High-intensity Interval Training Group Research Articles

Small-Sided Soccer Games Promote Greater Adaptations on Vertical Jump and Change-of-Direction Deficit and Similar Adaptations in Aerobic Capacity than High-Intensity Interval Training in Females

The objective of this study was to compare the effectiveness of both small-sided games (SSG) and short interval running-based high-intensity interval training (HIIT) programs over an 8-week period in fostering adaptations in aerobic capacity, change-of-direction abilities, and jumping performances of youth female soccer players. The study involved 48 female youth participants under the age of 19, competing at the regional level, who took part in a randomized controlled trial. Participants were assigned to either the SSG group, the HIIT group, or a control group, which involved regular in-field sessions. Assessments were conducted at baseline and after the 8-week training intervention, measuring aerobic capacity using the 30-15 intermittent fitness test (VIFT), change of direction (COD) using the 5-0-5 test, and jumping performance using the countermovement jump test (CMJ). Time 5 group analysis revealed significant interactions in CMJ (p = 0.005; ηp2= 0.213) and VIFT (p < 0.001; ηp2 = 0.433), although no significant interaction were found in COD deficit (p = 0.246; ηp2 = 0.060). Within-group analysis revealed that SSG significantly improved CMJ (p < 0.001), COD deficit (p < 0.001), and VIFT (p < 0.001). HIIT group also significantly improved CMJ (p = 0.029), COD deficit (p = 0.001), and VIFT (p < 0.001). As conclusion, the study revealed that SSG promoted significantly improvements in VIFT, CMJ and COD deficit, being significantly better than control group, while HIIT was only significantly better than control in VIFT. SSG revealed to be effective approach for favoring key physical attributes of female soccer players, being an interesting and recommended training approach to increase the ecology of the training practice, while favoring physical positive adaptations.

Jumping Interval Training: An Effective Training Method for Enhancing Anaerobic, Aerobic, and Jumping Performances in Aerobic Gymnastics

The aim of this study was to compare the effects of jumping interval training (JIT) and running high-intensity interval training (HIIT) on the aerobic, anaerobic and jumping performances of youth female aerobic gymnasts. A randomized controlled study was conducted over an 8-week period, involving 73 youth female athletes (16.2 ± 1.3 years old) of aerobic gymnastics. The study comprised two experimental groups (JIT and HIIT) and a control group. Participants in the experimental groups engaged in two additional training sessions per week alongside their regular training regimen, while the control group followed their usual training routine. Before and after the intervention period, gymnasts were assessed for their performance in the countermovement jump test (CMJ), the specific aerobic gymnastics anaerobic test (SAGAT) and the 20-m multistage fitness test. Significant interactions time × group were found in SAGAT (p < 0.001; = 0.495), CMJ (p < 0.001; = 0.338) and 20-m multistage fitness test (p < 0.001; = 0.500). The time × group analysis post-intervention revealed significantly lower scores in SAGAT for the control group compared to the JIT (p = 0.003) and HIIT (p = 0.034). Additionally, significantly higher scores were observed for the JIT group in the CMJ test compared to the HIIT (p = 0.020) and control (p = 0.028) groups following the intervention. Finally, the 20 m multistage fitness test post-intervention revealed significantly lower scores for the control group compared to JIT (p < 0.001) and HIIT (p < 0.001). Both JIT and HIIT are recommended training strategies to adopt in aerobic gymnastics for significantly improving the aerobic and anaerobic performances of athletes. However, JIT may be particularly relevant to use as it offers additional benefits in improving vertical jumping performances.

Eight weeks of high-intensity interval training versus stretching do not change the psychoneuroendocrine response to a social stress test in emotionally impulsive humans.

