Dealing with dehydration in the elderly
Elderly people are at a higher risk of dehydration due to physiological changes that occur as we age. Many conditions and increased physical or mental frailty also complicate the issue.
Drinking the right amount of water regulates our body temperature, gets nutrients to our cells, and keeps our organs healthy. It also plays a vital role in our mood and cognition. As such, carers and family members need to be aware of the common risk factors, the consequences, and how to recognise the signs of dehydration.

Risk factors in dehydration
Being in residential care is a recognised risk factor for dehydration. However, if your loved one has live-in care, particularly if they need dementia care, they can still be at risk.
Often, the first sign of dehydration is feeling thirsty. However, as we age, our thirst sensation naturally weakens, meaning we may not realise that our bodies need more water. This loss of thirst can be worse for those living with dementia or who have had a stroke.
Older people generally have a lower percentage of water in their bodies, which puts them at greater risk of dehydration, especially in hot weather.
Impaired renal function can also be a risk factor, as the hormones do not respond to dehydration as well.
Some medications such as laxatives and diuretics can exacerbate the likelihood of an elderly person becoming dehydrated, and if they are incontinent, they may deliberately restrict their intake of fluids, as they are worried about “accidents”.
Warfarin and dehydration
Dehydration can change the effectiveness of certain medications, so being aware of the signs of dehydration can help prevent medical emergencies.
Many older people take warfarin to reduce blood clots. Dehydration can lead to lower levels of fluid in the blood, causing it to thicken, and may reduce the effectiveness of Warfarin.
Those who take Warfarin also need to have regular blood tests to ensure they are on the right dose. Dehydration may impact these results, making it more difficult to work out how much warfarin they really need.
People who need assistance with feeding can be at higher risk, particularly if they live in a care home where staff skill levels differ, as there may be a general lack of awareness about how important hydration is.
If your loved one needs assistance with eating and drinking but receives at least 24-hours of care at home, their companion care provider can ensure that they have a sufficient fluid intake each day.
Consequences of dehydration
If an older person becomes dehydrated, they are more likely to be hospitalised and have an increased mortality risk. Even if they are only mildly dehydrated, they will feel tired and will have poorer concentration, memory problems and slower reaction times.
Other complications of dehydration include weakness, dizziness and an increased risk of falls.


