Energy expenditure estimation during brief and intensive activities

Abstract

The aim of this review is to show that exclusively using oxygen consumption for brief and high intensity activities considerably underestimates total energy expenditure calculation. Alternatively, measuring lactate accumulation in blood appears to be usefulness for such purpose.

Currently, there is no an ideal methodology to quantify to the non-aerobic energy expenditure. Muscle biopsy is a direct but invasive method. Moreover, it involves assuming that a very small sample reflects whole muscle´s metabolic events. On the other hand, the excess post-exercise oxygen consumption does not measure the heat released through the conversion of piruvate into lactate (irreversible process). Margaria et al., show that the rate at which lactate is accumulated (expressed as g/kg of body weight / minute) increases linearly with the corresponding metabolic power (in kcal/kg of body weight/minute). Di Prampero proposes to calculate the reciprocal of the slope which describes this relationship (which he calls β). Such a coefficient means the amount of energy per unit of body weight supplied by the accumulation of 1mMol of lactate in blood and its value is 3.0 ml O2/kg of weight/mMol.

During brief and intense activities, the fact of using the [Δ blood lactate] as a measurement of the non-aerobic lactic energy expenditure is a highly valuable tool, even though it is not completely precise.