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1.
Growth Horm IGF Res ; 63: 101445, 2022 04.
Artigo em Inglês | MEDLINE | ID: mdl-35168036

RESUMO

OBJECTIVE: Hyperoxic gas inhalation during exercise may negatively affect all-out sprint interval exercise (SIE)-induced hormonal, metabolic, and angiogenic responses. We investigated the effects of acute all-out SIE under systemic hyperoxia on hormonal, metabolic, and angiogenic responses. DESIGN: This was a randomised-crossover trial. Ten healthy males (mean ± standard error of age = 23.1 ± 0.9 years; height = 171.0 ± 1.6 cm; body mass = 66.2 ± 2.0 kg; body mass index = 22.6 ± 0.5 kg/m2) completed the following two experimental regimens: 1) SIE under normoxia and 2) SIE under systemic hyperoxia (FiO2 = 60%). The subjects performed four bouts of 30-s maximal cycling efforts with 4 min recovery between efforts. The circulating levels of hormonal (growth hormone, epinephrine, and norepinephrine), metabolic (glucose, free fatty acid, and lactate), and angiogenic (vascular endothelial growth factor, matrix metalloproteinase-2 and -9, and endostatin) markers were measured before and at 0 (immediately after the regimen), 30, and 120 min after both regimens. RESULTS: In response to both SIE regimens, the peak and mean power outputs gradually decreased over the intermittent exercise session compared with those in the first bout (p < 0.01) with no significant differences between the regimens. Both regimens significantly increased the circulating concentrations of all hormonal, metabolic, and angiogenic markers (p < 0.01). However, there were no significant differences in the levels of these markers in response to the two regimens at any time point (p > 0.05). CONCLUSION: These findings suggest that acute systemic hyperoxia does not influence the hormonal, metabolic, and angiogenic responses to all-out SIE.


Assuntos
Hiperóxia , Índice de Massa Corporal , Exercício Físico , Humanos , Masculino , Metaloproteinase 2 da Matriz , Fator A de Crescimento do Endotélio Vascular , Adulto Jovem
2.
Arch Physiol Biochem ; 128(1): 248-252, 2022 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31686532

RESUMO

CONTEXT: Resistance exercise training has recently been considered as an effective type of training to increase energy metabolism and insulin sensitivity. However, mechanisms of the resistance training-induced improvements in energy metabolism and insulin sensitivity have not been fully understood. Zinc-α2-glycoprotein (ZAG), which is a novel adipokine, has beneficial effects on energy metabolism and insulin sensitivity. OBJECTIVE: We investigated the effect of a single bout of resistance exercise on the ZAG concentration. METHODS: Nine healthy men were enrolled. They performed a single bout of resistance exercise (bench press and leg press) consisting of 10 repetitions of five sets at 70% of maximum strength with 90-s rests in between sets. Blood samples were obtained before and after acute resistance exercise to measure the ZAG concentration. RESULTS: The serum ZAG concentration significantly increased following acute resistance exercise. CONCLUSION: This result suggests that a single bout of resistance exercise may enhance the ZAG concentration.


Assuntos
Resistência à Insulina , Treinamento de Força , Glicoproteína Zn-alfa-2/sangue , Humanos , Masculino
3.
J Strength Cond Res ; 35(2): 436-441, 2021 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-30199444

RESUMO

ABSTRACT: Kon, M, Ikeda, T, Homma, T, and Suzuki, Y. Responses of angiogenic regulators to resistance exercise under systemic hypoxia. J Strength Cond Res 35(2): 436-441, 2021-Resistance exercise and hypoxia powerfully affect the secretions of angiogenic regulators. However, the effects of resistance exercise under acute systemic hypoxia on circulating levels of angiogenic regulators are unknown. Therefore, we investigated the effects of resistance exercise under systemic hypoxia on angiogenic regulator responses. Twelve healthy male subjects completed 2 experimental trials: (a) resistance exercise under normoxia (NRE), and (b) resistance exercise under systemic hypoxia (13% oxygen) (HRE) using a hypoxic generator. The subjects performed 2 consecutive resistance exercises (bench press and bilateral leg press), consisting of 5 sets with 10 repetitions at 70% of 1 repetition maximum with a 1-minute rest between sets. Serum vascular endothelial growth factor (VEGF), matrix metalloproteinase (MMP)-2, MMP-9, and endostatin concentrations were measured before exercise (and before exposure to hypoxia in the HRE trial) and at 0, 15, and 30 minutes after the resistance exercises. In both trials, serum VEGF, MMP-2, MMP-9, and endostatin concentrations significantly increased after the exercises compared with preexercise values (p < 0.05). At 0 minutes after exercise, the percentage change in VEGF concentration was significantly higher in the HRE trial compared with that in the NRE trial (p < 0.05). However, the exercise-induced changes in MMP-2, MMP-9, and endostatin concentrations did not differ between trials. The present results demonstrate that acute systemic hypoxia induces a greater resistance exercise-induced VEGF response, suggesting that hypoxia plays an important role in increasing the VEGF response to a bout of resistance exercise.


