Hydration's Impact on Fatigue Isn't Overhyped

"Drink more water" is such common advice it's easy to ignore, but the link between dehydration and fatigue is well-supported by research.

Losing just 2% of body weight in water (1.4L for a 70kg person) significantly impairs cognitive function and mood. By the time you feel thirsty, you're already 1-2% dehydrated. When you're tired and can't figure out why, drinking water is often the correct answer.

Realistic approach

"8 glasses a day" is a weakly-supported number. Needs vary by body size, activity level, climate, and diet. Instead of chasing a target, check two things:

1. Urine color: Pale yellow means adequate. Dark yellow means drink more.
2. Drink before thirst: Thirst means dehydration has already started.

For office workers, keeping a water bottle on your desk and sipping once an hour is often sufficient.