RESUMO
The aim of this cross-sectional study was to compare mobility and muscle strength in male former elite endurance and power athletes aged 66-91 years (n = 150; 50 men in both former elite athlete groups and in their control group). Agility, dynamic balance, walking speed, chair stand, self-rated balance confidence (ABC-scale), jumping height, and handgrip strength were assessed. Former elite power athletes had better agility performance time than the controls (age- and body mass index, BMI-adjusted mean difference -3.6 s; 95% CI -6.3, -0.8). Adjustment for current leisure time physical activity (LTPA) and prevalence of diseases made this difference non-significant (P = 0.214). The subjects in the power sports group jumped higher than the men in the control group (age- and BMI-adjusted mean differences for vertical squat jump, VSJ 4.4 cm; 95% CI 2.0, 6.8; for countermovement jump, CMJ 4.0 cm; 95% CI 1.7, 6.4). Taking current LTPA and chronic diseases for adjusting process did not improve explorative power of the model. No significant differences between the groups were found in the performances evaluating dynamic balance, walking speed, chair stand, ABC-scale, or handgrip strength. In conclusion, power athletes among the aged former elite sportsmen had greater explosive force production in their lower extremities than the men in the control group.
Assuntos
Atletas , Exercício Físico , Força Muscular , Idoso , Idoso de 80 Anos ou mais , Envelhecimento , Índice de Massa Corporal , Estudos de Casos e Controles , Estudos Transversais , Humanos , Masculino , Limitação da Mobilidade , Equilíbrio Postural , Velocidade de CaminhadaRESUMO
In randomized controlled trials (RCTs), with customized structured physical exercise activity (SPEA) interventions, the dose of leisure-time physical activity (LTPA) should exceed the LTPA dose of the nonexercising control (C) group. This increase is required to substantiate health improvements achievable by exercise. We aimed to compare the dose of SPEA, LTPA, and total LTPA (SPEA + LTPA) between a randomized Nordic walking (NW) group, a power-type resistance training (RT) group, and a C group during a 12-week exercise intervention in obese middle-aged men (n = 144) with impaired glucose regulation. The dose of physical activity was measured with diaries using metabolic equivalents. No significant difference (P > 0.107) between the groups was found in volume of total LTPA. The volume of LTPA was, however, significantly higher (P < 0.050) in the C group than in the NW group, but not compared with the RT group. These results indicate that structured exercise does not automatically increase the total LTPA level, possibly, as a result of compensation of LTPA with structured exercise or spontaneous activation of the C group. Thus, the dose of total LTPA and the possible changes in spontaneous LTPA should be taken into account when implementing a RCT design with exercise intervention.
Assuntos
Terapia por Exercício , Atividades de Lazer , Obesidade/terapia , Treinamento Resistido , Caminhada/fisiologia , Terapia por Exercício/métodos , Humanos , Masculino , Equivalente Metabólico , Pessoa de Meia-Idade , Atividade Motora/fisiologia , Fatores de TempoRESUMO
AIMS/HYPOTHESIS: This study aimed to determine whether lifestyle intervention lasting for 4 years affected diabetes incidence, body weight, glycaemia or lifestyle over 13 years among individuals at high risk of type 2 diabetes. METHODS: Overweight, middle-aged men (n = 172) and women (n = 350) with impaired glucose tolerance were randomised in 1993-1998 to an intensive lifestyle intervention group (n = 265), aiming at weight reduction, dietary modification and increased physical activity, or to a control group (n = 257) that received general lifestyle information. The primary outcome was a diagnosis of diabetes based on annual OGTTs. Secondary outcomes included changes in body weight, glycaemia, physical activity and diet. After active intervention (median 4 years, range 1-6 years), participants still free of diabetes and willing to continue their participation (200 in the intervention group and 166 in the control group) were further followed until diabetes diagnosis, dropout or the end of 2009, with a median total follow-up of 9 years and a time span of 13 years from baseline. RESULTS: During the total follow-up the adjusted HR for diabetes (intervention group vs control group) was 0.614 (95% CI 0.478, 0.789; p < 0.001). The corresponding HR during the post-intervention follow-up was 0.672 (95% CI 0.477, 0.947; p = 0.023). The former intervention group participants sustained lower absolute levels of body weight, fasting and 2 h plasma glucose and a healthier diet. Adherence to lifestyle changes during the intervention period predicted greater risk reduction during the total follow-up. CONCLUSIONS/INTERPRETATION: Lifestyle intervention in people at high risk of type 2 diabetes induces sustaining lifestyle change and results in long-term prevention of progression to type 2 diabetes.
