Relationship Between Dual-Energy X-Ray Absorptiometry, Ultrasonography, and Anthropometry Methods to Estimate Muscle Mass and Muscle Quality in Older Adults.

Decreased muscle quality (MQ) may explain functional capacity impairments during aging. Thus, it is essential to verify the interaction between MQ and functional capacity in older adults. We investigated the relationship between MQ and functional capacity in older adults (n = 34; 66.3 ± 4.6 year). MQ was estimated by maximum strength of knee extensors normalized to thigh muscle mass. Maximum strength was assessed on an isokinetic dynamometer (peak torque), while dual-energy X-ray absorptiometry (DXA), ultrasonography, and anthropometry were used to determine thigh muscle mass. Functional capacity was verified by 30-s sit to stand and timed up and go tests. Significant correlations were found between MQ assessed by DXA with 30-s sit to stand (r = .35; p < .05) and timed up and go (r = -.47; p < .05), and MQ assessed by anthropometry with timed up and go (r = -.41; p < .05), but not between MQ assessed by ultrasonography with functional capacity (p > .05). No significant relationship between muscle mass with functional capacity was observed. Thus, MQ assessed by DXA and MQ assessed by anthropometry may partially explain functional capacity in older adults. Interestingly, muscle mass alone did not explain performance in functional tests in this population.

Effects of omega-3 supplementation on muscle damage after resistance exercise in young women: a randomized placebo-controlled trial.

BACKGROUND: Omega-3 is a nutritional strategie that have been used to recover muscles from exercise-induced muscle damage in a preventive perspective. AIM: To verify whether omega-3 (ω-3) supplementation after a session of resistance exercise facilitates muscle recovery in women undergoing a balanced diet. METHODS: This clinical trial was registered under the number NCT02839525. Thirty healthy women (22.2 ± 3.3 years) participated in this double-blinded, placebo-controlled trial. They were randomly distributed into ω-3 (n=15) and placebo (n=15) groups. They ingested ω-3 fish oil (3200 mg/day) or placebo (olive oil) at the dinner after the exercise bout (10 sets of 10 unilateral eccentric contractions in a knee extension chair), as well as at lunch for the three subsequent days. In addition, both groups followed a balanced diet along the four days. Muscle soreness and maximal isometric and isokinetic voluntary contractions were assessed immediately before, and 24, 48, and 72 hours after the resistance exercise. MAIN FINDINGS: There was no significant group-time interaction for any outcome. Participants presented increased levels of muscle soreness and reduced muscle strength capacity along the three days after exercise. There was no difference between placebo and ω-3 groups. CONCLUSION: Supplementation of ω-3 fish oil for three days after resistance exercise provided no additional benefits compared to placebo supplementation on recovery of healthy young women following a balanced diet.

Supplementation of Probiotics and Its Effects on Physically Active Individuals and Athletes: Systematic Review.

The aim of this study was to conduct a systematic review of the effects of probiotic supplementation on physically active individuals. The participants, interventions, comparisons, outcome and study design inclusion criteria were (a) studies involving healthy adults or older subjects of both sexes who did physical exercise (including athletes and physically active individuals), (b) interventions with probiotics, (c) inclusion of a control group, (d) outcomes not previously defined, and (e) clinical trials and randomized clinical trials, with no language or date restrictions. The search was conducted in the following scientific databases: MEDLINE, Embase, SciELO, Scopus, and Lilacs. Search terms were "Probiotics" OR "Prebiotics" OR "Microbiota" AND "Exercise" OR "Athletes." The articles were first screened by title and abstract by two independent reviewers and disagreements resolved by a third reviewer. Data were extracted independently by the same two reviewers; results were extracted in duplicate and then compared to avoid errors. A total of 544 articles were retrieved and 24 were included. A total of 1,680 patients were included, most of them being male (n = 1,134, 67.5%), with a mean age of 30.9 ± 6.1 years. Following probiotic supplementation, positive effects have been reported for several outcomes including respiratory tract infection, immunologic markers, and gastrointestinal symptoms in both athletes and nonathletes. However, published studies have distinct protocols and measured outcomes, and some of them have small sample size and failed to prove beneficial effect on probiotic supplementation, leading to inconclusive results for standardized supplementation protocols.

[Dietary intake and cardiovascular risk among people living with HIV/AIDS]. / Consumo alimentar e risco cardiovascularem pessoas vivendo com HIV/AIDS.

