Weeks Of Moderate-intensity Continuous Training Research Articles

The effects of high-intensity interval training/moderate-intensity continuous training on the inhibition of fat accumulation in rats fed a high-fat diet during training and detraining

BackgroundCompared with moderate-intensity continuous training (MICT), high-intensity interval training (HIIT) has at least a comparable effect on inhibiting an increase in fat. However, few studies have been conducted to examine the effects of detraining on body fat in rats fed a high-fat diet. The present study aimed to compare the effects of 10 weeks of HIIT or MICT as well as 6 weeks of detraining on body fat in rats fed a high-fat diet.MethodsAfter being fed a high-fat diet for 8 weeks, 54 female rats were randomly assigned to six groups: (1) CON-10, sedentary control for 10 weeks; (2) MICT-10, 10 weeks of MICT; (3) HIIT-10, 10 weeks of HIIT; (4) CON-16, sedentary control for 16 weeks; (5) MICT-16, 10 weeks of MICT followed by 6 weeks of training cessation; and (6) HIIT-16, 10 weeks of HIIT followed by 6 weeks of training cessation. The training was performed 5 days/week. The subcutaneous adipose tissue (inguinal; SCAT), visceral adipose tissue (periuterine; VAT) and serum lipid profile were analysed after 10 or 16 weeks. Adipose tissue triglyceride lipase (ATGL) protein expression in VAT was assessed by western blotting.ResultsHIIT-10 and MICT-10 prevented the increase in SCAT, VAT and serum lipid levels seen in the CON group. During the 6-week detraining period, HIIT continued to prevent the increase in adipose tissue mass observed in the CON group, whereas MICT at least maintained this inhibition. The inhibition of fat mass increase was mainly the result of preventing adipocyte hypertrophy. The HIIT-10 and HIIT-16 groups showed the highest ATGL protein expression.ConclusionsHIIT has a comparable effect to MICT on inhibiting fat accumulation in female rats; however, the inhibition of SCAT and VAT increase by HIIT is superior to MICT after short-term training cessation.Graphical

The Effect of 8 Weeks of Moderate Intensity Continuous Training on the Expression of Apoptotic Genes in Heart Tissue of Aged Rats

Introduction: Aging process with progressive decrease of cardiac function is due to the death of cardiac myocyte characterized by apoptosis. On the other hand, physical activity not only improves heart function­, but also reduces the risk of heart disease. Therefore, the aim of this study was to investigate the effect of 8 weeks of continuous moderate exercise on BAX, P53, and caspase 3 gene expression in the heart tissue of aged male rats. Method: In this experimental study, 16 male Wistar rats with an average age of 19±2.25 months and weight of 350.02±20.12 grams were randomly divided into two groups of moderate intensity continuous training (MT) and control (C). The continuous aerobic exercise program (MICT) was performed for 8 weeks and five sessions per week with an intensity of 60-75% of the maximum speed. Then, 48 hours after the last exercise session, heart tissue was removed under general anesthesia. BAX, P53, and caspase 3 gene expression values were measured by real time PCR method. Independent t statistical method was used in SPSS 21 software for data analysis. Results: The results showed that performing eight weeks of moderate-intensity continuous training caused a significant decrease in the apoptotic indices of BAX (P=0.012), P53 (P=0.015), and caspase 3 (P=0.002) in the heart tissue of elderly rats compared to the control group. Conclusion: It seems­ that regular aerobic exercises with moderate intensity can significantly reduce the apoptosis index of heart tissue and the aging process.

Comparison of Eight Weeks of Moderate-intensity Continuous Training (MICT) and High-intensity Intermittent Training (HIIT) with Sodium Citrate Supplementation on PGC-1α Expression

Introduction: Sports activity increases the expression of PGC-1α, the regulatory factor of mitochondrial biogenesis. This study aimed to investigate the effect of eight weeks of Moderate-intensity Continuous Training (MICT) and High-intensity Intermittent Training (HIIT), along with sodium citrate supplementation, on PGC-1α expression in male Wistar rats. Method: Forty rats were placed in the following five groups: Control, MICT, MICT+sodium citrate, HIIT, and HIIT+sodium citrate. The continuous training group ran for eight weeks and five sessions per week with an average intensity of 70% of the maximum running speed for 15-30 minutes. The interval training group ran for 12 minutes with an intensity range of 50% and 90%. In addition to exercise, the exercise+supplement groups received 15 mmol/l sodium citrate supplement daily. The expression of PGC-1α in the soleus muscle was measured by the western blot method. Data analysis was done using one-way analysis of variance and Tukey's post hoc test. Results: The PGC-1α protein expression increased in both the training groups and the training+supplement groups compared to the control group (P=0.001). Furthermore, adding sodium citrate could significantly increase the PGC-1α expression in the MICTgroup+supplement compared to the MICT group (P=0.005). However, the HIIT had a higher effect on PGC-1α expression than the MICT group. Conclusion: Despite the effectiveness of both training methods, sodium citrate supplementation before HIIT could have more synergistic effects in increasing the expression of PGC-1α.

