Mild dehydration (approximately 0.72% of body weight) significantly impairs cognitive functions, including memory, attention, energy, anxiety, and mood.

noli's read

The creator relies on a specific study (Adan, 2012) to illustrate the cognitive impact of fluid loss. Scientific research generally confirms that hydration is crucial for brain function, with meta-analyses (such as that by Wittbrodt & Millard-Stafford, 2018) showing that tasks requiring sustained attention or executive functions can indeed be affected at 1% to 2% dehydration. However, the 0.72% figure cited is very specific to an isolated study; scientific literature generally considers effects to become clinically robust and reproducible beyond the 1% to 2% threshold. The advice is therefore based on a physiological reality, but it tends to present a very low limit as a universal standard for dysfunction. The impact on mood and anxiety is documented, although these variables are often influenced by the study context (e.g., heat, exercise). It is therefore accurate to state that hydration levels play a role, without concluding that a minor variation is systematically disabling for daily life.

the sources

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