This cross-sectional study evaluated the food intake patterns related to cardiovascular risk disease among people living with HIV/AIDS (PLWHA) with viral suppression and receiving highly active antiretroviral therapy (HAART). Food intake was obtained by the annual food frequency questionnaire, separated into two groups, healthy and unhealthy food related intake and cardiovascular disease. Data were analyzed using Student's t Test for independent samples or the Mann-Whitney U Test and Fisher's exact test, with a significance level of p < 0.05. The sample consisted of 45 individuals with HIV/AIDS (60% female). The intake of unhealthy foods for cardiovascular risk was greater compared to the intake of healthy foods, both in men (3.91 ± 0.26 vs. 2.79 ± 0.32 p = 0.01) and women (3.40 ± 0.23 vs. 2.60 ± 0.29 p = 0.04). Metabolic syndrome prevalence was 33.3% in men and 37% in women. Men presented hypertriglyceridemia (50%) and low HDL (44%) and women presented central obesity (54%, p = 0.05 vs. men) hypercholesterolemia (66.7% p = 0.02 vs. men) and hypertriglyceridemia (46%). Study results indicate the presence of unhealthy food intake patterns and a high prevalence of cardiovascular risk factors in the evaluated subjects.

O presente estudo analisou o consumo alimentar e a presença de fatores de risco cardiovasculares em pessoas vivendo com HIV/AIDS (PVHA) em uso regular de antirretrovirais. O consumo alimentar foi avaliado por meio de questionário de frequência alimentar anual, dividido em alimentos protetores e não protetores para doença cardiovascular (DCV). Os dados foram calculados pelo Teste t de Student para amostras independentes, pelo Teste U de Mann-Whitney e pelo teste exato de Fischer, considerando significativo p < 0,05. A amostra consistiu de 45 PVHA (60% do sexo feminino). O consumo de alimentos não protetores para o risco cardiovascular foi maior do que o de alimentos protetores nos homens (3,91 ± 0,26 vs. 2,79 ± 0,32 p = 0,01) e nas mulheres (3,40 ± 0,23 vs. 2,60 ± 0,29 p = 0,04). A prevalência de síndrome metabólica foi 33,3% nos homens e 37% nas mulheres. Os homens apresentaram hipertrigliceridemia (50%) e baixas concentrações de HDL-c (44%), enquanto que as mulheres apresentaram hipertrigliceridemia (46%), hipercolesterolemia (66,7%, p < 0,02 vs. homens) e obesidade central (54%, p < 0,05 vs. homens). Os resultados deste estudo indicam a presença de padrão de consumo alimentar inadequado e elevada prevalência de fatores de risco relacionados às DCV nos indivíduos avaliados.

Consumo alimentar e risco cardiovascularem pessoas vivendo com HIV/AIDS / Dietary intake and cardiovascular risk among people living with HIV/AIDS

Resumo O presente estudo analisou o consumo alimentar e a presença de fatores de risco cardiovasculares em pessoas vivendo com HIV/AIDS (PVHA) em uso regular de antirretrovirais. O consumo alimentar foi avaliado por meio de questionário de frequência alimentar anual, dividido em alimentos protetores e não protetores para doença cardiovascular (DCV). Os dados foram calculados pelo Teste t de Student para amostras independentes, pelo Teste U de Mann-Whitney e pelo teste exato de Fischer, considerando significativo p < 0,05. A amostra consistiu de 45 PVHA (60% do sexo feminino). O consumo de alimentos não protetores para o risco cardiovascular foi maior do que o de alimentos protetores nos homens (3,91 ± 0,26 vs. 2,79 ± 0,32 p = 0,01) e nas mulheres (3,40 ± 0,23 vs. 2,60 ± 0,29 p = 0,04). A prevalência de síndrome metabólica foi 33,3% nos homens e 37% nas mulheres. Os homens apresentaram hipertrigliceridemia (50%) e baixas concentrações de HDL-c (44%), enquanto que as mulheres apresentaram hipertrigliceridemia (46%), hipercolesterolemia (66,7%, p < 0,02 vs. homens) e obesidade central (54%, p < 0,05 vs. homens). Os resultados deste estudo indicam a presença de padrão de consumo alimentar inadequado e elevada prevalência de fatores de risco relacionados às DCV nos indivíduos avaliados.

