High-intensity Interval Training Group Research Articles

Comparison of high-intensity interval training and moderate-intensity continuous training on cardiopulmonary function, cardiac autonomic function and vascular function in adolescent boys with obesity: A randomized controlled trial.

Adolescent obesity can impair cardiopulmonary function, vascular elasticity, endothelial function, and vago-sympathetic balance. While moderate-intensity continuous training (MICT) benefits cardiovascular health in obese adolescents, the effects of high-intensity interval training (HIIT) are less understood. We hypothesize that HIIT may be more effective than MICT in improving VO2peak, vascular elasticity, endothelial function, and vago-sympathetic balance in obese adolescent boys. Forty four participants were randomly assigned to the HIIT (10×1-min at 85%-95% peak HR, intersperse with 2-min active recovery at 60%-70% peak HR) or MICT (35min at 65%-75% peak HR) for an 8-week program. The primary outcome measured was the change in VO2peak with secondary outcomes including brachial-ankle pulse wave velocity (baPWV), flow-mediated dilation (FMD), and heart rate variability (HRV). Forty four adolescent boys with obesity (age, 14±1years old, body mass index, 31.6±1.3kg/m2) were enrolled and 43 (97.73%) completed the 8-week exercise. No significant difference of VO2peak was found between the HIIT and MICT group (p=0.243). There was no significant difference of baPWV between the groups (p=0.789). Change in FMD% was significantly higher in the HIIT group compared to the MICT group (p<0.001). The Change in HRV-high frequency (HRV-HF; p=0.009) and HRV-low frequency/high frequency (HRV-LF/HF; p=0.035) was significantly higher in the HIIT group compared to the MICT group. Among adolescent boys with obesity, 8-week HIIT and MICT had similar effects on improving VO2peak. HIIT may be superior to MICT to improve endothelial function and vago-sympathetic balance.

Interaction of three weeks HIIT and vitamin D supplementation on some oxidant and inflammatory factors in heart tissue of middle-aged rats

Abstract Aging causes changes in the structure and function of the heart, which increases the number of free radicals and provides the basis for the increase of inflammatory cytokines. Therefore, this study aimed to investigate the interaction of three weeks of high-intensity interval training and vitamin D supplementation on NOX, SOD, NF-κB, and Nrf-2 in the heart tissue of middle-aged rats. In this experimental study, 21 middle-aged rats in the age range of 10-12 months were purchased from the Pasteur Institute and randomly divided into high-intensity interval training (HIIT) (n = 8), HIIT+VitD (n = 8), and Sham (n = 6) groups. After two weeks of adaptation, HIIT was performed for three week and vitamin D was gavage with a dose of 500 units/kg. Finally, the variables were measured through real-time PCR, and a one-way analysis of variance was used for statistical analysis. The results of data analysis showed that after three weeks, the expression of NOX () and SOD () genes increased significantly in the HIIT group compared to the HIIT+VitD group. The interaction of three weeks of high-intensity interval training with vitamin D supplementation can improve oxidative indices, but this effect was more significant in the exercise group.

Activation patterns of intracellular signaling pathways in cardiac hypertrophy induced by different exercise modes in rats

Abstract Introduction Cardiac remodeling and hypertrophy cause as adaptive responses to physiological and pathological stimuli. Physiological cardiac hypertrophy is characterized by normal or enhanced cardiac function and myocardial metabolism, and induces concentric and eccentric hypertrophy by different exercise modes, without cardiac dysfunction and fibrosis. Each formative mechanism of cardiac hypertrophy is regulated by distinct and/or similar cellular signaling pathways. Activation of cardiac intracellular signaling pathway of phosphoinositide 3- kinase (PI3K) is involved in an underlying mechanism of developed eccentric cardiac hypertrophy by aerobic exercise training (AT). However, the activation patterns of intracellular signaling pathways of physiological cardiac hypertrophy by different exercise modes remain unclear. Purpose The purpose of this study was to investigate the activation patterns of intracellular signaling pathways in cardiac hypertrophy induced by different exercise modes, including AT, resistance training (RT), and high intensity interval training (HIIT). Methods Forty male 10-week-old Sprague-Dawley (SD) rats were divided into four groups; sedentary control (Con, n=10), AT (treadmill running, 60 min at 30 m/min, 5 days/wk for 8 wk, n=10), RT (ladder climbing, 8-10 sets/day, 3 d/wk for 8 wk, n=10), HIIT (14 repeats of 20-s swimming session with 10-s pause between sessions, 4 d/wk for 6 wk from 12-wk-old, n=10) groups. As a cardiac hypertrophic intracellular signaling pathways, PI3K protein expression level and mTOR and MAPK (ERK1/2, JNK1/2 and p38) phosphorylation levels in rat hearts were measured by Western blotting analysis. Results The hearts of rats in each training group developed cardiac hypertrophy. Moreover, the enzyme activity of oxidative phosphorylation in the skeletal muscle was promoted in the AT group, the oxidative phosphorylation and glycolytic enzyme activities were promoted in the HIIT group, and muscle hypertrophy occurred in the RT group. Levels of PI3K protein expression and mTOR phosphorylation in the heart were significantly higher in the AT, RT, and HIIT groups as compared to the Con group (each p&amp;lt;0.05). Additionally, p38 phosphorylation level in the heart was significantly higher in the RT group as compared to the Con, AT, and HIIT groups (each p&amp;lt;0.05). Furthermore, p44 ERK phosphorylation level in the heart of the RT group was significantly higher than that in the AT and HIIT groups (each p&amp;lt;0.05), but p42 ERK phosphorylation level did not differ among four groups. JNK1/2 (p46/p54) phosphorylation level in the heart was significantly higher in the RT group as compared to the Con group (p&amp;lt;0.05). Conclusion These findings suggest that the activation of PI3K-mTOR signaling pathway in the heart may be involved in the development of AT, RT and HIIT-induced cardiac hypertrophy, and the MAPK signaling activation may affect the development of cardiac hypertrophy by RT.

