Low-intensity Continuous Exercise Research Articles

Effect of Individualized Nutritional Therapy Combined with Low-intensity Continuous Exercise on Pregnancy Outcomes in Patients with Gestational Diabetes

Objective: To study the effect of individualized nutrition therapy combined with low intensity continuous exercise on gestational diabetes mellitus (GDM) control and pregnancy outcome. Methods: A total of 72 GDM patients diagnosed and treated in our hospital from October 2022 to October 2023 were randomly divided into an observation group and a control group. Individualized nutritional therapy combined with low-intensity continuous exercise therapy and conventional therapy were given, respectively. The blood glucose level, biochemical indexes, depression score, anxiety score and pregnancy outcome of the patients were observed and compared. Results: After individualized nutrition therapy combined with low-intensity continuous exercise, compared with the control group, the levels of fasting blood glucose, 2h postprandional blood glucose, glycated protein, albumin, total cholesterol, and triacylglycerol of the patients in the observation group were significantly reduced, and the depression and anxiety of the patients in the observation group were significantly alleviated, and the pregnancy complications were significantly reduced. Conclusion: Individualized nutrition therapy combined with low-intensity continuous exercise can effectively control gestational diabetes and improve pregnancy outcomes.

Acute effects of combined cycling and plyometrics on vertical jump performance in active males.

The aim of this study was to analyze the acute effects of high vs low-intensity cycling efforts, combined with plyometrics, on vertical jump performance. Twenty-four physically active men (mean ± SD: 23 ± 2 years, 72.1 ± 10.1 kg, 1.73 ± 0.07 m) were randomly divided into two groups: experimental group (EXP, n = 16) and control group (CON, n = 8). EXP competed 2 experimental trials in a random order: (a) short high-intensity interval exercise (HI + Plyo) [5 × 10 s of cycling ("all-out")/50 s active rest] or (b) low-intensity continuous exercise (LO + Plyo) [5 min of cycling at 75% of the HRmax)], along with 3 × 10 plyometric bounds (drop jumps)/1 min rest between sets. CON used a preconditioning activity of 13 min of low intensity cycling at ~60% of HRmax. Both EXP interventions significantly increased (p ≤ 0.05) the countermovement jump (CMJ) height at 1 min, 3 min, 6 min and 9 min compared to baseline, while the CON remained unchanged. There were no significant differences in CMJ performance enhancement between HI + Plyo (largest 11.2% at 9 min) and LO + Plyo (largest 15.0% at 3 min) at any time-point, suggesting that the plyometric component may be most important, with HR recovery taking slightly longer following HI + Plyo. The findings suggest that CMJ performance can be enhanced following high or low-intensity cycling combined with plyometric preconditioning activities in active males, the optimum recovery period likely to be individual-specific.

Time-Course of Redox Status, Redox-Related, and Mitochondrial-Dynamics-Related Gene Expression after an Acute Bout of Different Physical Exercise Protocols.

We investigated the magnitude of exercise-induced changes in muscular bioenergetics, redox balance, mitochondrial function, and gene expression within 24 h after the exercise bouts performed with different intensities, durations, and execution modes (continuous or with intervals). Sixty-five male Swiss mice were divided into four groups: one control (n = 5) and three experimental groups (20 animals/group), submitted to a forced swimming bout with an additional load (% of animal weight): low-intensity continuous (LIC), high-intensity continuous (HIC), and high-intensity interval (HII). Five animals from each group were euthanized at 0 h, 6 h, 12 h, and 24 h postexercise. Gastrocnemius muscle was removed to analyze the expression of genes involved in mitochondrial biogenesis (Ppargc1a), fusion (Mfn2), fission (Dnm1L), and mitophagy (Park2), as well as inflammation (Nos2) and antioxidant defense (Nfe2l2, GPx1). Lipid peroxidation (TBARS), total peroxidase, glutathione peroxidase (GPx), and citrate synthase (CS) activity were also measured. Lactacidemia was measured from a blood sample obtained immediately postexercise. Lactacidemia was higher the higher the exercise intensity (LIC < HIC < HII), while the inverse was observed for TBARS levels. The CS activity was higher in the HII group than the other groups. The antioxidant activity was higher 24 h postexercise in all groups compared to the control and greater in the HII group than the LIC and HIC groups. The gene expression profile exhibited a particular profile for each exercise protocol, but with some similarities between the LIC and HII groups. Taken together, these results suggest that the intervals applied to high-intensity exercise seem to minimize the signs of oxidative damage and drive the mitochondrial dynamics to maintain the mitochondrial network, similar to low-intensity continuous exercise.