Assuntos
Diabetes Mellitus Tipo 2/prevenção & controle , Estilo de Vida , Adulto , Glicemia/metabolismo , Peso Corporal/fisiologia , Diabetes Mellitus Tipo 2/epidemiologia , Exercício Físico/fisiologia , Feminino , Humanos , Masculino , Pessoa de Meia-IdadeRESUMO
AIMS: We analysed the Finnish Diabetes Prevention Study data in order to evaluate how the new HbA(1c) -based criterion compares with the oral glucose tolerance test in diagnosing Type 2 diabetes among high-risk individuals during a prospective average follow-up of 4 years. METHODS: In the Diabetes Prevention Study, 172 men and 350 women who were overweight and had impaired glucose tolerance at baseline were randomized into an intensive lifestyle intervention or a control group. The oral glucose tolerance test and HbA(1c) measurements were performed annually until the diagnosis of diabetes using the World Health Organization 1985 criteria. RESULTS: The sensitivity of the HbA(1c) ≥ 6.5% (≥ 48 mmol/mol) as a diagnostic criterion for Type 2 diabetes was 35% (95% CI 24%, 47%) in women and 47% (95% CI 31%, 64%) in men compared with diagnosis based on two consecutive oral glucose tolerance tests. The corresponding sensitivities for HbA(1c) ≥ 6.0% (≥ 42 mmol/mol) were 67% (95% CI 55%, 77%) and 68% (95% CI 51%, 82%). The participants with HbA(1c) ≥ 6.5% (≥ 48 mmol/mol) and diabetes based on the oral glucose tolerance test were more obese and had higher fasting glucose and 2-h glucose concentrations than those who had a diabetic oral glucose tolerance test but HbA(1c) < 6.5% (< 48 mmol/mol). There were no differences in the predictive performance of baseline fasting glucose, oral glucose tolerance test and HbA(1c) . CONCLUSIONS: Of those with diabetes diagnosis based on two oral glucose tolerance tests during the Diabetes Prevention Study follow-up, 60% would have remained undiagnosed if diagnosis had been based on HbA(1c) ≥ 6.5% (≥ 48 mmol/mol) criterion.
Assuntos
Diabetes Mellitus Tipo 2/diagnóstico , Hemoglobinas Glicadas/metabolismo , Sobrepeso/complicações , Adulto , Biomarcadores/metabolismo , Diabetes Mellitus Tipo 2/epidemiologia , Diabetes Mellitus Tipo 2/prevenção & controle , Feminino , Finlândia/epidemiologia , Teste de Tolerância a Glucose , Humanos , Masculino , Pessoa de Meia-Idade , Sobrepeso/epidemiologia , Estudos Prospectivos , Curva ROC , Sensibilidade e EspecificidadeRESUMO
AIMS: The aim of this study was to investigate the prevalence of cardiovascular autonomic neuropathy in persons with previously diagnosed impaired glucose tolerance and to characterize associations between components of metabolic syndrome and cardiovascular autonomic neuropathy in the Finnish Diabetes Prevention Study cohort. METHODS: Two hundred and sixty-eight individuals with impaired glucose tolerance at baseline in the Finnish Diabetes Prevention Study, but not diagnosed with diabetes during follow-up, were studied for cardiovascular autonomic neuropathy. At the second annual follow-up visit after the end of lifestyle intervention, we performed deep-breathing and active orthostatic tests to detect possible parasympathetic and sympathetic dysfunction. To describe metabolic characteristics, anthropometric measurements, an oral glucose tolerance test and assessments for HbA(1c,) serum lipids and blood pressure were carried out. RESULTS: Prevalence of parasympathetic dysfunction was 25% and prevalence of sympathetic dysfunction was 6%, with no difference between the former intervention and control group participants or between men and women. Subjects with parasympathetic dysfunction were older, more obese (weight, waist circumference, body mass index) and had higher triglyceride concentration compared with those with normal parasympathetic function (P<0.01 for all). Parasympathetic dysfunction was not significantly associated with other characteristics of metabolic syndrome; for example, high cholesterol, glucose and insulin levels or HbA(1c) . Correlations between the Expiration/Inspiration (E/I) ratio (the longest heart beat duration in expiration divided by the shortest heart beat duration in inspiration) and measures reflecting obesity were statistically significant in the pooled population and in men but not in women. CONCLUSIONS: Cardiovascular autonomic neuropathy is common in persons with impaired glucose tolerance. Obesity, especially among men, seems to play an important role in the early pathogenesis of cardiovascular autonomic neuropathy.
