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1.
FASEB J ; 38(14): e23770, 2024 Jul 31.
Artigo em Inglês | MEDLINE | ID: mdl-38995817

RESUMO

Repeated bouts of high-intensity interval training (HIIT) induce an improvement in metabolism via plasticity of melanocortin circuits and attenuated hypothalamic inflammation. HIF-1α, which plays a vital role in hypothalamus-mediated regulation of peripheral metabolism, is enhanced in the hypothalamus by HIIT. This study aimed to investigate the effects of HIIT on hypothalamic HIF-1α expression and peripheral metabolism in obese mice and the underlying molecular mechanisms. By using a high-fat diet (HFD)-induced obesity mouse model, we determined the effect of HIIT on energy balance and the expression of the hypothalamic appetite-regulating neuropeptides, POMC and NPY. Moreover, hypothalamic HIF-1α signaling and its downstream glycolytic enzymes were explored after HIIT intervention. The state of microglia and microglial NF-κB signaling in the hypothalamus were also examined in vivo. In vitro by using an adenovirus carrying shRNA-HIF1ß, we explored the impact of HIF-1 signaling on glycolysis and NF-κB inflammatory signaling in BV2 cells. Food intake was suppressed and whole-body metabolism was improved in exercised DIO mice, accompanied by changes in the expression of POMC and NPY. Moreover, total and microglial HIF-1α signaling were obviously attenuated in the hypothalamus, consistent with the decreased levels of glycolytic enzymes. Both HFD-induced microglial activation and hypothalamic NF-κB signaling were significantly suppressed following HIIT in vivo. In BV2 cells, after HIF-1 complex knockdown, glycolysis and NF-κB inflammatory signaling were significantly attenuated. The data indicate that HIIT improves peripheral metabolism probably via attenuated HFD-induced microglial activation and microglial NF-κB signaling in the hypothalamus, which could be mediated by suppressed microglial HIF-1α signaling.


Assuntos
Hipotálamo , Subunidade alfa do Fator 1 Induzível por Hipóxia , Inflamação , Camundongos Endogâmicos C57BL , Microglia , Transdução de Sinais , Animais , Subunidade alfa do Fator 1 Induzível por Hipóxia/metabolismo , Subunidade alfa do Fator 1 Induzível por Hipóxia/genética , Microglia/metabolismo , Masculino , Camundongos , Hipotálamo/metabolismo , Inflamação/metabolismo , Treinamento Intervalado de Alta Intensidade , Obesidade/metabolismo , Dieta Hiperlipídica/efeitos adversos , Condicionamento Físico Animal/fisiologia , NF-kappa B/metabolismo , Pró-Opiomelanocortina/metabolismo , Pró-Opiomelanocortina/genética , Neuropeptídeo Y/metabolismo
2.
J Physiol ; 2024 Sep 20.
Artigo em Inglês | MEDLINE | ID: mdl-39303144

RESUMO

Pre-clinical murine and in vitro models have demonstrated that exercise suppresses tumour and cancer cell growth. These anti-oncogenic effects of exercise were associated with the exercise-mediated release of myokines such as interleukin (IL)-15. However, no study has quantified the acute IL-15 response in human cancer survivors, and whether physiological adaptations to exercise training (i.e. body composition and cardiorespiratory fitness) influence this response. In the present study breast, prostate and colorectal cancer survivors (n = 14) completed a single bout of high-intensity interval exercise (HIIE) [4×4 min at 85-95% heart rate (HR) peak, 3 min at 50-70% HR peak] before and after 7 months of three times weekly high-intensity interval training (HIIT) on a cycle ergometer. At each time point venous blood was sampled before and immediately after HIIE to assess the acute myokine (IL-15, IL-6, IL-10, IL-1ra) responses. Markers of inflammation, cardiorespiratory fitness and measures of body composition were obtained at baseline and 7 months. An acute bout of HIIE resulted in a significant increase in IL-15 concentrations (pre-intervention: 113%; P = 0.013, post-intervention: 102%; P = 0.005). Post-exercise IL-15 concentrations were associated with all other post-exercise myokine concentrations, lean mass (P = 0.031), visceral adipose tissue (P = 0.039) and absolute V ̇ O 2 ${{\dot{V}}_{{{{\mathrm{O}}}_{\mathrm{2}}}}}$ peak (P = 0.032). There was no significant effect of 7 months of HIIT on pre- or post-HIIE IL-15 concentrations (P > 0.05). This study demonstrates HIIE is a sufficient stimulus to increase circulating IL-15 and other myokines including IL-6, IL-10 and IL-1ra which may be clinically relevant in the anti-oncogenic effect of exercise and repetitive exposure to these effects may contribute to the positive relationship between exercise and cancer recurrence. KEY POINTS: Exercise has been demonstrated to reduce the risk of cancer recurrence. Pre-clinical murine and in vitro models have demonstrated that exercise suppresses tumour and cancer cell growth, mediated by exercise-induced myokines (IL-6 and IL-15). High-intensity interval exercise significantly increased myokines associated with the anti-oncogenic effect of exercise and the magnitude of response was associated with lean mass, but training did not appear to influence this response. Given IL-15 has been implicated in the anti-oncogenic effect of exercise and is being explored as an immunotherapy agent, high-intensity interval exercise may improve outcomes for people living beyond cancer through IL-15-mediated pathways. Interventions that increase lean mass may also enhance this response.