Effect of Training Intensity on HIF-1a Gene Expression and Cardiac TG Content in Rats with Non-Alcoholic Fatty Liver Disease

Introduction: HIF-1a is an important regulator in response to hypoxia that affects various genes involved in energy metabolism. The aim of this study was to investigate the effect of exercise intensity on HIF-1a gene expression and cardiac TG content in rats with non-alcoholic fatty liver disease.&#x0D; Methods: The present study was performed experimentally on 40 male Wistar rats. Mice were randomly divided into 4 groups. The control groups, low-intensity endurance training and intense interval training, consumed high-fat food for 16 weeks, and then the two training groups participated in exercise for 8 weeks. Furthermore, sham group, which used standard food during this period, at the end of training, the expression level of HIF-1a and the amount of intra-tissue fat of the heart were measured in 4 groups. HIF-1a expression was assessed using real-time PCR and TG assay on an auto-analyzer. SPSS software version 16 and analysis of variance were used to analyze the data.&#x0D; Results: The results showed that there was a significant difference in the expression of HIF-1a gene between the control and the sham groups, HIIT and LIET groups (P=0.001). Moreover, there was a significant difference in triglyceride between HIIT and LIET groups compared to the sham and control groups, but no significant difference was observed between HIIT and LIET groups (P=0.0001).&#x0D; Conclusion: The results showed that intense intermittent exercise and low-intensity continuous exercise may reduce cardiac triglyceride content by decreasing HIF-1a expression and increasing fatty acid oxidation.

Estimation of minute ventilation by heart rate for field exercise studies

The aim of this study was to develop predictive equations for minute ventilation based on heart rate, and to test the precision of the equations in two forms of endurance exercise. Eighteen men (age 27.8 ± 5.4 years old, maximal oxygen uptake 45.4 ± 8.3 ml·kg−1·min−1) performed a maximal progressive cycle test in which minute ventilation and heart rate were continually measured and further used to establish the proposed equations with quadratic and exponential adjustments. In the second and third laboratory visits, sixteen participants completed two cycling bouts, one high-intensity interval exercise and one low-intensity continuous exercise. The minute ventilation and heart rate were measured in both exercises and the validity of the equations tested. The Bland-Altman analysis showed agreement between the minute ventilation and estimated equations for interval and continuous exercise. There was no difference between the minute ventilation obtained from both equations and the minute ventilation directly measured during the interval exercise. However, the quadratic equation underestimated the minute ventilation during continuous exercise (p < 0.05). While both equations seem to be suitable to estimate minute ventilation during high-intensity interval exercise, the exponential equation is recommended for low-intensity continuous exercise.

Independent and Combined Effects of All-Out Sprint and Low-Intensity Continuous Exercise on Plasma Oxidative Stress Biomarkers in Trained Judokas

The purpose of this study was to assess oxidative stress biomarkers prior to and following different forms of exercise. Ten elite male judokas (age: 18.1 ± 1.7 years, athletic experience: 6 years with a training frequency of 6 Judo-sessions/week) performed three cycle ergometry sessions comprising a 30 s Wingate test (MAX), 30 min at 60% maximal-aerobic-power-output (LOW) or these two exercise protocols combined (COMBINED) in a repeated-measures design. Venous blood-samples were collected before, and 0(P0), 5(P5), 10(P10) and 20(P20) min after each exercise protocol and assessed for malondialdehyde concentration ([MDA]), glutathione peroxidase (GPX), superoxide dismutase (SOD) and glutathione reductase (GR) content, and total-antioxidant-status (TAS). Plasma [MDA] was found to be increased above baseline at P0 and P5 in the MAX, LOW and COMBINED conditions (p < 0.05), but was greater at P10 and P20 in the LOW condition compared to MAX and COMBINED conditions (p < 0.05). Blood GPX and SOD content increased above baseline at P0 in MAX and COMBINED and at P5 in LOW (p < 0.05), with GR content being similar between groups at P0 and P5 (p > 0.05). 20 min post-exercise, GPX, SOD, GR content and TAS were lower in the MAX compared to the LOW and COMBINED conditions (p < 0.05). In conclusion, the findings from this study reveal that redox-related biomarkers exhibited divergent response dynamics following different forms of exercise, which might have implications for understanding the mechanisms of exercise-induced skeletal muscle fatigue and adaptive remodeling.