Abstract This cross-sectional study evaluated the food intake patterns related to cardiovascular risk disease among people living with HIV/AIDS (PLWHA) with viral suppression and receiving highly active antiretroviral therapy (HAART). Food intake was obtained by the annual food frequency questionnaire, separated into two groups, healthy and unhealthy food related intake and cardiovascular disease. Data were analyzed using Student's t Test for independent samples or the Mann-Whitney U Test and Fisher's exact test, with a significance level of p < 0.05. The sample consisted of 45 individuals with HIV/AIDS (60% female). The intake of unhealthy foods for cardiovascular risk was greater compared to the intake of healthy foods, both in men (3.91 ± 0.26 vs. 2.79 ± 0.32 p = 0.01) and women (3.40 ± 0.23 vs. 2.60 ± 0.29 p = 0.04). Metabolic syndrome prevalence was 33.3% in men and 37% in women. Men presented hypertriglyceridemia (50%) and low HDL (44%) and women presented central obesity (54%, p = 0.05 vs. men) hypercholesterolemia (66.7% p = 0.02 vs. men) and hypertriglyceridemia (46%). Study results indicate the presence of unhealthy food intake patterns and a high prevalence of cardiovascular risk factors in the evaluated subjects.

Dietary intake in high-level swimmers. A 32-week prospective cohort study

AIMS: To determine whether high-level swimmers present adequate energy and macronutrient intake during each training phase of the season. METHODS: A 32-week prospective cohort study was conducted with 18 elite swimmers (10 men, 20±2 years; 8 women, 20±3 years) from a competitive swimming club. This period comprised two training macrocycles, each one divided in four training phases: general, mixed, specific and competition. Dietary intake, estimated energy expenditure and daily energy requirements were assessed in every training phase. Body composition was evaluated five times throughout the season. Energy and macronutrient consumption were compared with the energy expenditure and the literature recommendations, respectively. RESULTS: Athletes maintained a relatively constant dietary intake throughout the season, regardless the different needs of each training phase. The balance between energy consumption and expenditure was negative in all training phases (p=0.02; d between 1.5-6.2) for women, while men did so in half of phases (p<0.01; d between 0.3-4.1). Swimmers had higher protein intake than recommendations in 73% of the evaluations, while carbohydrate and lipids intake were lower than recommendations in 76% and 69% of the evaluations, respectively. CONCLUSION: Athletes did not meet the energy demands and specific macronutrient requirements of each training phase of the competitive season.(AU)

Effects of protein supplementation in older adults undergoing resistance training: a systematic review and meta-analysis.

BACKGROUND: Older individuals present reductions in muscle mass and physical function, as well as a blunted muscle protein synthesis response to amino acid administration and physical activity. Although resistance training is an effective intervention to slow down muscle impairments in the elderly, there is no consensus whether a combination with protein supplementation could offer additional benefits to an older population. OBJECTIVE: We aimed to systematically summarize and quantify whether protein supplementation could optimize the effects of resistance training on muscle mass and strength in an aged population. DESIGN: A structured literature search was conducted on MEDLINE (PubMed), Cochrane, EMBASE and LILACS databases. The search had no period or language restrictions. Inclusion criteria comprised study design (randomized controlled trials-RCTs), sample mean age (60 years and over) and intervention (a resistance training program for a period of 6 weeks or longer combined with protein or amino acids supplementation). Two independent reviewers performed the study selection and data extraction. Continuous data on fat-free mass, muscle mass and muscle strength were pooled using a random-effects model. RESULTS: Of the 540 articles reviewed, 29 eligible articles underwent full-text evaluation. Nine RCTs (462 subjects) met the inclusion criteria and were included in the study. The mean age of the participants ranged from 61 to 79 years old. Protein supplementation protocols varied widely throughout the studies. Three studies used quantities related to the body mass of the participants and the other six trials provided supplements in daily amounts, independently of subjects' body masses. Overall, protein supplementation in combination with resistance training was associated with gains in fat-free mass, resulting in a standardized mean difference (SMD) of 0.23 [95% confidence interval (CI), 0.05-0.42]. However, protein supplementation was not associated with changes in muscle mass (0.14, 95% CI -0.05 to 0.32) or muscle strength (0.13, 95% CI -0.06 to 0.32). LIMITATIONS: Studies among the very elderly population are scarce. The variation regarding the supplementation protocol, namely the different protein sources, amounts and timing of ingestion, also made it harder to compare the results. The general quality of the studies was low, reflecting increased risk of bias in some studies. Despite these limitations, this systematic review provides a general overview of the role of protein supplementation with no other added macronutrients to augment muscle mass and strength during resistance training in older adults. CONCLUSION: Combining protein supplementation with resistance training is effective for eliciting gains in fat-free mass among older adults, but does not seem to increase muscle mass or strength.

