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1.
Front Nutr ; 6: 161, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31681787

RESUMO

Purpose: The purpose of this observational study was to examine the incidence of exercise-associated hyponatremia (EAH) in a 246-km continuous ultra-marathon. Methods: Over 2 years, 63 male finishers of the annual Spartathlon ultra-marathon foot race from Athens to Sparta, Greece were included in the data analysis. A blood sample was drawn from an antecubital vein the day before the race as well as within 15 min post-race and analyzed for sodium concentration. During the second year of data collection, blood was also drawn at the 93-km checkpoint (n = 29). Height and weight were measured pre and post-race. Results: Mean race time of all subjects was 33 ± 3 h with a range of 23.5 and 36.0 h. Of the 63 finishers recruited, nine began the race with values indicative of mild hyponatremia. Seven runners were classified as hyponatremic at the 93-km checkpoint, three of whom had sodium levels of severe hyponatremia. After the race, 41 total finishers (65%) developed either mild (n = 27, 43%) or severe hyponatremia (n = 14, 22%). Mean change in bodyweight percentage and serum sodium from pre-race to post-race was -3.6 ± 2.7% (-2.5 ± 1.9 kg) and -6.6 ± 5.6 mmol·L-1, respectively. Pre-race serum sodium level was not a significant predictor of post-race serum sodium levels (ß = 0.08, R 2 = 0.07, P = 0.698), however, there was a significant negative association between change in bodyweight percentage and post-race serum sodium concentration (ß = -0.79, R 2 = 0.29, P = 0.011). Conclusion: The incidence of EAH of 52 and 65%, when excluding or including these individuals with pre-race hyponatremia, was the highest reported in current literature.

2.
Rural Remote Health ; 18(2): 4425, 2018 05.
Artigo em Inglês | MEDLINE | ID: mdl-29788745

RESUMO

INTRODUCTION: Obesity has become one of the major health risks in childhood, significantly affecting children's health and physical fitness. Although the marked increase of obesity in urban areas is well established, evidence is limited in remote and isolated areas with adverse socioeconomic features. The aim of this study was to examine the prevalence of obesity and its association with physical performance indices in young school-aged children living in 18 remote and isolated Greek islands. METHODS: Four hundred and sixty-three children (244 boys, 219 girls), aged 5-12 years underwent a series of physical fitness tests including 20 m sprint, standing long jump, 1 kg medicine ball throw, agility T-test and sit-and-reach test. Age and gender BMI cut-off points were determined according to World Health Organisation (WHO) norms. RESULTS: The prevalence of obesity was 23.8% and 13.2% for boys and girls, respectively. A negative body mass index (BMI) main effect was observed for weight-bearing activities, such as 20 m sprint (F=6.21, p=0.000, η2=0.041) and standing long jump (F=11.369, p=0.000, η2=0.074), while medicine ball throw was positively correlated with BMI in children aged 9-12 years. CONCLUSION: The results of this study confirmed previous findings on obesity prevalence in Greece. A negative association was also found between BMI and physical fitness indices and, in particular, in weight-bearing activities. It is critical to establish physical education interventions and physical fitness programs at schools, aiming to increase motivation for physical activity participation.


Assuntos
Obesidade Pediátrica/epidemiologia , Aptidão Física/fisiologia , População Rural/estatística & dados numéricos , Fatores Etários , Índice de Massa Corporal , Pesos e Medidas Corporais , Criança , Pré-Escolar , Estudos Transversais , Exercício Físico , Feminino , Grécia/epidemiologia , Humanos , Masculino , Força Muscular/fisiologia , Corrida/fisiologia , Fatores Sexuais , Fatores Socioeconômicos
3.
Appl Physiol Nutr Metab ; 38(8): 823-9, 2013 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-23855269