Research supports physical activity as a method to heighten stress resistance and resilience through positive metabolic alterations mostly affecting the neuroendocrine system. High-intensity interval training (HIIT) has been proposed as a highly effective time-saving method to induce those changes. However, existing literature relies heavily on cross-sectional analyses, with few randomised controlled trials highlighting the necessity for more exercise interventions. Thus, this study aims to investigate the effects of HIIT versus an active control group on the stress response to an acute psychosocial stressor in emotionally impulsive humans (suggested as being strong stress responders). The study protocol was registered online (DRKS00016589) before data collection. Sedentary, emotionally impulsive adults (30.69 ± 8.20 y) were recruited for a supervised intervention of 8 weeks and randomly allocated to either a HIIT (n = 25) or a stretching group (n = 19, acting as active controls). Participants were submitted to a test battery, including saliva samples, questionnaires (self-efficacy- and perceived stress-related), visual analogue scales (physical exercise- and stress-related), and resting electroencephalography and electrocardiography assessing their reaction to an acute psychological stressor (Trier Social Stress Test) before and after the exercise intervention. HIIT increased aerobic fitness in all participants, whereas stretching did not. Participants from the HIIT group reported perceiving exercising more intensively than those from the active control group (ƞp2 = 0.108, p = 0.038). No further group differences were detected. Both interventions largely increased levels of joy post-TSST (ƞp2 = 0.209, p = 0.003) whilst decreasing tension (ƞp2 = 0.262, p < 0.001) and worries (ƞp2 = 0.113, p = 0.037). Finally, both interventions largely increased perceived levels of general self-efficacy (ƞp2 = 0.120, p = 0.029). This study suggests that 8 weeks of HIIT does not change the psychoneuroendocrine response to an acute psychological stress test compared to an active control group in emotionally impulsive humans. Further replications of supervised exercise studies highly powered with active and passive controls are warranted.

Effects of 12 Weeks of Moderate-intensity Continuous Exercise and High-intensity Interval Exercise on Cognitive Function in Elderly Subjects

OBJECTIVES This study analyzed the possibility of brain function activation after exercise training of high-intensity interval exercise and moderate-intensity continuous exercise in elderly people.METHODS The subjects of the study were elderly female people aged 65 years or older and were divided into three groups : control group, moderate-intensity continuous training (MICT), and high-intensity interval training (HIIT). Changes of body composition, physical fitness, cognitive function, and cognitive function-related blood variables were compared between before and after 12 weeks of exercise training.RESULTS Body weight, BMI (body mass index), and WHR (waist hip ratio) of body composition in HIIT group decreased significantly (p&lt;0.05) after exercise training, and there was no significant difference in MICT group and the control group. HIIT group significantly (p&lt;0.05) improved in grip strength, muscular endurance, flexibility, balance, cardiorespiratory endurance, and walking ability after exercise training, while MICT group showed significant (p&lt;0.05) improvements only in flexibility, balance, and cardiorespiratory endurance. Regarding blood variables, HIIT group showed significant (p&lt;0.05) differences in BDNF (brain-derived neurotrophic factor), irisin, and β-amyloid after exercise training, MICT group showed significant (p&lt;0.05) differences only in β-amyloid. Cognitive function in HIIT group and MICT group significantly (p&lt;0.05) improved in terms of temporal and spatial orientation, memory, and total scores after exercise training. During the recovery phase after one session of high-intensity interval exercise, blood lactic acid concentration increased significantly.CONCLUSIONS This study was confirmed the possibility of giving that high-intensity interval exercise for the elderly not only produces positive changes in body composition and improves physical fitness and cognitive function, but also frequently stimulates lactate production, helping to activate brain function through changes in BDNF and irisin in the blood.

The Protective Effects of High-Intensity Interval Training Combined with Q10 Supplementation on Learning and Memory Impairments in Male Rats with Amyloid-β-Induced Alzheimer's Disease.

Oxidative stress plays a major role in the progression of Alzheimer's disease (AD)-related cognitive deficits. This study was done to determine the protective effects of coenzyme Q10 (CoQ10) and high-intensity interval training (HIIT) alone and in combination for eight continuous weeks, on oxidative status, cognitive functions, and histological changes in the hippocampus in amyloid-β (Aβ)-induced AD rats. Ninety male Wistar rats were randomly assigned to the sham, control, Q10 (50 mg/kg of CoQ10; P.O.), HIIT (high intensity: 4 min running at 85-90% VO2max, low intensity: 3 min running at 50-60% VO2max), Q10 + HIIT, AD, AD+Q10, AD+HIIT, and AD+Q10 + HIIT groups. The results showed that Aβ injection reduced cognitive functions in the Morris water maze (MWM) test and recognition memory in the novel object recognition test (NORT), which was accompanied by a decrease in total thiol groups, catalase, and glutathione peroxidase activities, an increase in malondialdehyde levels, and neuronal loss in the hippocampus. Interestingly, pretreatment with CoQ10, HIIT, or both, could markedly improve the oxidative status and cognitive decline in the MWM and NOR tests, and hinder neuronal loss in the hippocampus of Aβ-induced AD rats. Therefore, a combination of CoQ10 and HIIT can improve Aβ-related cognitive deficits, probably through an amelioration in hippocampal oxidative status and prevention of neuronal loss.