3.
J Physiol ; 602(7): 1313-1340, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38513062

RESUMO

High-intensity exercise stimulates glycolysis, subsequently leading to elevated lactate production within skeletal muscle. While lactate produced within the muscle is predominantly released into the circulation via the monocarboxylate transporter 4 (MCT4), recent research underscores lactate's function as an intercellular and intertissue signalling molecule. However, its specific intracellular roles within muscle cells remains less defined. In this study, our objective was to elucidate the effects of increased intramuscular lactate accumulation on skeletal muscle adaptation to training. To achieve this, we developed MCT4 knockout mice and confirmed that a lack of MCT4 indeed results in pronounced lactate accumulation in skeletal muscle during high-intensity exercise. A key finding was the significant enhancement in endurance exercise capacity at high intensities when MCT4 deficiency was paired with high-intensity interval training (HIIT). Furthermore, metabolic adaptations supportive of this enhanced exercise capacity were evident with the combination of MCT4 deficiency and HIIT. Specifically, we observed a substantial uptick in the activity of glycolytic enzymes, notably hexokinase, glycogen phosphorylase and pyruvate kinase. The mitochondria also exhibited heightened pyruvate oxidation capabilities, as evidenced by an increase in oxygen consumption when pyruvate served as the substrate. This mitochondrial adaptation was further substantiated by elevated pyruvate dehydrogenase activity, increased activity of isocitrate dehydrogenase - the rate-limiting enzyme in the TCA cycle - and enhanced function of cytochrome c oxidase, pivotal to the electron transport chain. Our findings provide new insights into the physiological consequences of lactate accumulation in skeletal muscle during high-intensity exercises, deepening our grasp of the molecular intricacies underpinning exercise adaptation. KEY POINTS: We pioneered a unique line of monocarboxylate transporter 4 (MCT4) knockout mice specifically tailored to the ICR strain, an optimal background for high-intensity exercise studies. A deficiency in MCT4 exacerbates the accumulation of lactate in skeletal muscle during high-intensity exercise. Pairing MCT4 deficiency with high-intensity interval training (HIIT) results in a synergistic boost in high-intensity exercise capacity, observable both at the organismal level (via a treadmill running test) and at the muscle tissue level (through an ex vivo muscle contractile function test). Coordinating MCT4 deficiency with HIIT enhances both the glycolytic enzyme activities and mitochondrial capacity to oxidize pyruvate.


Assuntos
Treinamento Intervalado de Alta Intensidade , Transportadores de Ácidos Monocarboxílicos , Músculo Esquelético , Animais , Camundongos , Lactatos , Camundongos Endogâmicos ICR , Camundongos Knockout , Músculo Esquelético/metabolismo , Músculo Esquelético/fisiologia , Piruvatos/metabolismo , Transportadores de Ácidos Monocarboxílicos/genética , Transportadores de Ácidos Monocarboxílicos/metabolismo , Proteínas Musculares/metabolismo
4.
Stroke ; 55(9): 2202-2211, 2024 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-39113181

RESUMO

BACKGROUND: Limited evidence supports the effects of short-interval high-intensity interval training (HIIT) for improving cardiorespiratory fitness (V̇O2peak) after stroke. We aimed to compare the effects of 12 weeks of short-interval HIIT versus moderate-intensity continuous training (MICT) on V̇O2peak, cardiovascular risk factors, and mobility outcomes among individuals ≥6 months poststroke. METHODS: This study was a multi-site, 12-week randomized controlled trial (NCT03614585) with an 8-week follow-up. Participants were randomized into 3 d/wk of HIIT (10×1 minute 80%-100% heart rate reserve interspersed with 1 minute 30% heart rate reserve [19 minutes]) or MICT (20-30 minutes 40%-60% heart rate reserve). Secondary outcomes of the trial, including V̇O2peak, cardiovascular risk factors (carotid-femoral pulse wave velocity, blood pressure, and waist-hip ratio), and mobility (6-minute walk test, 10 m gait speed), were reported. Linear mixed model analyses with a group×study time point interaction evaluated between-group differences. RESULTS: Of the 305 potential participants, 82 consented (mean [SD] age 64.9 [9.3] years, 32 females [39%], 1.8 [1.2] years poststroke) and were randomized to HIIT (n=42, mean [SD] baseline V̇O2peak 17.3 [5.9] mL/kg·min) or MICT (n=40, mean [SD] baseline V̇O2peak 17.2 [6.0] mL/kg·min). Participants attended 82% of visits (n=2417/2952). No adverse events occurred during the study period. A significant group×study time point interaction was found (χ2=8.46; P=0.015) for V̇O2peak at 12 weeks (mean difference, 1.81 [95% CI, 0.58-3.04]; P=0.004) whereby the HIIT group had greater gains in V̇O2peak (∆3.52 mL/kg·min [95% CI, 2.47-4.57]; P<0.001) compared with the MICT group (∆1.71 mL/kg·min [95% CI, 0.55-2.86]; P=0.001). There was no between-group difference in V̇O2peak (mean difference, 1.08 [95% CI, -0.26 to 2.42]; P=0.11) at 8-week follow-up. No group×study time point interactions were found for cardiovascular risk factors or mobility outcomes. CONCLUSIONS: Short-interval HIIT may be an effective alternative to MICT for improving V̇O2peak at 12 weeks postintervention. REGISTRATION: URL: https://clinicaltrials.gov; Unique identifier: NCT03614585.


