Avaliação nutricional e antropométrica de praticantes de exercício físico em ginásio

A preocupação acrescida com a condição e aparência física, refletem-se em cuidados com o estado de saúde e bem-estar e são, nos últimos anos, responsáveis pela expansão dos ginásios e health clubs.Mas, atividade física e a alimentação estão intimamente ligadas, tanto no que respeita à estética como também, com maiores preocupações, no que respeita à saúde. Daí que as duas vertentes estejam ligadas à imagem de pessoas saudáveis e vigorosas. Na verdade, a capacidade de rendimento do organismo melhora com a nutrição adequada. A avaliação da composição corporal é um importante aspeto na determinação da condição física e permite-nos observar as alterações fisiológicas produzidas pelos programas de atividade física e/ou alimentares, oferecendo informações quanto a sua eficiência ou possíveis correções a serem efetuadas. Pretendeu-se com o presente estudo caracterizar os hábitos alimentares e a composição corporal dos indivíduos praticantes de exercício físico num ginásio do Concelho de Coimbra. A amostra foi constituída por 50 indivíduos, 22 do sexo masculino e 28 do sexo feminino, com idades compreendidas entre os 18 e os 57 anos. Estes indivíduos têm em comum o facto de praticarem exercício físico num mesmo ginásio, de uma forma sistemática há pelo menos 6 meses. Para a caracterização dos hábitos de AF dos participantes no estudo foi utilizada a versão curta do International Physical Activity Questionnaire (IPAQ). Para avaliação nutricional recorreu-se ao Questionário Semiquantitativo de Frequência Alimentar (QSFA), elaborado pelo Serviço de Higiene e Epidemiologia da Faculdade de Medicina da Universidade do Porto. A conversão dos alimentos em nutrientes foi realizada recorrendo ao programa informático Food Processor Plus ® versão 7.0. Foram ainda avaliados os seguintes parâmetros antropométricos: peso, altura, perímetro abdominal, IMC, massa gorda e massa magra. As análises estatísticas foram efetuadas com recurso ao Programa Estatístico SPSS (Statistical Package for the Sciences) para o Windows, versão 20.0. O nível de significância estatística foi mantida em 5% (p<0,05). A análise dos dados permitiu retirar as seguintes conclusões: Os frequentadores de ginásio são na sua maioria indivíduos do sexo feminino (56%), jovens com uma idade média de 27±7 anos. A maioria dos participantes do estudo praticava EF (exercício físico) há 39 meses, no entanto no grupo existe uma grande variabilidade, existindo indivíduos que praticam EF há 6 meses, e outros que o fazem há 180 meses. Praticam EF com uma frequência média de 3,5±1,3 sessões/semana a que corresponde uma prática de EF 6,40±3,2 h/semana. A maioria apresentava um Perímetro Abdominal (PA) de 85,2±6,3 cm, Índice de Massa Corporal (IMC) normal (23,1± 2,6 kg/m2), valores de Massa Gorda (MG) (23,9%) e de Massa Muscular (MM) de 34,6±7,9%. Observou-se uma diminuição da MG com o tempo de prática de exercício de 25,3% (praticantes entre 6-12 meses) vs 20,9% (praticantes> 48 meses). Esta influência temporal, embora sem significado estatístico, verifica-se também relativamente ao perímetro abdominal e IMC, embora neste último numa razão inversa, caracterizada pelo seu aumento. O tipo de exercício praticado influencia a composição corporal: praticantes de exercício aeróbio apresentam um perímetro abdominal inferior (82,3±6,0 cm) aos praticantes de outro tipo de exercícios porém acompanhado de uma percentagem de massa gorda superior (29,4±6,0%).Os praticantes de exercício de resistência apresentam valores de MG de 16,0±7,4%. No estudo por nós realizado, constatou-se inadequação na quantidade energética consumida, face às necessidades efetivas da amostra. Embora a ingestão de hidratos de carbono, de fibra e de lípidos se apresente dentro dos limites recomendados a ingestão de proteína ultrapassa os valores recomendados.Os resultados obtidos mostram que o tipo de exercício bem como o tempo de prática de exercício influenciam a composição corporal. Verificou-se ainda que a alimentação dos participantes no estudo não é adequada do ponto de vista nutricional e para além disso os hábitos nutricionais não parecem influir na composição corporal da amostra. Mais estudos serão necessários para que os hábitos alimentares dos praticantes de exercício em ginásios e health clubs sejam bem conhecidos e os profissionais da área tenham mais informações e possam orientar melhor os praticantes de exercício físico regular em ginásios e health clubs de modo a otimizar os resultados pretendidos através de um aconselhamento nutricional individualizado.

COPD control: Can a consensus be found?