Assuntos
Glicemia/metabolismo , Diabetes Mellitus Tipo 2/sangue , Neuropatias Diabéticas/sangue , Intolerância à Glucose/sangue , Hemoglobinas Glicadas/metabolismo , Obesidade/sangue , Adulto , Idoso , Diabetes Mellitus Tipo 2/complicações , Diabetes Mellitus Tipo 2/epidemiologia , Neuropatias Diabéticas/epidemiologia , Neuropatias Diabéticas/etiologia , Feminino , Finlândia/epidemiologia , Intolerância à Glucose/complicações , Intolerância à Glucose/fisiopatologia , Humanos , Masculino , Pessoa de Meia-Idade , Obesidade/complicações , Obesidade/epidemiologia , PrevalênciaRESUMO
BACKGROUND AND AIM: The common single nucleotide polymorphism (SNP) in the FTO (fat mass and obesity associated) gene has been consistently associated with an increased risk of obesity. We investigated whether the SNP rs9939609 (T/A) of the FTO is associated with risk factors of cardiovascular diseases (CVD), including serum levels of C - reactive protein (CRP), the chemokine RANTES (Regulated on Activation, Normal T Cell Expressed and Secreted; CCL5), and serum and lipoprotein lipids in the Finnish Diabetes Prevention Study (DPS). Furthermore, we examined whether the rs9939609 increased the CVD risk in the DPS and if these results could be replicated in a larger cross-sectional population-based random sample of Finnish men (the METSIM). METHODS AND RESULTS: In the DPS, altogether 490 (BMI≥25kg/m(2)) subjects with impaired glucose tolerance were genotyped for rs9939609. Cardiovascular morbidity and mortality data were collected during the median follow-up of 10.2 years. The replication study was a population-based cross-sectional study of 6214 men. In the DPS, the AA genotype of rs9939609 was associated, independently of BMI, with increased RANTES (p=0.002) and decreased HDL cholesterol concentrations (p=0.007) in men. During the follow-up, the AA genotype was associated with an adjusted 2.09-fold risk (95% CI 1.17-3.73, p=0.013) of CVD in men. In the METSIM Study, the association with a history of myocardial infarction was replicated in the subgroup of men with type 2 diabetes. CONCLUSION: We suggest that the variation in the FTO gene may contribute to the development of CVD in men with an abnormal glucose metabolism.
Assuntos
Glicemia/metabolismo , Doenças Cardiovasculares/epidemiologia , Doenças Cardiovasculares/genética , Polimorfismo de Nucleotídeo Único , Proteínas/genética , Idoso , Dioxigenase FTO Dependente de alfa-Cetoglutarato , Glicemia/análise , Proteína C-Reativa/análise , Doenças Cardiovasculares/patologia , Estudos Transversais , Feminino , Finlândia/epidemiologia , Seguimentos , Genótipo , Intolerância à Glucose/genética , Humanos , Masculino , Pessoa de Meia-Idade , Proteínas/metabolismo , Fatores de RiscoRESUMO
AIMS/HYPOTHESIS: Subclinical inflammation confers an increased risk of type 2 diabetes, cardiovascular disease, neurodegenerative disorders and other age-related chronic diseases. Physical activity and diet can attenuate systemic immune activation, but it is not known which individual components of a comprehensive lifestyle intervention are most effective in targeting subclinical inflammation. METHODS: We used data from the baseline examination and the 1 year follow-up of a subsample of 406 of 522 participants of the Finnish Diabetes Prevention Study (DPS) to estimate the effect of individual components of lifestyle intervention on C-reactive protein (CRP) and IL-6 levels, which represent the best characterised proinflammatory risk factors for type 2 diabetes. Changes in metabolic markers, dietary patterns and exercise were analysed to determine which were most strongly associated with the anti-inflammatory effect of lifestyle changes. RESULTS: Lifestyle intervention reduced circulating levels of CRP (p < 0.001) and IL-6 (p = 0.060). Increases in fibre intake and moderate to vigorous leisure time physical activity (LTPA), but not total LTPA, predicted decreases in CRP and/or IL-6 and remained associated even after adjustment for baseline BMI or changes in BMI during the first year of the study. Changes in carbohydrate or fat intake were either weakly or not linked to reductions in CRP and IL-6. CONCLUSIONS/INTERPRETATION: The present study assessed the individual effects of dietary and physical activity measures on low-grade inflammation in individuals at high cardiometabolic risk. Our results underline the importance of moderate to vigorous LTPA and a diet rich in natural fibre, and this should be emphasised in lifestyle recommendations.