Assuntos
Treinamento de Força , Endostatinas , Exercício Físico , Humanos , Hipóxia , Masculino , Fator A de Crescimento do Endotélio Vascular
4.
Arch Physiol Biochem ; 127(3): 223-227, 2021 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-31232102

RESUMO

CONTEXT: Insulin resistance is the main triggering factor for type 2 diabetes. Recently, it has been reported that high-intensity sprint interval training (SIT) was effective for improving glucose metabolism and insulin sensitivity despite lower training volume. However, the mechanisms underlying the SIT-induced increases in glucose metabolism and insulin sensitivity have not been well-understood. Follistatin-like 1 (FSTL1) and apelin, which are novel myokines, have a favourable effect on glucose metabolism. OBJECTIVE: We examined the impact of acute SIT on FSTL1 and apelin secretions. METHODS: Eight healthy men were enrolled in this study. The subjects performed acute SIT consisting of four 30-s all-out cycling efforts with 4-min rest periods. Blood samples were obtained before and after the acute SIT to measure FSTL1 and apelin concentrations. RESULTS: FSTL1 and apelin both significantly increased following acute SIT. CONCLUSION: Acute SIT may be an effective stimulus for increasing of FSTL1 and apelin secretions.


Assuntos
Apelina/metabolismo , Proteínas Relacionadas à Folistatina/metabolismo , Treinamento Intervalado de Alta Intensidade , Adulto , Voluntários Saudáveis , Humanos , Resistência à Insulina , Masculino
5.
Respir Physiol Neurobiol ; 283: 103544, 2021 01.
Artigo em Inglês | MEDLINE | ID: mdl-32927097

RESUMO

Hypoxia in working muscles during exercise may be associated with increased oxidative stress. Inhalation of hyperoxic gas diminishes the hypoxia within working muscles during exercise. Exposure to hyperoxia increases the expression of the antioxidant HSP27. We investigated the effects of acute high-intensity interval exercise (HIE) under hyperoxia on HSP27 levels and oxidative stress responses. Eight male subjects participated in two experiments: 1) normoxic HIE (NHIE) and 2) hyperoxic (60 % oxygen) HIE (HHIE). HIE consisted of four 30-s all-out cycling bouts with 4-min rest between bouts. Levels of serum oxidative stress markers (d-ROMs and LPO), HSP27, BAP, IL-6, and TNF-α significantly increased after both trials. The HIE-induced changes in d-ROMs, LPO, and HSP27 levels were significantly lower in the HHIE trial than in the NHIE trial. These findings suggest that inhaling hyperoxic gas during exercise might diminish oxidative stress induced by all-out HIE.


Assuntos
Proteínas de Choque Térmico HSP27/sangue , Treinamento Intervalado de Alta Intensidade , Hiperóxia/sangue , Hipóxia/sangue , Estresse Oxidativo/fisiologia , Espécies Reativas de Oxigênio/sangue , Adulto , Humanos , Masculino , Adulto Jovem
6.
Sports (Basel) ; 8(12)2020 Dec 14.
Artigo em Inglês | MEDLINE | ID: mdl-33327399

