The reversible oxidation/reduction of polypyrrole films coating a platinum electrode is studied here in NaCl aqueous solution by cyclic voltammetry at different scan rates. Reacting polypyrrole films are dense gels constituted by molecular (polymeric) electrochemical machines, ions and water, mimicking the intracellular matrix of living cells. Both, the extension of the reaction (the consumed charge) and the electrical energy consumed by the oxidation and reduction reactions change as a function of the scan rate or of the imposed frequency. That means that the reaction involving conformational, or allosteric, movements of the reacting polymeric chains senses the imposed working energetic conditions. A theoretical description of the attained empirical results is presented getting the sensing equations. An important energetic asymmetry exists for those reactions between oxidation and reduction consumed energies. Technological outlooks related to the efficiency of electrochemical energy transducers are presented. Results are translated to biological organs as muscles constituted by chemical molecular machines working under demand of higher energies by brain suggesting how the back signal informing the brain about the working energetic conditions can be generated. (C) 2017 Elsevier Ltd. All rights reserved.