Energy expenditure over 24 hours on low physical activity programmes in human subjects

The Fifth World Food Survey (FAO, 1986) has defined energy malnutrition as an intake below maintenance requirement and has suggested that maintenance requirement is equal to 1.4 times the resting metabolic rate (RMR), or, alternatively, 1.4 X RMR minus twice the standard deviation of the variation between normal subjects. In order to give substance to these numbers, we have measured the 24-h energy expenditure on two different physical activity programmes. The measurements were made on 38 men and 18 women, all apparently healthy and weighing about 65 kg. The measurements were performed at 24 degrees C and ambient humidity and the subjects wore clothes such as to be within the thermal comfort range. Measurements of the RMR were also performed. In one of the programmes, the average value of the 24-h energy expenditure divided by the RMR was found to be identical in men and women and equal to 1.38 X RMR. In another programme, with more intense physical activity, the corresponding number was 1.53 X RMR. In all three series of measurements, the coefficient of variation between subjects was found to be the same, ie between 6 and 8 per cent.