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1.
J Sports Sci ; 38(9): 1009-1017, 2020 May.
Artículo en Inglés | MEDLINE | ID: mdl-32160828

RESUMEN

During 20 m shuttle tests, obese adolescents may have difficulty achieving maximum cardiorespiratory performance due to the presence of braking-relaunch phases (BRP). Nineteen obese adolescents aged 15.2 ± 1.5 years (body mass index [BMI] = 39.7 ± 5.9 kg.m-2) performed three graded walking exercises on a 50 m track at speeds between 3 and 6 km/h: a continuous-straight-line protocol (C), a continuous protocol that required turning back every 30 sec (C-BRP) and an intermittent protocol that consisted of successively walking then resting for 15 sec (15-15). Oxygen uptake (VO2), aerobic cost of walking (Cw), ventilation (VE) and rating of perceived exertion (RPE) were measured at each stage during the protocols. During C-BRP, the responses were not significantly higher compared with C (p > 0.30). During 15-15, the VO2, Cw and VE were ~ 15 to 25% lower than during C beginning at 4 km/h (p < 0.05). In obese adolescents, the respiratory impact of sudden directional changes during the 20 m shuttle-type test appeared to be minor at walking speeds. During the 15-15 test, the intensity increases more progressively, and this design may encourage obese adolescents to walk further than during a continuous test.


Asunto(s)
Capacidad Cardiovascular/fisiología , Obesidad Pediátrica/fisiopatología , Percepción/fisiología , Esfuerzo Físico/fisiología , Respiración , Caminata/fisiología , Adolescente , Metabolismo Energético/fisiología , Prueba de Esfuerzo , Femenino , Humanos , Masculino , Consumo de Oxígeno/fisiología , Obesidad Pediátrica/psicología
2.
Braz J Med Biol Res ; 53(3): e9391, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-32077467

RESUMEN

The oxygen uptake (V˙O2) kinetics during onset of and recovery from exercise have been shown to provide valuable parameters regarding functional capacity of both chronic obstructive pulmonary disease (COPD) and chronic heart failure (CHF) patients. To investigate the influence of comorbidity of COPD in patients with CHF with reduced ejection fraction on recovery from submaximal exercise, 9 CHF-COPD male patients and 10 age-, gender-, and left ventricle ejection fraction (LVEF)-matched CHF patients underwent constant-load exercise tests (CLET) at moderate and high loads. The V˙O2, heart rate (HR), and cardiac output (CO) recovery kinetics were determined for the monoexponential relationship between these variables and time. Within-group analysis showed that the recovery time constant of HR (P<0.05, d=1.19 for CHF and 0.85 for CHF-COPD) and CO (P<0.05, d=1.68 for CHF and 0.69 for CHF-COPD) and the mean response time (MRT) of CO (P<0.05, d=1.84 for CHF and 0.73 for CHF-COPD) were slower when moderate and high loads were compared. CHF-COPD patients showed smaller amplitude of CO recovery kinetics (P<0.05) for both moderate (d=2.15) and high (d=1.07) CLET. Although the recovery time constant and MRT means were greater in CHF-COPD, CHF and CHF-COPD groups were not differently affected by load (P>0.05 in group vs load analysis). The ventilatory efficiency was related to MRT of V˙O2 during high CLET (r=0.71). Our results suggested that the combination of CHF and COPD may further impair the recovery kinetics compared to CHF alone.


Asunto(s)
Terapia por Ejercicio/métodos , Tolerancia al Ejercicio/fisiología , Ventilación Voluntaria Máxima/fisiología , Consumo de Oxígeno/fisiología , Enfermedad Pulmonar Obstructiva Crónica/rehabilitación , Recuperación de la Función/fisiología , Anciano , Humanos , Cinética , Masculino , Persona de Mediana Edad , Enfermedad Pulmonar Obstructiva Crónica/fisiopatología
3.
Int J Sports Med ; 41(3): 141-153, 2020 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-31935777