Effects of Moderate-Intensity Continuous Training and High-Intensity Interval Training on Testicular Oxidative Stress, Apoptosis and m6A Methylation in Obese Male Mice.

Exercise is an effective way to improve reproductive function in obese males. Oxidative stress and apoptosis are important pathological factors of obesity-related male infertility. Accumulating studies have demonstrated that N6-methyladenosine (m6A) methylation is associated with obesity and testicular reproductive function. Our study aimed to investigate and compare the effect of 8 weeks of moderate-intensity continuous training (MICT) and high-intensity interval training (HIIT) on testicular oxidative stress, apoptosis and m6A methylation in obese male mice. Male C57BL/6 mice were randomly allocated into the four groups: normal diet (ND) group, high-fat diet (HFD) group, high-fat diet with moderate-intensity continuous training (HFD-MICT) group and high-fat diet with high-intensity interval training (HFD-HIIT) group. Mice in the HFD-MICT and HFD-HIIT groups were subjected to 8 weeks of MICT or HIIT treadmill protocols after 12 weeks of HFD feeding. We found that MICT and HIIT increased the protein expression of Nrf2, HO-1 and NQO-1 in the testes of obese mice, and HIIT increased it more than MICT. The Bax/Bcl-2 ratio, Cleaved Caspase-3 protein expression and TUNEL-positive cells were consistently up-regulated in the testes of obese mice, but MICT and HIIT restrained these HFD-induced effects. In addition, HFDs increased m6A levels and the gene expression of METTL3, YTHDF2 and FTO in the testes, but these effects were reversed by MICT and HIIT. However, HIIT was more effective than MICT in reducing m6A methylation in the testes of obese mice. These results demonstrate that both MICT and HIIT protected against HFD-induced oxidative stress, apoptosis and m6A methylation in testicular tissues; as a result, testicular morphological and functional impairment improved. In particular, HIIT was more beneficial than MICT in increasing the mRNA expression of steroidogenic enzymes and testicular antioxidant capacity and decreasing m6A methylation in the testes of HFD-fed mice.

The Effect of Eight Weeks of Moderate-Intensity Continuous Training and High Intensity Interval Training along with Citrus aurantium L on some Cardiac Mitochondrial Biogenesis Markers in the Heart Tissue of Elderly Rats

The Effect of Eight Weeks of Moderate-Intensity Continuous Training and High Intensity Interval Training along with Citrus aurantium L on some Cardiac Mitochondrial Biogenesis Markers in the Heart Tissue of Elderly Rats

EFFECT OF MICT AND HIIT ON CARDIOMETABOLIC RISK AND BODY COMPOSITION IN OBESE BOYS

ABSTRACT Introduction: The prevalence of childhood obesity has increased and is associated with the development of several chronic diseases. Moderate-intensity continuous training is recommended as the main exercise method for treating obesity. However, in overweight and obese individuals, high-intensity interval training models have similar or greater fat reduction potential than moderate-intensity continuous training. Objective: This study aimed to compare the effects of 12 weeks of moderate-intensity continuous training and high-intensity interval training on cardiometabolic parameters, body composition, and cardiorespiratory fitness in obese adolescent boys. Methods: Fifty-six obese boys, aged 10-16 years old, were included. Anthropometric measurements, blood pressure, body composition, oxygen consumption, glucose, insulin, and the lipid profile were assessed. Participants were assigned to moderate-intensity continuous training (n=20), high-intensity interval training (n=20), and control (n=16) groups. The moderate-intensity continuous training sessions consisted of 90 minutes of cycling/walking exercises and the high-intensity interval training sessions consisted of 15 minutes of warm-up, 15-18 minutes of interval exercises, and 15 minutes of cool-down. Both were performed three times a week. A two-way mixed-model factorial analysis of variance (ANOVA) with repeated measures was used. Results: In the high-intensity interval training group, there was an increase in relative and absolute oxygen consumption and a reduction in diastolic blood pressure. However, in the moderate-intensity continuous training group, there were increases in relative oxygen consumption and high-density lipoproteins, as well as reductions in anthropometric measurements, fat mass, and triglycerides. Conclusion: Moderate-intensity continuous training may be a better protocol for the reduction of fat mass, anthropometric measurements, and improvement of the lipid profile, while high-intensity interval training may be more effective in improving blood pressure among obese boys. Both exercises improve cardiorespiratory fitness. Level of evidence II; Therapeutic studies - investigation of treatment results.

