Reduced thermoregulatory thermogenesis in undernutrition

Adaptive responses to chronic energy deficiency could occur in one of the important components of energy expenditure ie, regulatory thermogenesis. We assessed the thermogenic responses to standardized noradrenaline (NA) infusions in undernourished labourers, as well as in normally nourished control subjects. There was a significant suppression (greater than 60 per cent) of NA-stimulated oxygen consumption in the undernourished, which remained statistically significant even when the responses were corrected for fat-free mass differences. This first report of a suppression in regulatory thermogenesis indicates its important role in the adaptive response to lower than required energy intakes in human subjects.