RESUMEN

This study analyzed the effects of physical exercise interventions on cardiovascular endpoints in childhood cancer survivors. Relevant articles were systematically searched in PubMed, CINAHL, and Web of Science databases (since inception to 11th September 2019). We performed a meta-analysis (random effects) to determine the mean difference (expressed together with 95% confidence intervals) between pre- and post-intervention values for those cardiovascular endpoints reported in more than three studies. Twenty-seven studies (of which 16 were controlled studies) comprising 697 participants were included. Only three studies reported adverse events related to exercise interventions. Exercise resulted in an increased performance on the 6-minute walk distance test (mean difference=111 m, 95% confidence interval=39-183, p=0.003) and a non-significant trend (mean difference=1.97 ml∙kg-1∙min-1, 95% confidence interval=-0.12-4.06, p=0.065) for improvement in peak oxygen uptake. Furthermore, left ventricular ejection fraction was preserved after exercise interventions (mean difference=0.29%, 95% confidence interval=-1.41-1.99, p=0.738). In summary, exercise interventions might exert a cardioprotective effect in childhood cancer survivors by improving - or attenuating the decline of - physical capacity and cardiovascular function. Further studies, particularly randomized controlled trials, are needed to confirm these benefits.


Asunto(s)
Supervivientes de Cáncer , Capacidad Cardiovascular/fisiología , Terapia por Ejercicio , Presión Sanguínea/fisiología , Niño , Endotelio Vascular/fisiología , Prueba de Esfuerzo , Frecuencia Cardíaca/fisiología , Humanos , Consumo de Oxígeno/fisiología , Volumen Sistólico/fisiología
5.
Int J Sports Med ; 41(4): 209-218, 2020 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-31958874

RESUMEN

We hypothesised that vagal withdrawal and increased venous return interact in determining the rapid cardiac output (CO) response (phase I) at exercise onset. We used lower body negative pressure (LBNP) to increase blood distribution to the heart by muscle pump action and reduce resting vagal activity. We expected a larger increase in stroke volume (SV) and smaller for heart rate (HR) at progressively stronger LBNP levels, therefore CO response would remain unchanged. To this aim ten young, healthy males performed a 50 W exercise in supine position at 0 (Control), -15, -30 and -45 mmHg LBNP exposure. On single beat basis, we measured HR, SV, and CO. Oxygen uptake was measured breath-by-breath. Phase I response amplitudes were obtained applying an exponential model. LBNP increased SV response amplitude threefold from Control to -45 mmHg. HR response amplitude tended to decrease and prevented changes in CO response. The rapid response of CO explained that of oxygen uptake. The rapid SV kinetics at exercise onset is compatible with an increased venous return, whereas the vagal withdrawal conjecture cannot be dismissed for HR. The rapid CO response may indeed be the result of two independent yet parallel mechanisms, one acting on SV, the other on HR.


Asunto(s)
Gasto Cardíaco/fisiología , Ejercicio Físico/fisiología , Frecuencia Cardíaca/fisiología , Presión Negativa de la Región Corporal Inferior , Volumen Sistólico/fisiología , Adulto , Presión Sanguínea/fisiología , Humanos , Masculino , Consumo de Oxígeno/fisiología , Nervio Vago/fisiología , Resistencia Vascular/fisiología , Adulto Joven
6.
BMC Public Health ; 20(1): 22, 2020 Jan 08.
Artículo en Inglés | MEDLINE | ID: mdl-31914965

RESUMEN

BACKGROUND: Sedentary behavior (SB) and cardiorespiratory fitness (CRF) are important issues in occupational health. Developing a questionnaire to concurrently assess workers' SB and CRF could fundamentally improve epidemiological research. The Worker's Living Activity-time Questionnaire (WLAQ) was developed previously to assess workers' sitting time. WLAQ can be modified to evaluate workers' CRF if additional physical activity (PA) data such as PA frequency, duration, and intensity are collected. METHODS: A total of 198 working adults (93 women and 105 men; age, 30-60 years) completed anthropometric measurements, a treadmill exercise test for measuring maximal oxygen consumption (VO2max), and modified WLAQ (m-WLAQ, which included questions about PA data additional to the original questions). Multiple regression analyses were performed to develop prediction equations for VO2max. The generated models were cross-validated using the predicted residual error sum of squares method. Among the participants, the data of 97 participants who completed m-WLAQ twice after a 1-week interval were used to calculate intraclass correlation coefficient (ICC) for the test-retest reliability analyses. RESULTS: Age (r = - 0.29), sex (r = 0.48), body mass index (BMI, r = - 0.20), total sitting time (r = - 0.15), and PA score (total points for PA data, r = 0.47) were significantly correlated with VO2max. The models that included age, sex, and BMI accounted for 43% of the variance in measured VO2max [standard error of the estimate (SEE) = 5.04 ml·kg- 1·min- 1]. These percentages increased to 59% when the PA score was included in the models (SEE = 4.29 ml·kg- 1·min- 1). Cross-validation analyses demonstrated good stability of the VO2max prediction models, while systematic underestimation and overestimation of VO2max were observed in individuals with high and low fitness, respectively. The ICC of the PA score was 0.87 (0.82-0.91), indicating excellent reliability. CONCLUSIONS: The PA score obtained using m-WLAQ, rather than sitting time, correlated well with measured VO2max. The equation model that included the PA score as well as age, sex, and BMI had a favorable validity for estimating VO2max. Thus, m-WLAQ can be a useful questionnaire to concurrently assess workers' SB and CRF, which makes it a reasonable resource for future epidemiological surveys on occupational health.