Exercise training improves cardiac function and regulates myocardial mitophagy differently in ischaemic and pressure‐overload heart failure mice

What is the central question of this study? What are the cardioprotective effects of different aerobic exercises on chronic heart failure with different aetiologies, and is mitophagy involved? What is the main finding and its importance? Moderate-intensity continuous training may be the 'optimum' modality for improving cardiac structure and function in ischaemic heart failure, while both moderate-intensity continuous training and high-intensity interval training were suitable for pressure-overload heart failure. Various mitophagy pathways, especially parkin-dependent pathways, participated in the protective effects of exercise on heart failure. The cardioprotective effects of different aerobic exercises on chronic heart failure with different aetiologies and whether mitophagy is involved remain elusive. In the current research, left anterior descending ligation and transverse aortic constriction surgeries were used to establish mouse models of heart failure, followed by 8weeks of moderate-intensity continuous training (MICT) and high-intensity interval training (HIIT). The results showed that for ischaemic heart failure MICT significantly improved ejection fraction (P<0.05) and fractional shortening (P<0.05), mitigated left ventricular end-systolic dimension (P<0.01), decreased brain natriuretic peptide (P<0.0001) and mitigated fibrosis (P<0.0001), while HIIT only decreased brain natriuretic peptide (P<0.0001) and fibrosis (P<0.0001). For pressure-overload heart failure, both MICT and HIIT significantly increased ejection fraction (P<0.0001) and fractional shortening (MICT: P<0.001, HIIT: P<0.0001), and reduced left ventricular end-diastolic and end-systolic dimensions, brain natriuretic peptide (P<0.0001), and fibrosis (MICT: P<0.01, HIIT: P<0.0001); HIIT was even better in reducing brain natriuretic peptide. Myocardial autophagy and mitophagy were compromised in heart failure, and the exercises improved myocardial autophagic flux and mitophagy inconsistently in heart failure with different aetiologies. Significant correlations were found between multiple mitophagy pathways and the cardioprotection of the exercises. Collectively, MICT may be the 'optimum' modality for ischaemic heart failure, while both MICT and HIIT (especially HIIT) were suitable for pressure-overload heart failure. Exercises differently improved myocardial autophagy/mitophagy, and multiple mitophagy-related pathways were closely implicated in cardioprotection of exercises for chronic heart failure.

Home-Based HIIT and Traditional MICT Prescriptions Improve Cardiorespiratory Fitness to a Similar Extent Within an Exercise Referral Scheme for At-Risk Individuals

Exercise referral schemes (ERS) are used to promote physical activity within primary care. Traditionally, ERS are conducted in a gym or leisure-center setting, with exercise prescriptions based on moderate-intensity continuous training (MICT). Home-based high-intensity interval training (Home-HIIT) has the potential to reduce perceived barriers to exercise, including lack of time and access to facilities, compared to traditional MICT prescription used with ERS and improve health related outcomes. We hypothesized that Home-HIIT would mediate greater improvement in cardiorespiratory fitness (CRF) by virtue of greater adherence and compliance to the exercise prescription, compared to MICT.Methods: Patients enrolled on an ERS (Liverpool, United Kingdom) were recruited for a pragmatic trial. Participants self-selected either 12 weeks of MICT (45–135 min/week at 50–70% HRmax) or Home-HIIT (4–9 min × 1 min intervals at ≥80% of HRmax, interspersed with 1 min rest). The primary outcome was the change in CRF (VO2peak) at post-intervention (12 weeks) and follow-up (3-month post intervention), using intention-to-treat analysis.Results: 154 participants (age 48 ± 10y; BMI 30.5 ± 6.1 kg/m2) were recruited between October 2017 and March 2019, 87 (56%) participants chose Home-HIIT and 67 (44%) MICT. VO2peak increased post-intervention in both groups (MICT 3.9 ± 6.0 ml.kg–1.min–1, Home-HIIT 2.8 ± 4.5 ml.kg–1.min–1, P < 0.001), and was maintained at follow-up (P < 0.001). Fat mass was only reduced post MICT (MICT −1.5 ± 6.3 kg, P < 0.05, Home-HIIT −0.2 ± 2.0 kg, P = 1.00), but the reduction was not maintained at follow-up (MICT −0.6 ± 5.1 kg, Home-HIIT 0.0 ± 2.2 kg, P > 0.05). Adherence to the prescribed programs was similar (MICT 48 ± 35%, Home-HIIT 39 ± 36%, P = 0.77).Conclusion: This is the first study to evaluate the use of Home-HIIT for individuals in a primary care setting. Contrary to our hypothesis, adherence to both exercise prescriptions was poor, and CRF improved to a similar extent in both groups with improvements maintained at 3-month follow-up. We provide evidence that, although not superior, Home-HIIT could be an effective and popular additional exercise choice for patients within primary care based ERS.Clinical Trial Registration: [ClinicalTrials.gov], identifier [NCT04553614].