Recognising dehydration
Common signs of dehydration include a dry mouth, tongue and lips. You may also notice that the elderly person has sunken eyes and dry, papery skin. They may seem to be unusually drowsy, confused or disoriented too. They might also feel dizzy because their blood pressure is low, however, and these signs are frequently seen in other conditions, so they might be due to another cause.
Spotting heat stroke
If you’re caring for a loved one – especially if they have dementia – it’s important to frequently check they’re not suffering any of the following symptoms. These can all indicate heat stroke:
- Headache
- Dizziness and confusion
- Loss of appetite and feeling sick.
- Excessive sweating and pale, clammy skin.
- Cramps in the arms, legs and stomach.
- Fast breathing or pulse.
- Temperature of 38C or above.
- Being very thirsty.
A person who is dehydrated may experience cramping in the limbs, or feel generally unwell. They can become irritable and have difficulty sleeping.
Symptoms of more severe dehydration include a weak, rapid pulse, faster than usual breathing, severe muscle cramps and contractions, and a bloated stomach.
Can dehydration cause blurred vision?
Blurred vision can be a sign of dehydration in the elderly, as the tear ducts can stop producing tears when there’s not enough water in the body. Tears are essential to keeping the eyes lubricated, comfortable and free from debris, so a lack of tears can easily lead to dry, irritated eyes and blurry vision.
Can dehydration cause headaches?
It’s estimated that the brain is three quarters water. As the control centre of all our bodily functions, feelings, and thoughts, preventing dehydration is crucial for keeping our brains working properly.
Fluid loss in the brain can cause it to temporarily shrink, pulling away from the skull and leading to a headache. If you or an elderly loved one experiences a sudden headache on a hot day, it could be a sign to drink more water.
The dehydration skin test
If you’re worried about a loved one who struggles to drink enough water, you may wonder if there’s an easy way to test and monitor hydration levels at home.
The easiest way to do this is with a simple skin test:
- Gently pinch the skin on the back of the hand, arm, or abdomen.
- Hydrated skin will spring back instantly.
- If the skin takes longer to bounce back, then dehydration is likely.
If you’re worried about dehydration, it’s always best to seek medical advice or call the NHS on 111.
Can dehydration cause high blood pressure?
Chronic, and regular bouts of dehydration in older adults have been linked to high blood pressure.
When you lose too much fluid, the water content of the blood decreases, and sodium levels can increase to dangerously high levels. To counteract this, the body starts to release a chemical that narrows the blood vessels, which can temporarily raise blood pressure.
Low blood pressure can also be a sign of dehydration, due to the decrease in overall blood volume.
Can dehydration cause a UTI?
When fluid is low, the body tries to store liquid in any way it can to ensure it has enough to keep functioning. One of the ways it does this is by preventing urination, however this can upset the concentration or balance of natural acids in urine, and lead to bacterial growth that causes urinary tract infections.
What to read next:
Click on an article below and it will open in a new tab, so you can come back to it once you’ve finished reading about the importance of staying hydrated:
How can dehydration be prevented?
The most important strategy for preventing dehydration is to recognise when the person’s fluid intake is inadequate and ensure they drink more.
Residents in care homes may not drink enough because they are worried about not being able to get to the toilet in time, particularly if they need assistance. They may be physically unable to reach a drink and may not receive the help they need to stay properly hydrated.
Staff training on the importance of hydration, monitoring of fluid intake, assistance when necessary and the provision of the person’s preferred fluids are all important in care homes.
If your loved one receives elderly care at home, try to ensure they drink a minimum of five eight-ounce glasses of water or clear fluids each day. They should always have a drink accessible, and it is a good idea to monitor fluid intake.
They should be offered a variety of fluids, both hot and cold and given the assistance they need if they are unable to drink independently. Your loved one may find drinking easier with an aid such as a cup with a handle or lid, or by using a straw depending on their condition.
When they take their medication, offer a full glass of water to help them swallow it.




How to encourage someone to stay hydrated
It can be difficult to persuade your loved one to drink the amount of fluid they need, especially when they do not feel thirsty or they are worried about incontinence. You could try the following strategies:
- Offer a choice of different drinks if they find water too tasteless or bland. They may like watered-down fruit juice, flavoured water or hot water with a slice of orange, lemon or lime. Low fat milk can also help replenish fluid and electrolytes (the electrically charged minerals that give the body energy) and is a tasty alternative to water.
- Approach them positively offering a drink as an attractive option rather than as a necessity.
- Offer drinks regularly and leave then accessible so that your loved one can take them little and often if they prefer.
- Avoid too much caffeine or alcohol. While tea may be the nation’s favourite drink, it does contain some caffeine, which can have a diuretic effect and lead to the urge to urinate more frequently. Switching to a decaffeinated variety is widely recommended.
- Encourage them to increase their fluid intake in warmer weather.
- Promote fluid intake more in the day than late at night if they have concerns about using the bathroom at night.
- You can try to top up their fluid intake with certain foods too. Yogurt, soups, and cottage cheese are all high in water and can be part of a nourishing meal too.
Staying hydrated in the heat
- Drink plenty of water – you should aim to drink at least eight glasses of water per day. If you’re looking after a loved one with dementia, be sure to remind them or support them to take on fluids.
- Understand your medication – there are certain prescriptions that may make it more likely for you to become dehydrated, especially in hot weather.
- Eat lots of vegetables – many vegetables have a high water content, and also provide the nutritional value you need to stay healthy in the heat. Melon, cucumber and celery are handy to pack in a picnic if you plan to be outside in the sun.
- Listen to your body – if you’re out in the sun, pay more attention than normal to what your body is telling you. Be alert to symptoms such as headaches, fatigue, nausea and lightheadedness.
- Mix up your fluids – water is always the best way to hydrate, but it’s not the only way. Cups of tea, glasses of squash and even a bowl of soup can help keep you hydrated.