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1.
Int J Sports Med ; 41(1): 36-43, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31747699

RESUMO

Subconcussive head impacts (SHI), defined as impacts to the cranium that do not result in concussion symptoms, are gaining traction as a major public health concern. The contribution of physiological factors such as physical exertion and muscle damage to SHI-dependent changes in neurological measures remains unknown. A prospective longitudinal study examined the association between physiological factors and SHI kinematics in 15 high school American football players over one season. Players wore a sensor-installed mouthguard for all practices and games, recording frequency and magnitude of all head impacts. Serum samples were collected at 12 time points (pre-season, pre- and post-game for five in-season games, and post-season) and were assessed for an isoenzyme of creatine kinase (CK-MM) primarily found in skeletal muscle. Physical exertion was estimated in the form of excess post-exercise oxygen consumption (EPOC) from heart rate data captured during the five games. Mixed-effect regression models indicated that head impact kinematics were significantly and positively associated with change in CK-MM but not EPOC. There was a significant and positive association between CK-MM and EPOC. These data suggest that when examining SHI, effects of skeletal muscle damage should be considered when using outcome measures that may have an interaction with muscle damage.


Assuntos
Futebol Americano/lesões , Cabeça/fisiopatologia , Músculo Esquelético/lesões , Esforço Físico/fisiologia , Adolescente , Fenômenos Biomecânicos , Concussão Encefálica/fisiopatologia , Creatina Quinase Forma MM/sangue , Futebol Americano/fisiologia , Humanos , Estudos Longitudinais , Masculino , Músculo Esquelético/enzimologia , Consumo de Oxigênio/fisiologia , Estudos Prospectivos , Estados Unidos
2.
J Sports Sci ; 38(1): 114-120, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31665975

RESUMO

Sedentary time (ST) has been inconsistently associated with adiposity and cardiorespiratory fitness in children in previous studies. We studied cross-sectional associations of ST, light physical activity (LPA), and moderate-to-vigorous physical activity (MVPA) with fat mass index (FMI) and cardiorespiratory fitness (estimated VO2max). Associations were evaluated with and without considering pattern of ST by bout length. We measured ST and activity by a wrist-worn accelerometer, FMI by bioelectrical impedance, and VO2max by Pacer test in 443 children (51.2% girls, 10.2 ± 0.6 years). Isotemporal substitution regression models estimated the effects of substituting ST, LPA, and MVPA on FMI and VO2max. Further models repeated analyses separating ST into short (<10 min) and long (≥10 min) bouts. Only replacing ST or LPA with MVPA was consistently associated with lower FMI and greater VO2max. When separated by bout length, only one unique association was found where replacing long ST bouts with short ST bouts was associated with lower FMI in girls only. In conclusion, activity pattern is associated with adiposity in girls and fitness in boys and girls. Separating ST into long and short ST bouts may be of minimal importance when assessing associations with adiposity and fitness using wrist-worn accelerometry in children.


Assuntos
Acelerometria/instrumentação , Adiposidade/fisiologia , Aptidão Cardiorrespiratória , Exercício/fisiologia , Monitores de Aptidão Física , Comportamento Sedentário , Índice de Massa Corporal , Criança , Estudos Transversais , Feminino , Humanos , Masculino , Consumo de Oxigênio/fisiologia , Fatores de Tempo
3.
Sports Health ; 12(1): 80-87, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-31710819

RESUMO

BACKGROUND: The prevalence of musculoskeletal (MSK) conditions is increasing, and although current guidelines for physical activity attempt to combat this, many fail to achieve the recommended targets. The present study sought to investigate whether regular tennis participation is more effective at enhancing MSK function than meeting the current international physical activity guidelines. HYPOTHESIS: Tennis players will display significantly enhanced MSK function when compared with age-matched healthy active nonplayers. STUDY DESIGN: Cross-sectional study. LEVEL OF EVIDENCE: Level 3. METHODS: Ninety participants (age range, 18-65 years) took part in this study; there were 43 tennis players (18 men, 25 women) and 47 nonplayers (26 men, 21 women). MSK function was assessed by cluster analysis of 3 factors: (1) electromyographic fatigability of prime movers during handgrip, knee extension, and knee flexion; (2) isometric strength in the aforementioned movements; and (3) body composition measured by bioelectrical impedance analysis. Maximal oxygen uptake was also assessed to characterize cardiorespiratory fitness. RESULTS: Tennis players displayed significantly greater upper body MSK function than nonplayers when cluster scores of body fat percentage, handgrip strength, and flexor carpi radialis fatigue were compared by analysis of covariance, using age as a covariate (tennis players, 0.33 ± 1.93 vs nonplayers, -0.26 ± 1.66; P < 0.05). Similarly, tennis players also demonstrated greater lower extremity function in a cluster of body fat percentage, knee extension strength, and rectus femoris fatigue (tennis players, 0.17 ± 1.76 vs nonplayers, -0.16 ± 1.70; P < 0.05). CONCLUSION: The present study offers support for improved MSK functionality in tennis players when compared with age-matched healthy active nonplayers. This may be due to the hybrid high-intensity interval training nature of tennis. CLINICAL RELEVANCE: The findings suggest tennis is an excellent activity mode to promote MSK health and should therefore be more frequently recommended as a viable alternative to existing physical activity guidelines.