Effects of different exercise modalities on cardiac dysfunction in heart failure with preserved ejection fraction.

AimsHeart failure with preserved ejection fraction (HFpEF) is an increasingly prevalent disease. Physical exercise has been shown to alter disease progression in HFpEF. We examined cardiomyocyte Ca2+ homeostasis and left ventricular function in a metabolic HFpEF model in sedentary and trained rats following 8 weeks of moderate‐intensity continuous training (MICT) or high‐intensity interval training (HIIT).Methods and resultsLeft ventricular in vivo function (echocardiography) and cardiomyocyte Ca2+ transients (CaTs) (Fluo‐4, confocal) were compared in ZSF‐1 obese (metabolic syndrome, HFpEF) and ZSF‐1 lean (control) 21‐ and 28‐week‐old rats. At 21 weeks, cardiomyocytes from HFpEF rats showed prolonged Ca2+ reuptake in cytosolic and nuclear CaTs and impaired Ca2+ release kinetics in nuclear CaTs. At 28 weeks, HFpEF cardiomyocytes had depressed CaT amplitudes, decreased sarcoplasmic reticulum (SR) Ca2+ content, increased SR Ca2+ leak, and elevated diastolic [Ca2+] following increased pacing rate (5 Hz). In trained HFpEF rats (HIIT or MICT), cardiomyocyte SR Ca2+ leak was significantly reduced. While HIIT had no effects on the CaTs (1–5 Hz), MICT accelerated early Ca2+ release, reduced the amplitude, and prolonged the CaT without increasing diastolic [Ca2+] or cytosolic Ca2+ load at basal or increased pacing rate (1–5 Hz). MICT lowered pro‐arrhythmogenic Ca2+ sparks and attenuated Ca2+‐wave propagation in cardiomyocytes. MICT was associated with increased stroke volume in HFpEF.ConclusionsIn this metabolic rat model of HFpEF at an advanced stage, Ca2+ release was impaired under baseline conditions. HIIT and MICT differentially affected Ca2+ homeostasis with positive effects of MICT on stroke volume, end‐diastolic volume, and cellular arrhythmogenicity.

Combining supervised run interval training or moderate-intensity continuous training with the diabetes prevention program on clinical outcomes.

The present study was designed to evaluate the 16weeks diabetes prevention program (DPP) combined with instructed run sprint interval training (INT) or moderate-intensity continuous training (MICT) on glycemic control, body composition, fitness, exercise adherence, and perceived exercise enjoyment in sedentary, adults with prediabetes. Participants completed three weekly supervised sessions of INT (4-10bouts of 30s maximal sprints followed by a 4min active recovery) or MICT (30-60min at 45-55% HRR) exercise coupled with the DPP for 16weeks. At baseline, 8 and 16weeks, participants completed fitness and clinical assessments as well as questionnaires to assess group and time differences. Twenty-nine study participants (INT n = 17, MICT n = 12) were randomized, however, significantly (p = 0.024) more participants withdrew from the INT (n = 11) than MICT (n = 4) treatment. There was no significant difference between groups in perceived exercise enjoyment, but, the MICT group significantly improved their perceived exercise enjoyment (10.8 ± 14.2; p = 0.021) from baseline to 16weeks. Both INT and MICT groups decreased their body weight (2.0 ± 0.8 vs. - 5.5 ± 1.4kg; p < 0.001), BMI (- 0.6 ± 0.3 vs. - 2.1 ± 0.5kg/m2; p < 0.001), body fat mass (1.4 ± 0.6 vs. - 4.2 ± 1.0kg; p < 0.001), fasting glucose (- 0.09 ± 0.01 vs. - 0.18 ± 0.02mmol/L; p = 0.020), and HbA1c (- 0.21 ± 0.09 vs. - 0.12 ± 0.12%; p = 0.001), respectively, however, the MICT had greater reductions (GxT: p ≤ 0.05) in body weight, BMI, and body fat than the INT group. Sixteen weeks of MICT is adhered to better and elicits greater improvements in body composition than INT. Nevertheless, both interventions similarly reduced fasting glucose and HbA1c in adults with prediabetes, suggesting either treatment could be effective for T2D prevention.