Asunto(s)
Capacidad Cardiovascular , Ejercicio Físico/fisiología , Salud Laboral , Consumo de Oxígeno/fisiología , Conducta Sedentaria , Encuestas y Cuestionarios , Adulto , Índice de Masa Corporal , Prueba de Esfuerzo , Femenino , Humanos , Masculino , Persona de Mediana Edad , Reproducibilidad de los Resultados , Factores de Tiempo
7.
J Exp Biol ; 223(Pt 2)2020 Jan 29.
Artículo en Inglés | MEDLINE | ID: mdl-31915201

RESUMEN

Climate change is impacting many, if not all, forms of life. Increases in extreme temperature fluctuations and average temperatures can cause stress, particularly in aquatic sessile ectotherms such as freshwater mussels. However, some species seem to thrive more than others in face of temperature-related stressors. Thermal tolerance may, for example, explain the success of invasive species. It is also known that mitochondria can play a key role in setting an ectothermic species' thermal tolerance. In this study, we aimed to characterize the mitochondrial thermo-tolerance in invasive and endemic freshwater mussels. With the use of high-resolution respirometry, we analyzed the mitochondrial respiration of two freshwater bivalve species exposed to a broad range of temperatures. We noticed that the invasive dreissenid Dreissena bugensis possessed a less thermo-tolerant mitochondrial metabolism than the endemic unionid Elliptio complanata This lack of tolerance was linked with a more noticeable aerobic metabolic depression at elevated temperatures. This decrease in mitochondrial metabolic activity was also linked with an increase in leak oxygen consumption as well as a stable maintenance of the activity of cytochrome c oxidase in both species. These findings may be associated both with the species' life history characteristics, as D. bugensis is more adapted to unstable habitats, in which selection pressures for resistance adaptations are reduced. Our findings add to the growing body of literature characterizing the mitochondrial metabolism of many aquatic ectotherms in our changing world.


Asunto(s)
Bivalvos/fisiología , Especies Introducidas , Mitocondrias/metabolismo , Animales , Bivalvos/metabolismo , Ecosistema , Complejo IV de Transporte de Electrones , Consumo de Oxígeno/fisiología
8.
Fisioter. Pesqui. (Online) ; 27(1): 57-63, jan.-mar. 2020. tab, graf
Artículo en Portugués | LILACS | ID: biblio-1090419

RESUMEN

RESUMO O objetivo deste estudo foi avaliar e comparar respostas metabólicas, cardiovasculares e ventilatórias do incremental shuttle walk test (ISWT) e do Glittre activities of daily living test (Glittre-ADL test). Trata-se de um estudo transversal, realizado com indivíduos saudáveis. A capacidade funcional (CF) foi avaliada pela distância percorrida e consumo de oxigênio pico (VO2pico) no ISWT e pelo tempo gasto e VO2 no Glittre-ADL test. Trinta indivíduos percorreram 656,67 (IC95%:608,8-704,5) metros no ISWT e executaram o Glittre-ADL test em 2,4 (IC95%:2,2-2,6) minutos. O VO2 pico do ISWT foi 27,8 (IC95%25,6-29,9) versus 22,2 (IC95%20,5-24,1)mL×kg−1×min−1 (p<0,001) no estado estável (EE) do Glittre-ADL test. As correlações entre distância percorrida no ISWT e o tempo gasto no Glittre-ADL test, o VO2pico do ISWT e o VO2 no EE do Glittre-ADL test e a FC no pico do ISWT e no EE do Glittre-ADL test foram de moderada a alta magnitude. O Glittre-ADL test apresenta menores respostas metabólicas, cardiovasculares e ventilatórias se comparado ao ISWT.