There are currently no reliable instruments for assessing the onset and progression of chronic obstructive pulmonary disease (COPD) or predicting its prognosis. Currently, a comprehensive assessment of COPD including several objective and subjective parameters is recommended. However, the lack of biomarkers precludes a correct assessment of COPD severity, which consequently hampers adequate therapeutic approaches and COPD control. In the absence of a definition of "well-controlled disease", a consensus regarding COPD control will be difficult to reach. However, COPD patient assessment should be multidimensional, and anchored in five points: control of symptoms, decline of pulmonary function, levels of physical activity, exacerbations, and Quality of Life. Several non-pharmacological and pharmacological measures are currently available to achieve disease control. Smoking cessation, vaccination, exercise training programs and pulmonary rehabilitation are recognized as important non-pharmacological measures but bronchodilators are the pivotal therapy in the control of COPD. This paper discusses several objective and subjective parameters that may bridge the gap between disease assessment and disease control. The authors conclude that, at present, it is not possible to reach a consensus regarding COPD control, essentially due to the lack of objective instruments to measure it. Some recommendations are set forth, but true COPD control awaits further objective assessments.

Skeletal muscle and nuclear hormone receptors: Implications for cardiovascular and metabolic disease

Skeletal muscle is a major mass peripheral tissue that accounts for similar to 40% of the total body mass and a major player in energy balance. It accounts for > 30% of energy expenditure, is the primary tissue of insulin stimulated glucose uptake, disposal, and storage. Furthermore, it influences metabolism via modulation of circulating and stored lipid (and cholesterol) flux. Lipid catabolism supplies up to 70% of the energy requirements for resting muscle. However, initial aerobic exercise utilizes stored muscle glycogen but as exercise continues, glucose and stored muscle triglycerides become important energy substrates. Endurance exercise increasingly depends on fatty acid oxidation (and lipid mobilization from other tissues). This underscores the importance of lipid and glucose utilization as an energy source in muscle. Consequently skeletal muscle has a significant role in insulin sensitivity, the blood lipid profile, and obesity. Moreover, caloric excess, obesity and physical inactivity lead to skeletal muscle insulin resistance, a risk factor for the development of type II diabetes. In this context skeletal muscle is an important therapeutic target in the battle against cardiovascular disease, the worlds most serious public health threat. Major risk factors for cardiovascular disease include dyslipidemia, hypertension, obesity, sedentary lifestyle, and diabetes. These risk factors are directly influenced by diet, metabolism and physical activity. Metabolism is largely regulated by nuclear hormone receptors which function as hormone regulated transcription factors that bind DNA and mediate the pathophysiological regulation of gene expression. Metabolism and activity, which directly influence cardiovascular disease risk factors, are primarily driven by skeletal muscle. Recently, many nuclear receptors expressed in skeletal muscle have been shown to improve glucose tolerance, insulin resistance, and dyslipidernia. Skeletal muscle and nuclear receptors are rapidly emerging as critical targets in the battle against cardiovascular disease risk factors. Understanding the function of nuclear receptors in skeletal muscle has enormous pharmacological utility for the treatment of cardiovascular disease. This review focuses on the molecular regulation of metabolism by nuclear receptors in skeletal muscle in the context of dyslipidemia and cardiovascular disease. (c) 2005 Published by Elsevier Ltd.

Prediction of functional capacity in chronic heart failure patients using myocardial tissue Doppler

Background. Exercise therapy improves functional capacity in CHF, but selection and individualization of training would be helped by a simple non-invasive marker of peak VO2. Peak VO2 in these pts is difficult to predict without direct measurement, and LV ejection fraction is a poor predictor. Myocardial tissue velocities are less load-dependent, and may be predictive of the exercise response in CHF pts. We sought to use tissue velocity as a predictor of peak VO2 in CHF pts. Methods. Resting 2D-echocardiography and tissue Doppler imaging were performed in 182 CHF pts (159 male, age 62±10 years) before and after metabolic exercise testing. The majority of these patients (129, 71%) had an ischemic cardiomyopathy, with resting EF of 35±13% and a peak VO2 of 13.5±4.7 ml/kg/min. Results. Neither resting EF (r=0.15) nor peak EF (r=0.18, both p=NS) were correlated with peak VO2. However, peak VO2 correlated with peak systolic velocity in septal (Vss, r=0.31) and lateral walls (Vsl, r=0.26, both p=0.01). In a general linear model (r2 = 0.25), peak VO2 was calculated from the following equation: 9.6 + 0.68*Vss - 0.09*age + 0.06*maximum HR. This model proved to be a superior predictor of peak VO2 (r=0.51, p=0.01) than the standard prediction equations of Wasserman (r= -0.12, p=0.01). Conclusions. Resting tissue Doppler, age and maximum heart rate may be used to predict functional capacity in CHF patients. This may be of use in selecting and following the response to therapy, including for exercise training.