Assuntos
Aptidão Cardiorrespiratória , Treinamento Intervalado de Alta Intensidade , Reabilitação do Acidente Vascular Cerebral , Acidente Vascular Cerebral , Humanos , Feminino , Masculino , Pessoa de Meia-Idade , Treinamento Intervalado de Alta Intensidade/métodos , Aptidão Cardiorrespiratória/fisiologia , Idoso , Reabilitação do Acidente Vascular Cerebral/métodos , Acidente Vascular Cerebral/fisiopatologia , Acidente Vascular Cerebral/terapia , Consumo de Oxigênio/fisiologia , Frequência Cardíaca/fisiologia , Terapia por Exercício/métodos
5.
Am J Physiol Endocrinol Metab ; 327(3): E241-E257, 2024 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-38922577

RESUMO

Obesity is advancing at an accelerated pace, and yet its treatment is still an emerging field. Although studies have demonstrated the role of the microbiota in the pathogenesis of obesity, this is the first study to show the effects of intermittent fasting (IF), combined or not with exercise, and high-intensity interval training (HIIT) on the gut microbiota composition in women with obesity. Our hypothesis is that IF combined with HIIT can promote the remodeling of the composition and function of the gut microbiota. Thirty-six women with obesity, aged between 18 and 40 yr, participated in the study. They were randomly divided into three groups: 1) IF associated with HIIT group [IF + exercise group (EX), n = 15]; 2) HIIT group (EX, n = 11); and 3) IF group (IF, n = 10). Interventions took place over 8 wk, and all assessments were performed preintervention and postintervention. The HIIT circuit was performed 3 times/wk, for 25 min/session. The IF protocol was a 5:2 (2 times/wk). Multiplex analysis of inflammatory cytokines, sequencing of the 16S rRNA gene, and gas chromatography to measure fecal concentrations of short-chain fatty acids (SCFAs) were performed. This study was registered on ClinicalTrials.gov (NCT05237154). Exercise increased fecal acetate concentrations (P = 0.04), but no changes were observed in the composition and functional profile of the microbiota. The interventions did not change the composition of the microbiota, but exercise may play a modulatory role in the production of acetate. This investigation provides clinical insights into the use of IF and HIIT for women with obesity.NEW & NOTEWORTHY This is the first investigation about alternate-day fasting combined with HITT on the gut microbiota of obese women. The study contributes to the advancement of human science involving IF and HIIT, popular strategies for managing obesity. Previous evidence has explored IF in modulating the microbiota in animal models or specific populations and clinical conditions. Despite the subtle outcomes, this study has relevance and originality in the field of gut microbiota knowledge.


Assuntos
Jejum , Microbioma Gastrointestinal , Treinamento Intervalado de Alta Intensidade , Obesidade , Humanos , Feminino , Microbioma Gastrointestinal/fisiologia , Treinamento Intervalado de Alta Intensidade/métodos , Adulto , Obesidade/microbiologia , Obesidade/terapia , Obesidade/metabolismo , Adulto Jovem , Adolescente , Ácidos Graxos Voláteis/metabolismo , Fezes/microbiologia , Jejum Intermitente
6.
Growth Factors ; 42(1): 24-35, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-37945531

RESUMO

This study investigated the influence of a 12-week high-intensity interval training (HIIT) and moderate-intensity continuous training (MICT) on irisin, fibroblast growth factor 21 (FGF21), and myostatin (MSTN) among men with type 2 diabetes mellitus (T2DM). Forty-five adult men with T2DM were randomly selected and assigned to receive and perform HIIT (4 × 4 min at 85-95% HRmax with three min of active rest at 50-60% HRmax in between) and MICT (walking/running continuously for 47 min at 60-70% HRmax) three sessions per week for 12 weeks, or to act as a non-exercise control (CON) group. The subjects' blood samples were collected at baseline and 48 hours after the last intervention session. Our research revealed that both interventions resulted in similar decreases in FGF21 and MSTN when compared to the CON (p < .01). However, only the HIIT group showed a significant increase in irisin (p < .01) compared to the CON. Further, improvements in insulin resistance, body composition, and VO2 peak were noted in both intervention groups compared with those of the CON group (p < .01). It seems that while either aerobic exercise strategy could be seen as a therapy for men with T2DM, HIIT had a more advantageous effect on the irisin response.


Assuntos
Diabetes Mellitus Tipo 2 , Fatores de Crescimento de Fibroblastos , Treinamento Intervalado de Alta Intensidade , Masculino , Adulto , Humanos , Treinamento Intervalado de Alta Intensidade/métodos , Diabetes Mellitus Tipo 2/terapia , Fibronectinas , Miostatina
7.
NMR Biomed ; 37(1): e5045, 2024 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-37852945

RESUMO

This study investigated the use of intravoxel incoherent motion imaging (IVIM) to compare skeletal muscle perfusion during and after high-intensity interval training (HIIT) and moderate-intensity continuous training (MICT) to determine the impact on fat oxidation outcomes. Twenty overweight volunteers were recruited for the study. Each participant received one HIIT intervention and one MICT intervention using a cycling ergometer. Participants underwent a magnetic resonance imaging scan before, immediately after, and 1 and 2 h after each intervention. The IVIM parameters (D, fD*) of the rectus femoris, vastus lateralis, and biceps femoris long head were obtained. Changes in IVIM parameters of these muscles after both exercise interventions were compared using a two-factor repeated measures analysis of variance. In the rectus femoris, the fD* increased immediately after exercise intervention (d = 0.69 × 10-3  mm2 /s, p < 0.0083) and 2 h after exercise intervention (d = 0.64 × 10-3  mm2 /s, p < 0.0083) compared with before exercise. The increase in the fD* in the HIIT group was greater than that in the MICT group (d = 0.32, p = 0.023). In the vastus lateralis, the fD* increased immediately after the exercise intervention (d = 0.53 × 10-3  mm2 /s, p < 0.001) and returned to the pre-exercise level 1 h after exercising. The increase in the fD* in the HIIT group was lower than that in the MICT group (d = -0.21, p = 0.015). For the biceps femoris long head, the fD* was not significantly different between the two exercise interventions before and after exercise. Furthermore, the fD* 60 min after the HIIT intervention correlated with maximal oxygen consumption (VO2max), whereas fD* immediately after the MICT intervention correlated with VO2max. In summary, IVIM parameters can be used to evaluate differences in muscle perfusion between HIIT and MICT, and show a correlation with VO2max.