Assuntos
Músculo Esquelético/fisiologia , Tênis/fisiologia , Adolescente , Adulto , Idoso , Composição Corporal , Aptidão Cardiorrespiratória/fisiologia , Análise por Conglomerados , Estudos Transversais , Feminino , Força da Mão , Humanos , Joelho/fisiologia , Masculino , Pessoa de Meia-Idade , Fadiga Muscular/fisiologia , Força Muscular/fisiologia , Consumo de Oxigênio/fisiologia , Adulto Jovem
4.
Chemosphere ; 240: 124974, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31726613

RESUMO

In this research, the continuous physiological changes of zebrafish (Danio rerio) in 0.1 µg/L thallium (Tl) in 15 days were investigated. The results showed that Tl(I) stress had a significant positive linear correlation with zebrafish ammonia nitrogen excretion (ANE) (p < 0.001), and the mean value of ANE in Tl(I) treatment (435 ±â€¯227 mg/kg/h) was approximately 2 times higher than in the control group (239 ±â€¯168 mg/kg/h), which suggested that ANE was suitable for Tl(I) stress assessment. A substantial difference based on oxygen consumption rate (OCR) between the control group (587 ±â€¯112 mg/kg/h) and Tl(I) treatment (260 ±â€¯88 mg/kg/h) with a high significance p < 0.001 could be observed, and the results indicated that Tl(I) played a negative role in OCR of zebrafish. The characteristics of both ANE and OCR changes under slight Tl(I) stress could be reflected by the ammonia quotient (AQ). It was noteworthy that AQ increased rapidly in first 6 h from 0.66 to 4.50, which was 3 times higher than 1.2, indicating rapid increase in both anaerobic energy utilization and protein metabolism in 0.1 µg/L Tl(I) exposure. It is concluded that the physiological changes of zebrafish based on metabolism can be regarded as a sensitive biological indicator of Tl(I) pollution, which could work as a substitute of potassium that disrupts the normal biological metabolism in the process of transport.


Assuntos
Tálio/toxicidade , Peixe-Zebra/metabolismo , Amônia/metabolismo , Animais , Cinética , Nitrogênio/metabolismo , Consumo de Oxigênio/fisiologia , Fatores de Tempo , Peixe-Zebra/fisiologia
5.
J Sports Med Phys Fitness ; 59(10): 1601-1607, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31694361

RESUMO

BACKGROUND: Outdoor exercise often proceeds in rainy conditions. However, there are very few studies reporting the physiological effects of cold with rain or wet-cold exposure on humans during exercise. The purpose of this study was to investigate the effects of rain on physiological responses during running exercise at 80% V̇Omax in the cold. METHODS: Twelve healthy men (age: 21.7±3.3 years; height: 1.760±0.085 m; body weight: 68.8±7.1 kg; maximal oxygen consumption: 67.3±5.00 mL/kg/min) exercised on a treadmill at 80% V̇Omax intensity for 60 minutes with rain (RAIN) or not (CON) at 5 °C. RESULTS: Rectal temperature was significantly lower in RAIN than in CON at 10, 40, 50, and 60 minutes (P<0.05). Mean weighted skin temperature was significantly lower in RAIN than in CON during exercise (P<0.05). Oxygen consumption and rating of perceived exertion were significantly higher in RAIN than in CON at 50 and 60 minutes (P<0.05). Plasma lactate was significantly higher in RAIN than in CON at 10 minutes and from 40 to 60 minutes (P<0.05). Plasma norepinephrine levels were significantly higher in RAIN than in CON at 10 minutes and from 40 to 60 minutes (P<0.05). CONCLUSIONS: These results suggest that rain increased heat loss during the early phase of exercise in the cold, then heat production increased and transiently suppressed cold stress. However, with time, body heat loss intensified due to increasing wet area, and then energy expenditure and plasma lactate increased due to cold stress. Therefore, rain may decrease exercise performance and affect sport safety.


Assuntos
Temperatura Baixa/efeitos adversos , Metabolismo Energético/fisiologia , Chuva , Corrida/fisiologia , Adolescente , Adulto , Regulação da Temperatura Corporal/fisiologia , Estudos de Casos e Controles , Teste de Esforço/métodos , Humanos , Ácido Láctico/sangue , Masculino , Consumo de Oxigênio/fisiologia , Temperatura Cutânea , Adulto Jovem
6.
Int Heart J ; 60(6): 1366-1372, 2019 Nov 30.
Artigo em Inglês | MEDLINE | ID: mdl-31735775