Compulsão alimentar e bulimia nervosa em praticantes de exercício físico / Compulsión alimentaria y bulimia nerviosa en practicantes de ejercicio físico

INTRODUÇÃO: Estudos nacionais mostram variações na prevalência de compulsão alimentar entre 14,9 a 18,1%, enquanto a bulimia nervosa (BN) apresenta-se em torno de 1 a 3,6%. Indivíduos que apresentam transtornos alimentares procuram espaços onde o exercício físico é estimulado e assim mascaram características da doença, exercitando-se compulsivamente após um episódio de compulsão alimentar. OBJETIVO: Identificar a prevalência de transtorno da compulsão alimentar periódica (TCAP) e bulimia nervosa em praticantes de exercício físico associando ao estado nutricional, modalidade, frequência, duração e objetivo da prática do exercício físico. MÉTODOS: Estudo transversal composto por 103 indivíduos maiores de 18 anos com idade média de 37,7 (DP±15,6) anos, de ambos os sexos, praticantes de exercício físico há pelo menos três meses ininterruptos antes do início da pesquisa. Para análise da prevalência de TCAP e BN foi utilizado o Questionário sobre Alimentação e Peso (QEWP-R) e um questionário específico sobre exercício físico. O estado nutricional foi classificado conforme o IMC. RESULTADOS: A prevalência de TCAP entre os indivíduos praticantes de exercício físico foi de 0,97%. Houve associação entre valores de IMC mais alto (p=0,026), idade menor (para TCAP p=0,036, BN p=0,01) e objetivo da prática de exercício físico declarado "estética" (para TCAP p=0,011 e BN p=0,043) com maiores pontuações nos escores de TCAP e BN. CONCLUSÃO: A prevalência de TCAP e BN encontrada neste estudo está de acordo com o referido na literatura internacional. Não foram encontradas associações entre compulsão alimentar e maior frequência ...

INTRODUCTION: National studies have shown variations on the prevalence of binge eating ranging from 14.9 to 18.1%, while Bulimia Nervosa rates (BN) have been reported from 1 a 3.6%. Individuals with eating disorders may look for environments where physical exercise is stimulated, and therefore mask their disease's characteristics, doing exercises compulsively after a binge eating episode. OBJECTIVE: To identify the prevalence of Binge Eating Disorder (BED) and BN in physical exercise practitioners, and verify its associations with nutritional status, modality, frequency, duration and the goals of the physical exercise practice. METHODS: Cross-sectional study composed with 103 individuals, over 18 years old, mean age 37.7 (SD±15.6) years old, of both genders, physical exercise practitioners for a period of at least three months uninterruptedly before the beginning of the study. In order to analyze the prevalence of BED and BN, the Questionnaire on Eating and Weight Patterns - Revised (QEWP-R) was used, as well as a specific questionnaire approaching physical exercise. The nutritional status was classified based on BMI. RESULTS: The BED prevalence in physical exercise practitioners was 0.97%. There were associations between higher BMI values (p= 0.026), lower age (TCAP p= 0.036; BN p= 0.01) and "aesthetics" goals as a reason for practicing physical exercise (TCAP p= 0.011; BN p= 0.043) with higher scores in BED and BN. CONCLUSION: The prevalence of BED and BN found in this study was in accordance to what has been reported in the international literature. No association was found between binge eating and higher frequency of physical exercise. .

INTRODUCCIÓN: Estudios nacionales muestran variaciones en la prevalencia de compulsión alimentaria entre 14,9 a 18,1%, mientras que la bulimia nerviosa (BN) se presenta en torno de 1 a 3,6%. Los individuos que presentan trastornos alimentarios buscan espacios en donde el ejercicio físico es estimulado y así enmascaran características de la enfermedad, ejercitándose compulsivamente después de un episodio de compulsión alimentaria. OBJETIVO: Identificar la prevalencia de trastorno de la compulsión alimentaria periódica (TCAP) y bulimia nerviosa en practicantes de ejercicio físico, asociando con el estado nutricional, modalidad, frecuencia, duración y objetivo de la práctica del ejercicio físico. MÉTODOS: Estudio transversal compuesto por 103 individuos, mayores de 18 años con edad promedio de 37,7 (DP±15,6) años, de ambos sexos, practicantes de ejercicio físico desde hace por lo menos tres meses ininterrumpidos antes del inicio de la encuesta. Para análisis de la prevalencia de TCAP y BN fue utilizado el Cuestionario sobre Alimentación y Peso (QEWP-R) y un cuestionario específico sobre ejercicio físico. El estado nutricional fue clasificado de acuerdo al IMC. RESULTADOS: La prevalencia de TCAP entre los individuos practicantes de ejercicio físico fue de 0,97%. Hubo asociación entre valores de IMC más altos (p=0,026), edad menor (para TCAP p=0,036, BN p=0,01) y objetivo de la práctica de ejercicio físico "estética" (para TCAP p=0,011 y BN p=0,043) con mayores puntuaciones en los escores de TCAP y BN. CONCLUSIÓN: La prevalencia de TCAP y BN encontrada en este estudio se encuentra de acuerdo con lo referido en la literatura internacional. No fueron encontradas asociaciones entre compulsión alimentaria y mayor frecuencia de ejercicio físico. .