Antioxidants and protein oxidation

Proteins are susceptible to oxidation by reactive oxygen species, where the type of damage induced is characteristic of the denaturing species. The induction of protein carbonyls is a widely applied biomarker, arising from primary oxidative insult. However, when applied to complex biological and pathological conditions it can be subject to interference from lipid, carbohydrate and DNA oxidation products. More recently, interest has focused on the analysis of specific protein bound oxidised amino acids. Of the 22 amino acids, aromatic and sulphydryl containing residues have been regarded as being particularly susceptible to oxidative modification, with L-DOPA from tyrosine, ortho-tyrosine from phenylalanine; sulphoxides and disulphides from methionine and cysteine respectively; and kynurenines from tryptophan. Latterly, the identification of valine and leucine hydroxides, reduced from hydroperoxide intermediates, has been described and applied. In order to examine the nature of oxidative damage and protective efficacy of antioxidants the markers must be thoroughly evaluated for dosimetry in vitro following damage by specific radical species. Antioxidant protection against formation of the biomarker should be demonstrated in vitro. Quantification of biomarkers in proteins from normal subjects should be within the limits of detection of any analytical procedure. Further to this, the techniques for isolation and hydrolysis of specific proteins should demonstrate that in vitro oxidation is minimised. There is a need for the development of standards for quality assurance material to standardise procedures between laboratories. At present, antioxidant effects on protein oxidation in vivo are limited to animal studies, where dietary antioxidants have been reported to reduce dityrosine formation during rat exercise training. Two studies on humans have been reported last year. The further application of these methods to human studies is indicated, where the quality of the determinations will be enhanced through inter-laboratory validation.

Novel ketone diet enhances physical and cognitive performance

Ketone bodies are the most energy-efficient fuel and yield more ATP per mole of substrate than pyruvate and increase the free energy released from ATP hydrolysis. Elevation of circulating ketones via high-fat, low-carbohydrate diets has been used for the treatment of drug-refractory epilepsy and for neurodegenerative diseases, such as Parkinson's disease. Ketones may also be beneficial for muscle and brain in times of stress, such as endurance exercise. The challenge has been to raise circulating ketone levels by using a palatable diet without altering lipid levels. We found that blood ketone levels can be increased and cholesterol and triglycerides decreased by feeding rats a novel ketone ester diet: chow that is supplemented with (R)-3-hydroxybutyl (R)-3-hydroxybutyrate as 30% of calories. For 5 d, rats on the ketone diet ran 32% further on a treadmill than did control rats that ate an isocaloric diet that was supplemented with either corn starch or palm oil (P < 0.05). Ketone-fed rats completed an 8-arm radial maze test 38% faster than did those on the other diets, making more correct decisions before making a mistake (P < 0.05). Isolated, perfused hearts from rats that were fed the ketone diet had greater free energy available from ATP hydrolysis during increased work than did hearts from rats on the other diets as shown by using [(31)P]-NMR spectroscopy. The novel ketone diet, therefore, improved physical performance and cognitive function in rats, and its energy-sparing properties suggest that it may help to treat a range of human conditions with metabolic abnormalities.

Nichtmedikamentöse Sekundärprävention der koronaren Herzkrankheit (KHK)