Assuntos
Diabetes Mellitus/prevenção & controle , Inflamação/prevenção & controle , Estilo de Vida , Glicemia/metabolismo , Pressão Sanguínea , Índice de Massa Corporal , Peso Corporal , Proteína C-Reativa/metabolismo , Calorimetria , Diabetes Mellitus/epidemiologia , Diabetes Mellitus/etiologia , Fibras na Dieta , Ingestão de Energia , Exercício Físico , Finlândia , Intolerância à Glucose/prevenção & controle , Humanos , Inflamação/complicações , Insulina/sangue , Atividades de Lazer , Pessoa de Meia-Idade , Educação de Pacientes como Assunto , Fatores de Risco , Circunferência da CinturaRESUMO
Single nucleotide polymorphisms (SNPs) in two genes regulating insulin secretion, SLC2A2 (encoding GLUT2) and ABCC8 (encoding SUR1), were associated with the conversion from impaired glucose tolerance (IGT) to type 2 diabetes (T2D) in the Finnish Diabetes Prevention Study (DPS). We determined whether physical activity (PA), assessed annually with a questionnaire, modified the association of SNPs in SLC2A2 and ABCC8 with the conversion to T2D in the combined intervention and control groups of the DPS. Finnish overweight subjects with IGT (N = 479) were followed for an average of 4.1 yr. The interaction of the SNPs with the change in PA on the conversion to T2D was assessed using Cox regression with adjustments for the other components of the intervention (dietary changes, weight reduction). The carriers of the common homozygous genotype of rs5393, rs5394, or rs5404 of SLC2A2 and rs3758947 of ABCC8 who were in the lower third of the change in moderate-to-vigorous PA during the follow-up had a 2.6- to 3.7-fold increased risk of developing T2D compared with the upper third, whereas the rare allele carriers seemed to be unresponsive to changes in moderate-to-vigorous PA (for the interaction of genotype with change in PA, P = 0.022-0.027 for the SNPs in SLC2A2, and P = 0.007 for rs3758947). We conclude that moderate-to-vigorous PA may modify the risk of developing T2D associated with genes regulating insulin secretion (SLC2A2, ABCC8) in persons with IGT.
Assuntos
Transportadores de Cassetes de Ligação de ATP/genética , Diabetes Mellitus Tipo 2/prevenção & controle , Terapia por Exercício , Intolerância à Glucose/terapia , Transportador de Glucose Tipo 2/genética , Polimorfismo de Nucleotídeo Único , Canais de Potássio Corretores do Fluxo de Internalização/genética , Canais de Potássio/genética , Receptores de Droga/genética , Transportadores de Cassetes de Ligação de ATP/fisiologia , Terapia Combinada , Diabetes Mellitus Tipo 2/epidemiologia , Diabetes Mellitus Tipo 2/genética , Progressão da Doença , Éxons/genética , Feminino , Finlândia/epidemiologia , Predisposição Genética para Doença , Intolerância à Glucose/dietoterapia , Intolerância à Glucose/genética , Transportador de Glucose Tipo 2/fisiologia , Promoção da Saúde , Humanos , Insulina/metabolismo , Secreção de Insulina , Masculino , Pessoa de Meia-Idade , Sobrepeso , Canais de Potássio/fisiologia , Canais de Potássio Corretores do Fluxo de Internalização/fisiologia , Regiões Promotoras Genéticas/genética , Receptores de Droga/fisiologia , Risco , Receptores de Sulfonilureias , Redução de PesoRESUMO
AIM: Human lifestyle has drastically changed during the past century as the share of physical work in daily life has decreased. The purpose of the present study was to examine the distribution of myosin heavy chain (MHC) isoforms in middle-aged sedentary persons, to compare the proportion of MHC isoforms of middle-aged and young sedentary persons and to demonstrate the effect of physical activity of MHC isoforms in middle-aged sedentary persons. METHODS: Eighty-nine middle-aged sedentary and 13 young sedentary persons volunteered for the study. Thirty middle-aged sedentary subjects participated in strength-conditional exercise program during 9 months. Vertical jumping height and maximal anaerobic work capacity were measured. Muscle samples were taken from vastus lateralis muscle. MHC isoform composition was determined by SDS-PAGE. RESULTS: Variation of MHC I and MHC IIa isoforms in middle-age sedentary persons demonstrated normal distribution. Significant differences of MHC isoform proportions between middle-aged and young sedentary participants were not observed. The proportion of MHC IIx decreased significantly after the exercise period that significantly improved the maximal anaerobic power and jumping height of participants. CONCLUSIONS: Normal distribution illustrated the proportion of MHC I and MHC IIa isoforms in 89 middle-aged sedentary persons while significant differences of MHC isoforms proportion between young and middle-aged sedentary persons were not observed. Even small increase of physical activity improved physical performance and decrease the MHC IIx proportion of middle-aged sedentary persons. Physically active lifestyle in middle age, when age-related changes have not started yet, may delay age-related changes in skeletal muscle.
