Isothermal microcalorimetry measures the heat produced or consumed by any physical, chemical or biological process. When studying biological processes it is often helpful to perform parallel experiments and controls using other techniques to interpret the calorimetric signal and discriminate the biological contribution from other heat releasing processes. If such parallel measurements are not possible, a reality check can also help in making sense of the data. Here we perform such reality check on the data presented in a recent paper and propose an alternative interpretation of the data keeping in mind the biological limitation of the cells tested. (C) 2014 Elsevier B.V. All rights reserved.