RESUMO

A single bout of high-intensity interval aerobic exercise has been shown to produce the same or greater metabolic benefits as continuous endurance exercise with considerably less energy expenditure, but whether this applies to very low density lipoprotein (VLDL) metabolism is not known. We sought to examine the effect of a single bout of high-intensity interval aerobic exercise on basal VLDL-triglyceride (TG) kinetics 14 and 48 h after exercise cessation to determine the acute and time-dependent effects of this type of exercise on VLDL-TG metabolism. Eight healthy sedentary men (age, 23.6 ± 6.1 years; body mass index, 23.1 ± 2.2 kg·m(-2), peak oxygen consumption (V̇O2peak), 36.3 ± 5.5 mL·kg(-1)·min(-1)) participated in three stable isotopically labeled tracer infusion studies: (i) 14 h and (ii) 48 h after a single bout of high-intensity aerobic interval exercise (60% and 90% of V̇O2peak in 4 min intervals for a total of 32 min; gross energy expenditure ∼500 kcal) and (iii) after an equivalent period of rest, in random order. Fasting plasma VLDL-TG concentration was 20% lower at 14 h (P = 0.046) but not at 48 h (P = 1.000) after exercise compared with the resting trial. VLDL-TG plasma clearance rate increased by 21% at 14 h (P < 0.001) but not at 48 h (P = 0.299) after exercise compared with rest, whereas hepatic VLDL-TG secretion rate was not different from rest at any time point after exercise. We conclude that high-intensity interval exercise reduces fasting plasma VLDL-TG concentrations in non-obese men the next day by augmenting VLDL-TG clearance, just like a single bout of continuous endurance exercise. This effect is short-lived and abolished by 48 h after exercise.


Assuntos
Metabolismo Basal , Triglicerídeos , Metabolismo Energético , Exercício Físico , Humanos , Metabolismo dos Lipídeos , Masculino , Triglicerídeos/sangue
4.
Int J Sport Nutr Exerc Metab ; 23(3): 245-51, 2013 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-23166200

RESUMO

UNLABELLED: There is a lack of studies concerning hydration status of young athletes exercising in the heat. PURPOSE: To assess preexercise hydration status in young soccer players during a summer sports camp and to evaluate body- water balance after soccer training sessions. METHODS: Initial hydration status was assessed in 107 young male soccer players (age 11-16 yr) during the 2nd day of the camp. Seventy-two athletes agreed to be monitored during 2 more training sessions (3rd and 5th days of the camp) to calculate dehydration via changes in body weight, while water drinking was allowed ad libitum. Hydration status was assessed via urine specific gravity (USG), urine color, and changes in total body weight. Mean environmental temperature and humidity were 27.2 ± 2 °C and 57% ± 9%, respectively. RESULTS: According to USG values, 95 of 107 of the players were hypohydrated (USG ≥ 1.020) before practice. The prevalence of dehydration observed was maintained on both days, with 95.8% and 97.2% of the players being dehydrated after the training sessions on the 3rd and 5th days, respectively. Despite fluid availability, 54 of the 66 (81.8%) dehydrated players reduced their body weight (-0.35 ± 0.04 kg) as a response to training, while 74.6% (47 out of the 63) further reduced their body weight (-0.22 ± 0.03 kg) after training on the 5th day. CONCLUSION: Approximately 90% of the young soccer players who began exercising under warm weather conditions were hypohydrated, while drinking ad libitum during practice did not prevent further dehydration in already dehydrated players.


Assuntos
Atletas , Desidratação/prevenção & controle , Ingestão de Líquidos/fisiologia , Futebol/fisiologia , Adolescente , Peso Corporal , Criança , Temperatura Alta , Humanos , Umidade , Modelos Lineares , Masculino , Prevalência , Estações do Ano , Manejo de Espécimes , Inquéritos e Questionários , Equilíbrio Hidroeletrolítico/fisiologia
5.
Med Sci Sports Exerc ; 45(3): 455-61, 2013 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-23073216

RESUMO

PURPOSE: The mechanisms by which exercise reduces fasting plasma triglyceride (TG) concentrations in women and the effect of negative energy balance independent of muscular contraction are not known.The aim of this study was to evaluate the effects of equivalent energy deficits induced by exercise or calorie restriction on basal VLDL-TG metabolism in women. METHODS: Eleven healthy women (age = 23.5 ± 2.7 yr, body mass index = 21.6 ± 1.4 kg·m-2; mean ± SD) underwent a stable isotopically labeled tracer infusion study to determine basal VLDL-TG kinetics after performing, in random order, three experimental trials on the previous day: (i) a single exercise bout (brisk walking at 60% of peak oxygen consumption for 123 ± 18 min, with a net energy expenditure of 2.06 ± 0.39 MJ, ∼500 kcal), (ii) dietary energy restriction of 2.10 ± 0.41 MJ, and (iii) a control day of isocaloric feeding and rest (zero energy balance). RESULTS: Fasting plasma VLDL-TG concentration was approximately 30% lower after the exercise trial compared with the control trial (P < 0.001), whereas no significant change was detected after the calorie restriction trial (P = 0.297 vs control). Relative to the control condition, exercise increased the plasma clearance rate of VLDL-TG by 22% (P = 0.001) and reduced hepatic VLDL-TG secretion rate by approximately 17% (P = 0.042), whereas hypocaloric diet had no effect on VLDL-TG kinetics (P > 0.2). CONCLUSION: (i) Exercise-induced hypotriglyceridemia in women manifests through a different mechanism (increased clearance and decreased secretion of VLDL-TG) than that previously described in men (increased clearance of VLDL-TG only), and (ii) exercise affects TG homeostasis by eliciting changes in VLDL-TG kinetics that cannot be reproduced by an equivalent diet-induced energy deficit, indicating that these changes are independent of the exercise-induced negative energy balance but instead are specific to muscular contraction.