RESUMEN El presente estudio tuvo el objetivo de evaluar y comparar las respuestas metabólicas, cardiovasculares y ventilatorias de incremental shuttle walk test (ISWT) y de Glittre activities of daily living test (Glittre-ADL test). Es un estudio transversal realizado con individuos sanos. La capacidad funcional (CF) se evaluó utilizando la distancia recorrida y consumo máximo de oxígeno (VO2máx) en el ISWT y el tiempo empleado y VO2 en el Glittre-ADL test. Treinta individuos caminaron 656,67 (IC95%:608,8-704,5) metros en el ISWT y realizaron el Glittre-ADL test en 2,4 (IC95%:2,2-2,6) minutos. El VO2 máx del ISWT fue de 27,8 (IC95%25,6-29,9) versus 22,2 (IC95%20,5-24,1)mL×kg−1×min−1 (p<0,001) en el estado estable (EE) del Glittre-ADL test. Las correlaciones entre la distancia recorrida en el ISWT y el tiempo empleado en el Glittre-ADL test, el VO2máx del ISWT y el VO2 en el EE de Glittre-ADL test y la FC en el máximo del ISWT y en el EE de Glittre-ADL test fueron de moderada a alta magnitud. El Glittre-ADL test presenta respuestas metabólicas, cardiovasculares y ventilatorias más bajas en comparación con el ISWT.


ABSTRACT The aim of the study was to assess and compare the cardiovascular, ventilatory and metabolic responses of the Incremental Shuttle Walk test (ISWT) and Glittre Activities of Daily Living test (Glittre-ADL test). This is a cross-sectional study with individuals. The functional capacity (FC) was evaluated by distance and peak oxygen consumption (VO2peak) in the ISWT and time spent and VO2 in Glittre-ADL test. Thirty individuals went through 656.67 (CI95%:608.8-704.5) meters at the ISWT and performed the Glittre-ADL test in 2.4 (CI95%:2.2-2.6) minutes. The peak VO2 of the ISWT was 27.8 (CI95%25.6-29.9) vs. 22.2 (CI95%20.5-24.1) mL×kg−1×min−1 (p<0.001) in the steady state (SS) of the Glittre-ADL test. Correlations between distance traveled in the ISWT and the time spent in Glittre-ADL test, VO2 peak of ISWT and VO2 in SS of Glittre-ADL test and HR at the ISWT peak and at the Glittre-ADL test SS were moderate to high magnitude. The Glittre-ADL test has lower metabolic, cardiovascular and ventilatory responses compared to ISWT, despite correlations between variables.


Asunto(s)
Humanos , Masculino , Femenino , Adulto , Persona de Mediana Edad , Prueba de Esfuerzo/métodos , Prueba de Paso/métodos , Rendimiento Físico Funcional , Consumo de Oxígeno/fisiología , Pruebas de Función Respiratoria , Espirometría , Actividades Cotidianas , Estudios Transversales , Reproducibilidad de los Resultados , Metabolismo Energético/fisiología , Capacidad Cardiovascular/fisiología
9.
Int J Sports Med ; 41(1): 36-43, 2020 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-31747699

RESUMEN

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.


Asunto(s)
Fútbol Americano/lesiones , Cabeza/fisiopatología , Músculo Esquelético/lesiones , Esfuerzo Físico/fisiología , Adolescente , Fenómenos Biomecánicos , Conmoción Encefálica/fisiopatología , Forma MM de la Creatina-Quinasa/sangre , Fútbol Americano/fisiología , Humanos , Estudios Longitudinales , Masculino , Músculo Esquelético/enzimología , Consumo de Oxígeno/fisiología , Estudios Prospectivos , Estados Unidos
10.
J Sports Sci ; 38(3): 288-295, 2020 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-31774371