Echo intensity is negatively associated with functional capacity in older women.

Muscle quality is an important component of the functional profile of the elderly, and previous studies have shown that both muscle quantity and quality independently contribute to muscle strength of the elderly. This study aimed to verify the association between quadriceps femoris muscle quality, analyzed by specific tension and echo intensity (EI), and rate of torque development (RTD) of the knee extensor muscles with the functional performance in elderly active women. Forty-five healthy, active elderly women (70.28 ± 6.2) volunteered to participate in this study. Quadriceps femoris muscle thickness and EI were determined by ultrasonography. Knee extension isometric peak torque and RTD were obtained from maximal isometric voluntary contraction curves. The 30-s sit-to-stand-up (30SS) test and usual gait speed (UGS) test were applied to evaluate functional performance. Rectus femoris EI presented a significant negative correlation with 30SS (r = -0.505, P < 0.01), UGS (r s = -0.347, P < 0.05), and isometric peak torque (r = -0.314, P < 0.05). The quadriceps femoris EI correlated negatively with 30SS (r = -0.493, P < 0.01) and isometric peak torque (r = -0.409, P < 0.01). The EI of the quadriceps femoris and all quadriceps muscle portions significantly correlated with RTD. RTD significantly correlated with physical performance in both functional tests (30SS = r = 0.340, P < 0.05; UGS = r s = 0.371, P < 0.05). We concluded that muscle EI may be an important predictor of functional performance and knee extensor power capacity in elderly, active women.

Strength training prior to endurance exercise: impact on the neuromuscular system, endurance performance and cardiorespiratory responses.

This study aimed to investigate the acute effects of two strength-training protocols on the neuromuscular and cardiorespiratory responses during endurance exercise. Thirteen young males (23.2 ± 1.6 years old) participated in this study. The hypertrophic strength-training protocol was composed of 6 sets of 8 squats at 75% of maximal dynamic strength. The plyometric strength-training protocol was composed of 6 sets of 8 jumps performed with the body weight as the workload. Endurance exercise was performed on a cycle ergometer at a power corresponding to the second ventilatory threshold until exhaustion. Before and after each protocol, a maximal voluntary contraction was performed, and the rate of force development and electromyographic parameters were assessed. After the hypertrophic strength-training and plyometric strength-training protocol, significant decreases were observed in the maximal voluntary contraction and rate of force development, whereas no changes were observed in the electromyographic parameters. Oxygen uptake and a heart rate during endurance exercise were not significantly different among the protocols. However, the time-to-exhaustion was significantly higher during endurance exercise alone than when performed after hypertrophic strength-training or plyometric strength-training (p <0.05). These results suggest that endurance performance may be impaired when preceded by strength-training, with no oxygen uptake or heart rate changes during the exercise.

Disordered eating behaviors and body image in male athletes.

OBJECTIVE: To identify disordered eating behaviors and body image dissatisfaction, as well as their relationship to body fat (BF), among male athletes in high risk sports for eating disorders. METHODS: One hundred and fifty-six male athletes were divided into the following categories: weight-class sports, sports where leanness improves performance, and sports with aesthetic ideals. BF was assessed and three questionnaires were used: the Eating Attitudes Test; the Bulimic Investigatory Test, Edinburgh; the Body Shape Questionnaire. RESULTS: Disordered eating behaviors and body image dissatisfaction were found in 43 (27.6%) and 23 athletes (14.7%), respectively, and an association was detected between the two variables (p < 0.001). Athletes with and without disordered eating behaviors did not differ in %BF (11.0 ± 5.2% and 9.8 ± 4.0%, respectively; p = 0.106). However, athletes with body image dissatisfaction had higher %BF than those who were satisfied (12.6 ± 5.9% and 9.7 ± 3.9%, respectively; p = 0.034). There were no differences in BF, frequency of disordered eating behaviors, and body image dissatisfaction between sports categories. CONCLUSION: Nearly one-quarter of athletes showed disordered eating behaviors, which was associated with body image dissatisfaction. Athletes with higher %BF were more likely to be dissatisfied with body image. There was no difference in eating behavior and body image between athletes from different sports categories.

Effects of resistance training associated with whey protein supplementation on liver and kidney biomarkers in rats.