High-Intensity Interval Training Performed by Young Athletes: A Systematic Review and Meta-Analysis.

Background: High-intensity interval training (HIIT) is as a time-efficient alternative to moderate- or low-intensity continuous exercise for improving variables related to endurance and anaerobic performance in young and adolescent athletes.Objectives: To assess original research about enhancement of endurance and anaerobic exercise performance in young and adolescent athletes performing HIIT.Method: Relevant articles published in peer-reviewed journals were retrieved from the electronic databases PubMed and SPORTDiscus in December 2017. Inclusion criteria were: (i) controlled trials (HIIT vs. alternative training protocol) with pre-post design; (ii) healthy young athletes (≤18 years); (iii) assessing variables related to endurance and exercise performance. Hedges' g effect size (ES), and associated 95% confidence intervals were calculated for comparison of any outcome between experimental (HIIT) and alternative training protocol.Results: Twenty four studies, involving 577 athletes (mean age: 15.5 ± 2.2 years), were included in this review. HIIT exerted no or small positive mean ES on peak oxygen uptake (VO2peak), running performance, repeated sprint ability, jumping performance and submaximal heart rate. Although the mean ES for changes in VO2peak with HIIT is small (mean g = 0.10±0.28), the average increase in VO2peak from pre to post HIIT-interventions were 7.2 ± 6.9% vs. 4.3 ± 6.9% with any other alternative intervention. HIIT largely and positively affected running speed and oxygen consumption at various lactate- or ventilatory-based thresholds, as well as for sprint running performance. Calculations showed negative mean ES for change-of-direction ability (large), and peak blood lactate concentrations (small). Mean duration per training session for HIIT was shorter than for control interventions (28 ± 15 min vs. 38 ± 24 min).Conclusion: The present findings suggest that young athletes performing HIIT may improve certain important variables related to aerobic, as well as anaerobic, performance. With HIIT, most variables related to endurance improved to a higher extent, compared to alternative training protocols. However, based on ES, HIIT did not show clear superiority to the alternative training protocols. Nevertheless, young athletes may benefit from HIIT as it requires less time per training session leaving more time for training sport specific skills.

인터벌 트레이닝이 2형 당뇨 마우스 골격근에서 GLUT-4 mRNA 발현과 심혈관 합병증 사이토카인에 미치는 영향

This study was investigated the effect of interval training on GLUT-4 mRNA expression of skeletal muscle and serum cytokines(IL-6, MCP-1, IL-10) concentration in diabetes mice. At 5 weeks of age, 57BL/KsJ-db/db mice(N=30) were randomly divide into three groups(n=10 in each group): diabetes group(DM), diabetes+low intensity training group(DM+LEX) and diabetes+high intensity interval training group(DM+HIT). Both training groups, the mice exercised treadmill for 30 min/day, 3 days/week for 8 weeks(low intensity continuous exercise vs high intensity interval exercise). Data analysis was done by using SPSS(Ver.20.0) and one-way ANOVA. The results of this study were follows: The GLUT-4 mRNA expression of skeletal muscle was significantly increased in both training group compared with control group, there was no significant difference between each training group. Serum pro-inflammatory cytokines(IL-6, MCP-1) levels were significantly lower in exercise groups than control group, whereas anti-inflammatory cytokine(IL-10) level was higher than control group. These results showed that HIT intervention can improve insulin sensitivity and inflammatory cytokine on cardiovascular diseases related with type 2 diabetes. HIT may be a valuable addition to a health-enhancing exercise program.

Exercise training in COPD: What is it about intensity?