RESUMEN

Although an association has been suggested between asthma, obesity, fitness and physical activity, the relationship between these parameters remains to be elucidated in adolescents. Six-hundred and sixteen adolescents were recruited (334 boys; 13.0 ± 1.1years; 1.57 ± 0.10m; 52.6 ± 12.9kg), of which 155 suffered from mild-to-moderate asthma (78 boys). Participants completed a 20-metre shuttle run test, lung function and 7-day objective physical activity measurements and completed asthma control and quality of life questionnaires. Furthermore, 69 adolescents (36 asthma; 21 boys) completed an incremental ramp cycle ergometer test. Although participants with asthma completed significantly fewer shuttle runs than their peers, peak V̇O2 did not differ between the groups. However, adolescents with asthma engaged in less physical activity (53.9 ± 23.5 vs 60.5 ± 23.6minutes) and had higher BMI (22.2 ± 4.8 vs 20.4 ± 3.7kg·m-2), than their peers. Whilst a significant relationship was found between quality of life and cardiorespiratory fitness according to peak V̇O2, only BMI was revealed as a significant predictor of asthma status. The current findings highlight the need to use accurate measures of cardiorespiratory fitness rather than indirect estimates to assess the influence of asthma during adolescence. Furthermore, the present study suggests that BMI and fitness may be key targets for future interventions seeking to improve asthma quality of life.


Asunto(s)
Asma/fisiopatología , Índice de Masa Corporal , Capacidad Cardiovascular/fisiología , Adolescente , Prueba de Esfuerzo , Femenino , Humanos , Masculino , Obesidad/fisiopatología , Consumo de Oxígeno/fisiología , Calidad de Vida , Análisis de Regresión , Pruebas de Función Respiratoria , Índice de Severidad de la Enfermedad
11.
J Sports Sci ; 38(1): 114-120, 2020 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-31665975

RESUMEN

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.


Asunto(s)
Acelerometría/instrumentación , Adiposidad/fisiología , Capacidad Cardiovascular , Ejercicio Físico/fisiología , Monitores de Ejercicio , Conducta Sedentaria , Índice de Masa Corporal , Niño , Estudios Transversales , Femenino , Humanos , Masculino , Consumo de Oxígeno/fisiología , Factores de Tiempo
12.
Sports Health ; 12(1): 80-87, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-31710819

RESUMEN

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.


Asunto(s)
Músculo Esquelético/fisiología , Tenis/fisiología , Adolescente , Adulto , Anciano , Composición Corporal , Capacidad Cardiovascular/fisiología , Análisis por Conglomerados , Estudios Transversales , Femenino , Fuerza de la Mano , Humanos , Rodilla/fisiología , Masculino , Persona de Mediana Edad , Fatiga Muscular/fisiología , Fuerza Muscular/fisiología , Consumo de Oxígeno/fisiología , Adulto Joven
13.
Int J Sports Med ; 41(2): 98-105, 2020 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-31842246

RESUMEN

This study investigated the effect of endurance training and regular post-exercise cold water immersion on changes in microvascular function. Nine males performed 3 sessions∙wk-1 of endurance training for 4 weeks. Following each session, participants immersed one leg in a cold water bath (10°C; COLD) for 15 min while the contra-lateral leg served as control (CON). Before and after training, microvascular function of the gastrocnemius was assessed using near-infrared spectroscopy, where 5 min of popliteal artery occlusion was applied and monitored for 3 min upon cuff release. Changes in Hbdiff (oxyhemoglobin - deoxyhemoglobin) amplitude (O-AMP), area under curve (O-AUC) and estimated muscle oxygen consumption (mVO2) were determined during occlusion, while the reperfusion rate (R-RATE), reperfusion amplitude (R-AMP) and hyperemic response (HYP) were determined following cuff release. Training increased O-AMP (p=0.010), O-AUC (p=0.011), mVO2 (p=0.013), R-AMP (p=0.004) and HYP (p=0.057). Significant time (p=0.024) and condition (p=0.026) effects were observed for R-RATE, where the increase in COLD was greater compared with CON (p=0.026). In conclusion, R-RATE following training was significantly higher in COLD compared with CON, providing some evidence for enhanced microvascular adaptations following regular cold water immersion.


Asunto(s)
Adaptación Fisiológica , Frío , Inmersión , Microcirculación , Músculo Esquelético/irrigación sanguínea , Acondicionamiento Físico Humano/fisiología , Resistencia Física/fisiología , Área Bajo la Curva , Hemoglobinas/metabolismo , Humanos , Masculino , Consumo de Oxígeno/fisiología , Oxihemoglobinas/metabolismo , Acondicionamiento Físico Humano/métodos , Arteria Poplítea/fisiología , Espectroscopía Infrarroja Corta/métodos , Adulto Joven
14.
Am J Cardiol ; 125(1): 76-81, 2020 01 01.
Artículo en Inglés | MEDLINE | ID: mdl-31703805

