Society. “It’s exhausting to be constantly solicited”: the brain also needs a vacation

Even when it has no task to accomplish, the brain never truly sleeps. It still consumes nearly 20% of the body's total energy, only 5% less than when it is mobilized to solve a problem, according to the B2V Memory Observatory. "The brain also activates during this so-called rest phase, but it does so differently and it involves a specific network, the default mode network," explains Francis Eustache, a researcher in neuropsychology and brain imaging.

This mode, which activates when we let our thoughts run free, plays an essential role in memory, introspection, creativity, and mental balance. Once work and screens are put aside, the mind gives way to the unexpected and daydreaming.

"It's a kind of mental wandering through time, into the past, looking toward the future, toward others," explains the president of the scientific council of the B2V Observatory of Memories. And this journey makes sense: it allows us to update what researchers call "autobiographical reasoning." "We need to tell our stories. This narrative of ourselves is largely constructed when we are children, and there is this need to update it. This activity is not done instinctively: the default mode network will also serve this purpose," explains the researcher.

And the brain hasn't evolved to process the flood of information and the noise of constant notifications, veritable "switches" that fragment attention. This digital overload tires cognitive circuits. So breaks are necessary to "regenerate" this conductor of the body.

"It's exhausting to be constantly solicited. These moments of quiet are necessary. The default mode is also a fight against anxiety," assures Francis Eustache. While a few minutes of disconnection from everyday life are enough to maintain cognitive performance, the brain needs longer periods to cut itself off from the intense outside world. But a partial disconnection is better than no disconnection, assures the scientist.

From walking in the forest to meditation and gardening, these moments of disconnection allow us to reactivate this introspective mode. "This allows us to remain in control of our thoughts, actions, and decisions, including the most important ones on a moral level," the researcher emphasizes. He concludes: "The default mode is what allows us to be fully ourselves. It's a richness."