Efeitos de variações metodológicas sobre a identificação do lactato mínimo

The aim of this study was to analyze the influence of increment pattern as well as the stage duration on lactate minimum (LM) determination. Volunteers were eight physical active males [22.4 + 1.9 years; 177 ± 4.2 cm; 73.6 ± 5.4 kg; 23,4 ± 1,3 kg.(m2)-1] that performed, on different days, two incremental tests on cycle ergometer after lactic acidosis induction through 30 seconds Wingate test. Test 1- initial load of 1.75 kp and increments of 0.25 kp at each stage of 3 min until volitional exhaustion to determine the intensity corresponding to LM (LM1); Test 2- the intensities were 0.5 kp below, 0.5 kp above and the intensity at LM1 (at), the test 2 was composed by two parts (2a - stages of 3 min and 2b - stages of 6 min). The lactate concentration ([lac]), heart rate (HR) and exercise intensities corresponding to LM observed during parts 2a (LM2a) and 2b (LM2b) were compared to LM1. Differences were observed between the [lac] corresponding to LM1 and LM2a (4.9 ± 2.4 vs 6.2 ± 1.9 mM), as well as between the HR corresponding to LM2b (167 ± 14 bpm) and the HR corresponding to LM1 (159 ± 17 bpm) and LM2a (158 ± 12 bpm) (p < 0.05). However, no differences were observed for the intensities corresponding to LM1, LM2a and LM2b (2.6 ± 0.3 vs 2.6 ± 0.5 vs 2.6 ± 0.3 kp, respectively). We concluded that the methodological variations applied on present study did not interfere on the exercise intensity corresponding to LM.O objetivo do presente estudo foi analisar a influência de diferentes intensidades e durações de estágios incrementais sobre a determinação do lactato mínimo (LM). Fizeram parte deste estudo oito homens fisicamente ativos [22,4 ± 1,9 anos; 177,0 ± 4,2 cm; 73,6 ± 5,4 kg; 23,4 ± 1,3 kg&#9679;(m²)-1] que realizaram, em dias diferentes, dois testes incrementais em cicloergômetro após hiperlactacidemia induzida por um teste de Wingate de 30 segundos. Teste 1- carga inicial de 1,75 kp e incrementos de 0,25 kp a cada estágio de três minutos até exaustão voluntária para determinar a intensidade correspondente ao LM (LM1). Teste 2- alternando-se as cargas entre 0,5 kp abaixo, 0,5 kp acima e na intensidade do LM1, o teste 2 foi composto por duas partes seqüenciais (2a - estágios de três minutos e 2b - estágios de seis minutos). As concentrações de lactato sangüíneo ([lac]), freqüência cardíaca (FC) e intensidades (int) correspondentes ao LM dos testes 2a (LM2a) e 2b (LM2b) foram comparadas com o LM1. Foram observadas diferenças entre as [lac] correspondentes ao LM1 e LM2a (4,9 ± 2,4 vs 6,2 ± 1,9 mM) bem como entre a FC correspondente ao LM2b (167 ± 14 bpm) e os valores de FC correspondentes ao LM1 (159 ± 17 bpm) e LM2a (158 ± 12 bpm) (p < 0,05). Contudo, não foram observadas diferenças entre as int correspondentes ao LM1, LM2a e LM2b (2,6 ± 0,3 vs 2,6 ± 0,5 vs 2,6 ± 0,3 kp, respectivamente). Concluímos que as variações metodológicas empregadas não resultaram em alterações na intensidade de exercício correspondente ao LM

Enfrentamento da Obesidade Infantil: ações familiares, condutas médicas e multidisciplinares de educação em saúde

A obesidade infantil é um problema de Saúde Pública em ascensão no mundo que traz muitos prejuízos ao indivíduo, à família, à sociedade e ao Governo. Por esse motivo, é necessário que haja uma atenção especial para a prevenção e o controle dessa doença de origem multifatorial com causas endógenas ou exógenas. Nesse sentido, a multidisciplinaridade de ações, como condutas e manuseios intervencionistas, voltados para a criança com obesidade e para a família, conduzidos por médicos, nutricionistas, psicólogos, professores e professores de educação física torna-se a base da prevenção e tratamento dessa doença. Os principais fatores desencadeantes da obesidade infantil são: emocionais, inadequação alimentar, inatividade física, desconhecimento familiar sobre a doença, sedentarismo e tempo excessivo de uso de aparelhos tecnológicos. Assim, o seguinte estudo tem o objetivo de fazer um levantamento bibliográfico sobre diferentes conhecimentos e condutas de profissionais da saúde na prevenção e tratamento de crianças com excesso de peso

Determination of the anaerobic threshold by blood lactate and glucose measurements in track tests for runners

