It is easy to forget to drink the standardized eight cups of water per day, and if it is hot outside, you have consumed dehydrators like alcohol, and based on a number of personal factors such as activity level and body size, you may require even more. Our bodies even allow us to not drink as much water as we need to. They can get by without much noticeable change or feelings of thirst by recycling the water we have already consumed. While this is an amazing feat, we still experience some effects of not drinking enough water.
The connection between dehydration and changes in cognitive performance have been widely explored. A study investigating the effects of health education on schoolchildren yielded some interesting results. Through a urine testing, sixty seven percent of the children were found to be dehydrated, which luckily improved by around twenty percent after the health education programs were given. However, when these children were given cognitive function tests, the children that were determined dehydrated performed significantly worse than the children with adequate hydration [1]. This example shows both the high frequency of dehydration in school-aged children and how it may be affecting their overall performance in school. It is to be noted that these high levels of dehydration have been seen in many studies centering children, and this is not a singular case. A similar study in adults looked at the effect of drinking water prior to taking a cognitive test after consuming no liquid since the previous night. The study subjects given water prior to taking the test performed significantly better at the tests, which were aimed to measure judgment, decision-making, and inhibition processes [2]. Even outside of an academic or professional environment, not drinking enough water may still have unwanted effects on your day. Mood and a decrease in athletic performance is another effect of dehydration that might be more obvious to us [4]. All of these factors combined can make us feel less good about ourselves and our environment, and the solution is fairly simple.
Additionally, it is important to address the fact that dehydration does not affect everyone equally. While people who are very active may notice a decrease in athletic performance or someone may notice mental fog or mood changes, but in a larger sense, at-risk health populations such as children or the elderly may experience more noticeable effects [3]. Many of the research into the connection between dehydration and cognition or other factors are done on healthy young adults, and may overlook some of the differences in the effects between the groups. While it is always a good idea to stay on top of hydration, if you or a loved one may be in one of these groups, it is even more important to take extra care to ensure needs are met.
Lastly, it is important to note that over-hydration can also be detrimental to your health and it is important to ask a doctor or find out how much water would be best for the individual and use that as a baseline. If you are unsure, the standard eight cups a day is, in most cases, a good start.
References
[1] Hend Samy Ibrahime et. al. 2020. Public health and Community Medicine, Faculty of Medicine, Cairo University. Effect of Hydration Status of School Children on Cognitive Performance and Impact of Health Education on Their Drinking Behavior. https://ejcm.journals.ekb.eg/article_167557_5cf1dca292ef7f871e2abd3758eefb80.pdf.
[2] Olivia C. Patsalos and Volker Thoma. 2019. Water supplementation after dehydration improves judgment and decision-making performance. https://link.springer.com/content/pdf/10.1007/s00426-018-1136-y.pdf.
[3] Danielle McCarney et. al. 2017. The Effect of Fluid Intake Following Dehydration on Subsequent Athletic and Cognitive Performance: a Systematic Review and Meta-analysis. https://link.springer.com/content/pdf/10.1186/s40798-017-0079-y.pdf.
[4] Natalie Pross. 2017. Effects of Dehydration on Brain Functioning: A Life-Span Perspective. https://karger.com/anm/article/70/Suppl.%201/30/42512.
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