The effects of moderate intensity training in a hypoxic environment on transcriptional responses in Thoroughbred horses.
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ABSTRACT:
SUBMITTER: Davie AJ
PROVIDER: S-EPMC5550905 | biostudies-other | 2017 Jul
REPOSITORIES: biostudies-other
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Project description:The healthy benefits of regular physical exercise are mainly mediated by the stimulation of oxidative and antioxidant capacities in skeletal muscle. Our understanding of the cellular and molecular responses involved in these processes remain often uncomplete particularly regarding muscle typology. The main aim of the present study was to compare the effects of two types of exercise training protocol: a moderate-intensity continuous training (MICT) and a high-intensity interval training (HIIT) on metabolic processes in two muscles with different typologies: soleus and extensor digitorum longus (EDL). Training effects in male Wistar rats were studied from whole organism level (maximal aerobic speed, morphometric and systemic parameters) to muscle level (transcripts, protein contents and enzymatic activities involved in antioxidant defences, aerobic and anaerobic metabolisms). Wistar rats were randomly divided into three groups: untrained (UNTR), n = 7; MICT, n = 8; and HIIT, n = 8. Rats of the MICT and HIIT groups ran five times a week for six weeks at moderate and high intensity, respectively. HIIT improved more than MICT the endurance performance (a trend to increased maximal aerobic speed, p = 0.07) and oxidative capacities in both muscles, as determined through protein and transcript assays (AMPK-PGC-1α signalling pathway, antioxidant defences, mitochondrial functioning and dynamics). Whatever the training protocol, the genes involved in these processes were largely more significantly upregulated in soleus (slow-twitch fibres) than in EDL (fast-twitch fibres). Solely on the basis of the transcript changes, we conclude that the training protocols tested here lead to specific muscular responses.
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Project description:BackgroundRecent studies point to a lower number and reduced severity of cases in higher altitude cities with decreased oxygen concentration. Specific literature has shown several benefits of physical training, so, in this sense, physical training with hypoxic stimulus appears as an alternative that supports the conventional treatments of the COVID-19 patient's recovery. Thus, this study's primary aim is to analyze the effects of moderate-intensity intermittent hypoxic training on health outcomes in COVID-19 recovered patients.MethodsA clinical trial controlled double-blind study was designed. Participants (30-69 years old) will be recruited among those with moderate to severe COVID-19 symptoms, approximately 30 days after recovery. They will be included in groups according to the training (T) and recovery (R) association with hypoxia (H) or normoxia (N): (a) TH:RH, (b) TN:RH, (c) TN:RN, and last (d) the control group. The 8-week exercise bike intervention will be carried out with a gradual load increase according to the established periods, three times a week in sets of 5 min, 90 to 100% of the anaerobic threshold (AT), and a 2.5-min break. Blood will be collected for genotyping. First, after 4 weeks (partial), after 8 weeks, and later, 4 weeks after the end of the physical training intervention, participants will perform assessments. The primary outcome is the maximum oxygen consumption (VO2peak). The secondary outcomes include lung function, inflammatory mediators, hematological, autonomic parameters, AT, body composition analysis, quality of life, mental health, anthropometric measurements, and physical fitness. The statistical analysis will be executed using the linear regression model with mixed effects at a 5% significance level.DiscussionThis study is designed to provide evidence to support the clinical benefits of moderate-intensity intermittent hypoxic training as a part of the treatment of patients recovered from COVID-19. It may also provide evidence on the efficacy and safety of intermittent hypoxic training in different health conditions. Lastly, this study presents an innovative strategy enabling up to 16 participants in the same training session.Trial registrationClinicalTrials.gov RBR-5d7hkv. Registered after the start of inclusion on 3 November 2020 with the Brazilian Clinical Trials Registry.
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Project description:A common inclusion criterion when assessing cerebrovascular (CVR) metrics is for individuals to abstain from exercise for 12-24 hr prior to data collections. While several studies have examined CVR during exercise, the literature describing CVR throughout post-exercise recovery is sparse. The current investigation examined CVR measurements in nine participants (seven male) before and for 8 hr following three conditions: 45-min moderate-continuous exercise (at ~50% heart-rate reserve), 25-min high-intensity intervals (ten, one-minute intervals at ~85% heart-rate reserve), and a control day (30-min quiet rest). The hypercapnic (40-60 mmHg) and hypocapnic (25-40 mmHg) slopes were assessed via a modified rebreathing technique and controlled stepwise hyperventilation, respectively. All testing was initiated at 8:00a.m. with transcranial Doppler ultrasound measurements to index cerebral blood velocity performed prior to the condition (pre) with serial follow-ups at zero, one, two, four, six, and eight hours within the middle and posterior cerebral artery (MCA, PCA). Absolute and relative MCA and PCA hypercapnic slopes were attenuated following high-intensity intervals at hours zero and one (all p < .02). No alterations were observed in either hypocapnic or hypercapnic slopes following the control or moderate-continuous exercise (all p > .13), aside from a reduced relative hypercapnic MCA slope at hours zero and one following moderate-continuous exercise (all p < .005). The current findings indicate the common inclusion criteria of a 12-24 hr time restriction on exercise can be reduced to two hours when performing CVR measures. Furthermore, the consistent nature of the CVR indices throughout the control day indicate reproducible testing sessions can be made between 8:00a.m. and 7:00p.m.