RESUMO

The aim of this study was to clarify whether the physiological fatigue status of elite speed skaters is influenced by the approximately five-month international competition season by comparing morning heart rate variability (HRV) at the beginning of the competition season (Japan Single Distances Championships: JSDC) with that at the end of the competition season (World Single Distances Championships: WSDC). Five international-class speed skaters participated in the study. HRV indices and subjective fatigue were measured each morning of the four days prior to the first races of the JSDC and WSDC in the 2007/2008 season. The parasympathetic HRV indices: root mean square of the successive R-R interval differences (RMSSD) (JSDC, 61.0 ms; WSDC, 42.1 ms; p < 0.05), high-frequency component power (HF) (JSDC, 1393 ms2; WSDC, 443 ms2; p < 0.05), and normalized unit of HF (HFnu) (JSDC, 53.2%; WSDC, 25.5%; p < 0.05) were lower for the WSDC than for the JSDC. The decrease in these indices may reflect the skaters' accumulated fatigue during the course of the competition season. Morning measurements of HRV may thus be an efficient way for elite speed skaters and coaches to objectively monitor physiological fatigue throughout the competition season.

7.
Respir Physiol Neurobiol ; 280: 103481, 2020 09.
Artigo em Inglês | MEDLINE | ID: mdl-32553888

RESUMO

This study investigated the effect of a practical hyperoxic high-intensity interval training (HIIT) on aerobic and anaerobic exercise capacity. Sixteen male athletes were randomized into 2 groups: normoxic HIIT (NHIIT, n = 8) group or hyperoxic HIIT (HHIIT, n = 8) group and trained for 3 weeks (2 days/week) on a cycle ergometer (2-min intervals, with 2-min rest between intervals) at maximal workload, which was obtained during a maximal graded exercise test under normoxia. All training sessions were performed until exhaustion. Participants performed maximal graded exercise, submaximal exercise, and 90-s maximal exercise tests before and after the training period. Maximal oxygen uptake (P < 0.01) increased significantly in both groups. Blood lactate curve during submaximal exercise improved significantly only in the HHIIT group (P < 0.01). Mean power output during maximal exercise increased significantly only in the HHIIT group (P = 0.02). This study demonstrated that a practical hyperoxic HHIIT might be effective for improving aerobic capacity and anaerobic performance.


Assuntos
Tolerância ao Exercício/fisiologia , Exercício Físico/fisiologia , Treinamento Intervalado de Alta Intensidade , Hiperóxia/sangue , Ácido Láctico/sangue , Oxigenoterapia , Desempenho Físico Funcional , Adolescente , Atletas , Humanos , Masculino , Distribuição Aleatória
8.
High Alt Med Biol ; 21(2): 160-166, 2020 06.
Artigo em Inglês | MEDLINE | ID: mdl-32013568

RESUMO

Background: Osteogenic responses induced by training under hypoxia remain unclear. We aimed to investigate whether intermittent hypoxic resistance training affects osteogenic responses. Materials and Methods: Sixteen male participants underwent resistance training under normoxia (NRT; n = 7) or hypoxia (HRT; O2 = 14.4%, n = 9), twice a week for 8 weeks. The HRT group exercised and rested for 30 minutes under hypoxia, with total hypoxic exposure time in one session of ∼60 minutes. At pre- and postexperiment, bone mineral density (BMD) of the whole body and right proximal femur was measured. At the first and last training sessions, bone alkaline phosphatase (BAP), osteocalcin (OC), cross-linked N-telopeptide of type I collagen (NTx), type I collagen cross-linked C-telopeptide (ICTP), interleukin-6 (IL-6), and blood lactate (La) concentration were analyzed at rest and postexercise. Results: BMD did not change with training and hypoxia. Although BAP, OC, and ICTP levels at rest significantly increased with training (p < 0.01, 0.05, and 0.05, respectively), they did not change with hypoxia. NTx and IL-6 did not change. Additionally, changing patterns of bone markers and La induced by a single bout of exercise were similar among groups in both training sessions. Conclusions: Short-term resistance training enhanced overall bone metabolism, regardless of the oxygen level. Hypoxia has no effects on osteogenic responses.


