RESUMOAtividades físicas beneficiam as esferas de vivência do idoso, por isso conhecer o nível de atividade física (NAF) e as principais barreiras à prática é relevante para planejar e desenvolver ações visando a um estilo de vida ativo dessa população. Em análise do NAF e das principais barreiras à prática de atividade física percebidas em idosos, 129 participantes responderam aos questionários Baecke modificado para idosos (QBMI) e de Barreiras. A média no NAF (QBMI) foi de 1,9 pontos e as barreiras mais percebidas foram: "doença" (52%); "necessidade de descanso" (47%); "falta de persistência" (46%); "suficientemente ativo" (41%). Foi também verificado que idosos mais ativos percebem menos barreiras do que os menos ativos. Conclui-se que: a) idosos apresentam baixo NAF; b) a percepção de pessoas idosas quanto a serem suficientemente ativas parece ser diferente do NAF recomendado; c) o NAF parece modular a percepção de barreiras.Palavras-chave: Atividade física. Idosos.

To clarify the source of human urine EGF, we studied EGF renal clearance in 20 healthy, young adult subjects. Immunoreactive EGF was measured hourly in EDTA plasma, heparin plasma, serum and urine of 12 males and 8 females during a 3 h study period. Plasma and urine creatinine and creatinine clearance were measured and calculated hourly. Mean (and SEM) creatinine clearance was similar in males and females (118 +/- 12 vs 105 +/- 6 ml/min). EGF was not detectable in plasma, whereas relatively high levels were measured in serum (2.5 +/- 0.25 vs 1.5 +/- 0.18 ng/ml in males and females respectively p less than 0.05). Urine EGF excretion averaged 1641 +/- 233 ng/h in males and 1507 +/- 191 ng/h in females (p greater than 0.05). A significant correlation was observed between urine creatinine and urine EGF concentrations in both male (r = 0.98, p less than 0.01) and female (r = 0.94, p less than 0.01) subjects. EGF immunoreactivity in urine and serum eluted from G-75 sephadex columns similarly to recombinant 6000 Mr hEGF. Urine excretion of EGF approximated 1.5 micrograms/h or 25 ng/mg creatine. The high concentrations of EGF found in urine in the face of non-detectable levels of EGF in plasma favor the hypothesis that EGF in urine is derived from kidney synthesis and secretion. The significant positive correlation between urine creatinine and urine EGF suggests a functional correlation between glomerular filtration and the process of tubular EGF excretion.