RESUMO

The Kihon Checklist (KCL) is a reliable tool for determining frailty status in the elderly. However, there is no information in the literature about the relationship between frailty status and exercise capacity. Here, we examined the associations between cardiopulmonary exercise testing parameters and frailty status in elderly patients with stable heart failure (HF).Ninety-two elderly patients with stable HF were evaluated using cardiopulmonary exercise testing and the KCL. A KCL score of 0-3 was classified as robust, 4-7 as pre-frail, and ≥ 8 as frail.Mean age, peak VO2, and KCL score were 81.7 years, 13.2 mL/kg/minute, and 10.7, respectively. KCL score was significantly correlated with peak VO2 (r = -0.527, P < 0.001) and peak work rate (r = -0.632, P < 0.001). In patients with frailty (n = 63), the peak work rate (WR) was significantly lower than it was in patients without frailty (n = 29; 39.9 versus 69.5 W, respectively; P < 0.001). Multivariate analysis revealed that peak WR and peak systolic blood pressure were significant, independent predictors of frailty (ß = -0.108 and -0.045, respectively). In a diagnostic performance plot analysis, a cutoff value for peak WR of 51.9 W was the best predictor of frailty.Frailty status was significantly associated with peak WR and peak systolic blood pressure in elderly patients with stable HF. Therefore, cardiopulmonary exercise testing may be useful for assessing frailty status in this patient population.


Assuntos
Tolerância ao Exercício/fisiologia , Exercício/fisiologia , Fragilidade/diagnóstico , Fragilidade/fisiopatologia , Insuficiência Cardíaca/fisiopatologia , Idoso , Idoso de 80 Anos ou mais , Pressão Sanguínea/fisiologia , Lista de Checagem , Teste de Esforço , Feminino , Fragilidade/complicações , Insuficiência Cardíaca/complicações , Humanos , Masculino , Consumo de Oxigênio/fisiologia , Valor Preditivo dos Testes
7.
Invest Ophthalmol Vis Sci ; 60(14): 4924-4930, 2019 11 01.
Artigo em Inglês | MEDLINE | ID: mdl-31770432

RESUMO

Purpose: In the dark, photoreceptor outer segments contain high levels of cyclic guanosine 3'-5' monophosphate (cGMP), which binds to ion channels, holding them open and allowing an influx of cations. Ion pumping activity, which balances cation influx, uses considerable amounts of adenosine triphosphate (ATP) and oxygen. Light reduces cation influx and thereby lowers metabolic demand. Blood vessels are compromised in the diabetic retina and may not be able to meet the higher metabolic demand in darkness. Emixustat is a visual cycle modulator (VCM) that reduces chromophore levels and, therefore, may mimic light conditions. We evaluated the effect of emixustat on oxygen consumption and cation influx in dark conditions. Methods: Cation influx was measured in rats using Mn2+-magnetic resonance imaging (MEMRI). Retinal oxygen profiles were recorded to evaluate oxygen consumption. In the MEMRI protocol, animals were treated with either emixustat or vehicle. In the oxygen protocol, animals were untreated or treated with emixustat. Results: In vehicle-treated animals, cation channel activity increased in the dark. Emixustat treatment reduced cation channel activity; activity was comparable to vehicle-treated controls in light conditions. In vehicle-treated animals, minimum retinal oxygen tension decreased as the retina recovered from a photobleach, indicating that more oxygen was being consumed. Emixustat treatment prevented the decrease in oxygen pressure after photobleach. Conclusions: Emixustat reduced the cation influx and retinal oxygen consumption associated with dark conditions. VCMs are a promising potential treatment for ischemic retinal neovascularization, such as that in diabetic retinopathy.


Assuntos
Adaptação à Escuridão/fisiologia , Manganês/metabolismo , Consumo de Oxigênio/fisiologia , Éteres Fenílicos/farmacologia , Propanolaminas/farmacologia , Retina/efeitos dos fármacos , Animais , Imagem por Ressonância Magnética , Masculino , Ratos , Ratos Endogâmicos BN , Ratos Long-Evans , Retina/metabolismo , cis-trans-Isomerases/antagonistas & inibidores
8.
Int J Sports Med ; 40(14): 886-896, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31648353

RESUMO

Exercise physiological responses can be markedly affected by acute hypoxia. We investigated cardiac autonomic and physiological responses to different hypoxic training protocols. Thirteen men performed three exercise sessions (5×5-min; 1-min passive recovery): normoxic exercise at 80% of the power output (PO) at the first ventilatory threshold (N), hypoxic exercise (FiO2=14.2%) with the same PO as N (HPO) and hypoxic exercise at the same heart rate (HR) as N (HHR). PO was lower in HHR (21.1±9.3%) compared to N and HPO. Mean HR was higher in HPO (154±11 bpm, p<0.01) than N and HHR (139±10 vs. 138±9 bpm; p=0.80). SpO2 was reduced (p<0.01) to a similar extent (p>0.05) in HPO and HHR compared to N. HR recovery (HRR) and HR variability indices were similar in N and HHR (p>0.05) but reduced in HPO (p<0.05), mirroring a delayed parasympathetic reactivation. Blood lactate and ventilation were similar in N and HHR (p>0.05) and increased in HPO (p<0.001). During recovery oxygen consumption and ventilation were similar in N and HHR (p>0.05) and increased in HPO (p<0.01). Moderate HR-matched hypoxic exercise triggers similar cardiac autonomic and physiological responses to normoxic exercise with a reduced mechanical load. On the contrary, the same absolute intensity exercise in hypoxia is associated with increased exercise-induced metabolic stress and delayed cardiac autonomic recovery.