High-Intensity interval training improves global longitudinal strain in patients with metabolic syndrome and high risk of heart failure

Abstract Background Metabolic syndrome (MS) has been associated with the development of myocardial dysfunction which can lead to heart failure (HF). It is possible to detect early signs of myocardial dysfunction by assessing the global longitudinal strain (GLS) in a transthoracic echocardiography. A reduced GLS is considered as a predictor of HF development. Preventive strategies are recommended in patients with MS to avoid the progression to HF. Although exercise improves cardiovascular and metabolic health in MS patients, it is unknown whether exercise can affect the evolution of GLS in a group of patients with MS who are under medical treatment. Purpose To assess the prevalence of myocardial dysfunction (i.e., reduced GLS) in a heterogeneous group of patients with MS who are under medical treatment, and to test in these patients if 16 weeks of high-intensity interval training (HIIT) can improve the GLS. Methods Seventy-seven volunteers with MS and without signs or symptoms of HF were randomized in one of two 16-week intervention: i). HIIT in stationary bikes 3 sessions/week, 50 minutes/session + medical treatment (HIIT group), or ii). medical treatment (CONTROL). Maximal oxygen consumption (VO2max), and GLS together with rutinary echocardiographic parameters were assessed before and after intervention. The effect of HIIT compared to CONTROL was analyzed by a split-plot ANOVA to compare the effects of time (pre vs. post) and group (HIIT vs. CONTROL), and the interaction between the two factors. Results Before intervention 48.9% of participants from the HIIT group, and 46.7% from the CON group had a reduced GLS (i.e., &amp;gt;17% for men and &amp;gt;18% for women). However, none of them had a reduced left ventricular ejection fraction (LVEF), signs of diastolic dysfunction or an abnormal VO2max (less than 80% of predicted VO2max). After the 16-week intervention, only individuals from the HIIT group improved their VO2max (time*group P&amp;lt;0.001). LVEF did not improve in any of the experimental groups (time P=0.278) HIIT group improved their GLS by 0.51%, whereas CONTROL group improved it by 0.05% without reaching statistical significance (time*group P=0.186). However, a subgroup analysis of GLS conducted among the participants from the HIIT group discriminated by their pre-intervention values (GLS normal or reduced), showed that individuals with reduced GLS improved significantly by 1,41% (P=0.001) whereas those with a normal GLS improved by 0.14% without reaching statistical significance (P=0.736, time*group P=0.009). Conclusions Myocardial dysfunction assessed by GLS is present in MS even in the absence of symptoms, diastolic dysfunction, or reductions in the LVEF. HIIT can reduce the risk of HF development by improving GLS in patients with MS and early signs of myocardial dysfunction.A. Overall changes in GLSB. Subgroup analysis of GLS pre vs. post

Effects of 2 Combined Training Protocols on the Aerobic and Anaerobic Fitness, Technical Skills, and Psychophysiological Responses in Young Soccer Players.