Assuntos
Restrição Calórica , Exercício Físico/fisiologia , Lipoproteínas VLDL/sangue , Triglicerídeos/sangue , Adulto , Glicemia/metabolismo , Metabolismo Energético , Ácidos Graxos/sangue , Feminino , Humanos , Insulina/sangue , Estatísticas não Paramétricas , Adulto Jovem
6.
Clin Sci (Lond) ; 116(2): 147-56, 2009 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-18554182

RESUMO

A single bout of prolonged aerobic exercise lowers plasma TAG (triacylglycerol) concentrations the next day by increasing the efficiency of VLDL (very-low-density lipoprotein)-TAG removal from the circulation. The effect of resistance exercise on VLDL-TAG metabolism is not known. Therefore we evaluated VLDL-TAG kinetics by using stable isotope-labelled tracers in eight healthy untrained men (age, 25.3+/-0.8 years; body mass index, 24.5+/-0.6 kg/m(2)) in the post-absorptive state in the morning on two separate occasions: once after performing a single 90-min bout of strenuous isokinetic resistance exercise (three sets x ten repetitions, 12 exercises at 80% of maximum peak torque production, with a 2-min rest interval between exercises) on the preceding afternoon and once after an equivalent period of rest. Fasting plasma VLDL-TAG concentrations in the morning after exercise were significantly lower than in the morning after rest (0.23+/-0.04 compared with 0.33+/-0.06 mmol/l respectively; P=0.001). Hepatic VLDL-TAG secretion rate was not different (P=0.31), but plasma clearance rate of VLDL-TAG was significantly higher (by 26+/-8%) after exercise than rest (31+/-3 compared with 25+/-3 ml/min respectively; P=0.004), and the mean residence time of VLDL-TAG in the circulation was significantly shorter (113+/-10 compared with 144+/-18 min respectively; P=0.02). Fasting plasma NEFA (non-esterified fatty acid; 'free' fatty acid) and serum beta-hydroxybutyrate concentrations were both significantly higher after exercise than rest (P<0.05), whereas plasma glucose and serum insulin concentrations were not different (P>0.30). We conclude that, in healthy untrained men, a single bout of whole-body resistance exercise lowers fasting plasma VLDL-TAG concentrations by augmenting VLDL-TAG removal from plasma. The effect appears to be qualitatively and quantitatively similar to that reported previously for aerobic exercise.


Assuntos
Exercício Físico/fisiologia , Lipoproteínas VLDL/sangue , Triglicerídeos/sangue , Adulto , Metabolismo Basal/fisiologia , Composição Corporal/fisiologia , Dieta , Metabolismo Energético/fisiologia , Teste de Esforço/métodos , Jejum/sangue , Jejum/fisiologia , Humanos , Insulina/sangue , Masculino , Consumo de Oxigênio/fisiologia , Adulto Jovem
7.
J Appl Physiol (1985) ; 105(4): 1228-36, 2008 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-18669933

RESUMO

Resistance training is considered less effective than endurance training in lowering plasma triglyceride (TG) concentrations. Acutely, however, a single bout of strenuous exercise, whether endurance or resistance, increases the efficiency of very low-density lipoprotein (VLDL)-TG removal from the circulation and leads to hypotriglyceridemia. The comparative effects of these two types of exercise on VLDL-TG metabolism are not known. We therefore examined basal VLDL-TG kinetics by using stable isotope-labeled tracers in seven healthy, nonobese, untrained young men in the postabsorptive state, the morning after a single 90-min bout of either low-intensity endurance exercise (approximately 30% of peak oxygen consumption) or high-intensity resistance exercise (3 sets of 10 repetitions for 12 exercises at 80% of peak torque production), matched for total energy expenditure (approximately 400 kcal), or an equivalent period of rest on the preceding afternoon. Compared with rest, resistance exercise lowered fasting plasma VLDL-TG concentration by -28 +/- 10% (P = 0.034), increased VLDL-TG plasma clearance rate by 30 +/- 8% (P = 0.003), and shortened the mean residence time (MRT) of VLDL-TG in the circulation by -36 +/- 11 min (P = 0.016), whereas endurance exercise had no effect (all P > 0.05). Basal VLDL-TG plasma clearance rate was greater (P = 0.003) and VLDL-TG MRT was shorter (P = 0.012) the morning after resistance than endurance exercise. We conclude that, for the same total energy expenditure, resistance exercise is more potent than endurance exercise in eliciting changes in VLDL-TG metabolism that have been linked with hypotriglyceridemia, and it should thus be considered as an alternative to or in addition to endurance exercise for the control of plasma TG concentrations.