Assuntos
Sistema Nervoso Autônomo/fisiologia , Exercício/fisiologia , Coração/inervação , Hipóxia/fisiopatologia , Adulto , Frequência Cardíaca/fisiologia , Humanos , Ácido Láctico/sangue , Masculino , Consumo de Oxigênio/fisiologia , Percepção/fisiologia , Esforço Físico/fisiologia , Taxa Respiratória , Adulto Jovem
9.
Int J Sports Med ; 40(14): 879-885, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31574544

RESUMO

The potential anti-fatigue and performance benefits of hydrogen rich water (HRW) have resulted in increased research interest over the past 5 years. The aim of this study was to assess physiological and perceptual responses to an incremental exercise protocol after administration of 600 ml HRW within 30 min before exercise. This randomized, double blinded placebo-controlled cross over study included twelve healthy males aged 27.1±4.9 years. The exercise protocol consisted of a 10 min warm-up at 1.0 W.kg-1, followed by 8 min at 2.0, 3.0, and 4.0 W.kg-1, respectively. Cardio-respiratory variables, lactate and ratings of perceived exertion (RPE) were assessed in the last minute of each step. A significantly lower blood lactate was found with HRW (4.0±1.6 and 8.9±2.2 mmol.l-1) compared to Placebo (5.1±1.9 and 10.6±3.0 mmol.l-1) at 3.0, and 4.0 W.kg-1, respectively. Ventilatory equivalent for oxygen and RPE exhibited significantly lower values with HRW (32.3±7.2, and 17.8±1.2 points, respectively) compared to Placebo (35.0±8.4, and 18.5±0.8 points, respectively) at 4 W.kg-1. To conclude, acute pre-exercise supplementation with HRW reduced blood lactate at higher exercise intensities, improved exercise-induced perception of effort, and ventilatory efficiency.


Assuntos
Ingestão de Líquidos , Exercício/fisiologia , Hidrogênio , Ácido Láctico/sangue , Percepção/fisiologia , Esforço Físico/fisiologia , Respiração , Água/química , Adulto , Método Duplo-Cego , Exercício/psicologia , Frequência Cardíaca/fisiologia , Humanos , Masculino , Fadiga Muscular/fisiologia , Consumo de Oxigênio/fisiologia , Adulto Jovem
10.
Braz J Med Biol Res ; 52(9): e8402, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31482976

RESUMO

Cardiopulmonary fitness assessment is a valuable resource to obtain quantitative indicators of an individual's physical performance. The cardiopulmonary exercise test (CPX), considered the gold standard test for this evaluation, is costly and difficult to be accessed by the general population. In order to make this evaluation more accessible, and to better reflect the performance of daily life activities, alternative tests were proposed. Morbidly obese patients present limitations that impair physical performance assessment and could benefit from a test of shorter duration, provided it is validated. This observational study aimed to validate the two-minute step test (2MST) as a tool to evaluate functional capacity (FC) in obese with comorbidities and morbidly obese patients, compared the 2MST with CPX as a measure of physical performance, and developed a predictive equation to estimate peak oxygen uptake (VO2) in the 2MST. The CPX and the 2MST were performed and metabolic and ventilatory parameters were recorded in 31 obese individuals (BMI>35 kg/m2). Pearson correlation and multiple linear regression analyses were performed to evaluate the peak VO2 best predictors. Bland-Altman analysis was performed to assess the agreement between the two methods. Peak VO2 measured by CPX and 2MST showed a strong correlation (r=0.70, P<0.001) and there was a moderate correlation between peak VO2 of the 2MST and the number of up-and-down step cycles (UDS) (r=0.55; P=0.01). The reference equation obtained was: VO2 (mL·kg-1·min-1) = 13.341 + 0.138 × total UDS - (0.183 × BMI), with an estimated standard error of 1.3 mL·kg-1·min-1. The 2MST is a viable, practical, and easily accessible test for FC. UDS and BMI can predict peak VO2 satisfactorily.


Assuntos
Aptidão Cardiorrespiratória/fisiologia , Tolerância ao Exercício/fisiologia , Frequência Cardíaca/fisiologia , Obesidade/fisiopatologia , Consumo de Oxigênio/fisiologia , Teste de Caminhada/métodos , Adolescente , Adulto , Comorbidade , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Obesidade Mórbida/fisiopatologia , Fatores de Tempo , Adulto Jovem
11.
Invest Ophthalmol Vis Sci ; 60(12): 3762-3767, 2019 09 03.
Artigo em Inglês | MEDLINE | ID: mdl-31499531