Exercise enhances hepatic mitochondrial structure and function while preventing endoplasmic reticulum stress and metabolic dysfunction-associated steatotic liver disease in mice fed a high-fat diet

Metabolic dysfunction-associated steatotic liver disease (MASLD) has attracted increasing attention from the scientific community because of its severe but silent progression and the lack of specific treatment. Glucolipotoxicity triggers endoplasmic reticulum (ER) stress with decreased beta-oxidation and enhanced lipogenesis, promoting the onset of MASLD, whereas regular physical exercise can prevent MASLD by preserving ER and mitochondrial function. Thus, the hypothesis of this study was that high-intensity interval training (HIIT) could prevent the development of MASLD in high-fat (HF)-fed C57BL/6J mice by maintaining insulin sensitivity, preventing ER stress, and promoting beta-oxidation. Forty male C57BL/6J mice (3 months old) comprised 4 experimental groups: the control (C) diet group, the C diet + HIIT (C-HIIT) group, the HF diet group, and the HF diet + HIIT (HF-HIIT) group. HIIT sessions lasted 12 minutes and were performed 3 times weekly by trained mice. The diet and exercise protocols lasted for 10 weeks. The HIIT protocol prevented weight gain and maintained insulin sensitivity in the HF-HIIT group. A chronic HF diet increased ER stress-related gene and protein expression, but HIIT helped to maintain ER homeostasis, preserve mitochondrial ultrastructure, and maximize beta-oxidation. The increased sirtuin-1/peroxisome proliferator-activated receptor-gamma coactivator 1-alpha expression implies that HIIT enhanced mitochondrial biogenesis and yielded adequate mitochondrial dynamics. High hepatic fibronectin type III domain containing 5/irisin agreed with the antilipogenic and anti-inflammatory effects observed in the HF-HIIT group, reinforcing the antisteatotic effects of HIIT. Thus, we confirmed that practicing HIIT 3 times per week maintained insulin sensitivity, prevented ER stress, and enhanced hepatic beta-oxidation, impeding MASLD development in this mouse model even when consuming high energy intake from saturated fatty acids.

Applicability of a supramaximal high-intensity interval training program for older adults previously not engaged in regular exercise; analyses of secondary outcomes from the Umeå HIT Study

This analysis of secondary outcomes investigated the applicability of supramaximal high-intensity interval training (HIT) with individually prescribed external intensity performed on stationary bicycles. Sixty-eight participants with a median (min; max) age of 69 (66; 79), at the time not engaged in regular exercise were randomized to 25 twice-weekly sessions of supramaximal HIT (20-min session with 10 × 6-s intervals) or moderate-intensity training (MIT, 40-min session with 3 × 8-min intervals).The primary aim was outcomes on applicability regarding; adherence to prescribed external interval intensity, participant reported positive and negative events, ratings of perceived exertion (RPE 6–20), and affective state (Feeling Scale, FS -5–5). A secondary aim was to investigate change in exercise-related self-efficacy (Exercise Self-Efficacy Scale) and motivation (Behavioural Regulations in Exercise Questionnaire-2).Total adherence to the prescribed external interval intensity was [median (min; max)] 89 % (56; 100 %) in supramaximal HIT, and 100 % (95; 100 %) in MIT. The supramaximal HIT group reported 60 % of the positive (112 of 186) and 36 % of the negative (52 of 146) events. At the end of the training period, the median (min; max) session RPE was 15 (12; 17) for supramaximal HIT and 14 (9; 15) for MIT. As for FS, the median last within-session rating was 3 (−1; 5) for supramaximal HIT and 3 (1; 5) for MIT. Exercise-related motivation increased (mean difference in Relative Autonomy Index score = 1.54, 95 % CI [0.69; 2.40]), while self-efficacy did not change (mean difference = 0.55, 95 % CI [-0.75; 1.82]), regardless of group.This study provide support for supramaximal HIT in supervised group settings for older adults.