In order to compare the Anaerobic Threshold (AT) determined by blood lactate (lac) and to verify the possibility of AT determination by blood glucose (gluc) measurements, 12 male endurance runners (aged 25.5 + 7.0) performed four running track tests: a) 3.000 m performance (Vm3Km); b) equilibrium point between lac production and removal (Lacmin): 1 x maximal 500 m followed by 6 x 800 m progressive bouts (87 to 98% of Vm3Km) with 45 sec rest. The velocity (vel) associated with lower [lac] was considered as AT; c) individual anaerobic threshold (IAT): 8 x 800 m progressive bouts (84 to 102% of Vm3Km), with 45 sec rest. The AT vel was determined considering lac kinetic during the test and recovery; d) AT of [4 mM] lac (Vel4mM): Interpolation between lac and vel in 2 x 1200 m at 85 and 100% of Vm3Km, with 10 minutes rest; e) the vel associated at lower glue during IAT ( 0.05; see table below). IAT Lacmin Vel4m

The role of physical activity and heart rate variability for the control of work related stress

[EN] Physical activity (PA) and exercise are often used as tools to reduce stress and therefore the risk for developing cardiovascular diseases (CVD). Meanwhile, heart rate variability (HRV) has been utilized to assess both stress and PA or exercise influences. The objective of the present review was to examine the current literature in regards to workplace stress, PA/exercise and HRV to encourage further studies. We considered original articles from known databases (PubMed, ISI Web of Knowledge) over the last 10 years that examined these important factors. A total of seven studies were identified with workplace stress strongly associated with reduced HRV in workers. Longitudinal workplace PA interventions may provide a means to improve worker stress levels and potentially cardiovascular risk with mechanisms still to be clarified. Future studies are recommended to identify the impact of PA, exercise, and fitness on stress levels and HRV in workers and their subsequent influence on cardiovascular healt

Traditional games resulted in post-exercise hypotension and a lower cardiovascular response to the cold pressor test in healthy children

[EN] The present study aimed to verify if blood pressure (BP) reactivity could be reduced through a previous single session of active playing when compared to sedentary leisure. Sixteen pre-pubertal healthy children participated in this study. After familiarization with procedures and anthropometric evaluation, participants performed three sessions in randomized order: (1) 30 min of traditional Brazilian games (PLAY); (2) 30 min of video game playing (DDR); and (3) 30 min of watching TV (TV). Each session lasted 80 min, being 10 min of rest; 30 min of intervention activity; and 40 min of recovery. After recovery, the Cold Pressor Test (CPT) was used for the assessment of acute cardiovascular reactivity. BP was recorded at 30 s and 1 min during the CPT. Analysis of variance showed post-exercise hypotension (PEH) only after PLAY, and that systolic and diastolic BP were significantly increased in all conditions during CPT. However, the magnitude of the CPT-induced BP response was significantly less in PLAY compared to DDR and TV. The PEH observed during recovery and the reduced BP response to CPT following playing traditional games may be due its higher cardiovascular and metabolic demand as was indicated by the increased heart rate, oxygen consumption, and BP. It was concluded that BP reactivity to stress may be reduced through a previous single session of traditional games and that PEH was recorded only after this exercise form. This benefit indicates a potential role of playing strategies for cardiovascular health in childhood

Resposta da razão testosterona/cortisol durante o treinamento de corredores velocistas e fundistas