RESUMO

Purpose: Diabetic retinopathy is characterized by disturbances in retinal blood flow mediated by capillary occlusion, intraretinal microvascular abnormalities (IRMAs), neovascularizations, and omega loops and reduplications. It is likely that the study of oxygen saturation in these abnormalities can provide knowledge about their role in the development of diabetic retinopathy. Methods: The oxygen saturation in IRMA vessels and venous loops and reduplications were studied in 40 diabetic patients with severe nonproliferative or proliferative diabetic retinopathy. The saturation values in the studied vascular abnormalities were compared to those of the larger retinal arterioles and venules. Results: There was a similar oxygen saturation (mean ± SD) in IRMAs observed to connect arterioles with venules (78.6% ± 11.8%, n = 22) and IRMAs connecting venules with venules (79.2% ± 9.0%, n = 12; P > 0.999). The saturation in IRMAs was significantly lower (P < 0.0002) than in arterioles (97.4% ± 5.2%, n = 40) and significantly higher (P < 0.0001) than the saturation in omega loops and reduplications (54.2% ± 19.3%, n = 6), which in turn showed no significant difference from the saturation in the venules (61.8% ± 6.8%, n = 40, P = 0.4). Conclusions: The findings suggest that the oxygen saturation in vascular abnormalities in diabetic retinopathy depends on the extent of arteriovenous (A-V) shunting, with venous saturation due to no A-V shunting in venous loops and reduplications, and intermediate oxygen saturation due to moderate shunting in IRMAs. This may precede the development of neovascularizations with arterial oxygen saturation due to high A-V shunting.


Assuntos
Malformações Arteriovenosas/fisiopatologia , Retinopatia Diabética/fisiopatologia , Oxigênio/sangue , Vasos Retinianos/anormalidades , Adulto , Diabetes Mellitus Tipo 1/fisiopatologia , Feminino , Humanos , Masculino , Microcirculação , Pessoa de Meia-Idade , Oximetria , Consumo de Oxigênio/fisiologia , Fluxo Sanguíneo Regional/fisiologia , Artéria Retiniana/anormalidades , Artéria Retiniana/fisiologia , Veia Retiniana/anormalidades , Veia Retiniana/fisiologia , Vasos Retinianos/fisiopatologia , Acuidade Visual/fisiologia
12.
Medicine (Baltimore) ; 98(36): e16860, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31490370

RESUMO

BACKGROUND: The blood glucose response to moderate-intensity exercise remains unclear for patients with type 2 diabetes (T2DM). In addition, little is known about determinants of blood glucose response to a 12-week moderate-intensity exercise training. Therefore, this study aimed to explore trends in blood glucose in response to a 12-week moderate-intensity exercise training in patients with T2DM and to explore the predictors of post-exercise blood glucose (PEBG) and exercise-induced glucose response (EIGR). METHODS: A prospective longitudinal study was conducted. Of the 66 participants with T2DM recruited from outpatient clinics of a medical center, 20 were eligible to enroll in a 12-week moderate-intensity exercise training. Participants were randomly assigned to 1 of 3 exercise times (morning, afternoon, or evening). Blood glucose were measured pre- and post-exercise. The EIGR was calculated by subtracting the PEBG from the before-exercise blood glucose (BEBG). Generalized estimating equations were used to examine the trends and predictors of PEBG and EIGR. RESULTS: The BEBG declined progressively (ß = -1.69, P < .001); while the PEBG (ß = -0.18, P = .08) remained stable over time during the 12-week exercise training. Higher BEBG predicted higher (ß = 0.53, P < .001) PEBG. Higher baseline maximum oxygen uptake (VO2max) contributed to a larger magnitude of EIGR; higher HgbA1c and BEBG predicted higher EIGR (ß = 0.27, P = .02; ß = 0.45, P < .001); afternoon or evening exercise predicted lower (ß = -13.2, P = .04; ß = -5.96, P = .005) EIGR than did morning exercise. CONCLUSIONS: A 12-week moderate-intensity exercise training appears safe for patients with T2DM. Time of day for exercise, baseline VO2max, and baseline metabolic control may influence the impact of exercise for individuals with T2DM. These findings provide considerations for design of optimal exercise training for T2DM patients.


Assuntos
Glicemia/metabolismo , Diabetes Mellitus Tipo 2/fisiopatologia , Diabetes Mellitus Tipo 2/terapia , Exercício/fisiologia , Adulto , Índice de Massa Corporal , Feminino , Humanos , Estudos Longitudinais , Masculino , Pessoa de Meia-Idade , Consumo de Oxigênio/fisiologia , Estudos Prospectivos
13.
Tuberk Toraks ; 67(2): 83-91, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-31414638

RESUMO

Introduction: The goals of chronic obstructive pulmonary disease (COPD) treatment are to relieve dyspnea, increase exercise capacity, and improve quality of life. The relation of exercise capacity, dyspnea level, and quality of life with long-term mortality is unclear. Aim of the study was to assess the effect of exercise capacity, dyspnea level and quality of life on long-term mortality risk in patients with COPD. Materials and Methods: Dyspnea level was assessed using the modified Medical Research Council (mMRC), Borg and Baseline Dyspnea Index (BDI) and Body Obstruction Dyspnea Exercise (BODE), health-related quality of life with St. George's Respiratory Questionnaire, and exercise capacity with the 6-minute walking test (6MWT) and cardiopulmonary exercise test. At the end of 8-year follow-up period, the relation between these tests and mortality was examined. Result: A total of 42 patients with stable COPD were included in the study. Sixteen patients died during the approximately 8-year follow-up period. Univariate analysis revealed that VO2 peak [HR: 1.845; CI: (1.336-2.55); p<0.001], BODE index [HR: 0.787; CI: (0.703-0.880); p<0.001], and SGRQ [HR: 1.073; CI: (1.028-1.119); p= 0.001] were significantly correlated to mortality risk. Multivariate Cox regression analysis revealed VO2 peak [HR: 1.031; CI: (0.683-1.120); p= 0.01] as the single significant predictor of mortality. VO2 peak less than 22.5 had a sensitivity of 82%, specificity of 80%, and area under the curve of 0.142 [95% CI: (0.027-0.257); p< 0.001] for mortality risk with ROC analysis. Conclusions: Cardiopulmonary disturbances during maximal exercise may be an important indicator of mortality risk.