The Effects of High-Intensity Interval Training and Moderate-Intensity Continuous Training on Body Mass Index and Cardiopulmonary Function in Obese College Students

Objective: To observe the effects of high-intensity interval training (HIIT) and moderate-intensity continuous training (MICT) on body mass index (BMI) and cardiopulmonary function in obese college students.Methods: Fifty obese students from the first to third year of our university were randomly selected to participate in this study and were randomly divided into two groups, with 25 students in each group participating in different training programs. The groups were divided into HIIT and MICT groups, respectively, and they participated in high-intensity interval training and moderate-intensity continuous training for 3 months. Before and after the different interventions, the average BMI, vital capacity, and resting heart rate were measured.Results: There was no significant difference in BMI measurements between the two groups of obese college students before the intervention (P&gt;0.05). Before and after the intervention, both groups showed a significant decrease in average BMI compared to before the intervention (P&lt;0.05). After the intervention, the average BMI of the MICT group was significantly lower than that of the HIIT group (P&lt;0.05). There was no significant difference in vital capacity and resting heart rate measurements between the two groups of obese college students before the intervention (P&gt;0.05). After different interventions, both groups showed a significant increase in average vital capacity and a significant decrease in average resting heart rate compared to before the intervention (P&lt;0.05). After the intervention, the average resting heart rate of the MICT group was significantly lower than that of the HIIT group (P&lt;0.05).Conclusion: Both high-intensity interval training and moderate-intensity continuous training can significantly improve BMI and cardiopulmonary function in obese college students, with moderate-intensity continuous training having certain advantages in improving BMI and resting heart rate.

High-intensity interval training (HIIT) and slow breathing interventions alleviate premature ejaculation (PE) symptoms

BackgroundPhysical exercise may alleviate premature ejaculation symptoms, a prevalent male sexual dysfunction linked to a series of negative outcomes for men and their partners. ObjectiveWe investigated the effectiveness of high-intensity interval training (HIIT) and slow breathing interventions on premature ejaculation symptoms and their relation to autonomic activity and attention regulation. MethodChinese adult men (N = 76, M = 21.89, SD = 3.32) with premature ejaculation completed one of the two-week interventions in their homes or as participants in a normal breathing control group; they reported their age, height, weight, physical activity level, premature ejaculation symptoms, and attention regulation. In the HIIT group, 26 participants engaged in a 7-minute HIIT each day. In the slow breathing group, 25 participants performed 7-minute slow breathing exercises per day while the 25 participants in the normal breathing group similarly performed normal breathing exercises. All participants measured their heart rate once before and five times (with one-minute intervals) after the intervention. When participants had penile-vaginal sex with their partners, they measured their heart rate once after ejaculation. ResultsTime × Intervention interaction was significant with lower levels of premature ejaculation symptoms on Days 12, 13, and 14 in the HIIT group (M ± SD = 16.19 ± 3.45, 15.96 ± 3.43, and 15.15 ± 3.62) compared to the normal breathing group (M ± SD = 17.68 ± 3.06, 17.68 ± 3.15, and 17.44 ± 3.25). Higher levels of attention regulation were associated with fewer premature ejaculation symptoms. We also found that a larger increase in heart rate from resting to after sex was associated with fewer premature ejaculation symptoms. ConclusionCompared to the control group, the efficacy of two weeks of HIIT exercise in mitigating PE symptoms suggests its potential as a novel treatment for PE.

Acute effects of high-intensity exercise on brain mechanical properties and cognitive function.