Assuntos
Treinamento Intervalado de Alta Intensidade , Humanos , Treinamento Intervalado de Alta Intensidade/métodos , Coxa da Perna/diagnóstico por imagem , Exercício Físico/fisiologia , Músculo Esquelético/diagnóstico por imagem , Imageamento por Ressonância Magnética
8.
Microvasc Res ; 151: 104616, 2024 01.
Artigo em Inglês | MEDLINE | ID: mdl-37890716

RESUMO

INTRODUCTION: Arterial hypertension is a global healthcare burden that affects macrovascular and microvascular structure and function and can promote vascular end-organ damage. This study aimed 1) to evaluate differences in microvascular health between normotensive individuals and patients with arterial hypertension and 2) to assess the effects of short-term high-intensity interval training (HIIT) on microvascular health in the subgroup with arterial hypertension as add-on treatment to antihypertensive medication. METHODS: In the cross-sectional part, central retinal arteriolar (CRAE) and venular diameter equivalent (CRVE), arteriolar-to-venular diameter ratio (AVR), and retinal oxygen saturation (O2-saturation) were investigated in 19 normotensive healthy controls (mean age 56 ± 7 years) and 41 patients with arterial hypertension (mean age 59 ± 7 years). In the subsequent randomized controlled trial (RCT), patients with arterial hypertension were randomized to an intervention group (HIIT 3×/week) or a control group that received standard physical activity recommendations after baseline assessment. Assessments of retinal vessel biomarkers and patients` characteristics were repeated after the intervention period of 8 weeks. RESULTS: In the cross-sectional part, individuals with normal blood pressure (BP) showed lower body mass index (BMI), body fat, 24 h systolic and diastolic BP, higher peak oxygen uptake, wider CRAE (174 ± 17 µm vs. 161 ± 17 µm, p = 0.009), and higher AVR (0.84 ± 0.05 vs. 0.79 ± 0.05, p = 0.003) compared to patients with hypertension. In the RCT, patients with arterial hypertension showed reduced BMI and fasting glucose levels after HIIT and control condition. In addition, the intervention group reduced body fat percentage (27.0 ± 5.5 vs. 25.8 ± 6.1, p = 0.023) and increased peak oxygen uptake (33.3 ± 5.7 vs. 36.7 ± 5.1, p < 0.001). No changes in BP were found in either group. The intervention group showed narrower CRVE (ß -4.8 [95 % CI, -8.85, -0.81] p = 0.020) and higher AVR (0.03 [0.01, 0.04] p < 0.001) after eight weeks of HIIT compared to the control group. No statistically significant changes in retinal O2-saturation were found in either group. CONCLUSION: Short-term HIIT proved to be an effective treatment to ameliorate hypertension-induced retinal microvascular abnormalities in patients with hypertension. Retinal vessel diameters may prove to be a sensitive biomarker to quantify treatment efficacy at the microvascular level, at the earliest possible stage in patients with hypertension.


Assuntos
Treinamento Intervalado de Alta Intensidade , Hipertensão , Humanos , Pessoa de Meia-Idade , Idoso , Saturação de Oxigênio , Hipertensão/diagnóstico , Hipertensão/terapia , Vasos Retinianos , Biomarcadores , Oxigênio
9.
Rev Cardiovasc Med ; 25(3): 102, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-39076951

RESUMO

Background: Cardiac rehabilitation (CR) is essential in reducing cardiovascular mortality and morbidity. High-intensity interval training (HIIT) has emerged as a promising exercise intervention for enhancing clinical outcomes in cardiac patients. This study aimed to investigate the effects of two short-term exercise-based programs employing HIIT and moderate-intensity continuous training (MICT) in comparison to a control group concerning blood pressure, body composition, and blood biomarkers in patients diagnosed with coronary artery disease (CAD). Methods: Seventy-two CAD patients (14% women) underwent randomization into three groups: HIIT, MICT, and control. The training programs encompassed six weeks of supervised treadmill exercises, conducted thrice weekly. MICT targeted ≈ 70-75% of peak heart rate (HRpeak), while HIIT was tailored to ≈ 85-95% of HRpeak. The control group received guidance on adopting healthy lifestyles. Outcome measurements included evaluations of blood pressure, body composition, and blood biomarkers. Results: In contrast to MICT, the HIIT exhibited superior improvements in body fat mass ( Δ %HIIT: 4.5%, p < 0.001 vs. Δ %MICT: 3.2%, p < 0.001), waist circumference ( Δ %HIIT: 4.1%, p = 0.002 vs. Δ %MICT: 2.5%, p = 0.002), hemoglobin A1c (HbA1c) ( Δ %HIIT: 10.4%, p < 0.001 vs. Δ %MICT: 32.3%, p < 0.001) and thyrotropin (TSH) ( Δ %HIIT: 16.5%, p = 0.007 vs. Δ %MICT: 3.1%, p = 0.201). Both HIIT and MICT induced significant enhancements across all variables compared to the control group. Conclusions: HIIT and MICT emerged as effective modalities for enhancing systolic and diastolic function, body composition, and blood biomarkers in CAD patients, with HIIT demonstrating incremental improvements over MICT. The absence of participation in exercise-based programs following cardiovascular events yielded less favorable outcomes. HIIT holds promise as an adjunct intervention in CR programs for CAD patients. Clinical Trial Registration: https://clinicaltrials.gov/ct2/show/NCT03538119.