Kilit, B, Chmura, P, Arslan, E, Soylu, Y, and Radziminski, Ł. Effects of 2 combined training protocols on the aerobic and anaerobic fitness, technical skills, and psychophysiological responses in young soccer players. J Strength Cond Res XX(X): 000-000, 2024-The study compared the effects of combining small-sided soccer games (SSGs) with high-intensity interval training (HIIT) and repeated sprint training (RST) on aerobic and anaerobic fitness, technical skills, and psychophysiological responses in young soccer players. Thirty-two male, adolescent, soccer players (aged 13.5 ± 0.3 years) were randomly divided into either the SSGs + HIIT group ( n = 16) or the SSGs + RST group ( n = 16) for combined training 3 times per week for 6 weeks. The players in the SSGs + HIIT group performed 12-18 minutes of runs at intensities (90-95%), whereas the players in the SSGs + RST group consisted of 3-4 sets of 5-7 times 15-m shuttle sprints (all-out efforts). Both training groups played 4 bouts of 2-a-side or 4-a-side SSGs with various game formats at 2-day intervals. Psychophysiological responses were determined during and after all training sessions. Before and after training interventions, the following physical performance tests were used: 5- to 30-m sprint time, countermovement jump, triple-hop distance, zigzag agility with the ball and without the ball, repeated sprint ability (RSA), 30-15 Intermittent Fitness Test, 3 corner run test, speed dribbling ability (SDA), Yo-Yo Intermittent Recovery Test Level 1, and Y-balance test. Our main findings were that the SSGs + RST group demonstrated greater improvement in 5-m sprint time, SDA time, and RSA in the meantime compared with the SSGs + HIIT ( p ≤ 0.05, d values ranging from 1.50 to 2.25). Moreover, the SSGs + RST group showed greater improvement in agility test responses ( p ≤ 0.05, d values ranging from 2.13 to 2.34) than the SSGs + HIIT group. However, the SSGs + HIIT induced higher perceived exertion, mental effort, and lower greater physical enjoyment meaningfully compared with the SSGs + RST ( p ≤ 0.05, d values ranging from 6.04 to 6.67). In conclusion, these results demonstrate that the SSGs + RST is an effective training program to improve young soccer players' speed and agility-based performance responses.

Impact of Combined Exercise and High-Intensity Interval Training on 6-Minute Walk Test Dynamics in Heart Failure Patients with Preserved Ejection Fraction: Results from the ExIC-FEp Trial

(1) Background: Heart failure with preserved ejection fraction (HFpEF) is a clinical challenge, with limited success from current therapeutic strategies. This study aimed to assess the impact of combined exercise (CE) and high-intensity interval training (HIIT) on key biomechanical parameters during the 6-minute walk test (6MWT) in HFpEF patients. (2) Methods: A randomized controlled trial was conducted in 76 sedentary HFpEF patients, divided into three groups as follows: the CE, HIIT, and control groups. CE involves aerobic and strength training, whereas HIIT includes high-intensity intervals. Cadence (steps per minute), distance, maximum heart rate (HRmax), and exercise intensity were measured pre- and postintervention. (3) Results: The results revealed significant improvements in cadence in the CE group compared with the control group (p = 0.009) for intention-to-treat analysis, and in the control and HIIT groups (p = 0.002) for per-protocol analysis. CE also significantly improved HRmax and exercise intensity, suggesting an enhanced cardiovascular response. In contrast, HIIT did not significantly affect these parameters. The correlation between cadence and distance covered during the 6MWT was strong in the overall group (r = 0.762, p &lt; 0.001). (4) Conclusions: These findings suggest that CE is an effective intervention to improve gait efficiency, cardiovascular response, and functional capacity in HFpEF patients, whereas HIIT may require further investigation in this population.

High-intensity interval training attenuates renal injury induced by myocardial ischemia-reperfusion in rats

Background: High-Intensity Interval Training (HIIT) has been recognized as an effective form of short-duration exercise. The purpose of this study was to assess whether HIIT could reduce renal injury induced by myocardial ischemia-reperfusion in rats. Methods: Male Sprague-Dawley rats were randomly assigned to the Sham Group (SHAM), Coronary Artery Occlusion (CAO) group, HIIT group, and Ischemic Precondition (IPC) group. Rats underwent 40 minutes of left anterior descending coronary artery occlusion under anesthesia, followed by 3 hours of reperfusion, to induce myocardial ischemia-reperfusion (MIR). Post-surgery, rats were sacrificed, and their blood, heart, and kidney tissues were examined. The HIIT group underwent 4 weeks of HIIT training before surgery. Results: HIIT intervention significantly reduced renal injury after MIR and the concentrations of Blood Urea Nitrogen (BUN) and Creatinine (CRE) in the serum. Moreover, pro-inflammatory cytokines, including Tumor Necrosis Factor-α (TNF-α), Interleukin-1β (IL-1β), and IL-6, were significantly decreased, while the anti-inflammatory cytokine IL-10 was significantly increased in the serum. Additionally, HIIT intervention suppressed the expression of FoxO1, BAX/Bcl-2 ratio, TNF-α, and Cleaved-caspase-3/caspase-3 ratio in kidney tissues, ultimately reducing renal cell apoptosis. Conclusion: This study is the first to demonstrate that HIIT has effects similar to IPC, significantly reducing renal injury after MIR. HIIT regulates the production of pro-inflammatory and anti-inflammatory cytokines, inhibits renal cell apoptosis, thereby reducing the occurrence of cardio-renal syndrome.