Previous studies have shown that engagement in even a single session of exercise can improve cognitive performance in the short term. However, the underlying physiological mechanisms contributing to this effect are still being studied. Recently, with improvements to advanced quantitative neuroimaging techniques, brain tissue mechanical properties can be sensitively and noninvasively measured with magnetic resonance elastography (MRE) and regional brain mechanical properties have been shown to reflect individual cognitive performance. Here we assess brain mechanical properties before and immediately after engagement in a high-intensity interval training (HIIT) regimen, as well as one-hour post-exercise. We find that immediately after exercise, subjects in the HIIT group had an average global brain stiffness decrease of 4.2% (p < 0.001), and an average brain damping ratio increase of 3.1% (p = 0.002). In contrast, control participants who did not engage in exercise showed no significant change over time in either stiffness or damping ratio. Changes in brain mechanical properties with exercise appeared to be regionally dependent, with the hippocampus decreasing in stiffness by 10.4%. We also found that one-hour after exercise, brain mechanical properties returned to initial baseline values. The magnitude of changes to brain mechanical properties also correlated with improvements in reaction time on executive control tasks (Eriksen Flanker and Stroop) with exercise. Understanding the neural changes that arise in response to exercise may inform potential mechanisms behind improvements to cognitive performance with acute exercise.

Effect of High-Intensity Interval Training on TCF7L2 Gene Expression in Hepatocytes of Obese Rats

&#x0D; &#x0D; &#x0D; Objective: Hepatic glucose release is greatly increased in the presence of obesity and related diseases. The research objective was to explore the impact of high intensity interval training (HIIT) on TCF7L2 gene expression in hepatocytes of obese rats.&#x0D; Materials and Methods: Out of 21 male Wistar rats aged 10 weeks years (220±10 g), obesity was induced in 14 rats by 8-week high-fat diet. The rats were then divided into normal (n=7), obese control (n=7), and HIIT obese (n=7) groups. Rats in the HIIT group completed 8 weeks of HIIT/5 days weekly, whereas the other groups were inactive. After intervention, TCF7L2 gene expression in hepatocytes, insulin resistance and glucose compared using ANOVA /Tukey’s post hoc test between groups by SPSS-22.&#x0D; Results: Obesity induction led to a significant decrease in TCF7L2 gene expression (P: 0.011) and an increase in blood glucose (P: 0.009) and insulin resistance (P: 0.019) compared with the normal group (P&lt; 0.001). On the other hand, interval training led to a significant increase in TCF7L2 gene expression (P: 0.029) and a decrease in blood glucose (P&lt; 0.001) and insulin resistance (P&lt; 0.001) in the obese group compared with the control group.&#x0D; Conclusion: The observed enhancement in fasting blood glucose levels among obese rats could be linked to increased TCF7L2 gene expression in liver cells, which appears to be a response to interval training intervention. Nevertheless, understanding the main mechanisms responsible for observed changes requires further studies in this field.&#x0D; &#x0D; &#x0D;

HIIT serves as an efficient training strategy for basketball players by improving blood fluidity and decreasing oxidative stress.

A challenge for coaches and athletes is to find the best combination of exercises during training. Considering its favorable effects, HIIT has been very popular recently. The goal of this study was to investigate anthropometric features, performance, erythrocyte deformability, plasma viscosity (PV) and oxidative stress in response to acute and long-term (6 weeks) HIIT in adolescent basketball players. 22 sportsmen between the ages of 14-16 were included. Tabata protocol was applied to the HIIT group in addition to their routine training program 3 days/week, for 6 weeks. Erythrocyte deformability was determined using an ectacytometer (LORCA), PV with a rotational viscometer. Total oxidant status (TOS), total antioxidant status (TAS) were measured by kits. HIIT for 6 weeks induced an improvement in performance tests and waist circumference. 6 weeks of HIIT resulted in a decrement, while the last exercise session yielded an increment in RBC deformability. PV and TOS of HIIT groups were decreased on the 6th week. Our results demonstrate that, HIIT in addition to the routine exercise program is beneficial for improving performance and blood fluidity as well as decreasing oxidative stress in basketball players. Therefore, HIIT seems as an efficient training strategy for highly-trained individuals.