Most of the current guidelines for pulmonary rehabilitation recommend higher, over lower, intensity exercise training for COPD. Typically, we consider intensity of exercise training to be a key component of any exercise training programme. Whilst studies of young individuals have demonstrated that higher exercise training intensity results in greater improvements in exercise capacity, the evidence for older patients is not so clear cut. In COPD, there is limited evidence regarding the optimal intensity of exercise training. Using both physiological (peak exercise capacity) and patient-centred (e.g. quality of life) outcomes, it remains inconclusive if higher intensity exercise training bestows any greater benefit than low-intensity exercise. If we examine the data from interval training studies, which used both high- and low-intensity interval and continuous exercise, we are able to generate more data for comparison. Unfortunately, these data are challenging to interpret due to heterogeneity in how interval training was prescribed. However, when we normalize the interval training data for training volume and examine the change in peak cycling power, there is a relationship between training intensity and increase in peak power (Wpeak , r = 0.68, P < 0.05). Hence, whilst there is an inconclusive amount of evidence to support this intervention based on studies that only examined high- versus low-intensity continuous exercise, the additional data from interval training studies would suggest that higher intensity may be superior in terms of increases in Wpeak . Future studies should focus on establishing a threshold and an optimal training intensity for COPD.

An acute bout of high-intensity intermittent swimming induces glycogen supercompensation in rat skeletal muscle

High-intensity intermittent exercise substantially increases muscle glucose transport, which is thought to be the rate-limiting step for glycogen synthesis. In the present study, we compared muscle glycogen supercompensation after high-intensity intermittent exercise with that observed after low-intensity continuous exercise in rats. Four- to five-week-old male Sprague-Dawley rats performed either low-intensity swimming (240 min of swimming exercise with a weight equivalent to 1% of their body mass; LOW) or high-intensity swimming (twenty 30-s swimming bouts with 30 s rest between bouts with a weight equivalent to 16% of their body mass; HIGH) to deplete muscle glycogen. After the glycogen-depleting exercise, rats were given a rodent chow diet plus 5% glucose solution for 6 h or 24 h. Immediately after the two types of exercise, glycogen concentration in rat epitrochlearis muscle was similarly depleted. After the 6-h and 24-h recovery periods, muscle glycogen concentrations in both the HIGH and LOW groups were restored well above the normally fed state. Furthermore, muscle glycogen accumulation in the HIGH group for the 6-h and 24-h recovery periods was not significantly different from that observed in the LOW group. The high-intensity intermittent swimming exercise also induced muscle glycogen supercompensation in well-trained rats that had performed 7 days of endurance swimming training (6 h per day). Our results indicate that high-intensity intermittent exercise as well as low-intensity continuous exercise could induce glycogen supercompensation in rat skeletal muscle.

Cardiorespiratory and metabolic costs of continuous and intermittent exercise in man.

1. Cardiorespiratory and metabolic responses to paired patterns of continuous and intermittent exercise with the same average power output were studied in eight men. Heart rate, ventilation and pulmonary gas exchange were measured during the different patterns of exercise performed on a cycle ergometer. The recovery oxygen volume was measured over 30 min of loadless pedalling. Needle biopsy samples of the vastus lateralis muscle were taken before, during and after completion of the exercise for measurement of muscle metabolites.2. Heart rate, ventilation, oxygen intake, respiratory exchange ratio, and blood lactate concentration were generally higher with intermittent compared with continuous exercise as were the accumulated totals for heart beats, ventilation and oxygen intake. Muscle biopsy samples tended to have higher lactate and lower phosphocreatine contents in intermittent exercise. The lactate concentration in muscle and blood water was the same during loadless pedalling before exercise but was significantly higher in muscle than blood during exercise. This concentration gradient was larger in intermittent than in continuous exercise.3. Work efficiency, calculated from the total oxygen cost of work in excess of a loadless pedalling control, was significantly lower in intermittent exercise. The explanation is thought to be connected with the observation that when the work was performed at a high rate in short bursts a large part of the oxidative recovery took place after the contraction during the rest periods, whereas in the low intensity continuous exercise the oxygen was mainly utilized while the work was being performed. This indicates that for part of the time in the intermittent exercise the muscle was working under anaerobic conditions. Although the possibility exists that the efficiency of resynthesis of phosphagen may be reduced in this form of activity, it is more likely that the result described is due to the greater amount of lactate formed in the intermittent exercise.