RESUMEN

Impaired cardiorespiratory fitness (CRF) in heart failure (HF) is influenced by a complex array of cardiac and extracardiac factors. The study aimed to identify clinical determinants of CRF measured as peak oxygen consumption (peak VO2) in HF patients, and to determine a peak VO2 prediction model using regression equations. Retrospective analysis of 200 HF patients who completed treadmill cardiopulmonary exercise testing and underwent Doppler echocardiography and/or biomarker analysis on the same day was performed. After univariate linear regression analysis, a multivariate peak VO2 prediction model was developed using significant variables in a stepwise linear regression analysis. In subjects with repeated testing, Pearson's correlation was used to assess correlations between measured and predicted change in peak VO2 (Δpeak VO2) over time. Mean age was 57 years, with 55% being male. Stepwise linear regression was used to generate a weighted model for peak VO2: 30.895 + (-0.112•age[years]) + (0.296•hemoglobin [g/dl]) + (-0.101•E/e'[unit change]) + (-0.202• body mass index [kg/m2]) + (-0.593• N-terminal pro-brain natriuretic peptide [logN pg/ml])) + (-1.349•CRP [log mg/L]). Predicted peak VO2 correlated strongly with measured peak VO2 in HF with reduced ejection fraction and HF with preserved ejection fraction patients (r = +0.63, p <0.001; r = +0.64, p <0.001, respectively). Predicted Δpeak VO2 correlated with measured Δpeak VO2 (r = +0.23, p <0.001). In conclusion, in patients with HF across a wide range of left ventricular ejection fraction, age, systemic inflammation, oxygen carrying capacity, obesity, and elevated filling pressures are the strongest predictors of impaired CRF. The proposed CRF model allows prediction of peak VO2 in HF patients and may be used to estimate peak VO2 changes over time.


Asunto(s)
Prueba de Esfuerzo/métodos , Tolerancia al Ejercicio/fisiología , Insuficiencia Cardíaca/fisiopatología , Ventrículos Cardíacos/fisiopatología , Consumo de Oxígeno/fisiología , Volumen Sistólico/fisiología , Función Ventricular Izquierda/fisiología , Ecocardiografía Doppler , Femenino , Estudios de Seguimiento , Insuficiencia Cardíaca/diagnóstico , Ventrículos Cardíacos/diagnóstico por imagen , Humanos , Masculino , Persona de Mediana Edad , Pronóstico , Estudios Retrospectivos
15.
Chemosphere ; 240: 124974, 2020 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-31726613

RESUMEN

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.


Asunto(s)
Talio/toxicidad , Pez Cebra/metabolismo , Amoníaco/metabolismo , Animales , Cinética , Nitrógeno/metabolismo , Consumo de Oxígeno/fisiología , Factores de Tiempo , Pez Cebra/fisiología
16.
Mayo Clin Proc ; 95(2): 255-264, 2020 02.
Artículo en Inglés | MEDLINE | ID: mdl-31883698

RESUMEN

OBJECTIVE: To begin the process of developing global reference standards for adults from directly measured cardiorespiratory fitness (CRF). METHODS: Percentiles of maximal oxygen consumption (VO2max) for men and women were determined for each decade from 20 through 79 years of age using International data from the Fitness Registry and Importance of Exercise: A National Database (FRIEND-I) along with previously published data from seven studies. FRIEND-I data from January 1, 2014, through January 1, 2019, included 11,678 maximal treadmill tests from three countries, whereas the previously published reports included 32,329 maximal treadmill tests from six countries. RESULTS: FRIEND-I data revealed significant differences between sex and age groups for VO2max (P<0.01). For the 20- to 29-years of age group, the 50th percentile VO2max in men and women were 49.5 mLO2⋅kg-1⋅min-1 and 40.6 mLO2⋅kg-1⋅min-1, respectively. VO2max declined an average of 9% per decade with the 50th percentile for the 70- to 79-years of age group having a VO2max of 30.8 mLO2⋅kg-1⋅min-1 in men and 25.0 mLO2⋅kg-1⋅min-1 in women. These results were similar in magnitude and direction to the previously published literature. Within both the FRIEND-I and previously published data there were CRF differences between countries. CONCLUSION: This report begins to establish global reference standards for CRF. Continued development of FRIEND-I will increase global representation providing an improved ability to identify and stratify CRF risk categories.