Assuntos
Osso e Ossos/metabolismo , Hipóxia , Osteogênese , Treinamento de Força , Biomarcadores , Densidade Óssea , Humanos , Masculino , Osteocalcina
9.
Physiol Rep ; 7(14): e14194, 2019 07.
Artigo em Inglês | MEDLINE | ID: mdl-31359633

RESUMO

All-out sprint interval training (SIT) is speculated to be an effective and time-efficient training regimen to improve the performance of aerobic and anaerobic exercises. SIT under hypoxia causes greater improvements in anaerobic exercise performance compared with that under normoxia. The change in oxygen concentration may affect SIT-induced performance adaptations. In this study, we aimed to investigate the effects of all-out SIT under hyperoxia on the performance of aerobic and anaerobic exercises. Eighteen college male athletes were randomly assigned to either the normoxic sprint interval training (NST, n = 9) or hyperoxic (60% oxygen) sprint interval training (HST, n = 9) group and performed 3-week SIT (six sessions) consisting of four to six 30-sec all-out cycling sessions with 4-min passive rest. They performed maximal graded exercise, submaximal exercise, 90-sec maximal exercise, and acute SIT tests on a cycle ergometer before and after the 3-week intervention to evaluate the performance of aerobic and anaerobic exercises. Maximal oxygen uptake significantly improved in both groups. However, blood lactate curve during submaximal exercise test significantly improved only in the HST group. The accumulated oxygen deficit (AOD) during 90-sec maximal exercise test significantly increased only in the NST group. The average values of mean power outputs over four bouts during the acute SIT test significantly improved only in the NST group. These findings suggest that all-out SIT might induce greater improvement in aerobic exercise performance (blood lactate curve) but impair SIT-induced enhancements in anaerobic exercise performance (AOD and mean power output).


Assuntos
Limiar Anaeróbio , Treinamento Intervalado de Alta Intensidade/métodos , Hiperóxia/fisiopatologia , Adaptação Fisiológica , Atletas , Tolerância ao Exercício , Humanos , Ácido Láctico/sangue , Masculino , Adulto Jovem
10.
Appl Physiol Nutr Metab ; 44(1): 47-51, 2019 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-29953821

RESUMO

High-intensity interval training (HIIT) is known to be an effective exercise training regimen to improve energy substrate metabolism and insulin sensitivity. However, the underlying mechanisms of improvement in insulin sensitivity due to HIIT have not yet been fully clarified. C1q/tumor necrosis factor-related protein (CTRP) 1 and CTRP9, which are adiponectin paralogs and novel adipokines, have favorable effects on energy substrate metabolism and insulin sensitivity. The purpose of this study was to investigate the effects of a single bout of HIIT on CTRP1 and CTRP9 secretions in healthy men. Eight healthy male subjects (mean ± SE: age, 23.4 ± 1.1 years; height, 172.1 ± 1.7 cm; body mass, 68.0 ± 2.0 kg; body mass index, 22.9 ± 0.5 kg/m2) participated in this study. They performed a single bout of HIIT consisted of four 30-s maximal cycling bouts with 4 min of rest between bouts using a cycle ergometer. Blood samples were collected before the exercise, at 0 (immediately after the exercise), 15, 30, and 120 min after the single bout of HIIT. Serum CTRP1, CTRP9, and high-molecular-weight (HMW) adiponectin concentrations were measured using enzyme-linked immunosolvent assay kits. CTRP1 concentration significantly increased at 120 min after the HIIT. CTRP9 concentration also significantly increased immediately after the single bout of HIIT. In contrast, there were no significant differences in HMW adiponectin concentration before and after the acute HIIT. These findings suggest that a single bout of HIIT may stimulate CTRP1 and CTRP9 secretions in healthy men.


Assuntos
Adiponectina/sangue , Glicoproteínas/sangue , Treinamento Intervalado de Alta Intensidade/métodos , Contração Muscular , Músculo Esquelético/metabolismo , Proteínas/metabolismo , Adulto , Ciclismo , Voluntários Saudáveis , Humanos , Masculino , Fatores de Tempo , Peptídeos e Proteínas Associados a Receptores de Fatores de Necrose Tumoral , Fator de Necrose Tumoral alfa/sangue , Regulação para Cima , Adulto Jovem
11.
Appl Physiol Nutr Metab ; 40(6): 575-81, 2015 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-25941765