10.
Exp Physiol ; 2024 Jul 16.
Artigo em Inglês | MEDLINE | ID: mdl-39014554

RESUMO

While it is well-established that a period of interval training performed at near maximal effort, such as speed endurance training (SET), enhances intense exercise performance in well-trained individuals, less is known about its effect on cardiac morphology and function as well as blood volume. To investigate this, we subjected 12 Under-20 Danish national team ice hockey players (age 18 ± 1 years, mean ± SD) to 4 weeks of SET, consisting of 6-10 × 20 s skating bouts at maximal effort interspersed by 2 min of recovery conducted three times weekly. This was followed by 4 weeks of regular training (follow-up). We assessed resting cardiac function and dimensions using transthoracic echocardiography and quantified total blood volume with the carbon monoxide rebreathing technique at three time points: before SET, after SET and after the follow-up period. After SET, stroke volume had increased by 10 (2-18) mL (mean (95% CI)), left atrial end-diastolic volume by 10 (3-17) mL, and circumferential strain improved by 0.9%-points (1.7-0.1) (all P < 0.05). At follow-up, circumferential strain and left atrial end-diastolic volume were reverted to baseline levels, while stroke volume remained elevated. Blood volume and morphological parameters for the left ventricle, including mass and end-diastolic volume, did not change during the study. In conclusion, our findings demonstrate that a brief period of SET elicits beneficial central cardiac adaptations in elite ice hockey players independent of changes in blood volume.

11.
Exp Physiol ; 109(10): 1710-1727, 2024 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-39207362

RESUMO

High-intensity interval training (HIIT) has shown significant results in addressing adiposity and risk factors associated with obesity. However, there are no studies that investigate the effects of HIIT on contractility and intracellular Ca2+ handling. The purpose of this study was to explore the impact of HIIT on cardiomyocyte contractile function and intracellular Ca2+ handling in rats in which obesity was induced by a saturated high-fat diet (HFD). Male Wistar rats were initially randomized into a standard diet and a HFD group. The experimental protocol spanned 23 weeks, comprising the induction and maintenance of obesity (15 weeks) followed by HIIT treatment (8 weeks). Performance was assessed using the maximum oxygen consumption test ( V ̇ O 2 max ${{\dot{V}}_{{{{\mathrm{O}}}_{\mathrm{2}}}{\mathrm{max}}}}$ ). Evaluation encompassed cardiac, adipose and skeletal muscle histology, as well as contractility and intracellular Ca2+ handling. HIIT resulted in a reduction in visceral area, an increase in V ̇ O 2 max ${{\dot{V}}_{{{{\mathrm{O}}}_{\mathrm{2}}}{\mathrm{max}}}}$ , and an augmentation of gastrocnemius fibre diameter in obese subjects. Additionally, HIIT led to a decrease in collagen fraction, an increase in percentage shortening, and a reduction in systolic Ca2+/percentage shortening and systolic Ca2+/maximum shortening rates. HIIT induces physiological cardiac remodelling, enhancing the contractile function of cardiomyocytes and improving myofilament sensitivity to Ca2+ in the context of obesity. This approach not only enhances cardiorespiratory and physical performance but also reduces visceral area and prevents interstitial fibrosis.


Assuntos
Cálcio , Treinamento Intervalado de Alta Intensidade , Contração Miocárdica , Miócitos Cardíacos , Miofibrilas , Obesidade , Condicionamento Físico Animal , Ratos Wistar , Animais , Masculino , Obesidade/fisiopatologia , Obesidade/metabolismo , Obesidade/terapia , Miócitos Cardíacos/metabolismo , Miócitos Cardíacos/fisiologia , Cálcio/metabolismo , Condicionamento Físico Animal/fisiologia , Ratos , Treinamento Intervalado de Alta Intensidade/métodos , Contração Miocárdica/fisiologia , Miofibrilas/metabolismo , Dieta Hiperlipídica , Músculo Esquelético/metabolismo , Músculo Esquelético/fisiologia , Consumo de Oxigênio/fisiologia
12.
Exp Physiol ; 109(8): 1353-1369, 2024 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-38875101

RESUMO

We investigated the influence of short- and long-interval cycling exercise with blood flow restriction (BFR) on neuromuscular fatigue, shear stress and muscle oxygenation, potent stimuli to BFR-training adaptations. During separate sessions, eight individuals performed short- (24 × 60 s/30 s; SI) or long-interval (12 × 120 s/60 s; LI) trials on a cycle ergometer, matched for total work. One leg exercised with (BFR-leg) and the other without (CTRL-leg) BFR. Quadriceps fatigue was quantified using pre- to post-interval changes in maximal voluntary contraction (MVC), potentiated twitch force (QT) and voluntary activation (VA). Shear rate was measured by Doppler ultrasound at cuff release post-intervals. Vastus lateralis tissue oxygenation was measured by near-infrared spectroscopy during exercise. Following the initial interval, significant (P < 0.05) declines in MVC and QT were found in both SI and LI, which were more pronounced in the BFR-leg, and accounted for approximately two-thirds of the total reduction at exercise termination. In the BFR-leg, reductions in MVC (-28 ± 15%), QT (-42 ± 17%), and VA (-15 ± 17%) were maximal at exercise termination and persisted up to 8 min post-exercise. Exercise-induced muscle deoxygenation was greater (P < 0.001) in the BFR-leg than CTRL-leg and perceived pain was more in LI than SI (P < 0.014). Cuff release triggered a significant (P < 0.001) shear rate increase which was consistent across trials. Exercise-induced neuromuscular fatigue in the BFR-leg exceeded that in the CTRL-leg and was predominantly of peripheral origin. BFR also resulted in diminished muscle oxygenation and elevated shear stress. Finally, short-interval trials resulted in comparable neuromuscular and haemodynamic responses with reduced perceived pain compared to long-intervals.