Asunto(s)
Capacidad Cardiovascular/fisiología , Adulto , Anciano , Bases de Datos Factuales , Prueba de Esfuerzo/normas , Femenino , Humanos , Masculino , Persona de Mediana Edad , Consumo de Oxígeno/fisiología , Estándares de Referencia , Sistema de Registros
17.
Int J Occup Saf Ergon ; 26(1): 173-180, 2020 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-30664392

RESUMEN

Purpose. Physiologic demands of five common tasks in firefighting have been examined. Methods. Eight male volunteers, dressed up as smoke divers (+21 kg extra load), carried out the following tasks at constant pace for 5 min: walking at 1.4 m·s-1, walking (all walks at the same speed) while carrying a 10-kg ladder, walking carrying two hose packs of 16 kg together, walking carrying a 32-kg spreader tool and, finally, climbing up and down a ladder at a preset pace. A 5-min break separated each exercise. The heart rate, oxygen uptake and lung ventilation were measured continuously, and the blood lactate concentration was recorded after each task. Results. The end-exercise heart rate rose from 108 to 180 bpm from the first to last task, blood lactate concentration rose from 1 to 7 mmol·L-1, oxygen uptake rose from 19 to 48 ml·kg-1 min-1 and lung ventilation rose from 38 to 124 L·min-1. Discussion. Walking was an easy task even when dressed up as a smoke diver. Adding loads increased demands; ladder climbing taxed >90% of the subjects' aerobic power. Conclusions. The physiologic demands varied considerably between different tasks.


Asunto(s)
Bomberos , Consumo de Oxígeno/fisiología , Esfuerzo Físico/fisiología , Adulto , Prueba de Esfuerzo/métodos , Frecuencia Cardíaca/fisiología , Humanos , Ácido Láctico/sangre , Masculino , Persona de Mediana Edad , Análisis y Desempeño de Tareas , Adulto Joven
18.
Codas ; 31(6): e20180221, 2019.
Artículo en Portugués, Inglés | MEDLINE | ID: mdl-31800880

RESUMEN

PURPOSE: To evaluate the oxygen saturation, heart rate, length of hospital stay and weight preterm infants or preterm newborns (PTNBs) (in the Neonatal Intensive Care Unit in the diet supply by cup and finger feeding techniques, simultaneously with breastfeeding. METHODS: Simultaneous randomized clinical trial. Twenty-five preterm infants admitted to the Neonatal Intensive Care Unit of the Public Hospital from October 2011 to February 2012 were selected. The sample was divided into two groups: Eight preterm infants who received the diet in the cup probe group (CPG) who were born on the same day, and 17 by finger probe group (FPG) who were born on the odd day. In the diet offer, the minimum and maximum values of oxygen saturation (O2 Sat) and heart rate (HR) were recorded: before offering the diet, during and after the offer. RESULTS: Regarding the variables O2 Sat and HR, no statistically significant differences were observed between the groups, but in the group vs time factor, the groups showed differences, not continuous in the O2 Sat variable. Regarding weight, a statistically significant gain was observed for both groups, and in CPG the highest weight gain was due to the longer hospitalization time. It was verified that FPG presented shorter hospitalization time. CONCLUSION: There were no differences regarding O2 Sat and HR. However, when analyzing the time factor, the groups presented some differences, not continuous, indicating the need for other studies for a better understanding of the effect. The FPG presented shorter hospitalization time and the CPG infants had greater weight gain due to longer hospitalization time.


Asunto(s)
Métodos de Alimentación , Frecuencia Cardíaca/fisiología , Consumo de Oxígeno/fisiología , Alimentación Artificial/métodos , Lactancia Materna , Femenino , Humanos , Recien Nacido Prematuro , Tiempo de Internación , Masculino , Factores de Tiempo , Aumento de Peso
19.
J Sports Sci Med ; 18(4): 586-595, 2019 12.
Artículo en Inglés | MEDLINE | ID: mdl-31827342

