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During summer’s heat, it’s easy to become dehydrated without realizing it. And dehydration, which occurs when you lose more water via sweat and urine than you’ve taken in, can be especially dangerous for older adults.

A lack of sufficient fluid in the body can temporarily cause confusion and put you at risk for falls. When severe, dehydration can lead to a rapid or irregular heart rate, low blood pressure, fainting and even death. “How much water you have affects every body system,” says Jodi Stookey, an epidemiologist in San Francisco.

Staying well hydrated becomes more difficult with age because your sense of thirst tends to diminish with time. Diuretics, often prescribed for high blood pressure and heart failure, can exaggerate water loss. But you can protect yourself. Here’s how:

Know the signs

Dehydration can be challenging to detect as we age because classic signs such as dry mouth, thirst, fatigue and skin that doesn’t spring back quickly when pinched can also be caused by other factors. In fact, a 2015 review of research by the independent Cochrane Collaboration found that there was no single reliable test for dehydration.

The color of your urine can sometimes be a clue. In general, healthy urine is the shade of pale straw. The darker your urine, the less hydrated you may be. But aspirin, multivitamins and certain fruits and vegetables can also affect the shade of your urine.

If you suspect you might be dehydrated based on your urine’s color and/or the other signs mentioned, try drinking two to three full glasses of water during the course of an hour or two, advises Marvin M. Lipman, Consumer Reports’ chief medical adviser. If you still have symptoms of dehydration or don’t urinate within four hours, it’s wise to contact your doctor.

Getting enough

So how much — and what — should you drink? There’s really no overarching rule, and what’s appropriate can vary a good bit from person to person. Generally speaking, the heavier, taller and more active you are (and the hotter and more humid the weather is), the more fluids you need to take in to cover your losses. To make sure you get enough:

Drink before you feel parched. To make up for that reduced sense of thirst, sip preemptively. By the time you feel thirsty, you might be mildly dehydrated.

Sip small amounts throughout the day. If you find it difficult to consume a full glass of water all at once, drink a bit at a time, but frequently. Carrying a water bottle with you at all times can help remind you to drink.

Include other beverages and foods. All beverages (other than alcoholic drinks) will hydrate you, and that includes caffeinated drinks. Coffee and tea are mild diuretics, so they can cause you to urinate more. But they will add more to your liquid stores than you’ll lose, says Janet Mentes, a professor at the UCLA School of Nursing. Soup, fruits and vegetables are also good sources of liquid.

Take your health into consideration. Ask your doctor whether medical conditions you have or medications you take affect your hydration needs. And keep in mind that some health conditions, such as kidney disease and congestive heart failure, may make it dangerous to take in too much fluid. Your doctor can guide you.

Three surprising causes

Taking in too little liquid is an important factor in dehydration, but the following play a role as well:

•Infections that cause diarrhea, vomiting, excessive sweating and fever. Tara Cortes of New York University suggests calling a doctor if you vomit repeatedly or have a fever of more than 101 degrees for more than a day or diarrhea for more than two days.

•Medication that causes the kidneys to produce more urine, such as diuretics. Some over-the-counter drugs, such as laxatives, may also cause water loss.

•Health conditions, such as poorly controlled diabetes, that lead to excessive water loss. A 2016 study in the Annals of Family Medicine found that obese people were more likely than others to be inadequately hydrated. Having dementia, Parkinson’s disease or a stroke can also increase the chances of dehydration.

 Copyright 2017, Consumer Reports, Inc.

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