Efeitos da corrida prolongada realizada na intensidade correspondente ao início do acúmulo do lactato no sangue na força máxima isocinética em indivíduos ativos não atletas

OBJECTIVE: The objective of this study was to analyze the effects of prolonged continuous running performed at the intensity corresponding to the onset of blood lactate accumulation (OBLA), on the peak torque of the knee extensors, analyzed in relation to different types of contraction and movement velocities in active individuals. METHOD: Eight men (23.4 ± 2.1 years; 75.8 ± 8.7 kg; 171.1 ± 4.5 cm) participated in this study. First, the subjects performed an incremental test until volitional exhaustion to determine the velocity corresponding to OBLA. Then, the subjects returned to the laboratory on two occasions, separated by at least seven days, to perform five maximal isokinetic contractions of the knee extensors at two angular velocities (60 and 180º.s-1) under eccentric and concentric conditions. Eccentric peak torque (EPT) and Concentric peak torque (CPT) were measured at each velocity. One session was performed after a standardized warm-up period (5 min at 50% VO2max). The other session was performed after continuous running at OBLA until volitional exhaustion. These sessions were conducted in random order. RESULTS: There was a significant reduction in CPT only at 60º.s-1 (259.0 ± 46.4 and 244.0 ± 41.4 N.m). However, the reduction in EPT was significant at 60º.s-1 (337.3 ± 43.2 and 321.7 ± 60.0 N.m) and 180º.s-1 (346.1 ± 38.0 and 319.7 ± 43.6 N.m). The relative strength losses after the running exercise were significant different between contraction types only at 180º.s-1. CONCLUSION: We can conclude that, in active individuals, the reduction in peak torque after prolonged continuous running at OBLA may be dependent on the type of contraction and angular velocity.OBJETIVO: O objetivo deste estudo foi analisar os efeitos da corrida contínua prolongada realizada na intensidade correspondente ao início do acúmulo do lactato no sangue (OBLA) sobre o torque máximo dos extensores do joelho analisado em diferentes tipos de contração e velocidade de movimento em indivíduos ativos. MÉTODO: Oito indivíduos do gênero masculino (23,4 ± 2,1 anos; 75,8 ± 8,7 kg; 171,1 ± 4,5 cm) participaram deste estudo. Primeiramente, os sujeitos realizaram um teste incremental até a exaustão voluntária para determinar a velocidade correspondente ao OBLA. Posteriormente, os sujeitos retornaram ao laboratório em duas ocasiões, separadas por pelo menos sete dias, para realizar 5 contrações isocinéticas máximas para os extensores do joelho em duas velocidades angulares (60 e 180º.s-1) sob as condições excêntrica (PTE) e concêntrica (PTC). Uma sessão foi realizada após um período de aquecimento padronizado (5 min a 50%VO2max). A outra sessão foi realizada após uma corrida contínua no OBLA até a exaustão voluntária. Essas sessões foram executadas em ordem randômica. RESULTADOS: Houve redução significante do PTC somente a 60º.s-1 (259,0 ± 46,4 e 244,0 ± 41,4 N.m). Entretanto, a redução do PTE foi significante a 60º.s-1 (337,3 ± 43,2 e 321,7 ± 60,0 N.m) e 180º.s-1 (346,1 ± 38,0 e 319,7 ± 43,6 N.m). As reduções relativas da força após o exercício de corrida foram significantemente diferentes entre os tipos de contração somente a 180º.s-1. CONCLUSÃO: Podemos concluir que, em indivíduos ativos, a redução no torque máximo após uma corrida contínua prolongada no OBLA pode ser dependente do tipo de contração e da velocidade angular.Universidade Estadual Paulista Júlio de Mesquita Filho Instituto de Biociências de Rio Claro Departamento de Educação FísicaUniversidade Federal de São Paulo (UNIFESP) Departamento de Psicobiologia Instituto do SonoUNIFESP, Depto. de Psicobiologia Instituto do SonoSciEL

Effects of type of physical exercise and leisure activities on the depression scores of obese Brazilian adolescent girls