RESUMO

This study examined changes in toll-like receptor 4 (TLR-4)-expressing monocytes and lymphocyte subpopulations in response to continuous intensive exercise training in athletes, as well as the effect of coenzyme Q10 (CoQ10) supplementation on these changes. Eighteen male elite kendo athletes in Japan were randomly assigned to a CoQ10-supplementation group (n = 9) or a placebo-supplementation group (n = 9) using a double-blind method. Subjects in the CoQ10 group took 300 mg CoQ10 per day for 20 days. Subjects in the placebo group took the same dosage of placebo. All subjects practiced kendo 5.5 h per day for 6 consecutive days during the study period. Blood samples were collected 2 weeks before training, on the first day (day 1), third day (day 3), and fifth day of training (day 5), and 1 week after the training period (post-training) to ascertain TLR-4(+)/CD14(+) monocyte and lymphocyte subpopulations (CD3(+), CD4(+), CD8(+), CD28(+)/CD4(+), CD28(+)/CD8(+), and CD56(+)/CD3(-) cells) using flow cytometry analysis. The group × time interaction for TLR-4(+)/CD14(+) cells did not reach significance (p = 0.08). Within the CoQ10 group, the absolute number of TLR-4(+)/CD14(+) cells was significantly higher only at day 5. The placebo group showed a significant increase in the absolute number of TLR-4(+)/CD14(+) cells at day 3, day 5, and post-training (p < 0.05). There was no significant group × time interaction for any lymphocyte subpopulation. CD3(+), CD8(+), and CD56(+)/CD3(-) cells were significantly reduced at day 3 in both groups (p < 0.05). In conclusion, CoQ10 supplementation might downregulate the increase of TLR-4-expressing monocytes in response to continuous strenuous exercise training in kendo athletes.


Assuntos
Suplementos Nutricionais , Artes Marciais , Monócitos/efeitos dos fármacos , Resistência Física , Fenômenos Fisiológicos da Nutrição Esportiva , Receptor 4 Toll-Like/genética , Ubiquinona/análogos & derivados , Tecido Adiposo/metabolismo , Atletas , Composição Corporal , Índice de Massa Corporal , Doença Crônica , Método Duplo-Cego , Regulação para Baixo , Fadiga/prevenção & controle , Humanos , Inflamação/prevenção & controle , Subpopulações de Linfócitos/efeitos dos fármacos , Subpopulações de Linfócitos/metabolismo , Masculino , Monócitos/metabolismo , Receptor 4 Toll-Like/metabolismo , Ubiquinona/farmacologia , Adulto Jovem
12.
Growth Horm IGF Res ; 25(3): 121-6, 2015 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-25900847

RESUMO

OBJECTIVE: Sprint exercise and hypoxic stimulus during exercise are potent factors affecting hormonal and metabolic responses. However, the effects of different hypoxic levels on hormonal and metabolic responses during sprint exercise are not known. Here, we examined the effect of different hypoxic conditions on hormonal and metabolic responses during sprint exercise. DESIGN: Seven male subjects participated in three experimental trials: 1) sprint exercise under normoxia (NSE); 2) sprint exercise under moderate normobaric hypoxia (16.4% oxygen) (HSE 16.4); and 3) sprint exercise under severe normobaric hypoxia (13.6% oxygen) (HSE 13.6). The sprint exercise consisted of four 30s all-out cycling bouts with 4-min rest between bouts. Glucose, free fatty acids (FFA), blood lactate, growth hormone (GH), epinephrine (E), norepinephrine (NE), and insulin concentrations in the HSE trials were measured before exposure to hypoxia (pre 1), 15 min after exposure to hypoxia (pre 2), and at 0, 15, 30, 60, 120, and 180 min after the exercise performed in hypoxia. The blood samples in the NSE trial were obtained in normoxia at the same time points as the HSE trials. RESULTS: Circulating levels of glucose, FFA, lactate, GH, E, NE, and insulin significantly increased after all three exercise trials (P < 0.05). The area under the curve (AUC) for GH was significantly higher in the HSE 13.6 trial than in the NSE and HSE 16.4 trials (P < 0.05). A maximal increase in FFA concentration was observed at 180 min after exercise and was not different between trials. CONCLUSION: These findings suggest that severe hypoxia may be an important factor for the enhancement of GH response to all-out sprint exercise.