High-intensity interval training, but not Spirulina supplementation, changes muscle regeneration signaling proteins in aged rats with obesity and diabetes.

This study aimed to investigate changes in protein signaling associated with muscle regeneration in aged rats with obesity and diabetes following high-intensity interval training (HIIT) and SP supplementation. Forty male Wistar rats weighting 280-325 g were used in this study. Obesity was induced by eight weeks of a high-fat diet, and diabetes was induced by intraperitoneal injection of 40 mg/kg streptozocin. Rats were randomly divided into control (CON), sham, SP, HIIT, and HIIT+SP groups. HIIT was performed five times per week during the 8-week period. SP dose was 50 mg/kg. Real-time PCR was used to evaluate the expression of myogenin, MyoD1, and Pax7. The decreases in body mass in the HIIT, HIIT+SP and SP groups were significantly higher than those in the sham and CON groups (p=0.0001). The soleus muscle mass increased significantly only in the HIIT and HIIT+SP groups (p<0.01). HIIT+SP improved fasting blood glucose and insulin levels more than HIIT alone and SP (p<0.05), while HIIT increased the expression levels of myogenic factors more than other groups (p=0.0001). In conclusion HIIT alone had a significant impact on myogenic factors, whereas Spirulina had an effect only when combined with HIIT.

High-intensity interval training vs. yoga in improving binge eating and physical fitness in inactive young females

Yoga is effective in binge eating disorder (BED) treatment, but it does not seem effective enough to improve low physical fitness. In contrast, high-intensity interval training (HIIT) is effective in improving physical fitness but has never been studied in the context of BED. In the study, 47 young inactive females with mild to moderate BED were recruited and randomly assigned to a HIIT group (HIIT), a Yoga group (YG), or a control group (CG; age, 19.47 ± 0.74, 19.69 ± 0.874, and 19.44 ± 0.63 years; BMI, 21.07 ± 1.66, 21.95 ± 2.67, and 20.68 ± 2.61 kg/m2, respectively). The intervention groups participated in 8-week specific exercises, while the CG maintained their usual daily activity. Before and after the training, participants were evaluated for BED using the binge eating scale (BES) and for physical fitness. The obtained data were compared within groups and between groups, and a correlation analysis between BES and physical fitness parameters was performed. After the training, the YG presented significant improvements in BES (− 20.25%, p = 0.006, ηp2 = 0.408), fat mass (FM, − 3.13%, p = 0.033, ηp2 = 0.269), and maximal oxygen consumption (VO2max, 11.51%, p = 0.000, ηp2 = 0.601), whereas the HIIT showed significant improvements in body weight (BW, − 1.78%, p = 0.006, ηp2 = 0.433), FM (− 3.94%, p = 0.033, ηp2 = 0.285), and BMI (− 1.80%, p = 0.006, ηp2 = 0.428), but not in BES. Comparisons between groups revealed that both HIIT and YG had significantly higher VO2max levels than CG (HIIT 12.82%, p = 0.006, ηp2 = 0.088; YG: 11.90%, p = 0.009, ηp2 = 0.088) with no difference between HIIT and YG. Additionally, YG presented significantly lower BES than both HIIT (15.45%, p = 0.02, ηp2 = 0.03) and CG (11.91%, p = 0.022, ηp2 = 0.03). In conclusion, Yoga is an effective treatment for BED, but HIIT is not, despite its high efficacy in improving physical fitness.

