and anxiety (n = 9), in which outcomes were meta-analysed. HIIT + R, HIIT, and MIT were associated with improved HR-QoL vs. no exercise (i.e. usual care) [standardized mean difference, SMD: 1.53 (95% confidence interval 0.83; 2.24), 0.44 (0.15; 0.73), and 0.44 (0.20; 0.67), respectively]. In-person exercise was associated with larger and significant improvements [HR-QoL SMD: 0.51 (0.28; 0.74), depressive SMD: −0.55 (−1.03; −0.07), and anxiety symptoms SMD: −1.16 (−2.05; −0.26)] compared with no exercise, whereas home-based programmes were not significantly associated with improvements in these outcomes. Findings were robust in secondary (i.e. intervention duration and volume) and sensitivity analyses excluding high risk of bias studies. Conclusions Exercise training, especially in-person sessions, was associated with improved HR-QoL, depression and anxiety, independently of exercise type. However, this study raises concern about the effectiveness of home-based programmes in improving these outcomes. Study protocol was registered in PROSPERO (ID: CRD42023402569).
... The atherosclerotic cascade is preceded by vascular dysfunction, which greatly raises the risk of cardiovascular events like myocardial infarction or stroke. HIIT outperforms other types of training in terms of improving vascular function, which could be attributable to its positive effects on cardiorespiratory fitness, conventional cardiovascular disease (CVD) risk factors, oxidative stress, inflammation, and insulin sensitivity (Ramos et al., 2015). Recent studies report HIIT improves vascular function in those with metabolic disorders and cardiovascular illnesses and outperforms MICT in terms of time efficiency (Khalafi et al., 2022). ...
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Abstract Regular exercise produces a variety of physiological changes that improve exercise capacity and health, regardless of age, gender, or chronic illness status. Despite widespread physical inactivity due to time restrictions, High-Intensity Interval Training (HIIT) has evolved as a popular and time-saving strategy for strenuous exercise that improves physical fitness by increasing maximum oxygen uptake (VO2max) and muscle power. HIIT, which consists of brief bursts of intense activity at or near peak effort interspersed with intervals of rest or low-intensity exercise, causes a variety of physiological changes that improve exercise capacity and metabolic health in both clinical and healthy populations. Given the expanding scientific understanding and broad use of HIIT, this clinical commentary seeks to thoroughly investigate its definition, parameters, scientific foundations, multifarious benefits, and evidence acrossvaried groups and situations. Keywords High intensity interval training – scientific foundations – chronic health diseases – exercise – training
... Se recomienda continuar con estudios longitudinales para evaluar los efectos a largo plazo del HIIT y su impacto en diferentes poblaciones laborales y de salud.Controversias y desafíos futurosA pesar de los beneficios evidentes del HIIT en la composición corporal, todavía existen controversias y desafíos en la investigación en este campo. Por ejemplo, algunos estudios han informado resultados mixtos o contradictorios sobre los efectos del HIIT en la pérdida de grasa en poblaciones específicas, como individuos con sobrepeso u obesidad(Ramos et al., 2016). Además, la mayoría de los estudios hasta la fecha han examinado los efectos del HIIT en el corto plazo, y se necesitan más investigaciones longitudinales para evaluar sus efectos a largo plazo sobre la composición corporal y la salud metabólica. ...