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Project description:BackgroundObesity is associated with several comorbidities, such as cardiovascular disease and type 2 diabetes mellitus, and may have its origin in early life stages, such as in the lactation period, through metabolic programming. Physical activity aids in decreasing the chances of developing cardiovascular and metabolic diseases, even with small weight losses and, in children, can play an essential role in preventing weight gain and other health problems. The present study aimed to evaluate the effects of moderate intensity endurance training and high intensity interval training (HIIT) protocols on obesity-related parameters and cardiorespiratory capacity in overfed Wistar rats throughout the breastfeeding period.MethodsTwo days after birth, forty male and female Wistar rats were clustered into two groups: Control Litter Group (CL; ten animals/litter) and Reduced Litter Group (RL; four animals/litter). At weaning, RL animals were distributed randomly into three experimental groups: sedentary, moderate intensity endurance training and HIIT, while CL animals were clustered into a sedentary group.ResultsRL male and female body weight, before weaning, was significantly higher when compared with CL animals. This difference was maintained between CLSed and RLSed groups after weaning during all assessed periods. Adiposity was significantly higher in RLSed males when compared to CLSed males, and alterations in glycaemic metabolism were also observed. Endurance and HIIT protocols were efficient in improving maximal cardiorespiratory capacity, as well as concerning the glycemic metabolism and central fat accumulation of males and females submitted to childhood overfeeding by the litter reduction method.ConclusionsBoth moderate endurance training and HIIT protocols included in early life were efficient in reverting or preventing certain metabolic alterations as a consequence of overfeeding during breastfeeding in male and female Wistar rats.
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Project description:Physical activity is known as an effective strategy for prevention and treatment of Type 2 Diabetes. The aim of this work was to compare the effects of a traditional Moderate Intensity Continuous Training (MICT) with a High Intensity Interval Training (HIIT) on glucose metabolism and mitochondrial function in diabetic mice. Diabetic db/db male mice (N = 25) aged 6 weeks were subdivided into MICT, HIIT or control (CON) group. Animals in the training groups ran on a treadmill 5 days/week during 10 weeks. MICT group ran for 80 min (0° slope) at 50-60% of maximal speed (Vmax) reached during an incremental test. HIIT group ran thirteen times 4 minutes (20° slope) at 85-90% of Vmax separated by 2-min-rest periods. HIIT lowered fasting glycaemia and HbA1c compared with CON group (p < 0.05). In all mitochondrial function markers assessed, no differences were noted between the three groups except for total amount of electron transport chain proteins, slightly increased in the HIIT group vs CON. Western blot analysis revealed a significant increase of muscle Glut4 content (about 2 fold) and higher insulin-stimulated Akt phosphorylation ratios in HIIT group. HIIT seems to improve glucose metabolism more efficiently than MICT in diabetic mice by mechanisms independent of mitochondrial adaptations.
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Project description:IntroductionSince adolescents with obesity are prone to bone fragility during weight loss, the aim was to compare the impact of high-intensity interval training (HIIT) versus moderate-intensity continuous training (MICT) on bone density, geometry, and strength.MethodsSixty-one adolescents were randomly assigned to 2 cycling trainings (HIIT and MICT) and a control (CTR, without training) group. Anthropometry, dual-energy X-ray absorptiometry with hip structural analysis and the trabecular bone score (TBS) were assessed before and after the 16-week intervention.ResultsBody mass index (BMI) and fat mass (FM) percentage decreased at T1 versus T0 in both training groups (p < 0.001 for HIIT, p = 0.01 for MICT), though to a larger extent in HIIT (p < 0.05). Total body bone mineral density (BMD) and bone mineral content (BMC) increased in both training groups (p < 0.001), but to a greater extent in HIIT for BMC (p < 0.05). Lumbar spine BMD and BMC increased in both training groups (p < 0.001 for HIIT, p < 0.01 for MICT), with a time × group interaction between HIIT and CTR (p < 0.05) only. TBS increased in both training groups (p < 0.01 for HIIT, p < 0.05 for MICT). Hip BMD and BMC increased in both HIIT (p < 0.001 and p < 0.01) and MICT (p < 0.01 and p < 0.05). At the narrow neck (NN), endocortical diameter, width (p < 0.01), cross-sectional moment of inertia, and section modulus (Z) (p < 0.05) increased only in the HIIT group, such as BMD and Z (p < 0.05) at the intertrochanteric region (IT) and average cortical thickness (p < 0.001) and width (p < 0.05) at the femoral shaft. At the NN and IT, the buckling ratio decreased only in the HIIT group (p < 0.05), predicting higher resistance to fracture.ConclusionsIn addition to inducing greater BMI and FM percentage decreases in comparison to MICT, HIIT improves multisite bone density, geometry, and strength, which heighten the justification for HIIT as part of weight loss interventions in adolescents with obesity.
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