Assuntos
Atividade Motora/fisiologia , Cadeias Pesadas de Miosina/análise , Adulto , Envelhecimento/metabolismo , Limiar Anaeróbio/fisiologia , Eletroforese em Gel de Poliacrilamida , Teste de Esforço , Feminino , Humanos , Estilo de Vida , Masculino , Pessoa de Meia-Idade , Força Muscular/fisiologia , Exercícios de Alongamento Muscular , Músculo Esquelético/química , Miosina Tipo I/análise , Miosina Tipo II/análise , Miosina não Muscular Tipo IIA/análise , Aptidão Física/fisiologia , Isoformas de Proteínas/análiseRESUMO
Nocturnal motor breathing and cardiac activity were recorded by using the static charge-sensitive bed, and sleep habits were studied by questionnaire in 24 pairs of monozygotic twins discordant for their body mass index; the mean intrapair difference between co-twins was 6.7 kg/m2. Intrapair differences in sleep characteristics between co-twins were related to intrapair differences in physiological and anthropometric characteristics. Two questions were tested. First, do monozygotic twins discordant for body mass index differ in sleep behavior? Second, if they do, are differences in sleep associated with nongenetic differences in the body weight and metabolism or with other environmental factors? Obese twins had higher nocturnal motor activity levels, less quiet sleep, and more habitual snoring than did their nonobese co-twins. Differences in sleep were associated with obesity-related factors. However, habitual snoring did not explain other intrapair differences in sleep. It was concluded that relatively moderate obesity is associated with disruption of physiological structure of sleep as measured by the static charge-sensitive bed method and that this disruption seems not to be associated with snoring or breathing disturbances.
Assuntos
Obesidade/fisiopatologia , Sono/fisiologia , Tecido Adiposo/fisiologia , Adulto , Metabolismo Basal/fisiologia , Índice de Massa Corporal , Meio Ambiente , Feminino , Coração/fisiologia , Humanos , Masculino , Pessoa de Meia-Idade , Obesidade/psicologia , Escalas de Graduação Psiquiátrica , Mecânica Respiratória , Transtornos do Sono-Vigília/fisiopatologia , Gêmeos MonozigóticosRESUMO
In diabetes, the endogenous defence systems are overwhelmed, causing various types of stress in tissues. In this study, newly diagnosed or diet-treated type 2 diabetics (T2D) (n = 10) were compared with subjects with impaired glucose tolerance (IGT) (n = 8). In both groups, at resting conditions, blood samples were drawn for assessing metabolic indices and skeletal muscle samples (m. vastus lateralis) were taken for the measurements of cellular defence markers: thioredoxin-1 (TRX-1) and stress proteins HSP72, HSP90. The protein level of TRX-1 was 36.1% lower (P = 0.031) and HSP90 was 380% higher (P < 0.001) in the T2D than in the IGT subjects, with no significant changes in HSP72. However, after the adjustment of both analyses with HOMA-IR only HSP90 difference remained significant. In conclusion, level of TRX-1 in skeletal muscle tissue was lower while that of HSP90 was higher in T2D than in IGT subjects. This may impair antioxidant defence and lead to disruptions of protein homoeostasis and redox regulation of cellular defences. Because HSP90 may be involved in sustaining functional insulin signalling pathway in type 2 diabetic muscles and higher HSP90 levels can be a consequence of type 2 diabetes, our results are potentially important for the diabetes research.
Assuntos
Diabetes Mellitus Tipo 2/metabolismo , Intolerância à Glucose/metabolismo , Proteínas de Choque Térmico HSP90/metabolismo , Músculo Esquelético/metabolismo , Tiorredoxinas/metabolismo , Glicemia/metabolismo , Diabetes Mellitus Tipo 2/patologia , Feminino , Intolerância à Glucose/patologia , Proteínas de Choque Térmico HSP72/metabolismo , Humanos , Masculino , Pessoa de Meia-Idade , Músculo Esquelético/patologiaRESUMO
The purpose of this study was to evaluate and compare the effects of training either with a light load or without any load in a 16-week power-type strength training intervention in sedentary middle-aged subjects. A total of 85 subjects participated in the study. In a supervised 22-week training intervention, including 16 weeks of power-type strength training, 42 subjects (Light Load group=LL group) trained with a 1.1 kg weight on each ankle and 43 subjects (No Load group=NOL group) trained without any external load. Subjects were comparable concerning their training attendance, and anthropometric and physiological characteristics. Training effects were evaluated by measuring Vertical Squat Jump (VSJ), 20-metre Running Time (20 mRT), Maximal Anaerobic Cycling Power of leg muscles (MACP), and Maximal Oxygen Uptake (V.O (2 max)) before and after the intervention. The LL group improved VSJ and MACP significantly (p<0.05), compared with the NOL group. No difference between the groups was observed in 20 mRT or in V.O (2 max). To conclude, the external loads of 2.2 kg, in total, increased the efficiency of power-type strength training in vertical jumps and in anaerobic power in leg muscles, but not in sprint running.