Assuntos
Dispneia/fisiopatologia , Tolerância ao Exercício/fisiologia , Doença Pulmonar Obstrutiva Crônica/mortalidade , Qualidade de Vida , Idoso , Análise de Variância , Exercício , Teste de Esforço , Feminino , Seguimentos , Humanos , Estimativa de Kaplan-Meier , Masculino , Pessoa de Meia-Idade , Consumo de Oxigênio/fisiologia , Modelos de Riscos Proporcionais , Estudos Prospectivos , Doença Pulmonar Obstrutiva Crônica/terapia , Curva ROC , Sensibilidade e Especificidade , Inquéritos e Questionários
14.
Med Sci Sports Exerc ; 51(9): 1876-1883, 2019 09.
Artigo em Inglês | MEDLINE | ID: mdl-31415443

RESUMO

PURPOSE: Continuous and interval are the two types of aerobic exercise training commonly used for health promotion. We sought to determine which aerobic exercise training program results in larger health improvements in metabolic syndrome (MetS) individuals. METHODS: One hundred twenty-one MetS patients (age, 57 ± 8 yr; weight, 92 ± 15 kg; and MetS factors, 3.8 ± 0.8 components) with low initial cardiorespiratory fitness (CRF) (V˙O2peak, 24.0 ± 5.5 mL·kg·min) were randomized to undergo one of the following 16-wk exercise program: (a) 4 × 4-min high-intensity interval training at 90% of HRMAX (4HIIT group; n = 32), (b) 50-min moderate-intensity continuous training at 70% of HRMAX (MICT group; n = 35), (c) 10 × 1-min HIIT at 100% of HRMAX (1HIIT group; n = 32), or (d) no exercise control group (CONT; n = 22). We measured the evolution of all five MetS components (i.e., MetS Z Score) and CRF (assessed by V˙O2peak) before and after intervention. RESULTS: MetS Z score decreased 41% after 4HIIT (95% confidence interval [CI], 0.25-0.06; P < 0.01) and 52% in MICT (95% CI, 0.24-0.06; P < 0.01), whereas it did not change in 1HIIT (decreased 24%; 95% CI, -0.16 to 0.03; P = 0.21) and CONT (increased 20%; 95% CI, -0.19 to 0.04; P = 0.22). However, the three exercise groups improved similarly their V˙O2peak (4HIIT, 11%; 95% CI, 0.14-0.33; MICT, 12%; 95% CI, 0.18-0.36; and 1HIIT, 14%; 95% CI, 0.21-0.40 L·min; all P < 0.001). CONCLUSIONS: Our findings suggest that in sedentary individuals with MetS and low initial CRF level any aerobic training program of 16 wk with a frequency of three times per week is sufficient stimulus to raise CRF. However, the more intense but shorter 1HIIT training program is not effective on improving MetS Z score, and thus we caution its recommendation for health promotion purposes in this population.


Assuntos
Aptidão Cardiorrespiratória/fisiologia , Terapia por Exercício/métodos , Síndrome Metabólica/fisiopatologia , Síndrome Metabólica/terapia , Idoso , Peso Corporal/fisiologia , Metabolismo Energético/fisiologia , Feminino , Treinamento Intervalado de Alta Intensidade , Humanos , Masculino , Pessoa de Meia-Idade , Consumo de Oxigênio/fisiologia , Comportamento Sedentário
15.
Braz J Med Biol Res ; 52(9): e8392, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31411315

RESUMO

The term inflammaging is now widely used to designate the inflammatory process of natural aging. During this process, cytokine balance is altered, presumably due to the loss of homeostasis, thus contributing to a greater predisposition to disease and exacerbation of chronic diseases. The aim of the study was to analyze the relationship between pro-inflammatory markers and age in the natural aging process of healthy individuals. One hundred and ten subjects were divided into 5 groups according to age (22 subjects/group). Interleukin-6 (IL-6) and tumor necrosis factor α (TNF-α) were quantified using the ELISA method. High-sensitivity C-reactive protein (hsCRP) was analyzed by turbidimetry according to laboratory procedures. The main findings of this study were: a positive correlation between hsCRP and IL-6 as a function of age (110 subjects); women showed stronger correlations; the 51-60 age group had the highest values for hsCRP and IL-6; women presented higher values for hsCRP in the 51-60 age group and higher values for IL-6 in the 61-70 age group; and men showed higher values in the 51-60 age group for hsCRP and IL-6. In conclusion, the natural aging process increased IL-6 and hsCRP levels, which is consistent with the inflammaging theory; however, women presented stronger correlations compared to men (IL-6 and hsCRP) and the 51-60 age range seems to be a key point for these increases. These findings are important because they indicate that early preventive measures may minimize the increase in these inflammatory markers in natural human aging.