THE EFFECTS OF EXERCISE INTENSITY ON METABOLIC HEALTH IN PATIENTS WITH NAFLD AND TYPE 2 DIABETES: A COMPARATIVE STUDY

Introduction: Non-alcoholic fatty liver disease (NAFLD) and type 2 diabetes mellitus (T2DM) are chronic metabolic disorders that are increasingly prevalent globally, posing significant health challenges. Both conditions are linked to obesity, insulin resistance, and sedentary lifestyles, leading to severe complications such as cardiovascular diseases and liver cirrhosis. Exercise is a crucial lifestyle modification that improves metabolic health in these conditions, but the optimal exercise intensity remains debated. This study investigates the effects of different exercise intensities on metabolic health in patients with NAFLD and T2DM to provide insights for tailored exercise prescriptions. Materials and Methods: This randomized controlled trial involved 100 participants with NAFLD and T2DM, divided into two groups: MICT and HIIT, over 12 weeks. Participants were adults aged 30-65 years with confirmed NAFLD and T2DM, and a sedentary lifestyle. Exclusion criteria included other liver diseases, uncontrolled hypertension, severe diabetic complications, recent participation in a structured exercise program, and contraindications to exercise. Participants were randomly assigned to MICT or HIIT, with exercise sessions supervised by certified physiologists. Primary outcomes were liver fat content and insulin sensitivity, while secondary outcomes included lipid profiles, inflammatory markers, feasibility, and safety. Results: A total of 100 participants (50 per group) completed the study with comparable baseline characteristics. Both groups showed significant reductions in liver fat content and improvements in insulin sensitivity, with HIIT showing greater reductions (p=0.01 for liver fat, p=0.02 for insulin sensitivity). HIIT also led to more significant improvements in triglycerides, LDL, HDL, and inflammatory markers compared to MICT. Adherence rates were high in both groups, although slightly lower in the HIIT group, and dropout rates were comparable. Conclusion: Both MICT and HIIT significantly improve metabolic health in patients with NAFLD and T2DM, with HIIT yielding superior outcomes in reducing liver fat, improving insulin sensitivity, enhancing lipid profiles, and decreasing inflammatory markers. These findings support incorporating HIIT into exercise regimens for this population, highlighting its potential for greater metabolic health benefits. Future research should explore the long-term sustainability and broader applicability of HIIT and strategies to enhance adherence and safety.

High-Intensity Interval Training, but Not Whole-Body Cryostimulation, Affects Bone-Mechanosensing Markers and Induces the Expression of Differentiation Markers in Osteoblasts Cultured with Sera from Overweight-to-Obese Subjects.

Background/Objectives: Although there have been some clinical observations made, the mechanistic effects on bone metabolism of whole-body cryostimulation and high-intensity interval training (HIIT), either alone or in combination, are still debated. Here, we have investigated their effects on circulating osteo-immune and bone metabolic markers (osteopontin, osteocalcin, sclerostin, dikkopf-related protein 1, and fibroblast-growth factor 23) and their potential effects on osteoblast differentiation and function, in vitro, by treating SaOS-2 osteoblast-like cells with the sera obtained from the subjects who had undergone the different interventions or untreated control subjects. Methods: Sixty-seven inactive, overweight-to-obese participants (body mass index = 31.9 ± 5.0 kg·m-2, 42 ± 13 years old) were recruited and randomly assigned to one group: control (CTRL, n = 14), training (HIIT, 6 sessions, n = 13), WBC (CRYO, 10 sessions, n = 17) or training combined with WBC (CRYO-HIIT, n = 23). The interventions lasted 14 days. Results: While circulating markers analysis revealed more protective potential against resorption in HIIT than in WBC alone or combined, gene expression from in vitro analysis showed an induction of late bone metabolic markers in the HIIT group. Conclusions: These data suggest a potentially protective effect of HIIT in bone against resorption, while WBC maintains homeostasis by preventing any resorptive phenomena and limiting any anabolic activity even when stimulated by intensive exercise.

Comparing the effect of high-intensity interval exercise and voluntary exercise training on cognitive functions in rats

It is known that exercise increases brain-derived neurotrophic factor (BDNF) levels in the hippocampus, the brain region responsible for learning and memory, resulting in improved cognitive functions and learning processes. However, it is claimed that different types of exercise cause different responses in the brain. It is thought that lactate and osteocalcin secreted in response to exercise are associated with an increase in BDNF levels. However, there are not enough studies on this subject. This study aimed to compare the effects of high-intensity interval training (HIIT) and voluntary exercise training on cognitive performance and molecular connections. Male rats were randomly divided into control, voluntary exercise training and HIIT groups. The voluntary exercise group had free access to the voluntary wheel for 8 weeks. The HIIT group performed HIIT on the treadmill 3 days a week for 8 weeks. The rats underwent open field (OF), elevated plus maze (EPM) and Morris water maze (MWM) tests 24 h after the last exercise training. Then, after blood was drawn under anesthesia, the rats were sacrificed and their hippocampus tissues were separated. Glucocorticoid and BDNF levels in the blood were evaluated by enzyme-linked immunosorbent assay (ELISA), and osteocalcin and BDNF expressions in the hippocampus were evaluated by real-time quantitative reverse transcription-polymerase chain reaction (RT-PCR). Neither voluntary exercise training nor HIIT had any significant effect on behavioral parameters assessed by OF, EPM and MWM tests. However, BDNF expression in hippocampus tissue was higher in the HIIT group than in the control group. In addition, osteocalcin expression in hippocampus tissue was higher in the HIIT and voluntary exercise groups than in the control group. In conclusion, according to the findings we obtained from this study, although it does not have a significant effect on cognitive functions, the effect of HIIT on brain functions seems to be more effective than voluntary exercise.

Exercise as a modality to improve heart transplantation-related functional impairments: An article review.