Assuntos
Exercício Físico/fisiologia , Ácidos Graxos não Esterificados/sangue , Hormônios/sangue , Hipóxia/fisiopatologia , Oxigênio/metabolismo , Adulto , Humanos , Masculino , Adulto Jovem
14.
Front Physiol ; 5: 314, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-25206338

RESUMO

The present study aimed to investigate whether skeletal muscle from whole body creatine transporter (CrT; SLC6A8) knockout mice (CrT(-/y)) actually contained creatine (Cr) and if so, whether this Cr could result from an up regulation of muscle Cr biosynthesis. Gastrocnemius muscle from CrT(-/y) and wild type (CrT(+/y)) mice were analyzed for ATP, Cr, Cr phosphate (CrP), and total Cr (TCr) content. Muscle protein and gene expression of the enzymes responsible for Cr biosynthesis L-arginine:glycine amidotransferase (AGAT) and guanidinoacetate methyltransferase (GAMT) were also determined as were the rates of in vitro Cr biosynthesis. CrT(-/y) mice muscle contained measurable (22.3 ± 4.3 mmol.kg(-1) dry mass), but markedly reduced (P < 0.05) TCr levels compared with CrT(+/y) mice (125.0 ± 3.3 mmol.kg(-1) dry mass). AGAT gene and protein expression were higher (~3 fold; P < 0.05) in CrT(-/y) mice muscle, however GAMT gene and protein expression remained unchanged. The in vitro rate of Cr biosynthesis was elevated 1.5 fold (P < 0.05) in CrT(-/y) mice muscle. These data clearly demonstrate that in the absence of CrT protein, skeletal muscle has reduced, but not absent, levels of Cr. This presence of Cr may be at least partly due to an up regulation of muscle Cr biosynthesis as evidenced by an increased AGAT protein expression and in vitro Cr biosynthesis rates in CrT(-/y) mice. Of note, the up regulation of Cr biosynthesis in CrT(-/y) mice muscle was unable to fully restore Cr levels to that found in wild type muscle.

15.
Physiol Rep ; 2(6)2014 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-24907297

RESUMO

Hypoxia is an important modulator of endurance exercise-induced oxidative adaptations in skeletal muscle. However, whether hypoxia affects resistance exercise-induced muscle adaptations remains unknown. Here, we determined the effect of resistance exercise training under systemic hypoxia on muscular adaptations known to occur following both resistance and endurance exercise training, including muscle cross-sectional area (CSA), one-repetition maximum (1RM), muscular endurance, and makers of mitochondrial biogenesis and angiogenesis, such as peroxisome proliferator-activated receptor-γ coactivator-1α (PGC-1α), citrate synthase (CS) activity, nitric oxide synthase (NOS), vascular endothelial growth factor (VEGF), hypoxia-inducible factor-1 (HIF-1), and capillary-to-fiber ratio. Sixteen healthy male subjects were randomly assigned to either a normoxic resistance training group (NRT, n = 7) or a hypoxic (14.4% oxygen) resistance training group (HRT, n = 9) and performed 8 weeks of resistance training. Blood and muscle biopsy samples were obtained before and after training. After training muscle CSA of the femoral region, 1RM for bench-press and leg-press, muscular endurance, and skeletal muscle VEGF protein levels significantly increased in both groups. The increase in muscular endurance was significantly higher in the HRT group. Plasma VEGF concentration and skeletal muscle capillary-to-fiber ratio were significantly higher in the HRT group than the NRT group following training. Our results suggest that, in addition to increases in muscle size and strength, HRT may also lead to increased muscular endurance and the promotion of angiogenesis in skeletal muscle.

16.
PLoS One ; 8(7): e70823, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-23923026

RESUMO

Recent studies have revealed a new aspect of physiological regulation in which microRNAs (miRNAs) play fundamental roles in diverse biological and pathological processes. Furthermore, it was recently discovered that miRNAs are stably secreted into blood and that circulating miRNAs may play important roles in cell-cell communication. Here, we examined whether the circulating miRNA profile is affected by acute resistance exercise. Twelve males performed a resistance exercise session (bench press and leg press), consisting of five sets of 10 repetitions at 70% of maximum strength, with a 1 min rest between sets. Blood samples were taken before exercise, and at 0 and 60 min, 1 day, and 3 days after exercise. The circulating miRNA profile was determined by microarray analysis. Quantitative real-time PCR confirmed that the miR-149* level increased three days after resistance exercise. In contrast, the miR-146a and miR-221 levels decreased three days after resistance exercise. Our findings suggest that circulating miRNA levels change in response to acute resistance exercise, and miRNAs may play important roles in resistance-exercise-induced adaptation.