Assuntos
Exercício Físico , Hipolipoproteinemias/metabolismo , Lipoproteínas VLDL/sangue , Resistência Física , Triglicerídeos/sangue , Adulto , Glicemia/metabolismo , Metabolismo dos Carboidratos , Regulação para Baixo , Metabolismo Energético , Humanos , Hipolipoproteinemias/fisiopatologia , Insulina/sangue , Cinética , Metabolismo dos Lipídeos , Fígado/metabolismo , Masculino , Oxirredução
8.
Am J Physiol Endocrinol Metab ; 295(4): E851-8, 2008 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-18664593

RESUMO

A single bout of strenuous endurance exercise reduces fasting plasma triglyceride (TG) concentrations the next day (12-24 h later) by augmenting the efficiency of very low-density lipoprotein (VLDL)-TG removal from the circulation. Although much of the hypotriglyceridemia associated with training is attributed to the last bout of exercise, the relevant changes in VLDL-TG metabolism have never been investigated. We therefore examined basal VLDL-TG kinetics in a group of sedentary young men (n=7) who underwent 2 mo of supervised high-intensity interval training (3 sessions/wk; running at 60 and 90% of peak oxygen consumption in 4-min intervals for a total of 32 min; gross energy expenditure: 446+/-29 kcal) and a nonexercising control group (n=8). Each subject completed two stable isotope-labeled tracer infusion studies in the postabsorptive state, once before and again after the intervention (approximately 48 h after the last exercise bout in the training group). Peak oxygen consumption increased by approximately 18% after training (P 0.7) in VLDL-TG plasma clearance rate and the mean residence time of VLDL-TG in the circulation. No significant changes in VLDL-TG concentration and kinetics were observed in the nonexercising control group (all P >or= 0.3). We conclude that a short period of high-intensity interval aerobic training lowers the rate of VLDL-TG secretion by the liver in previously sedentary men. This is different from the mechanism underlying the hypotriglyceridemia of acute exercise; however, it remains to be established whether our finding reflects an effect of the longer time lapse from the last exercise bout, an effect specific to the type of exercise performed, or an effect of aerobic training itself.


Assuntos
Aerobiose/fisiologia , Lipoproteínas VLDL/metabolismo , Fígado/metabolismo , Aptidão Física/fisiologia , Triglicerídeos/metabolismo , Adulto , Limiar Anaeróbio/fisiologia , Antropometria , Composição Corporal/fisiologia , Calorimetria Indireta , Dieta , Humanos , Cinética , Lipídeos/sangue , Masculino , Metabolismo/fisiologia , Oxirredução
9.
J Sports Sci ; 26(9): 959-66, 2008 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-18569562

RESUMO

The aim of this study was to evaluate the utility of the RT3 accelerometer in young children, compare its accuracy with heart rate monitoring, and develop an equation to predict energy expenditure from RT3 output. Forty-two volunteers (mean age 12.2 years, s = 1.1) exercised at two horizontal and graded walking speeds (4 and 6 km.h(-1), 0% grade and 6% grade), and one horizontal running speed (8 km.h(-1), 0% grade), on a treadmill. Energy expenditure and oxygen consumption (VO2) served as the criterion measures. Comparison of RT3 estimates (counts and energy expenditure) demonstrated significant differences at 4, 6, and 8 km.h(-1) on level ground (P < 0.01), while no significant differences were noted between horizontal and graded walking at 4 and 6 km.h(-1). Correlation and regression analyses indicated no advantage of vector magnitude over the vertical plane (X) alone. A strong relationship between RT3 estimates and indirect calorimetry across all speeds was obtained (r = 0.633-0.850, P < 0.01). A child-specific prediction equation (adjusted R2 = 0.753) was derived and cross-validated that offered a valid energy expenditure estimate for walking/running activities. Despite recognized limitations, the RT3 may be a useful tool for the assessment of children's physical activity during walking and running.