Several studies have indicated that depressive states may lead to hypokinesia with diminished metabolic rate and energy use. Hypokinesia associated with certain eating behaviors may lead to an unfavorable energy balance that can contribute to the emergence and prevalence of obesity among children and adults. The purpose of the present study was to examine the possibility of reducing depression inventory scores in female adolescents with third-degree obesity while testing the effectiveness of different exercise programs in reducing anxiety and depression scores. The sample consisted of 40 female subjects (mean age 16 ± 1.56 years) divided into 4 groups (aerobic training, anaerobic training, leisure activities, and control). Subjects had a body mass index of 95% or more in relation to the 50th percentile. The aerobic program consisted of three ergometric bicycle sessions per week over a 3-month period (12 weeks) and the activities were prescribed after determining the anaerobic ventilatory threshold (VO2 threshold). Anaerobic training was based on the Wingate anaerobic power test. The leisure program consisted of a varied range of activities (games, exercises, etc.). A nutritionist interviewed the members of these two groups and the control group every week in order to adapt them to the nutritional guidelines proposed for the study. The study showed that all three programs (aerobic exercise, anaerobic exercise and leisure activities) were effective in reducing body mass. However, we found a significant reduction when analyzing the depression scores only for aerobic exercise (18.9 ± 9.33 to 10.6 ± 9.56 or 43.9%) but no significant alterations for anaerobic exercise (11.36 ± 5.23 to 9.63 ± 4.78 or 15.22%) and leisure (17.28 ± 7.55 to 15.07 ± 7.54 or 12.78%), thus indicating that in principle this type of activity could be included to improve emotional well-being of obese adolescent girls.Universidade Federal de São Paulo (UNIFESP) Escola Paulista de Medicina Programa de Pós-Graduação em NutriçãoUniversidade Federal de São Paulo (UNIFESP) Escola Paulista de Medicina Departamento de PsicobiologiaUniversidade Federal de São Paulo (UNIFESP) Escola Paulista de Medicina Departamento de PediatriaFaculdades Integradas Faculdade de Educação Física de Santo AndréInstituto do Sono Associação Fundo de Incentivo à PsicofarmacologiaUNIFESP, EPM, Programa de Pós-Graduação em NutriçãoUNIFESP, EPM, Depto. de PsicobiologiaUNIFESP, EPM, Depto. de PediatriaSciEL

Effects of sildenafil on autonomic nervous function during sleep in obstructive sleep apnea

OBJECTIVE: To evaluate the effects of sildenafil on the autonomic nervous system in patients with severe obstructive sleep apnea. METHODS: Thirteen male patients with severe obstructive sleep apnea (mean age 43±10 years with a mean body mass index of 26.7±1.9 kg/m²) received a single 50-mg dose of sildenafil or a placebo at bedtime. All-night polysomnography and heart rate variability were recorded. Frequency domain analysis of heart rate variability was performed for the central five-minute sample of the longest uninterrupted interval of slow wave and rapid eye movement sleep, as well as for one-minute samples during apnea and during slow wave and rapid eye movement sleep after resumption of respiration. RESULTS: Compared to the placebo, sildenafil was associated with an increase in the normalized high-frequency (HFnu) components and a decrease in the low/high-frequency components of the heart rate variability ratio (LF/HF) in slow wave sleep (p<0.01 for both). Differences in heart rate variability parameters between one-minute post-apnea and apnea samples (&#916;= difference between resumption of respiration and apnea) were assessed. A trend toward a decreasing magnitude of &#916;LF activity was observed during rapid eye movement sleep with sildenafil in comparison to placebo (p=0.046). Additionally, &#916; LF/HF in SWS and rapid eye movement sleep was correlated with mean desaturation (sR= -0.72 and -0.51, respectively, p= 0.01 for both), and &#916; HFnu in rapid eye movement sleep was correlated with mean desaturation (sR= 0.66, p= 0.02) and the desaturation index (sR= 0.58, p = 0.047). CONCLUSIONS: The decrease in arousal response to apnea/hypopnea events along with the increase in HFnu components and decrease in LH/HF components of the heart rate variability ratio during slow wave sleep suggest that, in addition to worsening sleep apnea, sildenafil has potentially immediate cardiac effects in patients with severe obstructive sleep apnea

Testing four methods to assess leaf area in young olive trees

Assessment of leaf area is of fundamental importance to calculate diverse physiological parameters such as the total rate of transpiration or photosynthesis of a plant or its leaf area index (LAI). This paper reports the determination of total leaf area in 3 year-old olive trees of two varieties using four different methods and leaf counting as the control method. Leaf area was determined on 7 plants of each variety, Arbequina and Cobrançosa, by thoroughly counting the total number of leaves on each plant and then multiplying by the average leaf area for each variety Leaf area of the same plants was then estimated by (1) the analysis, with software ImageJ, of a photo of each plant from a side or from the top, (2) the crown light scattering measured with a ceptometer (AccuPAR Model LP-80) in the ground at 10 and 20 cm from the trunk, (3) the analysis with software Hemisfer of a photo of the plant from the top, and finally (4) by the determination of the transpiration (mmol s-1) of each plant over a 2 hour period by a weighing method and dividing this value by the mean transpiration rate (E) of each plant, calculated from the measurement of stomatal conductance (gs) on 10 leaves with a porometer and mean air RH and leaf and air temperature over the same period. Both the ceptometer and the Hemisfer software give a value of leaf area index (LAI). In order to obtain the leaf area, LAI was divided by the projected area of the crown obtained on photos from the top. Average leaf area (n = 7 × 30) was 0,238 × 10-3 m2 and 0,264 × 10-3 m2 for Arbequina and Cobrançosa, respectively. Total leaf area of each plant varied from 3,38 m2 and 4,85 m2 for Arbequina and 0,86 m2 and 3,99 m2 for Cobrançosa. Ceptometer and analysis of photos from a side gave estimates of leaf area under 50% of the actual leaf area. Analysis of photos from the top gave on average 70% the actual values. The most accurate methods were analysis with software Hemisfer and by the ratio of transpiration by E which gave values 5% bellow or 20% above actual values, respectively