Heart transplantation (HT), the treatment choice of advanced heart failure patients, is proven effective in increasing the survival and functional status of the recipients. However, compared to normal controls, functional status is lower in HT recipients. Exercise given in cardiac rehabilitation has been shown to improve exercise capacity as measured with peak oxygen uptake (VO2 peak) and muscle strength after completion of the program and cessation of exercise results in loss of exercise benefits. Several factors related to cardiac denervation and the use of immunosuppressive agents in HT recipients result in functional impairments including cardiovascular, pulmonary, exercise capacity, psychological, and quality of life (QoL) problems. High-intensity interval training (HIIT) is the most common type of exercise used in HT recipients and given as a hospital-based program. Improvement of functional impairments was found to have occurred due to primarily musculoskeletal adaptations through improvement of muscle structure and aerobic capacity and cardiovascular adaptations. In general, exercise given after transplantation improved VO2 peak significantly and improvement was better in the HIIT group compared to moderate intensity continuous training or no-exercise groups. Improvement of QoL was ascribed to improvement of exercise capacity, symptoms, pulmonary function, physical capacity improvement, anxiety, and depression.

High-Intensity Interval Training Mitigates Sarcopenia and Suppresses the Myoblast Senescence Regulator EEF1E1.

The optimal exercise regimen for alleviating sarcopenia remains uncertain. This study aimed to investigate the efficacy of high-intensity interval training (HIIT) over moderate-intensity continuous training (MICT) in ameliorating sarcopenia. We conducted a randomized crossover trial to evaluate plasma proteomic reactions to acute HIIT (four 4-min high-intensity intervals at 70% maximal capacity alternating with 4 min at 30%) versus MICT (constant 50% maximal capacity) in inactive adults. We explored the relationship between a HIIT-specific protein relative to MICT, identified via comparative proteomic analysis, eukaryotic translation elongation factor 1 epsilon 1 (EEF1E1) and sarcopenia in a paired case-control study of elderly individuals (aged over 65). Young (3 months old) and aged (20 months old) mice were randomized to sedentary, HIIT and MICT groups (five sessions/week for 4 weeks; n = 8 for each group). Measurements included skeletal muscle index, hand grip strength, expression of atrophic markers Atrogin1 and MuRF1 and differentiation markers MyoD, myogenin and MyHC-II via western blotting. We examined the impact of EEF1E1 siRNA and recombinant protein on D-galactose-induced myoblast senescence, measuring senescence-associated β-galactosidase and markers like p21 and p53. The crossover trial, including 10 sedentary adults (32 years old, IQR 31-32) demonstrated significant alterations in the abundance of 21 plasma proteins after HIIT compared with MICT. In the paired case-control study of 84 older adults (84 years old, IQR 69-81; 52% female), EEF1E1 was significantly increased in those with sarcopenia compared to those without (14.68 [95%CI, 2.02-27.34] pg/mL, p = 0.03) and was associated with skeletal muscle index (R2 = 0.51, p < 0.001) and hand grip strength (R2 = 0.54, p < 0.001). In the preclinical study, aged mice exhibited higher EEF1E1 mRNA and protein levels in skeletal muscle compared to young mice, accompanied by a lower muscle mass and strength, increased cellular senescence and protein degradation markers and reduced muscle differentiation efficiency (all p < 0.05). HIIT reduced EEF1E1 expression and mitigated age-related muscle decline and atrophy in aged mice more effectively than MICT. Notably, EEF1E1 downregulation via siRNA significantly counteracted D-galactose-induced myoblast senescence as evidenced by reduced markers of muscle protein degradation and improved muscle differentiation efficiency (all p < 0.05). Conversely, treatments that increased EEF1E1 levels accelerated the senescence process (p < 0.05). Further exploration indicated that the decrease in EEF1E1 was associated with increased SIRT1 level and enhanced autophagy. This study highlights the potential of HIIT as a promising approach to prevent and treat sarcopenia while also highlighting EEF1E1 as a potential intervention target.

The Role of High-Intensity Interval Training (HIIT) vs. Moderate-Intensity Continuous Training (MICT) in Improving Cardiovascular Fitness in Patients with Coronary Artery Disease

