A surprisingly large share of all the energy the human body consumes goes toward a purpose unrelated to visible movement. What is this purpose, and about what fraction of total energy consumption does it use?

1. Beyond visible muscle activity, the body spends a large amount of energy maintaining electrical potentials across the membranes of living cells. 2. This use accounts for a full 25% of all the energy the body consumes, a much bigger share than most people would expect. 3. Nerve cells in particular rely on this electrical potential to generate nerve impulses, so it is not an incidental cost. 4. Digesting food, regulating temperature, and growing tissue are all real energy costs too, but none of them is the specific 25% figure attributed to cellular electrical potentials here. _Source: OpenStax College Physics (CC BY 4.0), Ch 7 "Work, Energy, and Energy Resources", section 7.8 Work, Energy, and Power in Humans_