Assuntos
Metabolismo Energético/fisiologia , Monitorização Ambulatorial/instrumentação , Caminhada/fisiologia , Aceleração , Análise de Variância , Calorimetria Indireta , Criança , Feminino , Frequência Cardíaca/fisiologia , Humanos , Masculino , Consumo de Oxigênio/fisiologia , Análise de Regressão
10.
Metabolism ; 56(8): 1037-43, 2007 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-17618947

RESUMO

Very low-density lipoprotein triacylglycerol (VLDL-TG) turnover rate was evaluated in the morning, 12 hours after a single bout of brisk walking (90 minutes at approximately 60% of VO2max; EXE), compared to a resting control period (CON) in 10 recreationally active men. VLDL-TG fractional catabolic rate was calculated from the decay in isotopic enrichment after a bolus injection of [2H5]glycerol. Plasma VLDL-TG concentration was 24% lower in the morning after the EXE trial compared to control (0.47+/-0.04 and 0.36+/-0.04 mmol L(-1), for CON and EXE, respectively; P<.01). Serum insulin (7.4+/-0.7 and 5.6+/-0.4 mIU L(-1), CON and EXE, respectively; P<.05) and plasma glucose (5.6+/-0.1 and 5.4+/-0.1 mmol/L, CON and EXE, respectively; P<.05) concentrations were also significantly lower in the EXE trial. Insulin sensitivity (homeostasis model assessment [HOMA] index) was improved by 27% in EXE compared with the CON trial (P<.05).VLDL-apolipoprotein B-100 and plasma fatty acid concentrations were similar in the two trials. Hepatic VLDL-TG secretion rates were not significantly affected by exercise (13.1+/-1.2 and 13.2+/-1.6 micromol.min(-1) for the CON and EXE trials, respectively), whereas VLDL-TG clearance rate increased by 36% (28.1+/-1.3 and 38.1+/-3.5 mL.min(-1) for the CON and EXE trials, respectively; P<.05). It is concluded that the decrease in fasting plasma VLDL-TG concentration observed 12 hours after brisk walking is related mainly to increased VLDL-TG clearance from plasma.


Assuntos
Lipoproteínas VLDL/metabolismo , Triglicerídeos/metabolismo , Caminhada/fisiologia , Adulto , Limiar Anaeróbio/fisiologia , Composição Corporal/fisiologia , Estatura/fisiologia , Peso Corporal/fisiologia , Dieta , Humanos , Resistência à Insulina/fisiologia , Masculino , Consumo de Oxigênio/fisiologia
11.
Eur J Appl Physiol ; 95(1): 35-41, 2005 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-15976998

RESUMO

In order to examine the physical and physiological demands of water polo, we assessed the profile of elite water polo players. Nineteen male professional water polo players (age: 25.5+/-5.0 years, height: 184.5+/-4.3 cm body mass: 90.7+/-6.4 kg) underwent body composition assessment by dual-energy X-ray absorptiometry. We also evaluated peak oxygen consumption VO2peak, lactate threshold (LT), energy cost of swimming (C s), anaerobic capacity and isokinetic shoulder strength. Body fat (%) was 16.8+/-4.4, lean mass (LM) 75.1+/-4.9 kg and bone mineral density (BMD) 1.37+/-0.07 g.cm(-2) . VO2peak was 57.9+/-7 ml.kg(-1). min(-1) . LT was identified at 3.9+/-0.7 mmol.l(-1) at a swimming velocity (v) of 1.33+/-0.05 m.s(-1) with a heart rate of 154+/-7 bpm, corresponding to an intensity of 83+/-9 of VO2peak. The average C s of swimming at the LT was 1.08+/-0.04 kJ.m(-1).C s at LT was correlated to body mass index (BMI) (r=0.22, P=0.04) and to swimming performance at 400 m (r=0.86, P=0.01) and 4 x 50 m (r=0.84, P<0.01). Internal rotator muscles were stronger compared to the external rotators by a 2:1 ratio. This study provides a quantitative representation of both physical and physiological demands of water polo and proposes a comprehensive battery of tests that can be used for assessing the status of a team.


Assuntos
Antropometria/métodos , Composição Corporal/fisiologia , Tamanho Corporal/fisiologia , Resistência Física/fisiologia , Esforço Físico/fisiologia , Natação/fisiologia , Natação/estatística & dados numéricos , Adulto , Grécia/epidemiologia , Humanos , Masculino , Consumo de Oxigênio/fisiologia , Esportes/fisiologia , Esportes/estatística & dados numéricos
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