Assuntos
Exercício Físico/fisiologia , Perfilação da Expressão Gênica , MicroRNAs/genética , Regulação da Expressão Gênica , Humanos , Masculino
17.
J Strength Cond Res ; 26(3): 611-7, 2012 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-22310510

RESUMO

Previous studies have shown that low-intensity resistance exercises with vascular occlusion and slow movement effectively increase muscular size and strength. Researchers have speculated that local hypoxia by occlusion and slow movement may contribute to such adaptations via promoting anabolic hormone secretions by the local accumulation of metabolites. In this study, we determined the effects of low-intensity resistance exercise under acute systemic hypoxia on metabolic and hormonal responses. Eight male subjects participated in 2 experimental trials: (a) low-intensity resistance exercise while breathing normoxic air (normoxic resistance exercise [NR]), (b) low-intensity resistance exercise while breathing 13% oxygen (hypoxic resistance exercise [HR]). The resistance exercises (bench press and leg press) consisted of 14 repetitions for 5 sets at 50% of maximum strength with 1 minute of rest between sets. Blood lactate (LA), serum growth hormone (GH), norepinephrine (NE), testosterone, and cortisol concentrations were measured before normoxia and hypoxia exposures; 15 minutes after the exposures; and at 0, 15, and 30 minutes after the exercises. The LA levels significantly increased after exercises in both trials (p ≤ 0.05). The area under the curve for LA after exercises was significantly higher in the HR trial than in the NR trial (p ≤ 0.05). The GH significantly increased only after the HR trial (p ≤ 0.05). The NE and testosterone significantly increased after the exercises in both trials (p ≤ 0.05). Cortisol did not significantly change in both trials. These results suggest that low-intensity resistance exercise in the hypoxic condition caused greater metabolic and hormonal responses than that in the normoxic condition. Coaches may consider low-intensity resistance exercise under systemic hypoxia as a potential training method for athletes who need to maintain muscle mass and strength during the long in-season.


Assuntos
Hormônio do Crescimento Humano/fisiologia , Hidrocortisona/fisiologia , Hipóxia/fisiopatologia , Norepinefrina/fisiologia , Treinamento de Força , Testosterona/fisiologia , Adulto , Estudos Cross-Over , Fadiga/etiologia , Hormônio do Crescimento Humano/sangue , Humanos , Hidrocortisona/sangue , Lactatos/sangue , Masculino , Norepinefrina/sangue , Oxigênio/sangue , Método Simples-Cego , Testosterona/sangue , Fatores de Tempo
18.
J Strength Cond Res ; 24(8): 2249-54, 2010 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-19918193

RESUMO

We aimed to determine the responses of salivary secretory immunoglobulin A (SIgA) and the incidence of upper respiratory tract infections (URTI) symptoms among elite speed skaters during an actual competition period. The subjects were 8 international-class elite speed skaters. Saliva samples were obtained 3, 2, and 1 days before the race, the day of the race, and 1 day after the race. Salivary secretory immunoglobulin A concentration was measured by enzyme immunoassay, and SIgA secretion rate was calculated. A visual analogue scale was used to subjectively assess fatigue and tension. Daily URTI symptoms were recorded by using a questionnaire. There was no statistically significant difference in the saliva flow rate (p = 0.69), SIgA concentration (p = 0.07), and subjective fatigue (p = 0.07) during the competition period. The SIgA secretion rate recorded for the day of the race was significantly high compared with that of 3 and 2 days before and 1 day after the race (p < 0.05). The subjective tension recorded on the race day was significantly high compared with that for 3, 2, and 1 days before the race (p < 0.05). Two subjects exhibited URTI symptoms after the race. These findings suggest that salivary SIgA in elite speed skaters increased after a tapering period and that an actual high-intensity speed skating race decreased salivary SIgA in elite speed skaters. These data also suggest that the incidence of URTI symptoms might be related to the SIgA level. Coaches may need to take precautions after competitions to minimize their athletes' contact with cold viruses and adjust training load for a few days after competition to improve the decreased mucosal immune function.


