Resposta fisiológica à caminhada em adultos residentes em Niterói, Rio de Janeiro: Pesquisa de nutrição, atividade física e saúde - PNAFS

Abstract

Walking is the most recommended type of physical activity not only to enhance energy expenditure (EE) but also to improve physical fitness in the general population and therefore, reduce the risk of various diseases. However, the EE of walking depends on the physical and physiological characteristics of the population. Thus, the purpose of the present study was to asses the physiological response to walking in a probabilistic sample (n=210) of adults (≥ 20 years of age) in the city of Niterói, Rio de Janeiro. The data were obtained during a sub-maximal incremental test in the treadmill. The stages lasted for 3 minutes each and the test started at a speed of 67 m.min-1 and slope of 0%. In the second stage, the slope was maintained at 0% and the speed was raised to 93.8 m.min-1. For the rest of the test the speed was maintained at 93.8 m.min-1 and the slope was raised by 2.5% at each stage until 10%. The metabolic equivalent (MET) was measured with the subjects sitting quietly. Measured MET (mean ± standard error) was lower both in women (2.85 ± 0.03 mL O2.kg-1.min-1) and men (2.97 ± 0.04 mL O2.kg-1.min-1) than the internationally recognized value of 3.5 mL O2.kg-1.min-1. EE expressed as multiples of either measured or estimated MET was practically equal between men and women at each intensity. The EE of walking at ground level and speeds of 67 and 93.8 m.min-1 calculated from the MET values of the Compendium of Physical Activities were very similar to the measured values for the population of Niterói. However, the intensity of walking was very different from the classifications used internationally. In fact, 30 minutes of walking at a moderate intensity was not enough to expend 200 kcal as it is recommended internationally for the reduction of mortality of chronic diseases. It is imperative that the prescription of activities be based on individual physiological information.