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1.
PLoS One ; 13(6): e0198388, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29889868

RESUMO

PURPOSE: Previous research shows that endurance performance can be enhanced by placebo ergogenic aids. This study investigates the ergogenic placebo response, which we define as an increase in objective and physiological effort without an increase in subjective effort, in competitive cyclists. The primary objective of this study is to explore the role of supplement salience in the ergogenic placebo response, while the secondary aim is to assess whether believing to have taken an inactive placebo supplement attenuates the desired ergogenic effect. METHODS: We employed a double-blind placebo-controlled study design and compared a high salience (pudding) to a low salience (capsules) ergogenic placebo supplement and to a no treatment control group. Thirty-four male athletes (30.0 ± 5.7 years) performed two self-regulated time trials on an isokinetic cycling ergometer, one without intervention serving as a baseline and one with intervention according to group assignment. At both time trials, power output (objective effort), blood lactate (physiological effort) and the rating of perceived exertion (subjective effort) were measured. RESULTS: Receiving a high salience supplement can increase physiological and objective effort without a proportional rise in subjective effort, suggesting a decoupling of perceived exertion and endurance performance. Low salience and control group both showed no such ergogenic placebo response. Athletes' belief concerning the true nature of the ergogenic aid (inactive placebo vs. ergogenic supplement) did not influence the ergogenic placebo response. CONCLUSION: High salience placebo ergogenic aids can elicit enhanced performance without the athlete noticing (exertion), and deception of athletes seems unnecessary as even believing to have received an inactive placebo supplement maintains the ergogenic placebo response.


Assuntos
Ácido Láctico/sangue , Substâncias para Melhoria do Desempenho/administração & dosagem , Esforço Físico/efeitos dos fármacos , Adulto , Atletas , Ciclismo , Cápsulas , Suplementos Nutricionais , Método Duplo-Cego , Humanos , Masculino , Substâncias para Melhoria do Desempenho/farmacologia , Projetos Piloto , Efeito Placebo , Projetos de Pesquisa
2.
Mol Cell Biochem ; 448(1-2): 251-263, 2018 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-29446045

RESUMO

Dietary administration of orotic acid (OA), an intermediate in the pyrimidine biosynthetic pathway, is considered to provide a wide range of beneficial effects, including cardioprotection and exercise adaptation. Its mechanisms of action, when applied extracellularly, however, are barely understood. In this study, we evaluated potential effects of OA on skeletal muscle using an in vitro contraction model of electrically pulse-stimulated (EPS) C2C12 myotubes. By analyzing a subset of genes representing inflammatory, metabolic, and structural adaptation pathways, we could show that OA supplementation diminishes the EPS-provoked expression of inflammatory transcripts (interleukin 6, Il6; chemokine (C-X-C Motif) ligand 5, Cxcl5), and attenuated transcript levels of nuclear receptor subfamily 4 group A member 3 (Nr4A3), early growth response 1 (Egr1), activating transcription factor 3 (Atf3), and fast-oxidative MyHC-IIA isoform (Myh2). By contrast, OA had no suppressive effect on the pathogen-provoked inflammatory gene response in skeletal muscle cells, as demonstrated by stimulation of C2C12 myotubes with bacterial LPS. In addition, we observed a suppressive effect of OA on EPS-induced phosphorylation of AMP-activated protein kinase (AMPK), whereas EPS-triggered phosphorylation/activation of the mammalian target of rapamycin (mTOR) was not affected. Finally, we demonstrate that OA positively influences glycogen levels in EP-stimulated myotubes. Taken together, our results suggest that in skeletal muscle cells, OA modulates both the inflammatory and the metabolic reaction provoked by acute contraction. These results might have important clinical implications, specifically in cardiovascular and exercise medicine.


Assuntos
Contração Muscular/efeitos dos fármacos , Mioblastos Esqueléticos/metabolismo , Ácido Orótico/farmacologia , Fator 3 Ativador da Transcrição/biossíntese , Animais , Quimiocina CXCL5/biossíntese , Proteínas de Ligação a DNA/biossíntese , Proteína 1 de Resposta de Crescimento Precoce/biossíntese , Estimulação Elétrica , Regulação da Expressão Gênica/efeitos dos fármacos , Interleucina-6/biossíntese , Camundongos , Mioblastos Esqueléticos/citologia , Proteínas do Tecido Nervoso/biossíntese , Receptores de Esteroides/biossíntese , Receptores dos Hormônios Tireóideos/biossíntese , Serina-Treonina Quinases TOR/biossíntese
3.
J Psychosom Res ; 93: 6-13, 2017 02.
Artigo em Inglês | MEDLINE | ID: mdl-28107894

RESUMO

OBJECTIVE: Chronic fatigue syndrome (CFS) is characterised by persistent fatigue, exhaustion, and several physical complaints. Research has shown cognitive behavioural therapy (CBT) and graded exercise training (GET) to be the most effective treatments. In a first step we aimed to assess the efficacy of heart rate variability biofeedback therapy (HRV-BF) as a treatment method comprising cognitive and behavioural strategies and GET in the pilot trial. In a second step we aimed to compare both interventions with regard to specific parameters. METHODS: The study was conducted in an outpatient treatment setting. A total of 28 women with CFS (50.3±9.3years) were randomly assigned to receive either eight sessions of HRV-BF or GET. The primary outcome was fatigue severity. Secondary outcomes were mental and physical quality of life and depression. Data were collected before and after the intervention as well as at a 5-month follow-up. RESULTS: General fatigue improved significantly after both HRV-BF and GET. Specific cognitive components of fatigue, mental quality of life, and depression improved significantly after HRV-BF only. Physical quality of life improved significantly after GET. There were significant differences between groups regarding mental quality of life and depression favouring HRV-BF. CONCLUSION: Both interventions reduce fatigue. HRV-BF seems to have additional effects on components of mental health, including depression, whereas GET seems to emphasise components of physical health. These data offer implications for further research on combining HRV-BF and GET in patients with CFS. TRIAL REGISTRATION: The described trial has been registered at the International Clinical Trials Registry Platform following the number DRKS00005445.