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Objetivo evaluar los efectos del entrenamiento de intervalos de alta intensidad (HIIT) en la composición corporal de funcionarios de la empresa Almidones de Sucre durante la pandemia de 2021. Metodología: Estudio de enfoque cuantitativo de tipo correlacional y de corte transversal; Se implementó un programa HIIT de 12 semanas con 30 participantes, evaluando cambios de composición corporal mediante mediciones del % de grasa corporal, peso óseo, peso muscular y peso residual con ISAK I perfil restringido. Se aplicó un pretest y un Postest de la intervención, y se aplicó análisis descriptivos e inferenciales, incluyendo pruebas ANOVA y de correlación de Pearson. Resultados: Los resultados mostraron una reducción significativa en el porcentaje de grasa corporal del 24.2% al 21.4% (p < 0.05) y un aumento en el porcentaje muscular del 40.8% al 43.0% (p < 0.05). No se observó cambios significativos en el peso óseo ni en el residual. Las correlaciones altas entre Pretest y Postest (r > 0.85) indicaron consistencia en los datos. Discusión: Los hallazgos son consistentes con estudios previos que destacan la eficacia del HIIT para mejorar la composición corporal y la salud metabólica. La reducción en del % de grasa corporal y el aumento en el peso muscular sugieren que el HIIT es una estrategia efectiva para mejorar la salud física en un periodo relativamente corto, incluso en el contexto de restricciones por la pandemia. Conclusión: El entrenamiento HIIT se presenta como una intervención eficaz para mejorar la composición corporal de los funcionarios de la empresa Almidones de Sucre, destacándose como una alternativa viable para mantener la salud y el bienestar durante tiempos de pandemia.
... Sessions are generally short, often lasting between 20 and 30 minutes. HIIT has a very high intensity during periods of effort, which can reach maximum VO 2 max (90% to 110% VO 2 max) [10][11][12]. Historically, moderate continuous running has been the most widely used modality in studies on bone tissue due to its ease of application [13][14][15][16]. In osteopenia conditions, compared to sedentariness, continuous running has shown osteoprotective effects [13,16]. ...
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Background It is accepted that the metabolic response of bone tissue depends on the intensity of the mechanical loads, but also on the type and frequency of stress applied to it. Physical exercise such as running involves stresses which, under certain conditions, have been shown to have the best osteogenic effects. However, at high intensity, it can be deleterious for bone tissue. Consequently, there is no clear consensus as to which running modality would have the best osteogenic effects. Aim Our objective was to compare the effects of three running modalities on morphological and micro-architectural parameters on forelimb bones. Methods Forty male Wistar rats were randomly divided into four groups: high intensity interval training (HIIT), continuous running, combined running ((alternating HIIT and continuous modalities) and sedentary (control). The morphometry, trabecular microarchitecture and cortical porosity of the ulna, radius and humerus were analyzed using micro-tomography. Results All three running modalities resulted in bone adaptation, with an increase in the diaphyseal diameter of all three bones. The combined running protocol had positive effects on the trabecular thickness in the distal ulna. The HIIT protocol resulted in an increase in both medio-lateral diameter and cortical bone area over total area (Ct.Ar/Tt.Ar) at the ulnar shaft compared with sedentary condition. Moreover, the HIIT protocol decreased the mean surface area of the medulla (Ma.Ar) according to sedentary condition at the ulnar shaft. Conclusion This study has shown that HIIT resulted in a decrease in trabecular bone fraction in favor of cortical bone area at the ulna.
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Objective: This systematic review and meta-analysis aimed to (I) evaluate the evidence on the effects of high-intensity interval training (HIIT) on systolic blood pressure (SBP) and diastolic blood pressure (DBP) in hypertensive patients; (II) determine whether HIIT impacts SBP and DBP differently; and (III) assess the clinical relevance of these effects. Methods: A comprehensive search was conducted across multiple electronic databases, resulting in the inclusion of seven randomized clinical trials in the meta-analysis. The outcomes were analyzed using random-effects models to compute mean differences (MD) and standardized mean differences (SMD) for SBP and DBP. Results: A small reduction in SBP was observed with HIIT interventions (MD −3.00; 95% CI −4.61 to −1.39; p < 0.0001; SMD −0.28; 95% CI −0.42 to −0.13; p = 0.0003). However, no statistically significant reductions were detected for DBP (MD −0.70; 95% CI −1.80 to 0.39; p = 0.21; SMD −0.07; 95% CI −0.22 to 0.08; p = 0.35). Despite demonstrating statistical significance for SBP, the effects did not reach clinical relevance. Conclusions: HIIT interventions yield small reductions in SBP, with minimal impact on DBP. These findings suggest limited clinical relevance in the management of hypertension. Further randomized controlled trials are necessary to standardize HIIT protocols, with specific emphasis on intensity control and manipulation, to better understand their potential role in hypertensive populations.
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