Effect of High-Intensity Interval Training on the Levels of Liver Fat Transporter Proteins (LFAB and CD36) in Rats with Fatty Liver

Background: Non-alcoholic fatty liver disease (NAFLD) is the most prevalent chronic liver condition linked to a rise in other metabolic disorders, such as type 2 diabetes and metabolic syndrome. Methods: Thirty 5-week-old rats with an average body weight of 165.4 ± 31.3 g were randomly assigned into two main groups: A sham group (10 rats) and an experimental group (20 rats, including control for fatty liver and exercise + fatty liver subgroups). The high-intensity interval training (HIIT) group underwent a HIIT protocol for 8 weeks, training 5 days per week. The data were analyzed using a dependent t-test and one-way analysis of variance (ANOVA), followed by Bonferroni's post hoc test. Results: Non-alcoholic fatty liver disease significantly increased CD36 and LFABP levels in liver tissue (P = 0.023 and P = 0.001, respectively). Eight weeks of interval training significantly decreased the levels of CD36 and LFABP in liver tissue (P = 0.019 and P = 0.007, respectively). Conclusions: The onset of non-alcoholic fatty liver elevates fatty acid transporter levels in liver tissue. However, eight weeks of HIIT markedly reduces these transporter levels.

Comparing high-intensity versus moderate-intensity exercise training in coronary artery disease patients: a randomized controlled trial with 6- and 12-month follow-up

Abstract Aim This study aimed to investigate the long-term effects of two exercise-based CR programs on physical activity (PA), sedentary behavior, physical fitness, quality of life (QoL), and mental health in coronary artery disease (CAD) patients. Subject and methods Seventy-two CAD participants were randomized (1:1:1) into HIIT, MICT, and control groups. Both training programs spanned 6 weeks with three supervised treadmill exercise sessions per week. MICT targeted ≈70–75% of peak heart rate (HR), while HIIT aimed for ≈85–95% of peak HR. The control group adhered to standard medical recommendations. Assessments at 6- and 12-months post-intervention included body composition, aerobic capacity, muscle strength, PA, SB, QoL, anxiety, and depression. Results Over the 6- and 12-month follow-up periods, both exercise groups maintained the levels of aerobic capacity (HIIT ≈ 19.6 ml kg−1 min−1, MICT ≈ 17.8 ml kg−1 min−1), QoL, and PA compared to baseline (p &lt; .001). Symptoms of anxiety and depression remained lower than baseline (p &lt; .001). The HIIT group demonstrated a significant decreasing trend in waist circumference (∆m3−m2% −2 cm, p = .033) compared to MICT (p = .016) and control (p = .001) at 6 months of follow-up. It was maintained at 12 months of follow-up with significant differences to MICT (p = .018) and control (p = .001). In contrast, the control group experienced deteriorations in body composition, SB, symptoms of anxiety, and depression, along with a decline in aerobic capacity over time. Conclusion Encouraging CAD patients to maintain elevated PA levels can promote cardiovascular, WC, and mental health. CR exercise programs can reduce cardiovascular risk factors and induce favorable lifestyle changes. Notably, HIIT demonstrated sustained improvements surpassing those of MICT. These findings underscore the importance of structured exercise-based CR programs in optimizing long-term outcomes for CAD patients. Trial Registration https://clinicaltrials.gov/ct2/show/NCT03538119 on May 25, 2018.

High-Intensity Interval Versus Moderate-Intensity Continuous Exercise Training on Glycemic Control, Beta Cell Function, and Aerobic Fitness in Women with Type 2 Diabetes.

Objective: This study aimed to compare the effects of High-Intensity Interval Training (HIIT) and Moderate-Intensity Continuous Training (MICT) on glycemic control, beta-cell function, and aerobic fitness in women with Type 2 Diabetes Mellitus (T2DM). Methods: Thirty-six women with T2DM were assigned equally to HIIT, MICT, and control (CON) groups. Participants in the exercise cohorts underwent a 12-week training regimen (three sessions per week), while the CON group maintained an inactive lifestyle. Glycaemia variables, beta-cell function, maximal oxygen uptake (VO2max), lipid profiles, and body composition were assessed at baseline and post-intervention. Results: Both HIIT and MICT interventions led to significant improvements in glucose, insulin, HbA1c, and insulin resistance index. Moreover, visceral adiposity index (VAI), lipid accumulation product (LAP), total cholesterol (TC), and low-density lipoprotein (LDL) levels significantly decreased in the HIIT and MICT groups after 12 weeks. Triglyceride (TG) levels decreased only after MICT, while high-density lipoprotein (HDL) levels increased after both interventions. Maximal oxygen uptake (VO2max), body mass, body mass index (BMI), and waist circumference (WC) significantly improved in all exercise groups. Notably, the HIIT group showed greater reductions in body mass compared to MICT. Nevertheless, beta-cell function remained unaltered after these two exercise regimens. Conclusion: Both HIIT and MICT interventions effectively managed T2DM in women, regardless of exercise intensity. The HIIT regimen can be considered for time-efficient lifestyle interventions in people with T2DM.