Assuntos
Biorretroalimentação Psicológica/métodos , Terapia por Exercício/métodos , Síndrome de Fadiga Crônica/psicologia , Síndrome de Fadiga Crônica/reabilitação , Frequência Cardíaca , Adulto , Terapia Combinada , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Projetos Piloto
4.
Int J Sport Nutr Exerc Metab ; 24(6): 623-31, 2014 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-24901677

RESUMO

Nutritional supplements (NS) are defined as concentrated sources of nutrients and other substances that have a nutritional or physiological effect and that are used in high frequency among athletes. The study aimed to create a prediction profile for young elite athletes to identify those athletes who have a higher relative risk for using NS. The second objective was to examine the hypothesis that the consumption of NS paves a gateway for the use of illicit drugs and doping substances. A self-designed anonymous paper-and-pencil questionnaire was used to examine the prevalence of NS consumption, doping, and illicit drug use in elite athletes with a mean age of 17 years (SD = 4 years). Logistic regression analysis was employed to assess whether NS consumption can be predicted by independent variables (e.g., biographical data, training characteristics, drug consumption behavior) to create the prediction profile for NS use. 55% and 5% of the athletes (n = 536) responded positively to having used NS and illicit drugs, respectively. Nutritional supplement consumption was positively correlated with age (OR: 1.92; CI: 1.21 to 3.05), the desire to enhance performance to become an Olympic or World Champion (OR: 3.72; CI: 2.33 to 6.01), and being educated about NS (OR: 2.76; CI: 1.73 to 4.45). It was negatively correlated with training frequency (OR: 0.55; CI: 0.35 to 0.86) and the use of nicotine (OR: 0.29; CI: 0.1 to 0.74) but did not correlate with illicit drug use and alcohol consumption. The present results show that NS are used on a large scale in elite sports. The prediction profile presented in this article may help to identify those athletes who have a high risk for using NS to plan potential education and prevention models more individually.


Assuntos
Atletas/psicologia , Suplementos Nutricionais/estatística & dados numéricos , Dopagem Esportivo/estatística & dados numéricos , Previsões , Adolescente , Adulto , Fatores Etários , Atletas/estatística & dados numéricos , Desempenho Atlético/psicologia , Criança , Dopagem Esportivo/tendências , Feminino , Alemanha , Humanos , Masculino , Razão de Chances , Substâncias para Melhoria do Desempenho/administração & dosagem , Análise de Regressão , Assunção de Riscos , Inquéritos e Questionários , Adulto Jovem
5.
Eur J Nutr ; 42(4): 195-200, 2003 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-12923650

RESUMO

BACKGROUND: Extensive exercise may promote the formation of reactive oxygen species and subsequently contribute to tissue damage. A compound which can protect cells and tissues is vitamin E. The vitamin E radical, formed during the radical scavenging process, can be reduced by vitamin C resulting in a higher level of the vitamin C radical (semidehydroascorbate free radical). An increase of the vitamin C radical, however, is assumed to exert prooxidative effects. AIM OF THE STUDY: To elucidate whether supplementation of vitamin E and exhaustive exercise lead to an increase of the vitamin C radical in human plasma. METHODS: A placebo controlled, cross over study with 13 male volunteers was carried out. After an 8 day supplementation period with 500 I.U. D-alpha-tocopherol, the subjects performed two exhaustive treadmill runs. Blood samples were collected at rest, 0, 0.25, 1, 3, 24 and 48 h after exercise. Serum was separated and concentrations of D-alpha-tocopherol and ascorbic acid were determined by HPLC. Vitamin C radical levels in plasma were assessed by electron paramagnetic resonance (EPR). RESULTS: Vitamin E and C both showed a tendency to decrease between 3 h and 24 h after exercise. Vitamin C radical level remained stable during the whole period. Neither vitamin E supplementation nor exercise had any influence on the plasma concentration of the vitamin C radical. CONCLUSIONS: Vitamin E supplementation under conditions of mild oxidative stress does not result in an increased vitamin C radical concentration.


Assuntos
Antioxidantes/farmacologia , Ácido Ascórbico/metabolismo , Ácido Desidroascórbico/análogos & derivados , Esforço Físico/fisiologia , Vitamina E/farmacologia , alfa-Tocoferol/sangue , Adulto , Antioxidantes/administração & dosagem , Ácido Ascórbico/sangue , Cromatografia Líquida de Alta Pressão , Estudos Cross-Over , Ácido Desidroascórbico/sangue , Ácido Desidroascórbico/metabolismo , Suplementos Nutricionais , Sequestradores de Radicais Livres/metabolismo , Radicais Livres/sangue , Radicais Livres/metabolismo , Humanos , Cinética , Masculino , Oxirredução , Estresse Oxidativo , Vitamina E/administração & dosagem
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