Acute or chronic effects of cannabinoids on spontaneous or pharmacologically induced yawning in rats

Abstract Yawning is a reflex or event that is not fully understood. It is controlled by many neurotransmitters and neuropeptides and can be induced pharmacologically by cholinergic or dopaminergic agonists. Amongst their many actions, cannabinoids acting on cannabinoid (CB 1 or CB 2 ) receptors can alter cholinergic and/or dopaminergic activity. This study examined the effects of D -THC. However, a high frequency of spontaneous yawning was observed 7 days after D 8 -THC discontinuation. These results suggest that cannabinoid agonists inhibited yawning induced by cholinergic or dopaminergic agonists. In addition, the increased frequency of spontaneous yawning following cessation of chronic administration of a cannabinoid agonist may be of importance as a withdrawal sign for these drugs.

Narcolepsia

BACKGROUND: Narcolepsy is a chronic neurological syndrome with prevalence between 0.018% and 0.040% without important ethnic differences. Narcolepsy is characterized by excessive daytime sleepiness and cataplexy. The pathophysiology of the illness is not known; even so it possesses genetic marker (allele HLA DQB1 *0602) and with abnormalities in the neurotransmission of hypocretin has been described in patients with narcolepsy. OBJECTIVES: Resume news discoveries in narcolepsy and show diagnoses and treatment options. METHODS: Bibliographic review. RESULTS AND DISCUSSION: The diagnoses of narcolepsy must be done with The International Classification of Sleep Disorders criteria. The hypocretin dosage is the best exam to confirm diagnose in narcoleptic patients with typical cataplexy. The treatment is carried through with behavior actions and symptomatic drugs that promote the vigil and control the cataplexy. Differential diagnoses as schizophrenia, epilepsy, depression and others sleep disorders need to be eliminated.CONTEXTO: Narcolepsia é uma síndrome neurológica crônica com prevalência entre 0,018% e 0,040% da população, sem diferenciações étnicas importantes. Caracteriza-se por sonolência e cataplexia. A fisiopatologia da doença não é totalmente conhecida, embora possua marcador genético (alelo HLA DQB1 *0602) e anormalidades na neurotransmissão de hipocretina descritos recentemente. OBJETIVOS: Resumir as recentes descobertas na narcolepsia e expor possibilidades diagnósticas e terapêuticas. METODOLOGIA: Revisão bibliográfica. RESULTADOS E DISCUSSÃO: O diagnóstico deve seguir os critérios da Classificação Internacional de Sono. A dosagem de hipocretina é o melhor exame para confirmar narcolepsia em pacientes com cataplexia típica. O tratamento deve ser realizado com medidas comportamentais e drogas sintomáticas que promovem a vigília e controlam a cataplexia. Diagnósticos diferenciais como esquizofrenia, epilepsia, depressão e doenças do sono devem ser descartados

Long-Term Effects of Metformin and Lifestyle Modification on Nonalcoholic Fatty Liver Disease Obese Adolescents

Objective. To assess the long-term effects of metformin in combination with lifestyle intervention and its association between insulin levels and the degree of steatosis at ultrasonography (US) in obese adolescents. Methods. Thirty-five postpubertal obese boys were randomized into two groups: one receiving metformin in combination with a multidisciplinary lifestyle intervention versus a placebo group, which also received the same intervention. The visceral, subcutaneous fat and degree of steatosis were measured by ultrasonography. Fasting blood samples were collected to analyze glucose, insulin, insulin resistance, and aminotransferases. Repeated ANOVA measures were used to compare changes over time and between groups, and Spearman's correlations were used to identify an association between insulin and the degree of steatosis at US. Results. There was a positive correlation between the degree of steatosis at US with insulin concentrations and HOMA-IR. Long-term therapy plus metformin significantly reduced body weight, body mass index, insulin, HOMA-IR, and visceral fat. Conclusions. Metformin was more effective than the placebo in improving clinical parameters associated with obesity and steatosis