For most of our lives, thirst provides a useful reminder that it is time to drink something. As we get older, that reminder may become less dependable.
MedlinePlus specifically identifies older adults as being at greater risk for dehydration because some people lose part of their sense of thirst as they age.[1] Research into aging and hydration has reached a similar conclusion. When older adults experience conditions that challenge their fluid balance, their sensation of thirst and their resulting fluid intake can be reduced compared with younger adults.[2]
For seniors, that makes a simple hydration routine worthwhile. Having something to drink regularly during the day can provide a reminder that no longer depends entirely on feeling thirsty.
Why Dehydration Becomes a Greater Concern With Age
Thirst is only part of the story.
Aging is accompanied by changes in the body’s water balance, kidney function and body composition. Chronic illnesses, medications, mobility limitations and difficulty obtaining drinks can add additional challenges. A review of dehydration in older adults identified diminished thirst, lower muscle mass, reduced kidney function, physical or cognitive limitations and the use of multiple medications among factors that can increase dehydration risk.[3]
Some medications can also increase fluid loss. Diuretics, for example, increase urination. Fever, vomiting, diarrhea and heavy sweating can cause the body to lose fluid more quickly.[4]
Hot weather deserves particular attention. An older adult who is normally well hydrated can face different needs during a heat wave, an illness or an unusually active day.
Dehydration Does Happen Among Seniors
This risk is more than theoretical.
A 2023 systematic review and meta-analysis examined 61 studies involving more than 22,000 adults age 65 and older who were not hospitalized. Using directly measured blood osmolality, which the researchers considered the most reliable measurement, the analysis estimated that about 24% of older adults were dehydrated.[5]
Researchers have also associated dehydration in older adults with poorer health outcomes, although some questions remain about which relationships are directly caused by dehydration.[3,6]
The practical lesson is fairly simple. Hydration deserves some attention during the day, especially for an older adult whose thirst may no longer provide an early reminder.
What Does Dehydration Look Like?
Possible signs of dehydration in adults include:
Dry mouth
Urinating less often than usual
Dark-colored urine
Fatigue
Dizziness
Increased thirst[1,4]
Severe dehydration can become a medical emergency.[4]
There is an additional complication for seniors. Traditional physical signs of dehydration may sometimes be less reliable in an older adult, making early dehydration harder to recognize.[3] Prevention can therefore be easier than waiting for unmistakable symptoms to appear.
Build Drinking Into the Day
A hydration routine does not have to be complicated.
For some seniors, it might mean having a beverage with every meal, keeping a drink within easy reach while reading or watching television, or drinking something when taking medications (when appropriate). Someone who spends time outdoors might make a habit of drinking before leaving home and again after returning.
Caregivers and family members can help by making beverages easy to obtain and offering them periodically, particularly to someone with limited mobility or memory problems.
Water is one option. Milk, juice, coffee, tea and other beverages also contain water. Foods can contribute meaningful amounts of water as well, especially fruits, vegetables, soups and similar foods.[7]
That last point is important because there is no universal number of glasses of plain water that every senior needs to drink. MedlinePlus notes that water requirements vary with age, sex, body size, physical activity and medical conditions, and that total water intake includes water obtained from both beverages and food.[7]
For now, the useful goal is simpler: develop a hydration routine that works for you rather than relying entirely on thirst to remind you.
Some People Need Individual Instructions
Drinking more fluid is not appropriate advice for everyone.
People with some kidney or heart conditions may have been instructed to limit fluids. Certain medications and medical conditions can also change an individual’s fluid needs. Seniors who have been given specific instructions about fluid intake should follow the guidance of their healthcare provider.
Anyone who is uncertain about how much fluid is appropriate can ask a physician, nurse or dietitian to help develop a daily plan.
Hydration habits do not need to dominate the day. A few dependable routines can make a difference. Keep beverages accessible, drink regularly, pay additional attention during illness or hot weather, and remember that as we grow older, thirst may arrive later than the need for fluid.
SOURCES
National Library of Medicine. Dehydration. MedlinePlus. U.S. Department of Health and Human Services.
Kenney WL, Chiu P. Influence of age on thirst and fluid intake. Med Sci Sports Exerc. 2001;33(9):1524-1532. doi:10.1097/00005768-200109000-00016.
Hooper L, Bunn D, Jimoh FO, Fairweather-Tait SJ. Water-loss dehydration and aging. Mech Ageing Dev. 2014;136-137:50-58. doi:10.1016/j.mad.2013.11.009.
National Library of Medicine. Dehydration: Medical Encyclopedia. MedlinePlus. U.S. Department of Health and Human Services.
Bunn DK, Hooper L, Welch AA. Low-intake dehydration prevalence in non-hospitalised older adults: systematic review and meta-analysis. Clin Nutr. 2023.
Masot O, Miranda J, SantamarĂa AL, Pueyo EP, Pascual A, BotiguĂ© T. Fluid intake recommendation considering the physiological adaptations of adults over 65 years: a critical review. Nutrients. 2020;12(11):3383.
National Library of Medicine. Water in diet. MedlinePlus Medical Encyclopedia. U.S. Department of Health and Human Services.