The aim of this study was to investigate the impact of whey protein (WP) supplementation and resistance training (RT) on liver and kidney biomarkers. The sedentary + WP group showed higher levels of plasma liver and kidney dysfunction markers compared with the other groups. In addition, WP supplementation associated with RT resulted in physiologic cardiac hypertrophy. WP supplementation without RT affected liver and kidney function.

Disordered eating behaviors and body image in male athletes

Objective: To identify disordered eating behaviors and body image dissatisfaction, as well as their relationship to body fat (BF), among male athletes in high risk sports for eating disorders. Methods: One hundred and fifty-six male athletes were divided into the following categories: weight-class sports, sports where leanness improves performance, and sports with aesthetic ideals. BF was assessed and three questionnaires were used: the Eating Attitudes Test; the Bulimic Investigatory Test, Edinburgh; the Body Shape Questionnaire. Results: Disordered eating behaviors and body image dissatisfaction were found in 43 (27.6%) and 23 athletes (14.7%), respectively, and an association was detected between the two variables (p < 0.001). Athletes with and without disordered eating behaviors did not differ in %BF (11.0±5.2% and 9.8±4.0%, respectively; p = 0.106). However, athletes with body image dissatisfaction had higher %BF than those who were satisfied (12.6±5.9% and 9.7±3.9%, respectively; p = 0.034). There were no differences in BF, frequency of disordered eating behaviors, and body image dissatisfaction between sports categories. Conclusion: Nearly one-quarter of athletes showed disordered eating behaviors, which was associated with body image dissatisfaction. Athletes with higher %BF were more likely to be dissatisfied with body image. There was no difference in eating behavior and body image between athletes from different sports categories. .

Perda de eletrólitos durante uma competição de duatlo terrestre no calor / Electrolyte losses during a land based duatlhon competition in the heat

Eventos esportivos prolongados, como o duatlo (6 km corrida, 26 km ciclismo e 4 km corrida) podem levar o atleta a um desequilíbrio hidroeletrolítico, devido a perdas elevadas de suor, em especial se realizados no calor. O presente estudo avaliou as perdas de sódio (Na+), potássio (K+) e cloreto (Cl-) durante uma competição de duatlo realizada no calor (31,2 ºC e 51 por cento de umidade relativa do ar), analisando a composição do suor e os níveis sanguíneos destes eletrólitos. Doze atletas fizeram parte deste estudo. Coletas de sangue foram realizadas antes e após a competição, e o suor foi coletado utilizando-se adesivos específicos. O tempo médio para completar a competição foi de 85,0 ± 6,57 min. O percentual de desidratação foi 3,0 ± 0,92 por cento. A reposição de líquidos perdidos durante a competição foi 31 ± 18,7 por cento. A taxa de sudorese foi 1,86 ± 0,56 Lòh-1. A concentração de Na+, K+ e Cl- no suor foi 71 ± 26,05 mmolòL-1, 5,43 ± 1,98 mmolòL-1 e 58,93 ± 25,99 mmolòLÕ, respectivamente. A perda total de Na+, K+ e Cl- no suor foi 132,11 ± 62,82 mmol, 10,09 ± 5,01 mmol e 109,75 ± 58,49 mmol, respectivamente. Em conclusão, os atletas não ingeriram líquido suficiente para repor o volume de fluidos perdido. Além disto, os participantes apresentaram elevada taxa de sudorese acompanhada de perdas de Na+, K+ e Cl-. Apesar disso, não ocorreram alterações nas concentrações de eletrólitos séricos.

Prolonged sports events such as duathlon (6 km running, 26 km cycling and 4 km running), may lead the athlete to a fluid and electrolyte imbalance, due to high sweat rates, especially in a hot environment. The present study evaluated sodium (Na+), potassium (K+) and chloride (Cl-) losses during a duathlon competition performed in the heat (31,2 ºC and 51 percent relative humidity), analyzing the sweat composition and blood levels of these electrolytes. Twelve athletes took part in this study. Blood samples were obtained pre- and post-exercise and sweat was collected using sweat patches. The average time to complete the competition was 85.0 ± 6.57 min. The percentage of dehydration was 3.0 ± 0.92 percent. The replacement of fluid losses was 31 ± 18.7 percent. The sweat rate was 1.86 ± 0.56 Lòh-1. Sweat Na+, K+, and Cl-concentrations were 71 ± 26.05 mmolòL-1, 5.43 ±1.98 mmolòL-1 and 58.93 ± 25.99 mmolòL-1, respectively. The total sweat loss of Na+, K+ and Cl- was 132.11± 62.82 mmol, 10.09 ± 5.01 mmol and 109.75 ± 58.49 mmol, respectively. In conclusion, the athletes did not drink enough liquid to replace their volume of fluid loss. Furthermore, the participants presented high sweat rate accompanied by losses of Na+, K+ and Cl-. However, serum electrolyte concentrations were not changed.

