Low Frequency Severe-Intensity Interval Training Markedly Alters Respiratory Compensation Point During Incremental Exercise in Untrained Male
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ABSTRACT:
SUBMITTER: Nakahara H
PROVIDER: S-EPMC7498695 | biostudies-literature | 2020 Jan
REPOSITORIES: biostudies-literature
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Project description:BackgroundMany individuals lose less weight than expected in response to exercise interventions when considering the increased energy expenditure of exercise (ExEE). This is due to energy compensation in response to ExEE, which may include increases in energy intake (EI) and decreases in non-exercise physical activity (NEPA). We examined the degree of energy compensation in healthy young men and women in response to interval training.MethodsData were examined from a prior study in which 24 participants (mean age, BMI, & VO2max = 28 yrs, 27.7 kg•m-2, and 32 mL?kg-1?min-1) completed either 4 weeks of sprint-interval training or high-intensity interval training. Energy compensation was calculated from changes in body composition (air displacement plethysmography) and exercise energy expenditure was calculated from mean heart rate based on the heart rate-VO2 relationship. Differences between high (? 100%) and low (< 100%) levels of energy compensation were assessed. Linear regressions were utilized to determine associations between energy compensation and ?VO2max, ?EI, ?NEPA, and ?resting metabolic rate.ResultsVery large individual differences in energy compensation were noted. In comparison to individuals with low levels of compensation, individuals with high levels of energy compensation gained fat mass, lost fat-free mass, and had lower change scores for VO2max and NEPA. Linear regression results indicated that lower levels of energy compensation were associated with increases in ?VO2max (p < 0.001) and ?NEPA (p < 0.001).ConclusionsConsiderable variation exists in response to short-term, low dose interval training. In agreement with prior work, increases in ?VO2max and ?NEPA were associated with lower energy compensation. Future studies should focus on identifying if a dose-response relationship for energy compensation exists in response to interval training, and what underlying mechanisms and participant traits contribute to the large variation between individuals.
| S-EPMC5731706 | biostudies-literature
Project description:This descriptive study aimed to explore the physiological factors that determine tolerance to exertion during high-intensity interval effort. Forty-seven young women (15-28 years old) were enrolled: 23 athletes from Taiwan national or national reserve teams and 24 moderately active females. Each participant underwent a maximal incremental INC (modified Bruce protocol) cardiopulmonary exercise test on the first day and high-intensity interval testing (HIIT) on the second day, both performed on a treadmill. The HIIT protocol involved alternation between 1-min effort at 120% of the maximal speed, at the same slope reached at the end of the INC, and 1-min rest until volitional exhaustion. Gas exchange, heart rate (HR), and muscle oxygenation at the right vastus lateralis, measured by near-infrared spectroscopy, were continuously recorded. The number of repetitions completed (Rlim) by each participant was considered the HIIT tolerance index. The results showed a large difference in the Rlim (range, 2.6-12.0 repetitions) among the participants. Stepwise linear regression revealed that the variance in the Rlim within the cohort was related to the recovery rates of oxygen consumption ([Formula: see text]), HR at the second minute after INC, and muscle tissue saturation index at exhaustion (R = 0.644). In addition, age was linearly correlated with Rlim (adjusted R = -0.518, p < 0.0001). In conclusion, the recovery rates for [Formula: see text] and HR after the incremental test, and muscle saturation index at exhaustion, were the major physiological factors related to HIIT performance. These findings provide insights into the role of the recovery phase after maximal INC exercise testing. Future research investigating a combination of INC and HIIT testing to determine training-induced performance improvement is warranted.
