Two recently published articles found that even a mild state of dehydration (>1% of body weight) can adversely affect our energy level, mood, and performance.
A research study (published in the Journal of Nutrition) with young women found that a mild state of dehydration was associated with degraded mood, increased perception of task difficulty, and headache symptoms. Interestingly, most aspects of cognitive performance was not affected.
Another study with young men (published in the British Journal of Nutrition) found that mild dehydration increased fatigue and tension/anxiety. It also induced adverse changes in vigilance and working memory.
How do you know if you’re dehydrated? When exercising, weigh yourself both before and after exercising (without clothes). For each pound you lose, drink 16oz of water to return your hydration level to pre-exercise levels. At any time of the day, check the color of your urine. It should be clear of slightly pale in color. If it’s darker – you’re dehydrated. Remember, these studies were done with participants who were only mildly dehydrated!