High-intensity interval training improves respiratory and cardiovascular adjustments before and after initiation of exercise.

Purpose: High-intensity interval training (HIIT) may induce training-specific physiological adaptations such as improved respiratory and cardiovascular adjustments before and after the onset of high-intensity exercise, leading to improved exercise performance during high-intensity exercise. The present study investigated the effects of HIIT on time-dependent cardiorespiratory adjustment during maximal exercise and before and after initiation of high-intensity exercise, as well as on maximal exercise performance. Methods: 21 healthy male college students were randomly assigned to HIIT group (n = 11) or control group (n = 10). HIIT group performed training on a cycle ergometer once a week for 8 weeks. The training consisted of three bouts of exercise at 95% maximal work rate (WRmax) until exhaustion. Before and after the HIIT program, dynamic cardiorespiratory function was investigated by ramp and step exercise tests, and HIIT-induced cardiac morphological changes were assessed using echocardiography. Results: HIIT significantly improved not only maximal oxygen uptake and minute ventilation, but also maximal heart rate (HR), systolic blood pressure (SBP), and time to exhaustion in both exercise tests (p < 0.05). Time-dependent increases in minute ventilation (VE) and HR before and at the start of exercise were significantly enhanced after HIIT. During high-intensity exercise, there was a strong correlation between percent change (from before to after HIIT program) in time to exhaustion and percent change in HRmax (r = 0.932, p < 0.001). Furthermore, HIIT-induced cardiac morphological changes such as ventricular wall hypertrophy was observed (p < 0.001). Conclusion: We have demonstrated that HIIT at 95% WRmax induces training-specific adaptations such as improved cardiorespiratory adjustments, not only during maximal exercise but also before and after the onset of high-intensity exercise, improvement of exercise performance mainly associated with circulatory systems.

Effects evaluation of different exercises on subclinical left ventricular dysfunction in obese rats by speckle-tracking echocardiography

ObjectiveTo identify subclinical left ventricle dysfunction (LVD) in obese rats by speckle-tracking echocardiography, and to evaluate the effects of 12-week Moderate-Intensity Continuous Training (MICT) or High-Intensity Interval Training (HIIT) on LV geometry, histology and function in obese rats. MethodsEighteen male standard or obese Sprague-Dawley rats were randomly divided into the Control group, the MICT group, and the HIIT group. Exercise interventions were conducted for 12 weeks, with equal total load and increased intensity gradient. Using dual-energy X-ray, two-dimensional speckle-tracking echocardiography, pulse Doppler, and HE staining to evalucate body shape, LV morphology, structure, and myocardial mechanics function. Results(1) Both MICT and HIIT have good weight loss shaping effect. (2) The LV of obese rats underwent pathological remodeling, with decreased longitudinal contractility and synchrony, and increased circumferential contractility and synchrony. (3) Exercise can inhibit LV pathological remodeling, improve myocardial mechanical function. HIIT is superior to MICT. (4) The global longitudinal strain of obese rats in the HIIT group showed a significant correlation with Fat% and Lean%. ConclusionObesity can induce LV pathological remodeling and subclinical dysfunction. Compared with MICT, 12-week HIIT can effectively inhibit the pathological remodeling of LV and promote the benign development of myocardial mechanical function in obese rats.

High-intensity interval training enhances mRNA expression of IGF1Ea in rat Achilles tendon.