Efeito do exercício de ultrarresistência sobre parâmetros de estresse oxidativo / Effect of the ultra-endurance exercise on oxidative stress parameters

INTRODUÇÃO: Exercícios de longa duração podem levar ao desequilíbrio entre os sistemas pró e antioxidante, acarretando dano a lipídeos, proteínas e DNA. Entretanto, alguns estudos avaliando triatlo Ironman observaram proteção aos lipídeos. OBJETIVO: Avaliar parâmetros de estresse oxidativo após uma competição de meio Ironman. MÉTODOS: Participaram 11 sujeitos com idade de 31,1 ± 3,3 anos, massa corporal de 72,4 ± 5,4kg, estatura de 176,2 ± 4,8cm, gordura corporal de 9,8 ± 3,3%, VO2máx na corrida de 60,7 ± 6,0mL/kg/min. Foram mensurados: dano a lipídeos através da quimiluminescência nos eritrócitos e TBARS no plasma, dano a proteínas através das carbonilas plasmáticas, ácido úrico e compostos fenólicos plasmáticos, assim como a atividade antioxidante enzimática da catalase, superóxido dismutase e glutationa peroxidase nos eritrócitos. RESULTADOS: Houve redução na atividade da enzima superóxido dismutase (23,24 ± 1,49 para 20,77 ± 2,69U SOD/mg proteína, p = 0,045), e aumento no ácido úrico (40,81 ± 10,68 para 60,33 ± 6,71mg/L, p < 0,001) logo após a competição. Não houve diferença estatisticamente significativa na atividade das enzimas antioxidantes catalase e glutationa peroxidase e nos compostos fenólicos totais, assim como não foi observado dano a lipídeos (TBARS e quimiluminescência) e proteínas (carbonilas). CONCLUSÃO: Esse grupo de atletas não sofreu estresse oxidativo, provavelmente devido à liberação de ácido úrico e outros antioxidantes no plasma.

Ultra-endurance exercises can cause imbalance between the pro and antioxidant systems, leading to lipid, protein and DNA damage. Nevertheless, some studies evaluating Ironman triathlon found protection to lipids. PURPOSE: To evaluate oxidative stress parameters after a half-Ironman competition. METHODS: Eleven subjects aged 31.1 ± 3.3 yr, body weight 72.4 ± 5.4 kg, height 176.2 ± 4.8 cm, body fat 9.8 ± 3.3%, VO2máx on run 60.7 ± 6.0 mL/kg/min, participated in this study. The following data were measured: lipid damage by chemoluminescence in erythrocyte and TBARS in plasma, protein damage by plasmatic carbonyls, uric acid and phenolic compounds, as well as the antioxidant enzymatic activity of catalase, superoxide dismutase and glutathione peroxidase in erythrocytes. RESULTS: Reduction in superoxide dismutase (23.24 ± 1.49 to 20.77 ± 2.69 U SOD/mg protein, p = 0.045), and increase in uric acid (40.81 ± 10.68 to 60.33 ± 6.71 mg/L, p < 0.001) were found immediately after the competition. No statistically significant differences were found in catalase and glutathione peroxidase or phenolic compounds. Lipid (TBARS and chemoluminescence) or protein (carbonyl) damage was not observed either. CONCLUSION: These athletes did not suffer oxidative stress, probably due to uric acid and other plasmatic antioxidants release in the plasma.

Hormônio do crescimento e exercício físico: considerações atuais: [revisão] / Growth hormone and physical exercise: current considerations: [revision]

Embora o hormônio do crescimento (GH) seja um dos hormônios mais estudados, vários de seus aspectos fisiológicos ainda não estão integralmente esclarecidos, incluindo sua relação com o exercício físico. Estudos mais recentes têm aumentado o conhecimento a respeito dos mecanismos de ação do GH, podendo ser divididos em: 1) ações diretas, mediadas pela rede de sinalizações intracelulares, desencadeadas pela ligação do GH ao seu receptor na membrana plasmática; e 2) ações indiretas, mediadas principalmente pela regulação da síntese dos fatores de crescimento semelhantes à insulina (IGF). Tem sido demonstrado que o exercício físico é um potente estimulador da liberação do GH. A magnitude deste aumento sofre influência de diversos fatores, em especial, da intensidade e do volume do exercício, além do estado de treinamento. Atletas, normalmente, apresentam menor liberação de GH induzida pelo exercício que indivíduos sedentários ou pouco treinados. Evidências experimentais demonstram que o GH: 1) favorece a mobilização de ácidos graxos livres do tecido adiposo para geração de energia; 2) aumenta a capacidade de oxidação de gordura e 3) aumenta o gasto energético.