Hintergrund: Die koronare Herzkrankheit (KHK) ist eine häufige und potenziell tödliche Erkrankung mit einer Lebenszeitprävalenz von über 20%. Allein in Deutschland wird die Zahl der durch die ischämische Herzerkrankung und des akuten Myokardinfarkts jährlich verursachten Todesfälle auf etwa 140.000 geschätzt. Ein Zusammenhang eng mit dem Lebensstil verbundener Risikofaktoren mit Auftreten und Prognose der KHK ist nachgewiesen. Durch Maßnahmen der nichtmedikamentösen Sekundärprävention wird versucht, diese Risikofaktoren positiv zu verändern sowie die KHK im Gegensatz zu palliativen interventionellen Therapiestrategien kausal zu behandeln. Zur Wirksamkeit der nichtmedikamentösen sekundärpräventiven Maßnahmen liegt eine ganze Reihe von Einzelstudien und -untersuchungen vor, eine systematische Analyse, die die Evidenz aller hauptsächlich angewandten Sekundärpräventionsstrategien zusammenfasst, fehlt unseres Wissens nach bislang jedoch. Auch eine Auswertung vorhandener Studien zur Kosten-Effektivität der Maßnahmen ist hierbei zu integieren. Fragestellung: Ziel dieses HTA-Berichts (HTA=Health Technology Assessment) ist die Erstellung einer umfassenden Übersicht der aktuellen Literatur zu nichtmedikamentösen Sekundärpräventionsmaßnahmen in der Behandlung der KHK, um diese Maßnahmen und deren Komponenten bezüglich ihrer medizinischen Wirksamkeit sowie Wirtschaftlichkeit zu beurteilen. Weiterhin sollen die ethischen, sozialen und rechtlichen Aspekte der nichtmedikamentösen Sekundärprävention und die Übertragbarkeit der Ergebnisse auf den deutschen Versorgungsalltag untersucht werden. Methodik: Relevante Publikationen werden über eine strukturierte und hochsensitive Datenbankrecherche sowie mittels Handrecherche identifiziert. Die Literaturrecherche wird in vier Einzelsuchen zu medizinischen, gesundheitsökonomischen, ethischen und juristischen Themen am 18.09.2008 durchgeführt und erstreckt sich über die vergangenen fünf Jahre. Die methodische Qualität der Publikationen wird von jeweils zwei unabhängigen Gutachtern unter Beachtung von Kriterien der evidenzbasierten Medizin (EbM) systematisch geprüft. Ergebnisse: Von insgesamt 9.074 Treffern erfüllen 43 medizinische Publikationen die Selektionskriterien, mit einem Nachbeobachtungszeitraum zwischen zwölf und 120 Monaten. Insgesamt ist die Studienqualität zufriedenstellend, allerdings berichtet nur ca. die Hälfte der Studien differenziert die Gesamtmortalität, während die übrigen Studien andere Outcomemaße verwenden. Die Wirksamkeit einzelner Sekundärpräventionsmaßnahmen stellt sich als sehr heterogen dar. Insgesamt kann langfristig eine Reduktion der kardialen sowie der Gesamtmortalität und der Häufigkeit kardialer Ereignisse sowie eine Erhöhung der Lebensqualität beobachtet werden. Vor allem für trainingsbasierte und multimodale Interventionen ist eine effektive Reduktion der Mortalität zu beobachten, während psychosoziale Interventionen besonders in Bezug auf eine Erhöhung der Lebensqualität effektiv zu sein scheinen. Für die ökonomischen Auswertungen werden 26 Publikationen identifiziert, die von ihrer Themenstellung und Studienart dem hier betrachteten Kontext zugeordnet werden können. Insgesamt kann festgestellt werden, dass sich die Studienlage zur multimodalen Rehabilitation sowohl bezüglich ihrer Menge als auch Qualität der Analysen besser darstellt, als dies für Evaluationen von Einzelmaßnahmen beobachtet werden kann. Die internationale Literatur bestätigt den multimodalen Ansätzen dabei zwar ein gutes Verhältnis von Kosten und Effektivität, untersucht jedoch nahezu ausschließlich ambulante oder häuslichbasierte Maßnahmen. Die Auswertung der Studien, die einzelne sich mit präventiven Maßnahmen in Hinblick auf ihre Kosten-Effektivität beschäftigen, ergibt lediglich positive Tendenzen für Interventionen der Raucherentwöhnung und des körperlichen Trainings. Im Hinblick auf psychosoziale Maßnahmen sowie auch die Ernährungsumstellung können aufgrund der unzureichenden Studienlage jedoch keine Aussagen über die Kosten-Effektivität getroffen werden. Insgesamt werden im Rahmen der Betrachtung sozialer Aspekte der nichtmedikamentösen Sekundärprävention elf Publikationen einbezogen. Die relativ neuen Studien bestätigen, dass Patienten mit niedrigem sozioökonomischen Status insgesamt schlechtere Ausgangsbedingungen und demnach einen spezifischen Bedarf an rehabilitativer Unterstützung haben. Gleichzeitig sind sich die Forscher jedoch uneinig, ob gerade diese Patientengruppe relativ häufiger oder seltener an den Rehabilitationsmaßnahmen teilnimmt. Bezüglich der Barrieren, die Patienten von der Teilnahme an den präventiven Maßnahmen abhalten, werden psychologische Faktoren, physische Einschränkungen aber auch gesellschaftliche und systemisch-orientierte Einflüsse genannt. Diskussion: Nichtmedikamentöse Sekundärpräventionsmaßnahmen sind sicher und in der Lage eine Reduktion der Mortalität sowie der Häufigkeit kardialer Ereignisse zu erzielen sowie die Lebensqualität zu erhöhen. Da nur wenige der methodisch verlässlichen Studien Teilnehmer über einen längeren Zeitraum von mindestens 60 Monaten nachverfolgen, müssen Aussagen über die Nachhaltigkeit als limitiert angesehen werden. Verlässliche Angaben in Bezug auf relevante Patientensubgruppen lassen sich nur sehr eingeschränkt machen ebenso wie im Hinblick auf die vergleichende Beurteilung verschiedener Maßnahmen der Sekundärprävention, da diese von eingeschlossenen Studien nur unzureichend erforscht wurden. Zukünftige methodisch verlässliche Studien sind notwendig, um diese Fragestellungen zu untersuchen und zu beantworten. Bezogen auf die Kosten-Effektivität nichtmedikamentöser sekundärpräventiver Maßnahmen kann aus den internationalen Studien eine insgesamt positive Aussage zusammengefasst werden. Einschränkungen dieser resultieren jedoch zum einen aus den Besonderheiten des deutschen Systems der stationären Rehabilitationsangebote, zum anderen aus den qualitativ mangelhaften Evaluationen der Einzelmaßnahmen. Studien mit dem Ziel der Bewertung der Kosten-Effektivität stationärer Rehabilitationsangebote sind ebenso erforderlich wie auch qualitativ hochwertige Untersuchungen einzeln erbrachter Präventionsmaßnahmen. Aus sozialer Perspektive sollte insbesondere untersucht werden, welche Patientengruppe aus welchen Gründen von einer Teilnahme an Rehabilitations- bzw. präventiven Maßnahmen absieht und wie diesen Argumenten begegnet werden könnte. Schlussfolgerung: Nichtmedikamentöse sekundärpräventive Maßnahmen sind in der Lage eine Reduktion der Mortalität und der Häufigkeit kardialer Ereignisse zu erzielen sowie die Lebensqualität zu erhöhen. Eine Stärkung des Stellenwerts nichtmedikamentöser Maßnahmen der Sekundärprävention erscheint vor diesem Hintergrund notwendig. Auch kann für einige Interventionen ein angemessenes Verhältnis von Effektivität und Kosten angenommen werden. Es besteht allerdings nach wie vor erheblicher Forschungsbedarf bezüglich der Wirksamkeitsbeurteilung nichtmedikamentöser Maßnahmen der Sekundärprävention in wichtigen Patientensubgruppen und der Effizienz zahlreicher angebotener Programme. Darüber hinaus ist weitere Forschung notwendig, um die Nachhaltigkeit der Maßnahmen und Gründe für die Nichtinanspruchnahme detailliert zu untersuchen. Vor allem gilt es jedoch den Versorgungsalltag in Deutschland, wie er sich für Ärzte, Patienten und weitere Akteure des Gesundheitswesens darstellt, zu untersuchen und den heutigen Stellenwert nichtmedikamentöser Maßnahmen aufzuzeigen.