Assuntos
Exercício Físico , Contração Muscular , Fadiga Muscular , Consumo de Oxigênio , Fluxo Sanguíneo Regional , Humanos , Masculino , Fadiga Muscular/fisiologia , Exercício Físico/fisiologia , Adulto , Fluxo Sanguíneo Regional/fisiologia , Consumo de Oxigênio/fisiologia , Contração Muscular/fisiologia , Músculo Esquelético/metabolismo , Músculo Esquelético/fisiologia , Músculo Esquelético/irrigação sanguínea , Músculo Quadríceps/metabolismo , Músculo Quadríceps/irrigação sanguínea , Músculo Quadríceps/fisiologia , Adulto Jovem
13.
Behav Brain Funct ; 20(1): 9, 2024 May 03.
Artigo em Inglês | MEDLINE | ID: mdl-38702776

RESUMO

BACKGROUND: In the present study, we investigated the effect of high-intensity interval training (HIIT) on cognitive behaviors in female rats with a high-fat diet + streptozotocin (STZ)-induced type 2 diabetes. METHODS: Twenty-four female rats were divided into four groups randomly (n = 6): control (C), control + exercise (Co + EX), diabetes mellitus (type 2) (T2D), and diabetes mellitus + exercise (T2D + EX). Diabetes was induced by a two-month high-fat diet and a single dose of STZ (35 mg/kg) in the T2D and T2D + EX groups. The Co + EX and T2D + EX groups performed HIIT for eight weeks (five sessions per week, running on a treadmill at 80-100% of VMax, 4-10 intervals). Elevated plus maze (EPM) and open field test (OFT) were used for assessing anxiety-like behaviors, and passive avoidance test (PAT) and Morris water maze (MWM) were applied for evaluating learning and memory. The hippocampal levels of beta-amyloid (Aß) and Tau were also assessed using Western blot. RESULTS: An increase in fasting blood glucose (FBG), hippocampal level of Tau, and a decrease in the percentage of open arm time (%OAT) as an index of anxiety-like behavior were seen in the female diabetic rats which could be reversed by HIIT. In addition, T2D led to a significant decrease in rearing and grooming in the OFT. No significant difference among groups was seen for the latency time in the PAT and learning and memory in the MWM. CONCLUSIONS: HIIT could improve anxiety-like behavior at least in part through changes in hippocampal levels of Tau.


Assuntos
Peptídeos beta-Amiloides , Ansiedade , Diabetes Mellitus Experimental , Hipocampo , Condicionamento Físico Animal , Proteínas tau , Animais , Feminino , Hipocampo/metabolismo , Proteínas tau/metabolismo , Ratos , Condicionamento Físico Animal/fisiologia , Condicionamento Físico Animal/métodos , Condicionamento Físico Animal/psicologia , Ansiedade/terapia , Ansiedade/psicologia , Ansiedade/metabolismo , Peptídeos beta-Amiloides/metabolismo , Diabetes Mellitus Experimental/metabolismo , Diabetes Mellitus Experimental/psicologia , Diabetes Mellitus Experimental/terapia , Treinamento Intervalado de Alta Intensidade/métodos , Aprendizagem em Labirinto/fisiologia , Diabetes Mellitus Tipo 2/metabolismo , Diabetes Mellitus Tipo 2/psicologia , Diabetes Mellitus Tipo 2/terapia , Comportamento Animal/fisiologia , Dieta Hiperlipídica/efeitos adversos , Ratos Sprague-Dawley
14.
J Sleep Res ; : e14299, 2024 Aug 06.
Artigo em Inglês | MEDLINE | ID: mdl-39108069

RESUMO

Sleep disturbances are common in individuals with posttraumatic stress disorder. Exercise interventions are a promising approach in the treatment of sleep disorders, but little is known about the efficacy of exercise interventions for sleep disturbances associated with posttraumatic stress disorder. A total of 40 individuals with posttraumatic stress disorder were randomized to six sessions of either high-intensity interval training or low-to-moderate-intensity training, administered within 12 days. Sleep quality was assessed over 24 days from baseline to post with the Pittsburgh Sleep Quality Index, a sleep log, and a waist-worn actigraphy. Analyses revealed that, regardless of group allocation, Pittsburgh Sleep Quality Index score improved significantly by 2.28 points for high-intensity interval training and 1.70 points for low-to-moderate-intensity training (d = 0.56 for high-intensity interval training; 0.49 for low-to-moderate-intensity training) over time, while there were no significant changes in any sleep log or actigraphy measure. Analysis of a subsample of those affected by clinically significant sleep disturbances (n = 24) revealed a significant time effect with no difference between exercise interventions: Pittsburgh Sleep Quality Index improved significantly by 2.65 points for high-intensity interval training and 2.89 points for low-to-moderate-intensity training (d = 0.53 for high-intensity interval training; 0.88 for low-to-moderate-intensity training), and actigraphy measure of wake after sleep onset was reduced significantly by 14.39 minutes for high-intensity interval training and 6.96 minutes for low-to-moderate-intensity training (d = 0.47 for high-intensity interval training; 0.11 for low-to-moderate-intensity training) from baseline to post. In our pilot study, we found an improvement in sleep quality from pre- to post-assessment. There were no significant differences between exercise groups. Further studies are needed to investigate whether the found time effects reflect the exercise intervention or unrelated factors.

15.
Mol Biol Rep ; 51(1): 374, 2024 Feb 29.
Artigo em Inglês | MEDLINE | ID: mdl-38421500

RESUMO

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 2.5 min treadmill running and 4.5 min rests between the bouts, 5 days per week for 9 weeks. 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 that Igf1Ea mRNA expression was enhanced in the HIIT group. Furthermore, Igfbp5 mRNA expression tended to be higher in the HIIT group. The 9-week HIIT program enhanced tenogenic Igf1Ea mRNA expression.


