Dehydration Linked to Cognitive Problems in Older Adults

A woman fills up a glass with water in Paris on April 27, 2014. (Getty Images)
A woman fills up a glass with water in Paris on April 27, 2014. (Getty Images)
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Dehydration Linked to Cognitive Problems in Older Adults

A woman fills up a glass with water in Paris on April 27, 2014. (Getty Images)
A woman fills up a glass with water in Paris on April 27, 2014. (Getty Images)

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.



Research: Walking 7,000 Steps a Day a Huge Boost to Health

Step up: Walking even just a little more every day could have big health benefits. Tolga Akmen / AFP/File
Step up: Walking even just a little more every day could have big health benefits. Tolga Akmen / AFP/File
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Research: Walking 7,000 Steps a Day a Huge Boost to Health

Step up: Walking even just a little more every day could have big health benefits. Tolga Akmen / AFP/File
Step up: Walking even just a little more every day could have big health benefits. Tolga Akmen / AFP/File

People who walk 7,000 steps a day have a dramatically lower risk of a broad range of serious health problems, the largest review of the evidence yet said Thursday.

The most widely promoted target for people tracking their number of steps is 10,000 -- but that figure reportedly originally came from a 1960s marketing campaign for a Japanese pedometer, AFP said.

To find a more scientific target, an international team of researchers sifted through 57 previous studies that covered 160,000 people.

The results published in the Lancet Public Health journal found that walking 7,000 steps a day nearly halved people's risk of early death from all causes, compared to 2,000 steps.

The study also looked into health problems not previously covered by research into step counts.

Walking 7,000 steps a day was linked to people's risk of dementia falling by 38 percent, depression dropping 22 percent and diabetes decreasing 14 percent.

It was also associated with lower rates of cancer and falls, though the researchers warned this was based on less evidence.

"You don't need to hit 10,000 steps a day to get major health benefits," Paddy Dempsey, a study co-author and medical researcher at Cambridge University, told AFP.

"The biggest gains happen before 7,000 steps, and then benefits tend to level off," he said.

While people's speeds vary widely, 7,000 steps adds up to roughly an hour of walking throughout the day.

Dempsey emphasized that people already managing 10,000 or more steps should keep it up.

But he had a message for people who might find 7,000 steps daunting: "don't be discouraged".

"If you're only getting 2,000–3,000 steps a day, aim to add an extra 1,000 steps. That's just 10–15 minutes of light walking spread across the day," he said.

Andrew Scott, a researcher at the University of Portsmouth not involved in the study, said that "it demonstrates that overall more is always better".

"People should not focus too much on the numbers, particularly on days where activity is limited," he added.

The World Health Organization recommends at least 150 minutes of moderate to intense physical activity a week. Nearly a third of people worldwide do not reach this target, according to the WHO.