Assuntos
Imunoglobulina A Secretora/análise , Saliva/imunologia , Patinação/fisiologia , Adulto , Feminino , Humanos , Masculino , Fadiga Muscular/imunologia , Fadiga Muscular/fisiologia , Infecções Respiratórias/imunologia , Infecções Respiratórias/fisiopatologia , Salivação/imunologia , Salivação/fisiologia , Fatores de Tempo
19.
Med Sci Sports Exerc ; 42(7): 1279-85, 2010 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-20019623

RESUMO

INTRODUCTION: Several recent studies have shown that resistance exercise combined with vascular occlusion effectively causes increases in muscular size and strength. Researchers speculated that the vascular occlusion-induced local hypoxia may contribute to the adaptations via promoting anabolic hormone secretions stimulated by local accumulation of metabolic subproducts. Here, we examined whether acute systemic hypoxia affects metabolic and hormonal responses to resistance exercise. METHODS: Twelve male subjects participated in two experimental trials: 1) resistance exercise while breathing normoxic air [normoxic resistance exercise (NR)] and 2) resistance exercise while breathing 13% oxygen [hypoxic resistance exercise (HR)]. The resistance exercises (bench press and leg press) consisted of 10 repetitions for five sets at 70% of maximum strength with 1-min rest between sets. Blood lactate, serum growth hormone (GH), epinephrine (E), norepinephrine (NE), insulin-like growth factor 1, testosterone, and cortisol concentrations were measured before normoxia and hypoxia exposures, 15 min after the exposures, and at 0, 15, 30, and 60 min after the exercises. RESULTS: Lactate significantly increased after exercises in both trials (P < 0.05). In the HR trial, GH and cortisol significantly increased after the exercise (P < 0.05) but not in the NR trial. The E, NE, insulin-like growth factor 1, and testosterone significantly increased after the exercises in both trials (P < 0.05). The mean values of lactate, GH, E, and NE after exercises were significantly higher in the HR trial than those in the NR trial (P < 0.05). CONCLUSIONS: These findings suggest that resistance exercise in hypoxic condition caused greater accumulation of metabolites and strong anabolic hormone response.


Assuntos
Epinefrina/metabolismo , Exercício Físico/fisiologia , Hormônio do Crescimento Humano/metabolismo , Hidrocortisona/metabolismo , Hipóxia/metabolismo , Norepinefrina/metabolismo , Adulto , Humanos , Fator de Crescimento Insulin-Like I/metabolismo , Ácido Láctico/metabolismo , Masculino , Treinamento de Força , Testosterona/metabolismo
20.
Eur J Appl Physiol ; 107(2): 227-33, 2009 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-19568765

RESUMO

This study examines the effects of 6-day intensive training on lymphocyte counts and their expression of CD95. Eight healthy Kendo athletes underwent 6-day Kendo training of about 310 min each day. Blood samples were collected at 2 weeks before (PRE), the first day (Day 1), third day (Day 3), fifth day (Day 5), and 1 week after the training period (POST) to determine lymphocyte counts and CD95 expression on CD95 lymphocytes (CD4(+), CD8(+)) using flow cytometry. The total lymphocyte counts were significantly lower at Day 3 than at PRE. The CD8(+) cell counts were significantly lower at Day 3 than at PRE. The percentage of CD95(+) lymphocytes was significantly higher at Day 1 and Day 3 than at PRE. The percentage of CD8(+)CD95(+) cells did not change significantly. The total lymphocyte counts decreased and a concomitant increase of CD95(+) lymphocyte was observed, whereas the decrease in CD8(+) cell counts was not associated with the increase in CD8(+)CD95(+) cells. Therefore, short-term high-intensity exercise induced a decrease in the T lymphocyte counts without increasing in CD95(+) expression.


Assuntos
Artes Marciais/fisiologia , Educação Física e Treinamento/métodos , Linfócitos T/citologia , Linfócitos T/metabolismo , Receptor fas/metabolismo , Adolescente , Humanos , Hidrocortisona/sangue , Contagem de Linfócitos , Esforço Físico/fisiologia , Fatores de Tempo , Adulto Jovem
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