Assuntos
Tendão do Calcâneo , Treinamento Intervalado de Alta Intensidade , Masculino , Animais , Ratos , Núcleo Celular , Matriz Extracelular , RNA Mensageiro/genética
16.
Gerontology ; 70(7): 701-714, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38574485

RESUMO

INTRODUCTION: Concurrent training has been shown to be a beneficial approach to improve overall health status in older adults. However, little is known about the adaptations of this type of training in the long term (i.e., after cessation of exercise), even less in older people affected by frailty syndrome. Therefore, this study aimed (i) to assess the effects of a 6-week concurrent training program composed of power-oriented resistance training and fast walking interval training on physical function, muscle power, disability in activities of daily living and frailty in pre-frail and frail older people, and (ii) to assess the effects of a 6-month detraining period on these outcomes. METHODS: A total of 59 pre-frail and frail older adults (>75 years old; Frailty Phenotype >1) were allocated into intervention (INT; n = 32; 81.8 years; 21 women) or control (CON; n = 27; 82.5 years; 19 women) groups. Primary outcomes of this study were Short Physical Performance Battery (SPPB), relative sit-to-stand (STS) power, Barthel index, Lawton scale and Frailty Phenotype. Assessments were performed at baseline (PRE), after the concurrent training programme (POST) and after 6 months of follow-up (DET) in both groups. Mixed model repeated measures ANOVA with Bonferroni's post hoc tests was used. RESULTS: Immediately after the intervention (∆ = POST-PRE), INT improved SPPB (∆ = 3.0 points; p < 0.001), relative STS power (∆ = 0.87 W·kg-1; p < 0.001) and reduced their frailty levels (∆ = -1.42 criteria; p < 0.001), while no changes were observed in CON. After 6 months of detraining (∆ = DET-PRE), INT showed higher SPPB (∆ = 2.2 points; p < 0.001), higher relative STS power (∆ = 0.73 W·kg-1; p < 0.001) and lower frailty (∆ = -1.24 criteria; p < 0.001) values than those reported at baseline, which were significantly different than those reported by CON. Both, Barthel index and Lawton scale values were not modified during the study in either group. CONCLUSIONS: The 6-week concurrent training program improved physical function, muscle power and reduced frailty in pre-frail and frail older people and these improvements were maintained above baseline levels after 6 months of detraining. However, due to the individual variability found, future studies of long-term responders versus non-responders in frail populations are required.


Assuntos
Atividades Cotidianas , Idoso Fragilizado , Fragilidade , Força Muscular , Treinamento Resistido , Caminhada , Humanos , Treinamento Resistido/métodos , Feminino , Masculino , Idoso , Idoso de 80 Anos ou mais , Força Muscular/fisiologia , Fragilidade/fisiopatologia , Fragilidade/reabilitação , Caminhada/fisiologia , Avaliação Geriátrica/métodos
17.
Arch Phys Med Rehabil ; 105(8): 1545-1558, 2024 08.
Artigo em Inglês | MEDLINE | ID: mdl-38199581

RESUMO

OBJECTIVES: The present study aimed to conduct meta-analysis to determine whether the high intensity interval training (HIIT) protocol is more beneficial in improving outcome measures compared to moderate continuous training (MCT) in people with multiple sclerosis (PwMS). It also aimed to systematically review the exercise protocols differences. DATA SOURCES: A search strategy, locating HIIT in PwMS, was executed in six databases, PubMed, EMBASE, Web of Science, Central Cochrane, Pedro, and Ovid MEDLine. STUDY SELECTION: Randomized control trials of HIIT utilizing cycle ergometer or recumbent stepper as exercise modalities were included in analysis. Intervention arms should include at least two intervention arms, including HIIT in one arm, and MCT in the other group. DATA EXTRACTION: Data extracted from each study includes the following items: basic details of the study (such as author, date of publication, location, and study design), participant characteristics (sample size, mean age, sex, mean disease duration, and extended disability status scale), specifications of the HITT protocol (exercise modality, session duration, number of intervals/session, interval intensity, recovery intensity, recovery interval, and adverse effect), as well as primary outcomes at baseline and post-intervention (cardiorespiratory fitness, fatigue, body composition, cognitive functions, and blood biomarkers). DATA SYNTHESIS: 22 studies included in the systematic review, 11 were included in random effects model pooled analysis. There was a significant effect in favor of HIIT for VO2max of cardiorespiratory functions compared to MCT (ES=0.45 95%, CI [0.14, 0.76], P=.004), and for memory domain of cognitive functions (ES=0.34 95% CI [0.05, 0.63], P=.02). Statistical significance was not achieved for the other variables. CONCLUSION: HIIT and MCT yield similar results in terms of fatigue, body composition, cognitive functions, and blood biomarkers. However, VO2max of cardiorespiratory functions and memory domain of cognitive functions were in favor of HIIT protocol.