| S-EPMC7217474 | biostudies-literature
Project description:Exercise has been shown to improve health status and prevent the progression and development of numerous chronic diseases associated with chronic inflammation
2018-11-12 | MSV000083129 | MassIVE
Project description:Numerous arthropods harbor maternally transmitted bacteria that induce the preferential death of males [1-7]. This sex-specific lethality benefits the bacteria because males are "dead ends" regarding bacterial transmission, and their absence may result in additional resources for their viable female siblings who can thereby more successfully transmit the bacteria [5]. Although these symbionts disrupt a range of developmental processes [8-10], the underlying cellular mechanisms are largely unknown. It was previously shown that mutations in genes of the dosage compensation pathway of Drosophila melanogaster suppressed male killing caused by the bacterium, Spiroplasma [10]. This result suggested that dosage compensation is a target of Spiroplasma. However, it remains unclear how this pathway is affected, and whether the underlying interactions require the male-specific cellular environment. Here, we investigated the cellular basis of male embryonic lethality in D. melanogaster induced by Spiroplasma. We found that the dosage compensation complex (DCC), which acetylates X chromatin in males [11], becomes mis-localized to ectopic regions of the nucleus immediately prior to the killing phase. This effect was accompanied by inappropriate histone acetylation and genome-wide mis-regulation of gene expression. Artificially induced formation of the DCC in infected females, through transgenic expression of the DCC-specific gene msl-2, resulted in mis-localization of this complex to non-X regions and early Spiroplasma-induced death, mirroring the killing effects in males. These findings strongly suggest that Spiroplasma initiates male killing by targeting the dosage compensation machinery directly and independently of other cellular features characteristic of the male sex.
| S-EPMC4879104 | biostudies-literature
Project description:Skeletal muscle tissue is a highly adaptable tissue, responding to the specific demands it is subjected to. High-intensity interval training (HIIT) has been shown to generate similar, or even greater, molecular changes in skeletal muscle as that of constant load longer-lasting endurance-type training at moderate intensities. Despite shorter exposure times, the higher intensity provided by HIIT training leads to greater metabolic perturbations and thereby larger improvements in mitochondrial content and maximal oxygen uptake. During a period of regular exercise training, the performance improvements follow a non-linear pattern with a relatively faster pace initially and a gradual ‘plateauing-off’ after weeks and months. It is believed that this ‘plateau effect’ is due to a blunting of the molecular responses to acute exercise with exercise training. In the present study we utilised an explorative global transcriptomic approach to investigate the phenomenon of transcriptional-level blunting of the acute exercise response in human skeletal muscle over the course of a three-week HIIT intervention. We hypothesize that the blunting of transcription at this time-point is specific to certain pathways, including metabolic regulation and that these genes have communal transcriptional regulation.
2021-09-01 | GSE163356 | GEO
Project description:This study compares the effect of two types of exercise training, i.e., moderate-intensity continuous training (MICT) or high-intensity interval training (HIIT) on the browning of subcutaneous white adipose tissue (scWAT) in obese male rats. Effects on fat composition, metabolites, and molecular markers of differentiation and energy expenditure were examined. Forty male Wistar rats were assigned to lean (n = 8) or obese (n = 32) groups and fed either a standard chow or high-fat obesogenic diet for 10 weeks. Eight lean and obese rats were then blood and tissue sampled, and the remaining obese animals were randomly allocated into sedentary, MICT, or HIIT (running on a treadmill 5 days/week) groups that were maintained for 12 weeks. Obesity increased plasma glucose and insulin and decreased irisin and FGF-21. In scWAT, this was accompanied with raised protein abundance of markers of adipocyte differentiation, i.e., C/EBP-?, C/EBP-?, and PPAR-?, whereas brown fat-related genes, i.e., PRDM-16, AMPK/SIRT1/PGC-1?, were reduced as was UCP1 and markers of fatty acid transport, i.e., CD36 and CPT1. Exercise training increased protein expression of brown fat-related markers, i.e., PRDM-16, AMPK/SIRT1/PGC-1?, and UCP1, together with gene expression of fatty acid transport, i.e., CD36 and CPT1, but decreased markers of adipocyte differentiation, i.e., C/EBP-?, C/EBP-?, and plasma glucose. The majority of these adaptations were greater with HIIT compared to MICT. Our findings indicate that prolonged exercise training promotes the browning of white adipocytes, possibly through suppression of adipogenesis together with white to beige trans-differentiation and is dependent on the intensity of exercise.
| S-EPMC7231004 | biostudies-literature
Project description:Twenty healthy subjects (25±5yrs) completed two high-intensity interval training interventions (training and retraining) lasting 8 weeks separated by 12 weeks of detraining. Measurements at baseline and after training, detraining and retraining included maximal oxygen consumption (V̇O2max), along with vastus lateralis biopsy for genome wide DNA methylation using Illumina Epic arrays in 5 of the participants for all conditions (baseline, training, detraining and retraining).
