Old people have more spit

Fluid supply for the elderly - current state of knowledge.

The topics at a glance:

What is the importance of water?

Drinking water is the most important food. The human organism can only get by for 2 to 4 days without water. Water is a component of all cells and body fluids. The water content in the human body varies between 50 and 70% depending on age, gender and body composition. In healthy adults about two thirds of the total body water is inside the body cells (intracellular) and one third outside (extracellular). These volume proportions are usually regulated and kept constant with the help of sodium. The amount of water in the body is closely related to the salinity of the body. Every salt intake (mainly sodium chloride / NaCl = table salt) in turn results in a corresponding water intake, which binds the corresponding amount of salt.

The water content of the body is regulated by the antidiuretic hormone (ADH) and the feeling of thirst. With the help of the hormone ADH, the kidneys regulate how much of the drinking water that is consumed should be excreted and how much remains in the body.
Water serves as a cell building material, as a solvent and means of transport in the metabolism, to control the acid-base balance and to regulate the body's temperature. The human body constantly excretes fluids through the kidneys, intestines, skin or, when breathing, through the lungs.

In order to maintain all bodily functions, people must regularly drink sufficient fluids. However, this is often a problem in old age. The feeling of thirst is reduced and the adaptability of the kidneys is reduced. If the intake of liquid and salt is too low, the kidneys of older people excrete large amounts of water and sodium, and the regulation of the water content is disturbed. Elderly people are less thirsty, a lack of fluids is often not even noticed, too much fluid is excreted with the urine. The same is true for sodium, which is normally also retained when you are dehydrated. Even small losses of fluid can have drastic health effects, especially in the elderly.

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How much water do older people need?

There are various recommendations for individual fluid requirements. Under normal conditions, the daily water balance in older people is around 2.3 liters. Assuming about 300 ml of oxidation water (produced by the burning of fatty acids and glucose) and about 700 ml of water from solid food, about 1.3 liters would have to be drunk to balance the fluid balance. Beverages containing caffeine can also be included in the balance.

Guide values ​​for the intake of water per day (65 years and older)
Water absorption from beverages1,310 ml
Water intake from solid food680 ml
Oxidation water260 ml
Total water uptake2,250 ml
Source: D-A-CH reference values ​​for nutrient intake. 2000


For seniors this requires a daily water supply through drinks and solid food of about 30 ml of water per kg of body weight. With high outside temperatures (further information: summer heat and drinking), strong wind, warm and dry heating air, a high consumption of table salt, a high protein intake as well as various illnesses with fever, vomiting or diarrhea, when taking diuretic drugs or laxatives and in general when exercising Exertion increases the need for fluids.
In people with heart failure, kidney disease or liver cirrhosis, it may be necessary to limit / balance the amount of fluid. The required amount of water should always be consumed in consultation with the attending physician.

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What are the causes of dehydration in old age?

With increasing age, on the one hand, the water content of the body decreases due to the decrease in muscle tissue. On the other hand, the feeling of thirst is significantly reduced, as aging sensory cells suppress the feeling of thirst. In addition, fluid excretion can be increased due to a decreased ability of the kidneys to concentrate and decreased sodium reabsorption by the kidneys. In addition, there is a change in hormone secretion with age.
Insufficient fluid intake can result from poor drinking habits as well as from an increasing need for help with drinking. Fear of going to the toilet at night, incontinence and prostate problems can be important obstacles to drinking.
Increased fluid losses can also result from frequent sweating and high ambient temperatures (e.g. summer heat, physical overexertion, overheated rooms). An increase in the volume of urine (osmotic diuresis) can be caused by hyperglycaemia. The use of certain medications (such as diuretics and laxatives) can result in increased fluid loss, as can the presence of multimorbidity (diabetes, chronic infections with fever, vomiting, chronic diarrhea). These losses must be compensated for by increasing the intake of fluids (in excess of the normal daily requirement).

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How common is dehydration and what are the effects?

Many older people drink too little. If the fluid intake is reduced, the body becomes dehydrated. The subsequent dehydration (desiccosis) can have drastic health effects. When specifying the frequency (prevalence) of dehydration and desiccosis in old age, a distinction must be made between seniors who live independently at home and those who live in nursing homes or are in hospitals. It should also be noted that the different methods used to record prevalence can lead to different results. For example, dehydration is a more common problem in nursing homes. In younger seniors living independently, studies have shown a rather low prevalence. The risk of dehydration only increases with age. The prevalence of overt dehydration in hospital patients over 65 years of age is probably 5-10%, and in people at risk of dehydration it is up to 50%.
The clinical symptoms that can be associated with dehydration and desiccosis first affect the functions of the skin and mucous membranes, then the circulatory system, the nervous system and other organs. Some of the symptoms occur more frequently in old age, so that it is not always possible to differentiate whether the symptoms were aggravated or caused by lack of water.
The water balance is strictly regulated, even a slight lack of fluid (1-2% loss of body mass) can cause clinical symptoms. With a deficiency of 2%, physical performance restrictions must be expected, a deficit of 20% is considered life-threatening. Dehydration is associated with a morbidity and mortality rate (illness and death rate) of 45% and more. About 17% of patients with the main diagnosis of dehydration die within 30 days of admission to hospital.