Assuntos
Treinamento Intervalado de Alta Intensidade , Esclerose Múltipla , Humanos , Treinamento Intervalado de Alta Intensidade/métodos , Esclerose Múltipla/reabilitação , Esclerose Múltipla/fisiopatologia , Terapia por Exercício/métodos , Ensaios Clínicos Controlados Aleatórios como Assunto
18.
Artigo em Inglês | MEDLINE | ID: mdl-38862032

RESUMO

OBJECTIVE: To explore the effect sizes of different high-intensity interval training (HIIT) protocols on cardiorespiratory parameters when compared with moderate-intensity continuous training (MICT) in different heart failure (HF) subtypes. DATA SOURCES: Electronic databases were searched from their inception date until January 23, 2023. STUDY SELECTION: Randomized controlled trials (RCTs) were included if they compared HIIT with MICT in patients with HF. The primary outcome was peak oxygen consumption (Vo2peak). Two reviewers independently evaluated 99 initially identified studies, resulting in the selection of 15 RCTs that met the eligibility criteria. DATA EXTRACTION: Data were extracted independently by 2 observers using a data extraction form drafted based on the CONSORT statement and the Template for Intervention Description and Replication; the methodological quality of the studies was analyzed individually based on the Tool for the Assessment of Study Quality in Exercise scale. DATA SYNTHESIS: Fifteen RCTs with 553 patients with HF were included in the systematic review. The included studies had moderate to good overall methodological quality. The results showed that HIIT was generally more effective than MICT at improving Vo2peak in patients with HF (n=541, 15 RCTs; MD: 1.49 mL/kg/min; I2=66%; P<.001). However, the effect size varied depending on the HF subtype and HIIT protocol used. For patients with HF with reduced ejection fraction (HFrEF), the long-interval (high-intensity interval lasting ≥4 min) and high-volume HIIT (high-intensity efforts in total ≥15 min) showed the largest benefits over the MICT (n=261, 6 RCTs; MD: 2.11 mL/kg/min; P<.001); followed by the short-interval (≤1 min) and high-volume HIIT (≥15 min; n=71, 3 RCTs; MD: 0.91 mL/kg/min; P=.12), and the short-interval and low-volume HIIT showed the least superiority over MICT (n=68, 3 RCTs; MD: 0.54 mL/kg/min; P=.05). For patients with HF with perceived ejection fraction, there was a modest beneficial effect from HIIT over MICT (n=141, 3 RCTs; MD: 0.55 mL/kg/min; P=.32). CONCLUSIONS: The long-interval and high-volume HIIT protocol may produce greater benefits than MICT for improving cardiopulmonary fitness in patients with HFrEF. Further research is needed to determine the optimal HIIT protocol for different HF subtypes and to provide definitive recommendations for clinical practice.

19.
Artif Organs ; 2024 Jul 23.
Artigo em Inglês | MEDLINE | ID: mdl-39041394

RESUMO

BACKGROUND: Consequences of spinal cord injury (SCI) with a sedentary lifestyle will progress to muscle weakness and muscle atrophy, leading to muscle fatigue. This study aimed to determine the feasibility and preliminary effects of high-intensity interval training (HIIT) using functional electrical stimulation (FES) cycling on changes in thigh muscle volume and muscle strength, in patients with incomplete SCI. METHODS: Eight incomplete SCI patients (mean age 50 years; 6 women) with stable SCI paraplegia (mean 6.75 years since injury) participated in the HIIT FES cycling (85%-90% peak Watts; 4 × 4-min intervals) three times a week (over 6 weeks). The main outcomes were adherence, participant acceptability, and adverse events. Secondary outcomes were muscle strength (peak torque) and leg volume changes. RESULTS: Our findings revealed that the program was well-received by participants, with high levels of adherence, positive feedback, and satisfaction, suggesting that it could be a promising option for individuals seeking to enhance their lower body strength and muscle mass. Additionally, all participants successfully completed the training without any serious adverse events, indicating that the program is safe for use. Finally, we found that the 6-week HIIT FES leg cycling exercise program resulted in notable improvements in isometric peak torque of the quadriceps (range 13.9%-25.6%), hamstring muscle (18.2%-23.3%), and leg volume (1.7%-18.2%). CONCLUSIONS: This study highlights HIIT FES leg cycling exercise program potential as an effective intervention for improving lower limb muscle function.

20.
Scand J Med Sci Sports ; 34(1): e14495, 2024 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-37724816

RESUMO

Sex differences in the cardiorespiratory and hemodynamic response to exercise exist due to differences in heart size, blood volume, and hemoglobin mass, eliciting higher maximal oxygen uptake (VO2max ) in men versus women. Data are equivocal whether sex differences in training responsiveness occur. This study investigated potential sex differences in the hemodynamic response (stroke volume (SV) and cardiac output (CO)) to high-intensity interval exercise (HIIE). Habitually active men (n = 15) and women (n = 13) underwent VO2max testing, followed by three HIIE sessions consisting of the 4 × 4, 10 × 1, and reduced exertion high-intensity training (REHIT), whose order was randomized. During exercise, oxygen uptake (VO2 ) and hemodynamic responses were determined. Results showed no sex difference in peak relative VO2 (p = 0.263), CO (p = 0.277), or SV (p = 0.116), although absolute values were higher in men (p < 0.05). Peak absolute (127.3 ± 20.6 vs. 115.2 ± 16.6 mL/beat, p = 0.004, d = 0.66) and relative SV (111.0 ± 15.5 vs. 100.7 ± 11.1% max, p = 0.005, d = 0.78) were higher with REHIT versus 4 × 4. No sex differences in mean relative VO2 , CO, or SV occurred (p > 0.05). Data showed lower mean VO2 during REHIT versus 4 × 4 (59.3 ± 6.8 vs. 65.8 ± 5.8 %VO2max , p < 0.001, d = 1.05) and 10 × 1 (59.3 ± 6.8 vs. 69.1 ± 7.4 %VO2max , p < 0.001, d = 1.4). Mean CO was lower in REHIT than 10 × 1 (79.8 ± 8.6 vs. 84.0 ± 7.4% max, p = 0.012, d = 0.53). Previously reported differences in VO2max response to HIIE may not be due to unique hemodynamic responses.


Assuntos
Treinamento Intervalado de Alta Intensidade , Caracteres Sexuais , Humanos , Feminino , Masculino , Exercício Físico/fisiologia , Hemodinâmica/fisiologia , Débito Cardíaco/fisiologia , Consumo de Oxigênio/fisiologia , Oxigênio
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