Background: Exercise is a crucial component of cardiac rehabilitation for patients with Coronary Artery Disease (CAD). High-Intensity Interval Training (HIIT) and Moderate-Intensity Continuous Training (MICT) are two commonly used exercise modalities, but their comparative effectiveness in improving cardiovascular fitness in CAD patients remains uncertain.Objective: To compare the effects of HIIT and MICT on cardiovascular fitness in patients with CAD.Methods: A randomized controlled trial was conducted at Therapy Plus Clinics, Architect Society, Lahore, Pakistan, with 44 participants (22 in each group). Participants were randomly assigned to either HIIT or MICT for a 12-week intervention. Cardiovascular fitness was assessed using VO₂ max, resting heart rate, and blood pressure measurements before and after the intervention. Data analysis was performed to compare the outcomes between the two groups.Results: The HIIT group showed a significant improvement in VO₂ max (25.2 ± 3.5 to 30.4 ± 4.2 mL/kg/min) compared to the MICT group (24.8 ± 3.7 to 27.2 ± 3.9 mL/kg/min, p = 0.01). Additionally, the HIIT group experienced a greater reduction in resting heart rate (72.5 ± 8.2 to 68.1 ± 7.9 bpm) compared to the MICT group (73.2 ± 7.8 to 70.3 ± 7.5 bpm, p = 0.04). Both groups showed reductions in systolic and diastolic blood pressures, but the differences were not statistically significant.Conclusion: HIIT appears to be more effective than MICT in improving cardiovascular fitness, as evidenced by greater enhancements in VO₂ max and reductions in resting heart rate. These findings suggest that HIIT may be a superior exercise modality for CAD patients, offering a time-efficient alternative to traditional moderate-intensity exercise. Further research is needed to explore long-term effects and broader applicability.

Effect of high-intensity interval training and moderate-intensity continuous training on blood lactate clearance after high-intensity test in adult men.

This study compared the effects of High-intensity interval training (HIIT) and moderate-intensity continuous training (MICT) on blood lactate clearance. 21 adult males were equally and randomly assigned to the HIIT and MICT groups, and completed 8weeks of training. Before the training intervention, after 4weeks and 8weeks of training, all subjects were tested for blood lactate levels between 0 and 55min after the same high-intensity test. The results show that after 8weeks, blood lactate levels were significantly lower than pre-tests in both the HIIT and MICT groups at "0-55min" after high-intensity test (p < 0.05), and the blood lactate clearance percentage at15-min and 30-min in both groups were significantly higher than the pre-tests (P < 0.01). The blood lactate levels in the HIIT group were significantly lower than those in the MICT group at 15min and 30min after test (P < 0.05), and the blood lactate clearance percentage at 30min in the HIIT group was significantly higher than those in the MICT group (P < 0.05). In conclusion, both HIIT and MICT enhance blood lactate clearance in adult males post high-intensity test, with HIIT demonstrating superior effectiveness, making it a viable alternative to MICT.

Long-Term Effects of Three Different Exercise Training Modes on Cardiorespiratory Fitness of Female Flamenco Dancers

BACKGROUND: It is well established that high-intensity interval training (HIIT) is effective in enhancing athletes’ performance and improving the health of recreational exercisers. However, there is a dearth of comprehensive recommendations regarding the integration of HIIT into the exercise routines of flamenco dancers. Therefore, this study aimed to evaluate how three different 10-week training programs—including traditional flamenco training (control group, CG) alone or combined with HIIT or muscular strength and endurance training (MSET)—impact the cardiovascular fitness (maximal oxygen consumption, VO2max) of female flamenco dancers, specifically focusing on the effectiveness of additional training methods. METHODS: A group of 33 trained female flamenco dancers was randomly divided into three groups: HIIT (n=11), MSET (n=11), and a control group (CG, n=11). VO2max was assessed through breath-by-breath gas analysis during an incremental treadmill test. All participants, including the control group, engaged in uniform choreography sessions at moderate intensity (55–60% of reserve heart rate [HRR], 50 min/day, twice a week). In addition, the HIIT and MSET groups underwent supplementary training sessions twice a week (40 min/day) for 10 weeks, utilizing different techniques and intensities (HIIT: 80–90% of HRmax; MSET: 55–75% of HRmax). RESULTS: A statistically significant 19.7% improvement in aerobic capacity (VO2max) was observed in the HIIT group (p ≤ 0.05), with large effect sizes (ES) compared to MSET (p=0.011; ES = 2.423) and CG (p=0.034; ES=1.664). CONCLUSION: These findings indicate that HIIT training, when integrated with dance lessons, enhances aerobic capacity more effectively compared to traditional dance training alone or traditional dance training supplemented with MSET. Therefore, integrating HIIT into dance training programs as supplementary training may be particularly effective in improving aerobic capacity for female flamenco dancers.

The Release of Lipolytic Hormones during Various High-Intensity Interval and Moderate-Intensity Continuous Training Regimens and Their Effects on Fat Loss.

