Brain malfunction explains dehydration in elderly

December 18, 2007

As Australia faces another hot, dry summer, scientists from Melbourne’s Howard Florey Institute have warned that elderly people are at risk of becoming dehydrated because their brains underestimate how much water they need to drink to rehydrate.

Dehydration occurs when the body does not have enough water and this can happen rapidly in extreme heat or through exercise. Symptoms of dehydration can include headaches, lethargy and hallucinations. In extreme cases, dehydration may result in death.

Florey researchers Dr Michael Farrell, A/Prof Gary Egan and Prof Derek Denton discovered that a region in the brain called the mid cingulate cortex predicts how much water a person needs, but this region malfunctions in older people.

Dr Farrell said they infused old (age 65 to 74) and young (age 21 to 30) research participants with salty water to make them thirsty and then allowed them to drink as much water as they wanted.

“Although all participants had the same level of thirst, the older people only drank half as much water as the younger subjects,” Dr Farrell said.

“Using PET imaging we found in the older people, the mid cingulate cortex was ‘turned off’ much earlier by drinking small volumes.”

“This discovery helps explain why the elderly can become easily dehydrated,” he said.

The August 2003 European heatwave claimed around 52,000 lives through dehydration and other causes* – many of these were older people. France suffered the worst losses, with 14,802 people dying from the heatwave.

As climate change continues to be a hot global issue, the health implications for the elderly from rising summer temperatures add to this concern.

Dr Farrell recommended that older people ensure they drink enough water during hot weather.

“Adults should drink about eight glasses of water per day to prevent dehydration, and physically active people may need to drink more,” Dr Farrell said.

Source: Research Australia

Explore further: Drilling boom brings rising number of harmful waste spills

Related Stories

Drilling boom brings rising number of harmful waste spills

September 8, 2015

Carl Johnson and son Justin are third- and fourth-generation ranchers who for decades have battled oilfield companies that left a patchwork of barren earth where the men graze cattle in the high plains of New Mexico. Blunt ...

Solar-powered disaster relief

October 15, 2010

As water and fuel remained scarce in the weeks following the earthquake in Haiti earlier this year, one resource that relief teams could have used to help prevent dehydration literally surrounds the Caribbean island: the ...

How frogs and fish can help us learn to freeze humans

June 3, 2015

From Star Wars to Futurama to Alien, the idea that humans can be frozen in time in order to be awoken later is a well-established sci-fi trope. While stopping biological time or inducing long-term hibernation is still as ...

MDMA godfather Alexander Shulgin's legacy

June 6, 2014

The first time ecstasy impinged on the public consciousness in Britain was in November 1995, when an 18-year old Essex schoolgirl named Leah Betts died a few days after taking a tablet at a birthday party. The cause of her ...

Recommended for you

How the finch changes its tune

August 3, 2015

Like top musicians, songbirds train from a young age to weed out errors and trim variability from their songs, ultimately becoming consistent and reliable performers. But as with human musicians, even the best are not machines. ...

Machine Translates Thoughts into Speech in Real Time

December 21, 2009

( -- By implanting an electrode into the brain of a person with locked-in syndrome, scientists have demonstrated how to wirelessly transmit neural signals to a speech synthesizer. The "thought-to-speech" process ...


Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.