Assuntos
Envelhecimento/fisiologia , Imunossenescência/fisiologia , Inflamação/sangue , Adulto , Fatores Etários , Idoso , Biomarcadores/análise , Proteína C-Reativa/análise , Colesterol/sangue , Feminino , Humanos , Interleucina-6/sangue , Masculino , Pessoa de Meia-Idade , Consumo de Oxigênio/fisiologia , Fatores Sexuais , Triglicerídeos/sangue , Fator de Necrose Tumoral alfa/sangue , Adulto Jovem
16.
Eur J Appl Physiol ; 119(9): 2083-2094, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31372804

RESUMO

PURPOSE: The mediators of the perception of effort during exercise are still unclear. The aim of the present study was to examine physiological responses during runs using a rating of perceived exertion (RPE)-clamp model at the RPE corresponding to the gas exchange threshold (RPEGET) and 15% above GET (RPEGET+15%) to identify potential mediators and performance applications for RPE during treadmill running. METHODS: Twenty-one runners ([Formula: see text]max = 51.7 ± 8.3 ml kg-1 min-1) performed a graded exercise test to determine maximal oxygen consumption and the RPE associated with GET and GET + 15% followed by randomized 60 min RPE-clamp runs at RPEGET and RPEGET+15%. Mean differences for [Formula: see text], heart rate (HR), minute ventilation ([Formula: see text]), respiratory frequency ([Formula: see text], respiratory exchange ratio (RER), and velocity were compared across each run. RESULTS: After minute 14, [Formula: see text], RER and velocity did not differ across conditions, but decreased across time (p < 0.05). There was a significant (p < 0.05) condition × time interaction for [Formula: see text], where values were significantly higher during RPE-clamp runs at RPEGET+15% and decreased across time in both conditions. There were no differences across condition or time for HR, and only small difference between conditions for [Formula: see text]. CONCLUSIONS: HR and [Formula: see text] may play a role in mediating the perception of effort, while [Formula: see text], RER, and [Formula: see text] may not. Although HR and [Formula: see text] may mediate the maintenance of a perceptual intensity, they may not be sensitive to differentiate perceptual intensities at GET and GET + 15%. Thus, prescribing exercise using an RPE-clamp model may only reflect a sustainable [Formula: see text] within the moderate intensity domain.


Assuntos
Exercício/fisiologia , Esforço Físico/fisiologia , Corrida/fisiologia , Adulto , Teste de Esforço/métodos , Terapia por Exercício/métodos , Feminino , Frequência Cardíaca/fisiologia , Humanos , Masculino , Consumo de Oxigênio/fisiologia , Troca Gasosa Pulmonar/fisiologia , Taxa Respiratória/fisiologia , Ventilação/métodos , Adulto Jovem
17.
J Sports Sci ; 37(22): 2613-2624, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31423908

RESUMO

Foot orthoses and insoles are prescribed to runners, however their impact on running economy and performance is uncertain. The aim of this systematic review and meta-analysis was to determine the effect of foot orthoses and insoles on running economy and performance in distance runners. Seven electronic databases were searched from inception until June 2018. Eligible studies investigated the effect of foot orthoses or insoles on running economy (using indirect calorimetry) or running performance. Standardised mean differences (SMDs) were computed and meta-analyses were conducted using random effects models. Methodological quality was assessed using the Quality Index. Nine studies met the criteria and were included: five studies investigated the effect of foot orthoses on running economy and four investigated insoles. Foot orthoses were associated with small negative effects on running economy compared to no orthoses (SMD 0.42 [95% CI 0.17,0.72] p = 0.007). Shock absorbing insoles were also associated with negative effects on running economy, but an imprecise estimate (SMD 0.26 [95% CI -0.33,0.84] p = 0.83). Quality Index scores ranged from 4 to 15 out of 17. Foot orthoses and shock absorbing insoles may adversely affect running economy in distance runners. Future research should consider their potential effects on running performance.


Assuntos
Desempenho Atlético/fisiologia , Metabolismo Energético/fisiologia , Órtoses do Pé , Corrida/fisiologia , Fenômenos Biomecânicos , Calorimetria Indireta , Humanos , Consumo de Oxigênio/fisiologia
18.
Aerosp Med Hum Perform ; 90(9): 782-787, 2019 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-31426893

