Why dehydration can be deadly for older people

During a 2003 heat wave in Europe, more than 70,000 people is dead – most of the dehydration. An overwhelming number of these people were the elderly, in the 70s, 80s and 90s, many of whom lived alone. Gary Egan, a scientist previously affiliated with the Howard Florey Institute in Melbourne, wanted to understand why some people with access to water could eventually die of dehydration.

His thirst study, a collaboration with the University of Texas Research Imaging Center, suggests that people over 65 actually underestimate their thirst. Indeed, at a certain age, human beings lose the sensations that “tell” them to hydrate.

Specifically, Egan’s research shows that older people lose their ability to to feel thirst because their brain no longer communicates optimally with their body. Without a work signal to do so, many seniors, especially those who live alone, simply don’t drink enough water. Egan and his research partners believe this is what happened in Europe almost 20 years ago, when significant numbers of older people died during the 3-week heat wave.

In the experiment, published in Proceedings of the National Academy of Sciences, researchers induces thirst in two categories of subjects – people in their 20s versus those in their late 60s and early 70s – by asking each group to drink salt water. Then, all subjects were allowed to drink as much plain water as they wanted. “Although all participants had the same level of thirst, the elderly subjects drank only half the amount of water as the younger subjects,” said study co-author Michael Farrell. , in one Press release. “Using PET imaging that we found in older people, the mid-cingulate cortex was ‘turned off’ much earlier… This finding helps explain why older people can become dehydrated easily.”

The lack of internal motivation to hydrate is exacerbated by two additional factors: have less water in their bodies than younger people; and several drugs increase the risk of dehydration.

Chronic dehydration in the elderly

Water performs many functions in the body, from regulating temperature to helping pump blood to muscles. This is why dehydration can lead to disorientation and confusion, fatigue and muscle cramps, and even worse consequences. But these “non-specific” conditions are often misdiagnosed and even attributed to the natural effects of aging, Anne Vanderbilt, clinical nurse specialist at the Cleveland Clinic Center for Geriatric Medicine Recount the Cleveland Clinic.

It turns out that up to 40% of older people suffer from chronic underhydration, a SAGE Open Nursing to study from 2019 notes. Lead author Janet Mentes mentioned in a Press release that older people who are underhydrated and exposed to a virus or bacteria are more likely to develop an infection, such as urinary tract infections, pneumonia or other respiratory illnesses. If treated for the infection, a clinician may not recognize underlying underhydration and miss the opportunity to educate the individual on proper fluid intake. In fact, there are “significant health literacy gaps around hydration among older adults,” as noted in a 2017 study. Nutrition and healthy aging to study.

Dehydration even ranks among the ten most common diagnoses in hospitalizations for the elderly, according to a 2016 report. Frontiers of Molecular Biosciences paper found. In addition, health problems caused by dehydration counted for a 5% increase in avoidable emergency room visits among adults between 2008 and 2012, costs $1.14 billion per year in the United States, and results in increased mortality and morbidity.

Solutions for seniors

Unlike the now debunked wide recommendation to drink 8 glasses of water a day, the National Council on Aging suggests a more precise rule: individuals should calculate one-third of their body weight and drink that many ounces of fluid, taking into account how much of that water will come from the food we eat. Foods with high water content include watermelon, zucchini and strawberries.

Geriatricians to know it’s hard for someone in their 80s or 90s to drink a full glass of water in one sitting: bloating and frequent trips to the toilet often derail most older people from the path to hydration. Additionally, research has determined that bedwetting worries leave many older people waking up dehydrated, which is linked to an increased risk of falling. To address these concerns, Vanderbilt suggests offer older people small sips of water throughout the day and mix the water with flavorings to make it more palatable.