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bibliography * The PainScience Bibliography contains plain language summaries of thousands of scientific papers and others sources, like a specialized blog. This page is about a single scientific paper in the bibliography, Armstrong 2012.

Mild dehydration affects mood in healthy young women

Armstrong LE, Ganio MS, Casa DJ, Lee EC, McDermott BP, Klau JF, Jimenez L, Le Bellego L, Chevillotte E, Lieberman HR. Mild dehydration affects mood in healthy young women. J Nutr. 2012 Feb;142(2):382–8. PubMed #22190027.
Tags: random, water, headache, bad science, head, controversy, debunkery, head/neck, pain problems, scientific medicine

PainSci summary of Armstrong 2012?This page is one of thousands in the bibliography. It is not a general article: it is focussed on a single scientific paper, and it may provide only just enough context for the summary to make sense. Links to other papers and more general information are provided at the bottom of the page, as often as possible. ★☆☆☆☆?1-star ratings are for negative examples, fatally flawed papers, junk science, suspected fraud. Ratings are a highly subjective opinion, and subject to revision at any time. If you think this paper has been incorrectly rated, please let me know.

This research, funded in part by a giant corporation that sells bottled water, supposedly shows that surprising mild dehydration can make you a bit pissy and headachey.

The level of dehydration studied here is similar to what it takes to provoke thirst, and the effects on mood are presumably milder at the lower end of the range. So if the effect on mood is significant, we are probably also thirsty ... and if we’re not actually thirsty, the effect is probably pretty minor. That said, I might agree with the author’s conclusion that “increased emphasis on optimal hydration is warranted,” but I’m also guessing it’s not that big a deal, and I’m inclined to be rather cynical about it, because the conclusion is just so pitch-perfect for a study funded by a water bottling company.

Mood effects are not to be ignored, for sure, but they are also a lot less serious than the health effects that people tend to believe (mostly based on very successful fear-mongering by people selling ‘water cures’).

~ Paul Ingraham

original abstract

Limited information is available regarding the effects of mild dehydration on cognitive function. Therefore, mild dehydration was produced by intermittent moderate exercise without hyperthermia and its effects on cognitive function of women were investigated. Twenty-five females (age 23.0 ± 0.6 y) participated in three 8-h, placebo-controlled experiments involving a different hydration state each day: exercise-induced dehydration with no diuretic (DN), exercise-induced dehydration plus diuretic (DD; furosemide, 40 mg), and euhydration (EU). Cognitive performance, mood, and symptoms of dehydration were assessed during each experiment, 3 times at rest and during each of 3 exercise sessions. The DN and DD trials in which a volunteer attained a ≥1% level of dehydration were pooled and compared to that volunteer's equivalent EU trials. Mean dehydration achieved during these DN and DD trials was -1.36 ± 0.16% of body mass. Significant adverse effects of dehydration were present at rest and during exercise for vigor-activity, fatigue-inertia, and total mood disturbance scores of the Profile of Mood States and for task difficulty, concentration, and headache as assessed by questionnaire. Most aspects of cognitive performance were not affected by dehydration. Serum osmolality, a marker of hydration, was greater in the mean of the dehydrated trials in which a ≥1% level of dehydration was achieved (P = 0.006) compared to EU. In conclusion, degraded mood, increased perception of task difficulty, lower concentration, and headache symptoms resulted from 1.36% dehydration in females. Increased emphasis on optimal hydration is warranted, especially during and after moderate exercise.

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This page is part of the PainScience BIBLIOGRAPHY, which contains plain language summaries of thousands of scientific papers & others sources. It’s like a highly specialized blog.