Assuntos
Extremidade Inferior/fisiologia , Músculo Esquelético/fisiologia , Educação Física e Treinamento/métodos , Suporte de Carga/fisiologia , Adulto , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Consumo de Oxigênio/fisiologia , Esforço Físico/fisiologiaRESUMO
AIM: The aim of this study was to investigate the role of skeletal muscle fibre type in the regulation of glucose metabolism in middle-aged obese subjects with impaired glucose tolerance (IGT) during a 2-year exercise and dietary intervention. METHODS: Muscle biopsies (musculus vastus lateralis) were taken from 22 subjects belonging to the intervention group of the Finnish Diabetes Prevention Study [1]. According to their myosin heavy chain (MHC) profile at the baseline, the subjects were divided into two groups: IGT(slow) (n=10) with a high proportion of MHC I isoforms and IGT(fast) (n=12) with a high proportion of MHC II isoforms in the vastus lateralis muscle. The intervention consisted of dietary counselling, strength and power training and/or aerobic exercise. The amount of exercise was the same in both groups; the exercise frequency was 5.1+/-2.7 h/week in the IGT(slow) and 5.1+/-2.8 h/week in the IGT(fast) group. RESULTS: Fasting glucose (p<0.05), 2-h glucose (p<0.05), fasting insulin (p<0.05), haemoglobin A1c (HbA(1c)) (p<0.01) and insulin resistance (p<0.05) [homeostasis model assessment for insulin resistance (HOMA-IR)] decreased in the IGT(fast) group, whereas only the 2-h glucose and HbA(1c) concentrations decreased in the IGT(slow) group. The amount of the glycogen synthase kinase-3-alphabeta (GSK-3-alphabeta) decreased in the IGT(fast) group (p<0.05). Exercise training increased the lactate dehydrogenase (LDH) (p<0.01), LDH-1 (p<0.05) and citrate synthase (CS) (p<0.05) activities in the vastus lateralis muscle in the IGT(slow) group, but only the CS activity (p<0.05) in the IGT(fast) group. CONCLUSIONS: The glucose metabolism improved both in the IGT(slow) and IGT(fast) group during the 2-year exercise and dietary intervention. The change was more prominent in the IGT(fast) group than in the IGT(slow) group, associated with the decrease of the GSK-alphabeta protein expression in skeletal muscle. The exercise training improved both glycolytic and oxidative capacity in the vastus lateralis muscle. The glycolytic capacity improved in the IGT(slow) group and the oxidative capacity in both groups.
Assuntos
Exercício Físico , Intolerância à Glucose , Músculo Esquelético/fisiopatologia , Obesidade/sangue , Obesidade/terapia , Adulto , Idoso , Glicemia/metabolismo , Terapia Combinada , Dieta Redutora , Feminino , Seguimentos , Quinase 3 da Glicogênio Sintase/metabolismo , Humanos , Masculino , Pessoa de Meia-Idade , Fibras Musculares Esqueléticas/fisiologia , Músculo Esquelético/enzimologia , Músculo Esquelético/metabolismo , Cadeias Pesadas de Miosina/metabolismo , Obesidade/fisiopatologia , Fator A de Crescimento do Endotélio Vascular/metabolismo , Redução de PesoRESUMO
AIMS/HYPOTHESIS: The aim of this study was to investigate the effects of lifestyle intervention on the levels of plasminogen activator inhibitor (PAI-1) and fibrinogen in subjects participating in the Finnish Diabetes Prevention Study (DPS). METHODS: In five DPS centres, 321 subjects with impaired glucose tolerance (intervention group, n=163; control group, n=158) had their PAI-1 and fibrinogen levels measured at baseline and at the 1-year follow-up. Additional 3-year follow-up assessments were carried out in a sample of 97 subjects in one of the DPS centres (Turku). The intervention programme included an intensive lifestyle intervention aiming at weight reduction, healthy diet and increased physical activity. RESULTS: During the first intervention year, PAI-1 decreased by 31% in the intervention group but showed no change in the control group (p<0.0001). In the Turku subgroup, the decrease in PAI-1 persisted throughout the 3-year follow-up. Changes in PAI-1 were associated with the number of lifestyle changes made during the first year (p=0.008). Weight reduction was the most important factor explaining the decrease in PAI-1. Changes in fibrinogen levels did not differ between the groups. CONCLUSIONS/INTERPRETATION: In addition to the previously reported reduction in the risk of type 2 diabetes in DPS participants with impaired glucose tolerance, the intensive dietary and exercise intervention had beneficial long-term effects on fibrinolysis as indicated by the reduced levels of PAI-1. These results suggest that elevated PAI-1 levels in obese subjects with impaired glucose tolerance are mostly reversible by lifestyle changes, especially those geared to weight reduction.