Biochemical parameters response to weight loss in patients with non-alcoholic steatohepatitis.

Background: Non-alcoholic steatohepatitis (NASH) is a chronic liver disease that is capable of progressing to end-stage liver disease, but generally has a benign course. Non-alcoholic steatohepatitis (NASH) is a growing public health problem with no approved therapy. NASH projected to be the leading cause of liver transplantation in the United States by 2020. Obesity, non-insulin-dependent diabetes mellitus and hyperlipidaemia are the most common associations of the disease. Global prevalence of NASH is 10-24% amongst general population but increases to 25-75% in obese diabetic individuals. Objective: There is an urgent need for efficient therapeutic options as there is still no approved medication. The aim of this study was to detect changes in biochemical parameters including insulin resistance, cytokines, blood lipid profile and liver enzymes following weight loss in patients with non-alcoholic steatohepatitis. Materials and methods: One hundred obese patients with NASH, their age between 35-50 years, body mass index (BMI) from 30 to 35 Kg/m2 were included in the study in two subgroups; the first group (A) received moderate aerobic exercise training in addition to diet regimen , where the second group (B) received no treatment intervention. Results: The mean values of leptin, TNF-α, IL6, IL8, Alanine Aminotransferase (ALT), Aspartate Aminotransferase (AST), Homeostasis Model Assessment-Insulin Resistance- index (HOMA-IR), Total Cholesterol (TC), Low Density Lipoprotein Cholesterol (LDL-c) , Triglycerides (TG) and BMI were significantly decreased in group (A), where the mean value of Adiponectin and High Density Lipoprotein Cholesterol (HDL-c) were significantly increased, while there were no significant changes in group (B). Also, there was a significant difference between both groups at the end of the study. Conclusion: Weight loss modulates insulin resistance, adiponectin, leptin, inflammatory cytokine levels and markers of hepatic function in patients with nonalcoholic steatohepatitis.