2024-05-30 | GSE268211 | GEO
Project description:Background: Comparisons between high intensity interval training (HIIT) and continuous training (CT) regarding improvements of adolescents' cardiac function are scarce and the preferred intensity for cardiac improvement with restricted myocardial damage remains unknown. This study conducted a 4-weeks training in male adolescent rats under moderate (MI) or high intensity (HI) HIIT and CT programs, aiming to discover and compare exercise-induced myocardial adaptations towards these two training methods. Methods: 39 male adolescent Sprague-Dawley rats (aged 4 weeks) were randomly assigned to high intensity HIIT (HI-HIIT, n = 8), moderate intensity HIIT (MI-HIIT, n = 8), high intensity CT (HI-CT, n = 8), moderate intensity CT (MI-CT, n = 8) and sedentary control (SC, n = 7) groups. Rats in training groups were trained for 4 weeks and echocardiography was performed at baseline and after the final training. Serum creatine kinase myocardial band (CK-MB), cardiac troponin T (cTn-T) and untargeted metabolomics analysis were measured from blood samples collected 24 h after the final training. Results: HIIT groups had greater cardiac output improvement than CT groups while no significant difference was found between the HI-HIIT and the MI-HIIT groups. HI-CT group showed higher serum CK-MB and cTn-T levels compared to MI-HIIT, MI-CT and control groups. Untargeted metabolomics analysis identified eleven HI-HIIT-related metabolites, five MI-HIIT-related metabolites and two HICT-related metabolites. The majority of the identified metabolites were phospholipid-related. Phosphatidylglyceride 18 level was significantly different between the HI-CT and MI-CT groups, and was negatively associated with cTn-T in CT groups. Conclusion: HIIT and CT improve cardiac function of adolescent rats while the HIIT demonstrates better improvement and less myocardial damage. High and moderate training intensities in HIIT exert similar cardiac benefits. HI-CT induced myocardial damage might be associated with serum phospholipids.
| S-EPMC9274303 | biostudies-literature
Project description:The effect of all possible mutations at position 178 on the enantioselectivity of yeast surface-bound horseradish peroxidase (HRP) toward chiral phenols has been investigated. In contrast to their wild-type predecessor, most HRP mutants are enantioselective, with the Arg178Glu variant exhibiting the greatest, 25-fold, (S)/(R) preference. Using kinetic analysis of enzymatic oxidation of various substrate analogues and molecular modeling of enzyme-substrate complexes, this enantioselectivity enhancement is attributed to changes in the transition state energy due to electrostatic repulsion between the carboxylates of the enzyme's Glu178 and the substrate's (R)-enantiomer.
| S-EPMC2743472 | biostudies-literature
Project description:Exercise adherence is affected by factors including perceptions of enjoyment, time availability, and intrinsic motivation. Approximately 50% of individuals withdraw from an exercise program within the first 6 mo of initiation, citing lack of time as a main influence. Time efficient exercise such as high intensity interval training (HIIT) may provide an alternative to moderate intensity continuous exercise (MICT) to elicit substantial health benefits. This study examined differences in enjoyment, affect, and perceived exertion between MICT and HIIT. Twelve recreationally active men and women (age = 29.5 ± 10.7 yr, VO2max = 41.4 ± 4.1 mL/kg/min, BMI = 23.1 ± 2.1 kg/m2) initially performed a VO2max test on a cycle ergometer to determine appropriate workloads for subsequent exercise bouts. Each subject returned for two additional exercise trials, performing either HIIT (eight 1 min bouts of cycling at 85% maximal workload (Wmax) with 1 min of active recovery between bouts) or MICT (20 min of cycling at 45% Wmax) in randomized order. During exercise, rating of perceived exertion (RPE), affect, and blood lactate concentration (BLa) were measured. Additionally, the Physical Activity Enjoyment Scale (PACES) was completed after exercise. Results showed higher enjoyment (p = 0.013) in response to HIIT (103.8 ± 9.4) versus MICT (84.2 ± 19.1). Eleven of 12 participants (92%) preferred HIIT to MICT. However, affect was lower (p<0.05) and HR, RPE, and BLa were higher (p<0.05) in HIIT versus MICT. Although HIIT is more physically demanding than MICT, individuals report greater enjoyment due to its time efficiency and constantly changing stimulus.Trial registrationNCT:02981667.
| S-EPMC5226715 | biostudies-literature