Assuntos
Diabetes Mellitus/prevenção & controle , Intolerância à Glucose/metabolismo , Estilo de Vida , Adulto , Diabetes Mellitus Tipo 2/prevenção & controle , Dieta , Exercício Físico , Feminino , Fibrinogênio/metabolismo , Fibrinólise , Finlândia , Seguimentos , Humanos , Masculino , Pessoa de Meia-Idade , Inibidor 1 de Ativador de Plasminogênio/sangue , Redução de PesoRESUMO
The aerobic and anaerobic thresholds determined from venous lactate (AerTLa and AnTLa) or from ventilation and gas exchange (AerTr and AnTr) in relation to muscle fiber composition were compared. Twelve subjects were studied in double exercise tests carried out until voluntary exhaustion. They were divided into two groups according to their muscle fiber type in the vastus lateralis muscle: ST group with a majority of slow-twitch fibers (ST% = 66.0% +/- 7.3%) and FT group with a majority of fast-twitch fibers (ST% = 27.7% +/- 8.4%). A 2-min incremental exercise test protocol on a bicycle was used. There were no significant differences between the ST and FT groups in the VO2max or in the Lamax. Neither the AerT nor the AnT related to the VO2max (%) differed between the ST and FT groups. In the FT group the AnTLa occurred 0.70 min in the first test and 1.06 min in the second test earlier than the AnTr, whereas in the ST group the AnTLa occurred at the same time or 0.44 min later, respectively, than the AnTr (P less than 0.05). Expressed as VO2 the differences between thresholds were not so distinct. The results demonstrated that the mutual relation between the AnTLa and AnTr seemed to be dependent on the fiber type majority in exercising muscles (vastus lateralis) among untrained men.
Assuntos
Lactatos/sangue , Músculos/metabolismo , Consumo de Oxigênio , Troca Gasosa Pulmonar , Adulto , Aerobiose , Anaerobiose , Metabolismo Energético , Teste de Esforço , Humanos , Masculino , Ventilação Voluntária Máxima , Pessoa de Meia-Idade , Esforço Físico , VeiasRESUMO
A new method of aerobic threshold (AerT) determination, as a minimum of so-called lactate equivalent (Berg et al. 1980; Lehmann et al. 1983), was compared with the generally used method (AerT1) presented first by Wasserman et al. (1973). The comparison was made with data from 32 subjects in repeated maximal exercise tests on a bicycle ergometer. The AerT as a minimum of lactate equivalent was determined using both a computerized method for curve fitting (AerT3) and visual inspection (AerT2). AerT2 and AerT3 showed similarity: the regression coefficient was 0.88 and 0.95 and the correlation coefficient was 0.84 and 0.88 in the first and in the second tests, respectively. AerT1 and AerT2 showed similar mean estimated values, but AerT3 showed slightly higher mean values than AerT1 (p less than 0.05 and p less than 0.01) or AerT2 (p less than 0.01). The regression coefficients between AerT1 and AerT2 or AerT3 (0.60-0.71) showed different slopes from the identity (p less than 0.001). The corresponding correlation coefficients were 0.88 and 0.89 with AerT2, and 0.75 and 0.79 with AerT3 respectively in the first and second tests. However, in two thirds of all determinations the difference between these two estimation methods (AerT1 and AerT2) was less than or equal to 0.10 l O2.min-1. In conclusion, AerT as a minimum of lactate equivalent differed slightly from AerT determined using the traditional method. However, its determination criterion is unambiguous and allows objective computerized curve fitting. The physiological correlates of this new AerT index should be studied carefully before final evaluation of its usefulness in applications can be made.