Although growth hormone (GH) is one of the most extensively studied hormones, various aspects related to this hormone have not been completely established, including its relationship with physical exercise. Recent studies have contributed to the understanding of the mechanisms of action of GH, which can be divided into 1) direct actions mediated by intracellular signals that are triggered by the binding of GH to its receptor on the plasma membrane, and 2) indirect actions mediated mainly by the regulation of the synthesis of insulin-like growth factors (IGF). Physical exercise has been shown to be a potent stimulator of GH release, especially in young men and women. The magnitude of this increase is influenced by several factors, especially the intensity and volume of exercise, in addition to training status. In this respect, athletes normally present a lower exercise-induced GH release than sedentary or poorly trained individuals. Experimental evidence indicates that GH may 1) favor the mobilization of free fatty acids from adipose tissue for energy generation, 2) increase the capacity of fat oxidation, and 3) increase energy expenditure.

Oxidative stress after three different intensities of running.

In 8 trained subjects (T) and 9 untrained subjects (UT), lipid peroxidation (LPO), total antioxidant capacity (TRAP), superoxide dismutase, catalase, and glutathione peroxidase (GPx) activities were measured in the blood before and after three different intensities of exercise on the treadmill, determined from ventilatory threshold and maximal oxygen uptake data, obtained from a maximal aerobic power test. In plasma, LPO decreased from 3589 +/- 193 to 3274 +/- 223 cps x mg Hb(-1) (p < 0.05), and TRAP increased from 304 +/- 45 to 384 +/- 57 micromol x L(-1) trolox (p < 0.05) after high intensity exercise in T. GPx activity increased in the T group as compared to the UT group, after exercise in moderate (25.90 +/- 3.79 to 15.05 +/- 3.23 nM x min(-1) x mg protein(-1)) and high (21.75 +/- 4.91 to 12.1 +/- 2.46 nM x min(-1) x mg protein(-1)) intensities (p < 0.05). Superoxide dismutase activity increased after exercise at low (8.35 +/- 0.85 to 9.23 +/- 1.03 U SOD x mg protein(-1)) and moderate (8.89 +/- 0.98 to 10.44 +/- 0.86 U SOD x mg protein(-1)) intensity in UT (p < 0.05). There were no changes in catalase activity. These findings indicate that exercise in this model did not increase lipid peroxidation, probably because of the alterations in TRAP and enzymatic antioxidants.

Radicais livres de oxigênio e exercício: mecanismos de formação e adaptação ao treinamento físico / Oxygen free radicals and exercise: mechanisms of synthesis and adaptation to the physical training

O interesse acerca dos mecanismos de geração e adaptação de radicais livres de oxigênio (RLO) ao exercício aumentou significativamente a partir da demonstração de sua relação com o consumo de oxigênio. Os RLO são formados pela redução incompleta do oxigênio, gerando espécies que apresentam alta reatividade para outras biomoléculas, principalmente lipídios e proteínas das membranas celulares e, até mesmo, o DNA. As injúrias provocadas por estresse oxidativo apresentam efeitos cumulativos e estão relacionadas a uma série de doenças, como o câncer, a aterosclerose e o diabetes. O exercício físico agudo, em função do incremento do consumo de oxigênio, promove o aumento da formação de RLO. No entanto, o treinamento físico é capaz de gerar adaptações capazes de mitigar os efeitos deletérios provocados pelos RLO. Estas adaptações estão relacionadas a uma série de sistemas, dos quais os mais importantes são os sistemas enzimáticos, compostos pela superóxido dismutase, catalase e glutationa peroxidase, e o não enzimático, composto por ceruloplasmina, hormônios sexuais, coenzima Q, ácido úrico, proteínas de choque térmico e outros. Tais adaptações, apesar das controvérsias sobre os mecanismos envolvidos, promovem maior resistência tecidual a desafios oxidativos, como aqueles proporcionados pelo exercício de alta intensidade e longa duração. As técnicas de avaliação de estresse oxidativo, na maioria das vezes, não são capazes de detectar injúria em exercícios de curta duração. Dessa forma, esforços estão sendo feitos para o estudo de esforços físicos realizados por longos períodos de tempo ou efetuados até a exaustão. Novos marcadores de lesão por ação dos RLO estão sendo descobertos e novas técnicas para sua determinação estão sendo criadas. O objetivo deste trabalho é discutir os mecanismos da formação dos RLO e das adaptações ao estresse oxidativo crônico provocado pelo treinamento físico.