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I sat down two days ago with some ambition to write this column. In the end, I did not write a word. Why? As I explained to my girlfriend, “My brain wasn’t working.”
Try as I might, I found the whole idea of writing anything cogent too much. I did a quick scan of things that might have caused this state. I was not short on sleep. Neither had I eaten any wheat (I’ve found from experience this tends to turn my brain off).
Then I wondered if I might be dehydrated. It was about 4 p.m., and I could only remember passing water twice all day—not a good sign. Plus, there was no doubt in my mind that I had drunk only a small proportion of the water I would normally consume when in my own home.
I stepped up my water intake and felt quite quickly revived. It might have been a placebo response, but maybe not.
For New Year’s resolutions, I’d say many of us could do a lot worse than just to ensure we’re decently hydrated.
This morning I decided to see if there was any recent evidence on the impact of dehydration on mental functioning and indeed did come across a relevant study in the January issue of the Journal of Nutrition. In this research, 25 women were subjected to a variety of assessments of mood, mental functioning, and well-being in a normally hydrated state and a dehydrated state.
On one occasion, dehydration was induced with intermittent exercise but not heat. On another occasion, dehydration was induced not just with exercise, but also by administration of the diuretic drug furosemide.
Overall, dehydration with or without furosemide led to an average of a 1.36 percent decrease of body mass. Just to put this into perspective, for someone weighing 154 pounds, this would equate to about a quart of dehydration. In other words, this extent of dehydration would be described as mild.
At this level of dehydration, basic cognitive (brain) function was not significantly affected. But other functions were, including the amount of perceived effort used by the women to complete a task. With my experience yesterday, I could totally relate to this.
In addition, the concentration and mood of the women were also adversely affected. The women were also more fatigued and more prone to headaches. All this was the result of relatively mild dehydration.
None of this actually proves my inertia yesterday was caused by something as simple and rectifiable as dehydration but it is at least consistent with it.
For New Year’s resolutions, I’d say many of us could do a lot worse than just to ensure we’re decently hydrated. How much should we drink? I suggest enough to ensure our urine stays pale yellow in color throughout the day.
Dr. John Briffa is a London-based physician and author with an interest in nutrition and natural medicine. His website is DrBriffa.com.
