Sitting still, you may feel like your body is slowing down. Yet your brain continues to receive information, regulate functions, and maintain the activity of its cells. Resting the body is not a general stoppage of nervous work.
The Society for Neuroscience points out that at rest, the average adult’s brain uses about 20 percent of the body’s energy, compared to only a small fraction of its weight. Exchanges between cells and maintaining their functioning require a permanent energy supply.
This ratio is an order of magnitude, not a measure identical to any age or situation. Nor does it mean that a difficult thought suddenly consumes as much as a sports session. The surprise is more everyday: a large part of this expenditure is used to make an organ work, continuously, whose work we easily forget.
What we know
Order of magnitude for an adult at rest; neither universal value nor equivalence between reflection and physical exercise.
To go to the source
References consulted on September 21, 2026. Linked pages may be in another language.
Signaler une erreur ou apporter une précision