Do Short-Term Exercise Interventions Improve Cardiometabolic Risk Factors in Children?

To explore the impact of short-term exercise of varying intensity on traditional risk factors for cardiometabolic disease. A total of 109 children (mean age, 11.1 ± 0.8 years) were conveniently assigned to 5 weeks of moderate-intensity continuous training (MICT; n = 29) set at 65%-70% of maximum heart rate, high-intensity interval training (HIIT; n = 29; >80% maximum heart rate), combined training (HIIT + MICT; n = 27), or no training (control; n = 24). Two-way ANOVA (group × time) was used to evaluate the effects of training on all cardiometabolic disease risk factors. Effect sizes were calculated to assess the magnitude of difference. MICT, HIIT, and HIIT + MICT were associated with significantly improved resting heart rate (effect size, -0.4, -1.1, and -1.1, respectively; P < .0001), fasting glucose (effect size, -0.6, -0.9, and -0.1, respectively; P = .0004), peak oxygen consumption (effect size, 0.5, 0.9, and 0.5, respectively; P < .0001), and c-reactive protein (effect size, -0.2, -1.0, and -0.5, respectively; P = .0016). HIIT + MICT was significantly associated with reduced waist circumference (-5.4%; P < .0001) and waist-to-hip ratio (-2.5%; P < .0002) compared with MICT (7.0% and 6.3%, respectively) and HIIT (-0.5% and -1.3%, respectively). Short-term HIIT and MICT interventions are useful for improving cardiometabolic health in children. HIIT + MICT may provide superior reductions in central obesity indicators.

Two weeks of moderate-intensity continuous training, but not high-intensity interval training, increases insulin-stimulated intestinal glucose uptake.

Similar to muscles, the intestine is also insulin resistant in obese subjects and subjects with impaired glucose tolerance. Exercise training improves muscle insulin sensitivity, but its effects on intestinal metabolism are not known. We studied the effects of high-intensity interval training (HIIT) and moderate-intensity continuous training (MICT) on intestinal glucose and free fatty acid uptake from circulation in humans. Twenty-eight healthy, middle-aged, sedentary men were randomized for 2 wk of HIIT or MICT. Intestinal insulin-stimulated glucose uptake and fasting free fatty acid uptake from circulation were measured using positron emission tomography and [18F]FDG and [18F]FTHA. In addition, effects of HIIT and MICT on intestinal GLUT2 and CD36 protein expression were studied in rats. Training improved aerobic capacity (P = 0.001) and whole body insulin sensitivity (P = 0.04), but not differently between HIIT and MICT. Insulin-stimulated glucose uptake increased only after the MICT in the colon (HIIT = 0%; MICT = 37%) (P = 0.02 for time × training) and tended to increase in the jejunum (HIIT = -4%; MICT = 13%) (P = 0.08 for time × training). Fasting free fatty acid uptake decreased in the duodenum in both groups (HIIT = -6%; MICT = -48%) (P = 0.001 time) and tended to decrease in the colon in the MICT group (HIIT = 0%; MICT = -38%) (P = 0.08 for time × training). In rats, both training groups had higher GLUT2 and CD36 expression compared with control animals. This study shows that already 2 wk of MICT enhances insulin-stimulated glucose uptake, while both training modes reduce fasting free fatty acid uptake in the intestine in healthy, middle-aged men, providing an additional mechanism by which exercise training can improve whole body metabolism.NEW & NOTEWORTHY This is the first study where the effects of exercise training on the intestinal substrate uptake have been investigated using the most advanced techniques available. We also show the importance of exercise intensity in inducing these changes.