RESUMEN

Among adolescents empirical studies examining the total daily steps translation of the moderate-to-vigorous physical activity recommendation are scarce and inconsistent, and there are no previous studies with cadence-based steps and related to sedentary behavior. The main objective of the present study was to establish and compare the accuracy of daily step-based recommendations related to the moderate-to-vigorous physical activity and sedentary behavior thresholds in adolescents. The present study followed a cross-sectional design. A total of 126 adolescents (56 girls) aged 12-15 years old were assessed by ActiGraph GT3X accelerometers for eight consecutive days (moderate-to-vigorous physical activity, sedentary behavior, and steps) and the multistage 20-meter shuttle run test (cardiorespiratory fitness). ROC curve analyses showed that total daily steps (AUC = 0.94, 0.89-0.99; Threshold ≥ 11,111 steps/ day; P = 0.93; k = 0.67; p < 0.001) was a more appropriate indicator than cadence-based daily steps for distinguishing between physically active and inactive adolescents. Daily step-based thresholds represent a promising way to translate a total daily sedentary behavior threshold (e.g., total daily steps, AUC = 0.87, 0.81-0.93; Sensitivity = 0.87; Specificity = 0.70). Adolescents who met a favorable combination of step-based recommendations related to both physical activity and sedentary behavior thresholds had a higher probability of having a healthy cardiorespiratory fitness profile than those who did not meet either of them (e.g., risk ratio = 5.05, 1.69-15.08) or only the one related to physical activity (e.g., risk ratio = 4.09, 1.36-12.29). These findings may help policy-makers to provide accurate daily step-based recommendations that would simplify the physical activity and sedentary behavior thresholds for adolescents.


Asunto(s)
Ejercicio Físico/fisiología , Conducta Sedentaria , Acelerometría , Adolescente , Estatura , Índice de Masa Corporal , Capacidad Cardiovascular/fisiología , Niño , Estudios Transversales , Femenino , Humanos , Masculino , Consumo de Oxígeno/fisiología , Curva ROC , Circunferencia de la Cintura
20.
J Sports Sci Med ; 18(4): 636-644, 2019 12.
Artículo en Inglés | MEDLINE | ID: mdl-31827347

RESUMEN

Prediabetes is associated with impaired oxidative capacity and altered substrate utilization during exercise. The effects of continuous (CONT) versus interval (INT) exercise training on fat oxidation during an acute exercise bout at the same absolute and relative intensities are unknown in this population. Obese females/males (n = 17, n = 5) with prediabetes (BMI 32.2 ± 1.2 kg·m-2; age 62.8 ± 1.6 y; fasting glucose 103.4 ± 1.6 mg·dL-1; 2-hour glucose 153.7 ± 7.1 mg·dL-1; VO2peak 19.9 ± 1.0 mL·kg-1·min-1) were screened with a 75g OGTT. Subjects completed a peak oxygen consumption test and a submaximal exercise substrate utilization test consisting of 5min stages at absolute (30W) and relative (70%HRpeak) intensities before and after randomization to 12 sessions (60min each) of CONT (70% HRpeak) or INT (alternating 3min 90% HRpeak, 3min 50% HRpeak) over a two-week period. Body mass decreased and VO2peak increased more after INT than CONT (INT: -0.6 ± 0.2 kg, CONT: -0.1 ± 0.2 kg; p = 0.04; INT: 1.9 ± 0.6 mL/kg/min, CONT: 0.1 ± 0.6 mL·kg-1·min-1; p = 0.04). Training increased fat oxidation by 0.7 ± 0.2 mL·kg-1·min-1 during the absolute intensity test (p < 0.001), independent of intensity. During the relative intensity test, fat oxidation increased more after INT than CONT (INT: 1.3 ± 0.4 mL·kg-1·min-1, CONT: 0.3 ± 0.3 mL·kg-1·min-1; p = 0.03), with no difference in exercise energy expenditure between groups. Enhanced fat oxidation during the relative test was correlated with increased VO2peak (r = 0.53 p = 0.01). High intensity INT training enhances fat oxidation during the same relative intensity exercise in people with prediabetes.


Asunto(s)
Tejido Adiposo/metabolismo , Entrenamiento de Intervalos de Alta Intensidad , Obesidad/metabolismo , Estado Prediabético/metabolismo , Anciano , Glucemia/metabolismo , Índice de Masa Corporal , Capacidad Cardiovascular/fisiología , Metabolismo Energético/fisiología , Femenino , Prueba de Tolerancia a la Glucosa , Humanos , Masculino , Persona de Mediana Edad , Obesidad/sangre , Obesidad/complicaciones , Oxidación-Reducción , Consumo de Oxígeno/fisiología , Percepción/fisiología , Esfuerzo Físico/fisiología , Estado Prediabético/sangre , Estado Prediabético/complicaciones
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