RESUMO

INTRODUCTION: Critical mission tasks for Martian exploration have been identified and include specific duties that astronauts will have to perform despite any adverse effects of chronic microgravity. Specifically, astronauts may have to perform an emergency capsule egress upon return to Earth, which places specific demands on compromised cardiovascular and neuromuscular systems. Therefore, the purpose of this project was to determine the relationship between cardiorespiratory fitness and simulated capsule egress time.METHODS: There were 15 subjects who volunteered for this study. Vo2peak and peak power output (PPO) were determined on cycle and rowing ergometers. Critical power (CP) was determined by a 3-min all-out rowing test. Subjects then performed an emergency capsule egress on a mock-up of NASA's Orion space capsule. Peak metabolic data were compared between the cycling and rowing tests. Pearson's correlation was used to identify relationships between egress time and Vo2peak, PPO, and CP.RESULTS: Vo2peak, Vco2peak, and minute ventilation were not different between cycling and rowing tests. Cycling elicited a greater PPO than the rowing test. Egress time was negatively correlated to rowing PPO (r = -0.60), but not cycling or rowing Vo2peak, cycling PPO, or CP.CONCLUSIONS: Rowing PPO/kg correlates with egress time. Although individuals with higher PPO/kg were able to finish the task in less time, individuals with low fitness levels (Vo2peak ≤ 20 ml · kg-1 · min-1) could complete the egress within 2 mins. These results suggest that cardiorespiratory fitness should not limit emergency egress and that this can be assessed using rowing exercise.Alexander AM, Sutterfield SL, Kriss KN, Hammer SM, Didier KD, Cauldwell JT, Dzewaltowski AC, Barstow TJ, Ade CJ. Prediction of emergency capsule egress performance. Aerosp Med Hum Perform. 2019; 90(9):782-787.


Assuntos
Astronautas , Aptidão Cardiorrespiratória/fisiologia , Emergências , Voo Espacial/instrumentação , Adulto , Teste de Esforço , Feminino , Humanos , Masculino , Marte , Pessoa de Meia-Idade , Consumo de Oxigênio/fisiologia , Fatores de Tempo
19.
J Sports Sci ; 37(23): 2653-2659, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31419921

RESUMO

This study assessed the intra-individual reliability of oxygen saturation in intercostal muscles (SmO2-m.intercostales) during an incremental maximal treadmill exercise by using portable NIRS devices in a test-retest study. Fifteen marathon runners (age, 24.9 ± 2.0 years; body mass index, 21.6 ± 2.3 kg·m-2; V̇O2-peak, 63.7 ± 5.9 mL·kg-1·min-1) were tested on two separate days, with a 7-day interval between the two measurements. Oxygen consumption (V̇O2) was assessed using the breath-by-breath method during the V̇O2-test, while SmO2 was determined using a portable commercial device, based in the near-infrared spectroscopy (NIRS) principle. The minute ventilation (VE), respiratory rate (RR), and tidal volume (Vt) were also monitored during the cardiopulmonary exercise test. For the SmO2-m.intercostales, the intraclass correlation coefficient (ICC) at rest, first (VT1) and second ventilatory (VT2) thresholds, and maximal stages were 0.90, 0.84, 0.92, and 0.93, respectively; the confidence intervals ranged from -10.8% - +9.5% to -15.3% - +12.5%. The reliability was good at low intensity (rest and VT1) and excellent at high intensity (VT2 and max). The Spearman correlation test revealed (p ≤ 0.001) an inverse association of SmO2-m.intercostales with V̇O2 (ρ = -0.64), VE (ρ = -0.73), RR (ρ = -0.70), and Vt (ρ = -0.63). The relationship with the ventilatory variables showed that increased breathing effort during exercise could be registered adequately using a NIRS portable device.


Assuntos
Exercício/fisiologia , Músculos Intercostais/fisiologia , Consumo de Oxigênio/fisiologia , Espectroscopia de Luz Próxima ao Infravermelho/instrumentação , Trabalho Respiratório/fisiologia , Adulto , Desempenho Atlético/fisiologia , Teste de Esforço/métodos , Humanos , Masculino , Reprodutibilidade dos Testes , Taxa Respiratória/fisiologia , Corrida/fisiologia , Volume de Ventilação Pulmonar/fisiologia , Adulto Jovem
20.
J Sports Med Phys Fitness ; 59(8): 1311-1318, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31373189

RESUMO

BACKGROUND: The purpose of this study was to examine the relationship between select physiological variables and sprint triathlon performance. METHODS: Moderately trained male triathletes (N.=15) performed two graded maximal exercise tests, on a cycle ergometer and a treadmill. Anaerobic capacity was evaluated, on a cycle ergometer and a treadmill. Within two weeks before or after the testing, all triathletes participated in a sprint triathlon race (750 m sea swim, 20 km cycle, 5 km run). RESULTS: The results showed that significant correlations exist between VO2max during cycling (r=-0.811, P<0.05) or running (r=-0.757, P<0.05) and overall triathlon performance. Stepwise multiple linear regression analysis, with triathlon performance as the dependent variable and the physiological measures during running as the independent variables, showed that VO2max (mL.min-1.kg-1), Time_CF, CHO_rate @ VT and % body fat yielded the best prediction of performance (R2=0,912). When only the physiological variables from cycling were included into the model, the results showed that VO2max (mL.min-1), VO2max (mL.min-1.kg-1) and PFmax (rpm) explained 88% of the variation in sprint triathlon performance. CONCLUSIONS: Our data indicate that overall race time for moderately trained triathletes, competing over the sprint distance can be accurately predicted from maximal laboratory tests.


Assuntos
Ciclismo/fisiologia , Corrida/fisiologia , Natação/fisiologia , Tecido Adiposo/fisiologia , Adulto , Desempenho Atlético/fisiologia , Teste de Esforço/métodos , Humanos , Modelos Lineares , Masculino , Consumo de Oxigênio/fisiologia , Fatores de Tempo
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