Summary: Mild dehydration may impair sustained attention in middle-aged and older adults, although it does not affect other cognitive functions. The study included 78 adults aged 47 to 70 and assessed their hydration levels and cognitive performance.
The results showed that dehydration, common during typical daily activities, reduced attention span over 14 minutes. The results highlight the need for regular hydration to maintain cognitive function in older adults.
Highlights:
- Mild dehydration impairs sustained attention in middle-aged and older adults.
- Study participants aged 47 to 70 showed reduced attention span over 14 minutes when they were dehydrated.
- Good hydration is essential for maintaining cognitive functions, including sustained attention.
Source: Pennsylvania State University
Dehydration can cause a wide range of mild to severe symptoms, from temporary mood swings to life-threatening concerns. Researchers at Penn State’s Department of Biobehavioral Health studied how dehydration affects cognitive performance.
They found that even mild dehydration can decrease a person’s ability to pay attention to tasks over time. The findings highlight the importance of good hydration for people to function properly as they age.
The research team found that typical dehydration (the levels of dehydration that occur during non-strenuous daily activities) reduced individuals’ ability to pay attention to tasks longer than 14 minutes, but had no effect significant on other executive functions, such as working memory.
The results were published in the American Journal of Human Biology.
Led by Asher Rosinger, associate professor of biobehavioral health and anthropology and director of the Water, Health and Nutrition Laboratory, and Kyle Murdock, associate professor of biobehavioral health, the researchers evaluated 78 adults, ages 47 to 70, who had all have adequate access to drinking water, three times in three months.
“We chose to study middle-aged and older adults because that’s the age group where we start to see risk for cognitive decline,” Rosinger said.
Previous research has raised concerns about the impact of dehydration on cellular health, kidney function, biological acceleration of aging, chronic disease risk and early mortality. According to Rosinger, it also produced mixed results on cognitive performance.
Unlike previous studies that induced dehydration in participants, this study did not manipulate hydration status and instead assessed ad libitum dehydration – the natural dehydration of adults from typical real-life functions.
Participants were asked to avoid high-fat foods, caffeine, and exercise on the days they were assessed to measure their level of dehydration without these influences.
To determine hydration status, researchers analyzed the balance of dissolved particles, such as sodium or potassium, and water, called serum osmolality, in blood samples from each participant at three time points.
In Rosinger’s study, adults with serum osmolality greater than 300 milliosmoles per kilogram were defined as dehydrated. People who were dehydrated experienced a reduced ability to maintain attention. At each assessment, at least 29% and up to 39.1% of the group was dehydrated.
During each assessment, study participants completed surveys and four neurological tests measuring their inhibition, working memory, cognitive flexibility and sustained attention. The researchers found that the more dehydrated the participant, the less successful they were in the sustained attention task.
“This suggests that if a person drinks less water daily than their body needs, it may take them a little longer to complete some time-consuming tasks with a little more error,” Rosinger said.
Results indicated no significant link between dehydration and inhibition, working memory, or cognitive flexibility.
“The good news is that dehydration is only associated with poorer performance on tasks requiring sustained attention,” Rosinger said.
“This shows that in daily life, when adults are not experimentally dehydrated – such as sitting in a sauna or cycling for an hour without drinking water – their cognitive performance on short tasks is no different from of those who are better hydrated.”
The study’s main finding that dehydration only affects longer tasks has everyday implications. Since job responsibilities are often tasks that require sustained, uninterrupted attention, Rosinger emphasizes that hydration is essential for healthy cognitive functioning for these types of tasks.
“It’s important for older adults to drink water regularly,” Rosinger said. “It will improve their ability to maintain sustained attention, and it might give them a boost when they’re at work when they read that email from a colleague that continues to drone on but includes action items or when they are simply doing an intense version of the daily crossword with their friends.
Rosinger explained that greater awareness of hydration could benefit this population, especially since previous research from Penn State found that as people age, their feelings of thirst in response to dehydration gradually decreases.
“The relationship between hydration and cognitive performance is particularly important in middle-aged and older adults, given that they are more vulnerable to dehydration,” Rosinger said. “They start drinking less water.”
The findings also raise concerns about the magnitude of impacts on people’s physiological and cognitive health, Rosinger noted, particularly for those without reliable access to clean water.
“Much of my research career has been spent trying to understand the coping strategies that individuals and households employ to meet their water needs when they do not have access to clean water, as well as as the resulting health consequences or tradeoffs,” said Rosinger, who studies water insecurity and challenges related to water accessibility in addition to hydration needs.
“One of the things I’ve noticed is that they often limit the amount of water they consume or turn to less healthy drinks that they perceive as safer, like sugary drinks.”
Rosinger said he plans to continue studying the impact of hydration on adults vulnerable to dehydration, with the ultimate goal of improving access to clean, safe and reliable water that people can use for meet their water needs.
His future work aims to understand how extreme weather events and climate change affect access to clean water and how interventions can be applied to improve health and well-being.
“This issue is going to become increasingly important as temperatures rise in future climate scenarios, leading to increased water needs,” Rosinger said. “I would recommend that older people be careful – pun intended – about the amount of water they consume. »
About this news from research on cognition and aging
Author: Emily Eng
Source: Penn State
Contact: Emily Eng – Penn State
Picture: Image is credited to Neuroscience News
Original research: Free access.
“Ad libitum dehydration is associated with poorer performance on a sustained attention task but not with other measures of cognitive performance in middle-aged to older community-dwelling adults: a longitudinal study in the short term” by Asher Y. Rosinger et al. American Journal of Human Biology
Abstract
Ad libitum dehydration is associated with poorer performance on a sustained attention task but not other measures of cognitive performance in community-dwelling middle-aged to older adults: a longitudinal study short term
Objective
Hydration status and water consumption are essential for physiological health. Despite popular discourse that dehydration impairs cognitive performance, results are mixed in the literature. Therefore, we tested how hydration status was associated with cognitive performance in an ad libitum state over a 3-month period.
Methods
Data come from a short-term longitudinal study of middle-aged to older American adults (not= 78) measured three times (207 observations). All participants were scheduled to undergo 8:00 a.m. visits for baseline, two-week, and three-month exams during which they completed surveys, neuropsychological tests to measure cognitive performance, anthropometric measurements, and blood work for analysis of biomarkers.
Serum osmolality (Sosm) was measured as a biomarker of hydration status by osmometry. Four cognitive performance tasks were assessed, including inhibition, working memory, cognitive flexibility, and sustained attention.
Results
Panel random effects linear regressions demonstrate that there is an inverse association between dehydration and sustained attention, whereas there is no significant relationship between dehydration and inhibition, working memory and cognitive flexibility. Dehydrated adults (defined as Sosm > 300 mOsm/kg) performed significantly worse (B= 0.65 z-score; SD = 0.28; p= 0.020) on the sustained attention task than those who were not dehydrated, adjusting for fixed effects of time, age, body mass index, sex and education level.
Conclusion
This short-term longitudinal study found that dehydration was uniquely associated with poorer performance on a cognitive performance task requiring sustained attention. Maintaining adequate hydration may be increasingly important for middle-aged to older adults to ensure adequate cognitive function, particularly as water requirements increase in future climate scenarios.