A US research team has discovered a new link between dehydration and memory and other cognitive functions. The findings were highlighted in a report published Sunday by The Medical News Today Website.
Dehydration can cause headaches, lethargy, dizziness, and many other issues, depending on how severe it is. Studies have tended to focus on the effects of dehydration in younger populations — especially in the context of sports and fitness, where overexertion and abundant sweating can cause people to lose more fluids.
However, one segment of the population is particularly susceptible to dehydration: older adults. As we age, our water reserves decline due to reductions in muscle mass, our kidneys become less effective at retaining water, and hormonal signals that trigger thirst and motivate water intake become blunted.
And because adults also have a higher risk of cognitive impairment, researchers at the University of Pennsylvania looked at the cognitive performance in relation to hydration status and water intake among older adults, who may suffer from dehydration.
In their study published in the European Journal of Nutrition, the researchers analyzed the data of 2,506 participants, 1,271 women and 1,235 men aged 60 and over.
The Nutrition and Health Examination Survey collected these data in 2011–2014. All the participants gave blood samples, and provided information about what they had consumed throughout the day preceding the blood sample collection.
To measure each participant's hydration levels, the investigators looked at the concentration of different substances and compounds including sodium, potassium, glucose and urea nitrogen in their blood. All participants also undertook cognitive function tests, including tasks designed to assess verbal recall and fluency, and exercises focused on attention levels and working memory.
At first glance, the researchers found an association between appropriate hydration and good scores in the cognitive function tests. In particular, women appeared to display poorer cognitive performance when they were under-hydrated.
In the report published by The Medical News Today website on Sunday, the study's lead author Hilary Bethancourt said the test showed that those who were over-hydrated or under-hydrated performed the worst.
"It was interesting that even though this test took only a few minutes, it was the one most strongly associated with lower hydration levels," she added.
Although many questions remain to be answered, Bethancourt advises that older adults should not risk their health by overlooking proper hydration.