A razão entre as concentrações dos hormônios Testosterona e Cortisol (T/C) tem sido utilizada para um melhor controle das cargas de treinamento. Os objetivos deste estudo foram investigar e comparar o comportamento da razão T/C e sua relação com o volume e intensidade realizados durante um período de treinamento de atletas velocistas e fundistas. Corredores velocistas (CV-25,8 ± 3,5anos; 174 ± 7,2 cm, 71,1 ± 3,7 kg; n = 6) e fundistas (CF-27,5 ± 8,7 anos, 174 ± 3,8 cm, 67,7 ± 5,8 kg; n = 6), executaram o seguinte teste padronizado de corrida pré e pós um mesociclo de treino: 1 x 500 m à máxima intensidade e 6 x 800 m progressivos. Sangue venoso (5 ml) foi coletado em repouso, após a corrida de 500 m e ao final de 6 x 800 m para determinação das concentrações de testosterona e cortisol (radioimunoensaio). Os fundistas realizaram um maior volume de treinamento, enquanto os velocistas realizaram treinamentos de menor volume, porém mais intensos e com maior participação anaeróbia. Não houve diferen- ça significante para os valores médios da razão T/C para ambos os grupos após o período de treinamento. No entanto, quando se observa o comportamento individual da razão T/C, nota-se uma resposta adaptativa adequada para alguns indivíduos e inadequadas para outros, sendo que a maior incidência de queda da razão T/C foi observada entre os CF. Conclui-se que a utilização da razão T/C para o controle das cargas de treinamento deve ser feita individualmente, e que aparentemente esta variável sofre uma maior influência do volume do treinamento do que da intensidade do mesmo.Response of the testosterone to cortisol ratio during training for sprinters and endurance runners The testosterone/cortisol ratio (T/C) has been suggested for exercise evaluation and training control (BANFI et al., 1993). The purpose of this study was to investigate the plasma testosterone (T) and cortisol (C) responses during a period of training preparation for sprinters and endurance runners. Six endurance runners (ER; 27.5 ± 8.7 years; 174 ± 3.8 cm, 67.7 ± 5.8 kg; n = 6) and six sprinters (SR; 25.8 ± 3.5 years; 174 ± 7.2 cm, 71.1 ± 3.7 kg; n = 6 ) that were participating on the 1st phase (P1) of their training period volunteered to this study. The participants performed the following running test, before (pre) and after (post) accomplishing the 2nd phase (P2) of training: Standardized test of exercise- After an all-out 500 m for lactic acidosis induction, the subjects ran 6 x 800 m at intensities between 84 and 99% of their best 3 km performance. The levels of T and C were measured (radioimmunoassay) at rest and immediately after the 500 m all-out and at the end of the 6 x 800 m bouts. The ER performed a higher total training volume (TTV) with predominance of moderate to heavy intensity. The SR performed low TTV with a higher % of their TTV at higher intensities (heavy to severe intensities), mainly during P2. No differences were observed for the mean T/C results for both groups after P2. However, when the data are analyzed on individual basis, an adaptative response was observed for some athletes but not for others. A higher incidence of T/C decrease was observed for ER. It was concluded that the T/C ratio analyzes for training control must be done on individual basis. Also, volume instead of intensity of training seems to have higher influence on T/C ratio

Efeitos da alternância entre exercícios aeróbicos e resistência exercício em diferentes sessões de exercício concorrente em respostas pressão arterial de atletas: um estudo randomizado

Aerobic exercise (AE) and resistance exercise (RE) have shown benefits in preventing and / or controlling blood pressure (BP), although the influences of these two models (concurrent exercise) in a single session of exercise on BP are still unknown to the individual. Therefore, the aim of the present study was to verify the effects of the alternating between AE and RE in different concurrent exercise sessions on BP responses. In order to do so, ten young male athletes (22.6 ± 3.78 years, 70.3 ± 5.89 kg, 175.96 ± 5.83 cm, 6.8 ± 2.38 % body fat) participated in the study. The tests consisted of four randomized protocols, the sessions consisted of AE followed by RE (AR), RE followed by AE (RA), circuit (CC) (ER and EA alternating intermittently) and control session (CO) (without exercise). AE was performed on a treadmill at 90% of indirect minimum lactate and RE was performed on a circuit at 90% of 12 RM, alternating muscle segments in six exercises. BP was measured in all protocols and post-exercise recovery period (PERP) every 15 minutes during one hour. Results showed a significant decrease in systolic blood pressure (SBP) at the 45th minute of recovery (R45) and one-hour mean values of the PERP in the RA protocol when compared to its value at rest. Diastolic and mean BP showed no significant differences. Thus, the RA session promoted a more accentuated decrease in SBP when compared to the other sessions.O exercício aeróbico (AE) e exercícios resistidos (ER) têm demonstrado benefícios na prevenção e/ou controle da pressão arterial (PA), embora as influências destes dois modelos de exercícios (exercício concorrente) em uma única sessão sobre a PA ainda são desconhecidos. Desta forma, o objetivo do presente estudo foi verificar os efeitos da alternância entre EA e ER em diferentes sessões de exercícios concorrente sobre as respostas da PA. Participaram do estudo 10 jovens atletas do sexo masculino (22,6 ± 3,78 anos, 70,3 ± 5,89 kg, 175,96 ± 5,83 centímetros, 6,8 ± 2,38 % de gordura corporal). Os testes consistiram de quatro protocolos randomizados, sendo a sessão AR composta por EA seguido do ER, a sessão RA por ER seguido do EA (AR), a sessão circuito (CC) (ER e EA alternando de forma intermitente ) e a sessão de controle (CO) (sem exercício) . EA foi realizado em uma esteira a 90% do lactato mínimo indireto e o ER foi realizado em forma de circuito a 90% de 12 RM, alternado por segmento em seis exercícios. A PA foi mensurada em todos os protocolos, durante o momento repouso e no período de recuperação pós-exercício (REP). Observou-se uma redução da pressão arterial sistólica (PAS) aos 45 e 60 minutos de recuperação do protocolo RA em relação aos valores pré-exercício. A PA diastólica e média não apresentaram diferenças significativas. A sessão RA foi mais eficaz em demonstrar respostas hipotensoras em relação aos outros protocolos experimentais

Can poor sleep, body fat mass, and low physical activity contribute mutually to an increase in childhood obesity?