High-intensity interval training (HIIT) reportedly enhances the functional properties of the musculoskeletal system. However, the effects of HIIT on tendons remain unclear. Sixteen male rats were randomly assigned to the control (Con) or HIIT group (n = 8 in each group). Rats in the HIIT group executed the HIIT program consisting of 2.5min treadmill running and 4.5min rests between the bouts, 5days per week for 9weeks. Running speed, number of sets, and inclination were incrementally increased during the training period. Histological analysis revealed no apparent morphological changes in the extracellular matrix structure or nuclei of tenocytes between the groups. Real-time reverse transcription polymerase chain reaction analysis revealed thatIgf1EamRNA expression was enhanced in the HIIT group. Furthermore,Igfbp5mRNA expression tended to be higher in the HIIT group. The 9-week HIIT program enhanced tenogenic Igf1Ea mRNA expression.

A Comparative Study: Cardioprotective Effects of High-Intensity Interval Training Versus Ischaemic Preconditioning in Rat Myocardial Ischaemia-Reperfusion.

(1) Background: Years of research have identified ischemic preconditioning (IPC) as a crucial endogenous protective mechanism against myocardial ischemia-reperfusion injury, enhancing the myocardial cell's tolerance to subsequent ischemic damage. High-intensity interval training (HIIT) is promoted by athletes because it reduces exercise duration and improves metabolic response and cardiopulmonary function. Our objective was to evaluate and compare whether HIIT and IPC could reduce myocardial ischemia and reperfusion injury in rats. (2) Methods: Male Sprague-Dawley rats were divided into four groups: sham surgery, coronary artery occlusion (CAO), high-intensity interval training (HIIT), and ischemic preconditioning (IPC). The CAO, HIIT, and IPC groups experienced 40 min of coronary artery occlusion followed by 3 h of reperfusion to induce myocardial ischemia-reperfusion injury. Subsequently, the rats were sacrificed, and blood samples along with cardiac tissues were examined. The HIIT group received 4 weeks of training before surgery, and the IPC group underwent preconditioning before the ischemia-reperfusion procedure. (3) Results: The HIIT and IPC interventions significantly reduced the extent of the myocardial infarction size and the levels of serum troponin I and lactate dehydrogenase. Through these two interventions, serum pro-inflammatory cytokines, including TNF-α, IL-1β, and IL-6, were significantly decreased, while the anti-inflammatory cytokine IL-10 was increased. Furthermore, the expression of pro-apoptotic proteins PTEN, caspase-3, TNF-α, and Bax in the myocardium was reduced, and the expression of anti-apoptotic B-cell lymphoma 2 (Bcl-2) was increased, ultimately reducing cellular apoptosis in the myocardium. In conclusion, both HIIT and IPC demonstrated effective strategies with potential for mitigating myocardial ischemia-reperfusion injury for the heart.

The effect of pentoxifylline and different types of exercise training on coagulation factors in a rat endometriosis model

ObjectivesThis study evaluated the effects of high-intensity interval training (HIIT), moderate-intensity continuous training (MICT), and pentoxifylline (PTX) on coagulation factors, including the amount and percentage of lymphocytes, PLC, PLR, aPTT, PT, PT.I.N. R in a model of rats with endometriosis. MethodsEndometriosis was surgically induced in female SpragueDawley rats. The rats with confirmed endometrial implants were divided into control, MICT, pentoxifylline (D), HIIT+D, and MICT+D, HIIT groups. D and exercise interventions were performed for eight weeks. Then, the macroscopic size of endometriosis lesions was measured, and inflammatory factors (count and percentage of lymphocytes) and coagulation factors, including PLC, PLR, aPTT, PT, PT.I.N. R, and PLR in blood samples were evaluated. ResultsD significantly decreased the volume of lesions and significantly increased PT and PT.I.N. R in blood. HIIT decreased the volume of lesions and significantly increased PT. MICT did not cause significant effects on the target variables. MICT+D decreased the volume of lesions. HIIT+D significantly decreased the volume of lesions and PLC and increased aPTT as well as the count and percentage of lymphocytes, PT, and PT.I.N. R, and decreased PLR. ConclusionsAll interventions(except for MICT) especially HIIT+D and D by priority, induced a significant effect on reducing some indices of inflammation and coagulation.