Whole body vibration treatments in postmenopausal women can improve bone mineral density:results of a stimulus focussed meta-analysis

Whole body vibration treatment is a non-pharmacological intervention intended to stimulate muscular response and increase bone mineral density, particularly for postmenopausal women. The literature related to this topic is controversial, heterogeneous, and unclear despite the prospect of a major clinical effect. The aim of this study was to identify and systematically review the literature to assess the effect of whole body vibration treatments on bone mineral density (BMD) in postmenopausal women with a specific focus on the experimental factors that influence the stimulus. Nine studies fulfilled the inclusion criteria, including 527 postmenopausal women and different vibration delivery designs. Cumulative dose, amplitudes and frequency of treatments as well as subject posture during treatment vary widely among studies. Some of the studies included an associated exercise training regime. Both randomized and controlled clinical trials were included. Whole body vibration was shown to produce significant BMD improvements on the hip and spine when compared to no intervention. Conversely, treatment associated with exercise training resulted in negligible outcomes when compared to exercise training or to placebo. Moreover, side-alternating platforms were more effective in improving BMD values than synchronous platforms and mechanical oscillations of magnitude higher than 3 g and/or frequency lower than 25 Hz were also found to be effective. Treatments with a cumulative dose over 1000 minutes in the follow-up period were correlated to positive outcomes. Our conclusion is that whole body vibration treatments in elderly women can reduce BMD decline.However, many factors (e.g. amplitude, frequency and subject posture) affect the capacity of the vibrations to propagate to the target site; the adequate level of stimulation required to produce these effects has not yet been defined. Further biomechanical analyses to predict the propagation of the vibration waves along the body and assess the stimulation levels are required.

El concepto y la práctica de la actividad física y su relación con calidad de vida en los modelos teóricos de la salud

Los estudios acerca del concepto actividad física (AF) son diversos, presentando diferentes concepciones; su relación con calidad de vida suele estar generada dentro del discurso médico, que propende por la ejecución de la Actividad Física desde una mirada netamente biológica. Si bien esta disertación es importante, se debe tener en cuenta que los estudios relacionados con calidad de vida y la AF se basan en la condición de bienestar y percepción frente al estado de salud; dichos estudios no se han realizado desde las condiciones de vida y del contexto social. Si bien es cierto que la mirada médica y lo estudios objetivos son relevantes, ya que arrojan estadísticas que permiten abordar recomendaciones en cuanto a la actividad física, en este documento se elaboró una investigación de tipo cualitativo por medio de la revisión documental del concepto de actividad física, sus prácticas y su relación con calidad de vida, que abordan diferentes autores. Para ello se elige la base de datos PubMed por su énfasis en las publicaciones de salud; se seleccionan artículos publicados del 2004 y 2014, que estudien el concepto de actividad física, sus prácticas y relaciones con calidad de vida, para finalmente hacer un análisis desde los modelos de determinación y determinantes sociales. De esta forma se analiza la posición de los autores con respecto al concepto, sus prácticas y las relaciones que puede llegar a surgir con la calidad de vida. En esta investigación se obtuvo como resultados tendencias biológicas, psicológicas, sociales y culturales, en los cuales los autores dejan clara la posición médica ya que en la mayoría de investigaciones centran sus relaciones en la funcionalidad, y es a través de la visión terapéutica donde buscan el bienestar, la satisfacción de los pacientes que padecen cualquier enfermedad. Además, aparecen categorías emergentes como: cuerpo como medio de publicidad, cibernética que avanza vertiginosamente y el papel del poder en la actividad física que pueden ser contempladas para otros estudios.

Propiedades psicométricas de los instrumentos para la medición de la actividad física en adultos con discapacidad física relacionada con lesión de médula espinal: una revisión sistemática

Objetivo: Evaluar las propiedades psicométricas de los instrumentos para la medición de la actividad física en adultos de 18-65 años con discapacidad física por lesión de médula espinal. Materiales y métodos: Revisión sistemática. Las bases de datos de Medline, Scopus, Web of Science y 19 revistas especializadas fueron consultadas durante once días entre abril de 2015 y febrero de 2016 para identificar estudios originales de validación, sin límite de tiempo y que estuvieran publicados en español, francés y/o inglés. La calidad metodológica de los instrumentos de medición se evaluó usando las diferentes cajas de propiedades de la lista COSMIN. Resultados: Se identificaron 9229 referencias, de las cuales sólo 12 cumplieron los criterios de inclusión, dando como resultado 13 instrumentos de medición. Se evaluaron seis propiedades psicométricas. La propiedad más común fue la confiabilidad, además se observó que la calidad metodológica de los estudios incluidos no representa los resultados de las propiedades psicométricas de los instrumentos de medición. La calidad metodológica de los instrumentos para la evaluación de la actividad física en población con lesión medular espinal es “baja” para propiedades como consistencia interna, error de medición, sensibilidad, validez de criterio (con excepción del WISCI II que tiene buena validez) y excelente para validez de contenido y fiabilidad. Conclusión: Se ha encontrado que instrumentos empleados hasta el presente en la medición de la actividad física en población con discapacidad física relacionada con lesión de médula espinal han sido creados para otros tipos de discapacidad y otros instrumentos deben ser validados en futuros estudios.