Childhood obesity is a worldwide epidemic and a public health problem. Sleep is an important factor in this process, and its quality and duration are associated with metabolism, eating behavior, cognition, and psychology. Physical activity encompasses hormonal, thermoregulatory, fatiguing, and restorative processes, is a metabolic regulator of sleep, and modestly reduces body fat through elevated energy expenditure and metabolic regulation. The relationships among obesity, sleep, and physical activity in childhood need to be better understood. Physical activity regulates circadian rhythms and metabolic alterations that can improve sleep quality and minimally reduce adiposity and the incidence of obesity. Poor sleep quality is associated with higher body mass index and lower levels of physical activity, contributing to increased caloric intake through hormonal deregulation related to eating behavior. Thus, poor sleep contributes to higher energy intake and lower daily caloric expenditure through a sedentary lifestyle

Different order of combined exercises: acute effects on 24-hour blood pressure in young men

Verificar as respostas de 24 horas da pressão arterial (PA) em jovens adultos após diferentes ordens de execução do exercício aeróbio (EA) e resistido (ER). Participarão do estudo dez homens saudáveis (22,6 ± 70,3; 3.7 anos ± 5,8 kg; 175,9 ± 5,8 centímetros). O estudo consistiu em quatro sessões experimentais realizadas de forma aleatórias: EA + ER (AR); ER + EA (RA); Circuito Concorrente (CC) e controle (CO). Todas as sessões tiveram a mesma duração e intensidade, EA: 15 min a 90% do limar de lactato mínimo indireto; ER: 15min a 90% de 12 RM com 12 repetições (seis exercícios). A PA foi medida antes, durante e 1 h (Microlife® BP3A1C) após a realização de exercícios em laboratório e 23 h durante as atividades diárias, utilizando a medição da pressão arterial ambulatorial (Dyna-MAPA®). A pressão arterial sistólica (PAS) no período de 24 horas e de vigília, e a diastólica (PAD), no período de 24 horas, o sono e de vigília, e a média da PA no período de vigília foram menores na sessão RA em comparação com a sessão CO apresentando um tamanho do efeito de moderado a alto (d de Cohen = -0,46 / -0,78). A área sob a curva da PAD na sessão AR foi menor do que na sessão CO no período de vigília (1004 ± 82 vs. 1065 ± 107; p < 0,047) e 24 h (1456 ± 103 vs 1528 ± 132; p < 0,026) períodos. A sessão RA apresentou maiores pontos de redução da PA durante 24 horas em relação ao outros protocolos.To verify 24-hour blood pressure (BP) responses in young adults after different orders of aerobic (AE) and resistance exercises (RE). Anaerobic threshold (AT) and strength (12 RM) were evaluated in ten healthy men (22.6 ± 3.7yrs; 70.3 ± 5.8 kg; 175.9 ± 5.8 cm). Four experimental sessions: Aerobic + Resistance (AR); Resistance + Aerobic (RA); Concurrent circuit (CC) and control day (CO) were randomly performed. All sessions had the same duration and intensity, AE: 15 min at 90% of AT; ER: 15 min at 90% of 12 RM with 12 reps (6 exercises). BP was measured before, during and 1 h (Microlife® BP3A1C) after performing exercises in the laboratory and 23 h during daily activities using ambulatory blood pressure measurement (Dyna-MAPA®). Systolic BP (SBP) in 24 h and awake periods, and Diastolic BP (DBP) in 24 h, sleep and awake periods, and Mean BP in awake period were lower in RA session compared with CO session with moderate to high effect size (d de Cohen = -0.46/-0.78). The DBP area under the curve in RA was lower than CO in awake (1004 ± 82 vs. 1065 ± 107; p < 0.047) and 24 h (1456 ± 103 vs. 1528 ± 132; p < 0.026) periods. The SBP delta were lower in RA at 0-1 h (-12.0 mmHg), 2-3h (-16.5 mmHg), 6-7 h (-19.4 mmHg) and 10-11 h (-13.0 mmHg) compared with CO; lower in AR at 4-5h (-19.2 mmHg) and 6-7 h (-20.2 mmHg) compared with CO; and lower in CC at 2-3h (-15.6 mmHg) and 6-7 h (-17.5 mmHg) compared with CO. The DBP was lower at 4-5 h (-14.0 mmHg) in RA compared with CO. After performing RA exercises, there were greater decreases in BP during 24 h in young adults

Does Longer Leukocyte Telomere Length and Higher Physical Fitness Protect Master Athletes From Consequences of Coronavirus (SARS-CoV-2) Infection?

peerReviewe