Possible symptoms and consequences of dehydration in old age:

  • dry mucous membranes, dry mouth, decreased saliva production
  • Loss of performance, weakness, dizziness, apathy and lethargy
  • increased susceptibility to infection and risk of inflammation, fever
  • impaired perception and impairment of short-term memory, states of confusion
  • increased thirst, constipation, weight loss
  • Drop in blood pressure, racing heart
  • Seizures
  • Thrombosis
  • increased tendency to fall
  • changed drug effect
  • Increase in urea and creatinine
  • reduced amount of urine, concentrated urine
  • Circulatory and kidney failure

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How can you tell if you are dehydrated?

Even a dehydration of 1-2% loss of body mass can be clinically relevant. From a fluid deficiency of 2%, physical performance restrictions must be expected. However, it is difficult in practice to clinically assess the hydration status of an elderly person, as clinical signs can also appear in the normal aging process. Is the individual fluid requirement known at all? How can the demand actually be met?

Hints to a lack of fluids provide a reduced excretion of mostly dark, concentrated urine. Drinking and nutrition logs can provide information about decreased fluid intake. The answers to the following questions can provide clues:

  • Is an increased need for excessive fluid loss (e.g. fever, sweating, vomiting and diarrhea) taken into account?
  • Is more urine excreted (kidney dysfunction, diabetes)?
  • Can increased fluid loss be related to medication (diuretics, beta blockers, corticoids and others)?

General physical symptoms such as fatigue, muscle weakness, dry skin and mucous membranes, speech difficulties and dry mouth can indicate a lack of fluids. A change in body weight can also be a sign of a lack of fluids.

Various others Blood and urine tests (Creatinine and urea content, sodium concentration; color and specific gravity of urine) and anthropometric measurements (Skin thickness and blood flow) in combination with body weight, pulse and blood pressure can help to make reliable statements about the extent of dehydration. The bioelectrical impedance analysis is a non-invasive method for recording total body water.

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How can adequate hydration be achieved?

There are a number of measures and tricks that may not apply to everyone, but can help increase the amount of water you drink:

  • Prepare the drinking ration for the day (about 1.3 liters) in the morning
  • Always place drinks within sight and reach
  • vary between different drinks
  • To control drinking behavior, create a drinking plan for the day and add up the amount consumed in the evening
  • Refill empty glasses and cups (portions that are too large can be a deterrent) or replace them with filled ones
  • if necessary, use special drinking vessels (can be obtained from any medical supply store) or drinking straws
  • Introduce drinking rituals, for example a glass of water after waking up, a glass of water before every meal, afternoon coffee or "5 o'clock tea", the glass of water by the bed
  • Self-service options for drinks (drinking oases) and drinks machines are helpful in facilities
  • Facilitators should encourage people to drink between meals
  • Drinking together with residents, staff and relatives can be useful
  • individually preferred drinks and drinking vessels should be offered and there should be a choice between several cold and hot drinks
  • Seniors in need of care need adequate help and support
  • Also offer colored (colored) liquids for dementia patients

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Example of a daily drinking schedule for seniors

Daily drinking plan for seniors
breakfast2 cups of coffee or tea250 ml
Snack1 glass of fruit juice spritzer or buttermilk200 ml
Having lunch1 glass of mineral water200 ml
1 plate of soup150 ml
Snack1 large cup of tea or coffee200 ml
dinner2 cups of herbal tea300 ml
Late meal1 juice or wine spritzer, mineral water200 ml
Total1,500 ml

The less someone eats, the more they should drink, otherwise the water contained in solid food will be missing!

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Which drinks are suitable for adequate hydration?

  • Drinking and mineral water - depending on your tolerance - with or without carbon dioxide, especially calcium-rich (more than 150 mg / l) and magnesium-rich (more than 50 mg / l) mineral water
  • Fruit juice spritzers, diluted fruit juices
  • Herbal and fruit teas
  • Contrary to what is often stated otherwise, coffee and tea do contribute to the fluid supply
  • fruits and vegetables rich in water (such as melons, fruit compotes, tomatoes, cucumbers and others)
  • water-based foods (such as broths, soups, yogurt, buttermilk, kefir, and others)
  • Lemonades and cola drinks are less suitable for quenching thirst due to their high sugar content
  • There is nothing against an occasional glass of beer or wine if there are no health reasons to the contrary

Sometimes even less suitable drinks are still better than no drink at all!

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Where can I read more information?

  • Bischoff SC. Elderly Fluid Supply - A Critical Review of Current Knowledge and Established Recommendations. Aktuel Ernahrungsmed 37 (2012) 81-90
  • Federal Center for Health Education (BZgA): Drinking healthily in old age. Cologne 2020. www.gesund-aktiv-older-werden.de
  • German Nutrition Society. Drink in old age. Bonn 2012 (www.fitimalter-dge.de)
  • German Nutrition Society. Drink properly - stay fit. Bonn 2014. www.dge.de
  • German Nutrition Society. Fluid supply in clinics. DGE practical knowledge. Bonn 2012 (www.fitimalter-dge.de)
  • Heseker H, Odenbach V (Ed.) Nutrition of the elderly and those in need of care. Practical guidelines for needs-based care in old age. Hamburg: Behrs 08/2012
  • Huhn S. Practical Guide to Nutrition Management. Handouts for the implementation of the expert standard "nutrition management" in nursing practice. German Professional Association for Nursing Professions (Ed.) Potsdam 2009 (www.dbfk.de)