Actitudes hacia la Enfermedad del Alzheimer según el género y la edad de adultos colombianos

La enfermedad de Alzheimer (EA) es la demencia más frecuente y su prevalencia continúa en aumento tanto en Colombia como en el mundo. Esta investigación tuvo como objetivo explorar si las actitudes hacia la EA varían según la edad y género de 450 personas adultas colombianas. Se realizó un estudio exploratorio de corte transversal en el que se aplicó un cuestionario autodiligenciado. Se encontró que efectivamente hay algunas diferencias según la edad y el género en el componente cognoscitivo (creencias y conocimiento) y conductual (intención conductual y conducta) de las actitudes; y diferencias según el género en el componente afectivo. Se concluye que los conocimientos sobre la EA son escasos, que la tristeza es la emoción predominante hacia la EA y que es un tema de interés en el que predomina la idea de que afecta especialmente la memoria. Se discutieron los resultados reconociendo que esta es una aproximación inicial a las actitudes hacia la EA.

Increasing lactate turnover rate during exercise by means of altitude training and fructose ingestion : effects on substrate metabolism and endurance performance

Summary : With regard to exercise metabolism, lactate was long considered as a dead-end waste product responsible for muscle fatigue and a limiting factor for motor performance. However, a large body of evidence clearly indicates that lactate is an energy efficient metabolite able to link the glycolytic pathway with aerobic metabolism and has endocrine-like actions, rather than to be a dead-end waste product. Lactate metabolism is also known to be quickly upregulated by regular endurance training and is thought to be related to exercise performance. However, to what extent its modulation can increase exercise performance in already endurance-trained subjects is unknown. The general hypothesis of this work was therefore that increasing either lactate metabolic clearance rate or lactate availability could, in turn, increase endurance performance. The first study (Study I) aimed at increasing the lactate clearance rate by means of assumed interaction effects of endurance training and hypoxia on lactate metabolism and endurance performance. Although this study did not demonstrate any interaction of training and hypoxia on both lactate metabolism and endurance performance, a significant deleterious effect of endurance training in hypoxia was shown on glucose homeostasis. The methods used to determine lactate kinetics during exercise exhibited some limitations, and the second study did delineate some of the issues raised (Study 2). The third study (Study 3) investigated the metabolic and performance effects of increasing plasma lactate production and availability during prolonged exercise in the fed state. A nutritional intervention was used for this purpose: part of glucose feedings ingested during the control condition was substituted by fructose. The results of this study showed a significant increase of lactate turnover rate, quantified the metabolic fate of fructose; and demonstrated a significant decrease of lipid oxidation and glycogen breakdown. In contrast, endurance performance appeared to be unmodified by this dietary intervention, being at odds with recent reports. Altogether the results of this thesis suggest that in endurance athletes the relationship between endurance performance and lactate turnover rate remains unclear. Nonetheless, the result of the present study raises questions and opens perspectives on the rationale of using hypoxia as a therapeutic aid for the treatment of insulin resistance. Moreover, the results of the second study open perspectives on the role of lactate as an intermediate metabolite and its modulatory effects on substrate metabolism during exercise. Additionally it is suggested that the simple nutritional intervention used in the third study can be of interest in the investigation on the aforementioned roles of lactate. Résumé : Lorsque le lactate est évoqué en rapport avec l'exercice, il est souvent considéré comme un déchet métabolique responsable de l'acidose métabolique, de la fatigue musculaire ou encore comme un facteur limitant de la performance. Or la littérature montre clairement que le lactate se révèle être plutôt un métabolite utilisé efficacement par de nombreux tissus par les voies oxydatives et, ainsi, il peut être considéré comme un lien entre le métabolisme glycolytique et le métabolisme oxydatif. De plus on lui prête des propriétés endocrines. Il est connu que l'entraînement d'endurance accroît rapidement le métabolisme du lactate, et il est suggéré que la performance d'endurance est liée à son métabolisme. Toutefois la relation entre le taux de renouvellement du lactate et la performance d'endurance est peu claire, et, de même, de quelle manière la modulation de son métabolisme peut influencer cette dernière. Le but de cette thèse était en conséquence d'investiguer de quelle manière et à quel degré l'augmentation du métabolisme du lactate, par l'augmentation de sa clearance et de son turnover, pouvait à son tour améliorer la performance d'endurance de sujets entraînés. L'objectif de la première étude a été d'augmenter la clearance du lactate par le biais d'un entraînement en conditions hypoxiques chez des cyclistes d'endurance. Basé sur la littérature scientifique existante, on a fait l'hypothèse que l'entraînement d'endurance et l'hypoxie exerceraient un effet synergétique sur le métabolisme du lactate et sur la performance, ce qui permettrait de montrer des relations entre performance et métabolisme du lactate. Les résultats de cette étude n'ont montré aucun effet synergique sur la performance ou le métabolisme du lactate. Toutefois, un effet délétère sur le métabolisme du glucose a été démontré. Quelques limitations de la méthode employée pour la mesure du métabolisme du lactate ont été soulevées, et partiellement résolues dans la seconde étude de ce travail, qui avait pour but d'évaluer la sensibilité du modèle pharmacodynamique utilisé pour le calcul du turnover du lactate. La troisième étude a investigué l'effet d'une augmentation de la lactatémie sur le métabolisme des substrats et sur la performance par une intervention nutritionnelle substituant une partie de glucose ingéré pendant l'exercice par du fructose. Les résultats montrent que les composants dynamiques du métabolisme du lactate sont significativement augmentés en présence de fructose, et que les oxydations de graisse et de glycogène sont significativement diminuées. Toutefois aucun effet sur la performance n'a été démontré. Les résultats de ces études montrent que la relation entre le métabolisme du lactate et la performance reste peu claire. Les résultats délétères de la première étude laissent envisager des pistes de travail, étant donné que l'entraînement en hypoxie est considéré comme outil thérapeutique dans le traitement de pathologies liées à la résistance à l'insuline. De plus les résultats de la troisième étude ouvrent des perspectives de travail quant au rôle du lactate comme intermédiaire métabolique durant l'exercice ainsi que sur ses effets directs sur le métabolisme. Ils suggèrent de plus que la manipulation nutritionnelle simple qui a été utilisée se révèle être un outil prometteur dans l'étude des rôles et effets métaboliques que peut revêtir le lactate durant l'exercice.