Assuntos
Fisiologia/métodos , Adulto , Aerobiose , Limiar Diferencial , Metabolismo Energético , Humanos , Lactatos/sangue , Ácido Láctico , Masculino , Pessoa de Meia-Idade , Consumo de OxigênioRESUMO
The aim of this study was to compare the 'anaerobic threshold' (AnT) of subjects determined during a continuous 2-min incremental exercise test until exhaustion and the 'maximal lactate steady-state' (BLaSsmax) determined during prolonged exercise at constant loads corresponding to the subjects' AnT and/or 5-25% above and below it. Seventeen subjects performed an incremental exercise test and 1-5 prolonged exercise tests on a cycle ergometer until exhaustion at intervals of 1 week, and work rates, oxygen uptake (VO2) values and brachial venous blood lactate (BLa) levels were measured. It was proposed that when exercising at a constant workload below AnT, BLa would fall after having reached its peak; at the level of AnT, BLa reaches maximal steady-state (BLaSsmax); and above AnT, BLa increases continuously. Altogether, in 34 of 45 tests with a constant workload between 80 and 125% AnT, BLa values were as expected. In those cases in which BLaSsmax was reached, BLa increased on average by 3.8 mM from resting levels. This increase was 2.0 mM greater than that seen between resting levels and AnT during incremental exercise. There was no correlation between BLa values at BLaSsmax and at AnT, both when expressed as an increase in BLa (delta BLa) and absolute BLa concentration. Altogether, 81% of the variation in BLa concentration at BLaSsmax could be explained by the subjects' age, the percentage of slow-twitch fibres and BLa levels at rest. The AnT and BLaSsmax did not differ significantly, and these values were correlated (r = 0.83). Together, AnT and age accounted for 85% of the variation seen in BLaSsmax. The BLaSsmax did not correlate with AnT when fixed at a BLa concentration of 4 mM (AnT4mM). The three hypotheses tested in this study were confirmed, and the present results demonstrate that AnT correlates with BLaSsmax. The few exceptions to anticipated BLa kinetics were small in magnitude and could be explained by physiological variations.
Assuntos
Limiar Anaeróbio , Exercício Físico/fisiologia , Lactatos/sangue , Músculos/metabolismo , Adenosina Trifosfatases/análise , Adulto , Teste de Esforço , Frequência Cardíaca , Humanos , Ácido Láctico , Masculino , Pessoa de Meia-Idade , NADH Desidrogenase/análise , Consumo de OxigênioRESUMO
The reproducibility of the aerobic (AerT) and the anaerobic (AnT) threshold was studied in 33 men aged 20-50 years. They completed two maximal exercise tests on a bicycle ergometer. The thresholds, as VO2 (1 X min-1), were determined visually by two investigators using both the blood lactate and the respiratory indices. The respiratory variables were measured with a computerized breath-by-breath method; samples of venous blood were drawn every 2nd min and analysed enzymatically for lactate. The reproducibility of the AerT (r = 0.94) and of the AnT (r = 0.96) were equally good. The AnT can be determined either from blood lactate concentrations (AnTLa) or from ventilatory and gas exchange response (AnTr) during a 2-min incremental exercise test. They both also showed similar reproducibility: r = 0.93 for the AnTLa and r = 0.95 for the AnTr. The work rate and the measured physiological variables at the AerT and AnT, except for the blood lactacte concentration, were very reproducible. Age did not affect the reproducibility of the thresholds. The poor reproducibility of blood lactate concentration of the AnT confirmed our previous opinion that the fixed blood lactate levels of 2 and 4 mmol X 1(-1) are poor indicators of AerT and AnT.
Assuntos
Aerobiose , Anaerobiose , Metabolismo , Adulto , Envelhecimento , Limiar Diferencial , Frequência Cardíaca , Humanos , Lactatos/sangue , Masculino , Pessoa de Meia-Idade , Consumo de Oxigênio , Esforço Físico , Respiração , DescansoRESUMO
This study investigated whether the anaerobic threshold (AnT) could be used to predict prolonged work capacity measured as cycling time to exhaustion (= endurance time) and which factors, in addition to relative exercise intensity, could explain variation in endurance time. Theoretical exercise intensities corresponding to certain endurance times were also calculated. The hyperbolic and exponential functions between cycling time and relative work rate (WR[%]), as well as between cycling time and relative oxygen uptake (VO2[%]) were fitted to the pooled data (n = 45) of 17 subjects. The WR(%) and VO2(%) were expressed as a percentage of the subject's own AnT- and maximum-values. At WR corresponding to AnT (i.e., 70% of WRmax) an average subject could cycle 60 min according to both AnT- or maximum-related exponential function. When prediction was done for an endurance time of 4 h, the AnT-related exponential function gave 2.9%-units (= 11 W or approximately 0.15 O2 l.min-1) lower intensity level (51% of WRmax) than the maximum-related function (54% of WRmax). The WR(%) alone explained 54% and 70% of the variation in endurance time of the AnT-related and maximum-related exponential functions, respectively. Muscle fibre composition and initial blood lactate or relative muscle glycogen depletion (change in muscle glycogen as percentage) increased significantly the explanatory power of these models. The differences between the observed and expected exercise times correlated with blood lactate accumulation (r = -0.42; p less than 0.01), muscle fibre composition (r = 0.33; p less than 0.05) and relative muscle glycogen depletion (r = 0.67; p less than 0.01). It was concluded that the capacity for prolonged work measured as cycling time to exhaustion can be estimated by AnT-related power output, and that the exponential function model is the most suitable. Prediction power of the model can be improved by multiple regressions including muscle fibre composition, initial blood lactate level and relative muscle glycogen depletion.