To investigate the release of lipolytic hormones during various high-intensity interval training (HIIT) and moderate-intensity continuous training (MICT), and their effects on fat loss. 39 young women categorized as obese (with a body fat percentage (BFP) ≥30%) were randomly allocated to one of the following groups: all-out sprint interval training (SIT, n =10); supramaximal HIIT (HIIT120, 120%V̇O2peak, n = 10); HIIT (HIIT90, 90%V̇O2peak, n = 10), or MICT, (60%V̇O2peak, n = 9) for a twelve-week observation period consisting of 3 to 4 exercise sessions per week. Serum epinephrine (EPI) and growth hormone (GH) were measured during the 1st, 20th, and 44th training sessions. Body weight (BW), body mass index (BMI), whole-body fat mass (FM) and BFP were assessed pre- and post-intervention. Following the 1st and 20th sessions, significant increases in EPI (p < 0.05) were observed post-exercise in HIIT120 and HIIT90, but not in SIT and MICT. In the 44th session, the increased EPI was found in SIT, HIIT120, and HIIT90, but not in MICT (p < 0.05). For the GH, a significant increase was observed post-exercise in all groups in the three sessions. The increased EPI and GH returned to baselines 3 hours post-exercise. After the 12-week intervention, significant reductions in FM and BFP were found in all groups, while reductions in BW and BMI were only found in the SIT and HIIT groups. Greater reductions in FM and BFP, in comparison to MICT, were observed in the SIT and HIIT groups (p < 0.05). 12-week SIT, HIIT120, and HIIT90, in comparison to MICT, were more efficacious in fat reduction in obese women, partly benefiting from the greater release of lipolytic hormones during training sessions.

Cardiorespiratory Fitness Benefits of High-Intensity Interval Training After Stroke: A Randomized Controlled Trial.

Limited evidence supports the effects of short-interval high-intensity interval training (HIIT) for improving cardiorespiratory fitness (V̇O2peak) after stroke. We aimed to compare the effects of 12 weeks of short-interval HIIT versus moderate-intensity continuous training (MICT) on V̇O2peak, cardiovascular risk factors, and mobility outcomes among individuals ≥6 months poststroke. This study was a multi-site, 12-week randomized controlled trial (NCT03614585) with an 8-week follow-up. Participants were randomized into 3 d/wk of HIIT (10×1 minute 80%-100% heart rate reserve interspersed with 1 minute 30% heart rate reserve [19 minutes]) or MICT (20-30 minutes 40%-60% heart rate reserve). Secondary outcomes of the trial, including V̇O2peak, cardiovascular risk factors (carotid-femoral pulse wave velocity, blood pressure, and waist-hip ratio), and mobility (6-minute walk test, 10 m gait speed), were reported. Linear mixed model analyses with a group×study time point interaction evaluated between-group differences. Of the 305 potential participants, 82 consented (mean [SD] age 64.9 [9.3] years, 32 females [39%], 1.8 [1.2] years poststroke) and were randomized to HIIT (n=42, mean [SD] baseline V̇O2peak 17.3 [5.9] mL/kg·min) or MICT (n=40, mean [SD] baseline V̇O2peak 17.2 [6.0] mL/kg·min). Participants attended 82% of visits (n=2417/2952). No adverse events occurred during the study period. A significant group×study time point interaction was found (χ2=8.46; P=0.015) for V̇O2peak at 12 weeks (mean difference, 1.81 [95% CI, 0.58-3.04]; P=0.004) whereby the HIIT group had greater gains in V̇O2peak (∆3.52 mL/kg·min [95% CI, 2.47-4.57]; P<0.001) compared with the MICT group (∆1.71 mL/kg·min [95% CI, 0.55-2.86]; P=0.001). There was no between-group difference in V̇O2peak (mean difference, 1.08 [95% CI, -0.26 to 2.42]; P=0.11) at 8-week follow-up. No group×study time point interactions were found for cardiovascular risk factors or mobility outcomes. Short-interval HIIT may be an effective alternative to MICT for improving V̇O2peak at 12 weeks postintervention. URL: https://clinicaltrials.gov; Unique identifier: NCT03614585.

Effects of high-intensity interval and moderate-intensity continuous training on the anaerobic threshold of highly trained athletes in endurance sports: a systematic review with meta-analysis.

The anaerobic threshold (AT) is an important physiological index used as a parameter for predicting performance and evaluating adaptations induced by training. The aim of this study was to carry out a systematic literature review to survey the randomized studies that compared the effects of high-intensity interval training (HIIT) with the effects of moderate intensity continuous training (MICT) on the anaerobic threshold of highly trained athletes in endurance sports. The following databases were searched: MEDLINE, Embase, Cochrane Wiley, PubMed, SPORTDiscus, Web of Science, and ProQuest for randomized trials. The search terms covered the areas of HIIT and MICT. This study was registered in the International Prospective Register of Systematic under the number CRD42020155474. Three studies were included for the qualitative and quantitative synthesis, totaling 72 participants, of whom 28 belonged to the MICT group and 44 to the HIIT group. The summary result showed that HIIT promotes greater adaptation in the AT of highly trained athletes compared to continuous training (ES=0.73; 95% CI: 0.25-1.21); however, the certainty of evidence evaluated by the GRADE method is low and heterogeneity is high (I2=82%; P<0.01).