Training in hypoxia fails to further enhance endurance performance and lactate clearance in well-trained men and impairs glucose metabolism during prolonged exercise.

The aim of this study was to investigate the synergistic effects of endurance training and hypoxia on endurance performance in normoxic and hypoxic conditions (approximately 3000 m above sea level) as well as on lactate and glucose metabolism during prolonged exercise. For this purpose, 14 well-trained cyclists performed 12 training sessions in conditions of normobaric hypoxia (HYP group, n = 7) or normoxia (NOR group, n = 7) over 4 weeks. Before and after training, lactate and glucose turnover rates were measured by infusion of exogenous lactate and stable isotope tracers. Endurance performance was assessed during incremental tests performed in normoxia and hypoxia and a 40 km time trial performed in normoxia. After training, performance was similarly and significantly improved in the NOR and HYP groups (training, P < 0.001) in normoxic conditions. No further effect of hypoxic training was found on markers of endurance performance in hypoxia (training x hypoxia interaction, n.s.). In addition, training and hypoxia had no significant effect on lactate turnover rate. In contrast, there was a significant interaction of training and hypoxia (P < 0.05) on glucose metabolism, as follows: plasma insulin and glucose concentrations were significantly increased; glucose metabolic clearance rate was decreased; and the insulin to glucagon ratio was increased after training in the HYP group. In conclusion, our results show that, compared with training in normoxia, training in hypoxia has no further effect on endurance performance in both normoxic and hypoxic conditions or on lactate metabolic clearance rate. Additionally, these findings suggest that training in hypoxia impairs blood glucose regulation in endurance-trained subjects during exercise.

Training in hypoxia fails to further enhance endurance performance and lactate clearance in well-trained men and impairs glucose metabolism during prolonged exercise.

The aim of this study was to investigate the synergistic effects of endurance training and hypoxia on endurance performance in normoxic and hypoxic conditions (approximately 3000 m above sea level) as well as on lactate and glucose metabolism during prolonged exercise. For this purpose, 14 well-trained cyclists performed 12 training sessions in conditions of normobaric hypoxia (HYP group, n = 7) or normoxia (NOR group, n = 7) over 4 weeks. Before and after training, lactate and glucose turnover rates were measured by infusion of exogenous lactate and stable isotope tracers. Endurance performance was assessed during incremental tests performed in normoxia and hypoxia and a 40 km time trial performed in normoxia. After training, performance was similarly and significantly improved in the NOR and HYP groups (training, P < 0.001) in normoxic conditions. No further effect of hypoxic training was found on markers of endurance performance in hypoxia (training x hypoxia interaction, n.s.). In addition, training and hypoxia had no significant effect on lactate turnover rate. In contrast, there was a significant interaction of training and hypoxia (P < 0.05) on glucose metabolism, as follows: plasma insulin and glucose concentrations were significantly increased; glucose metabolic clearance rate was decreased; and the insulin to glucagon ratio was increased after training in the HYP group. In conclusion, our results show that, compared with training in normoxia, training in hypoxia has no further effect on endurance performance in both normoxic and hypoxic conditions or on lactate metabolic clearance rate. Additionally, these findings suggest that training in hypoxia impairs blood glucose regulation in endurance-trained subjects during exercise.