Why you are less thirsty as you get older, and how much you should drink

You might go through an entire winter morning without feeling thirsty. Perhaps you've had a cup of coffee with breakfast, but by lunchtime, you still haven't reached for a glass of water. It doesn't necessarily mean your body has enough fluid.

As we get older, our sense of thirst becomes less reliable. We may need water long before we actually feel like drinking it. That's why health experts recommend making drinking a regular habit rather than waiting for thirst to remind us.

The good news? You don't need to force down large glasses of plain water. Your daily cups of tea and coffee count, too.

Why older adults don't feel thirsty as quickly

Dutch neuropsychologist Erik Scherder recently drew attention to this problem in Het Spreekuur, a podcast from Dutch science magazine Quest. His advice is particularly relevant to older people: drink regularly, even when you don't feel thirsty.

There's a biological reason behind it.

According to Belgian health website Gezondheid.be, aging changes how the brain and hormones regulate thirst. The signals that normally tell us to drink become weaker.

Our bodies also contain less water as we age. Babies are approximately 75 percent water, while older adults may be closer to 50 to 55 percent.

With less water in reserve, dehydration can become a problem more easily. Someone over 65 might therefore need a drink without experiencing the familiar sensation of thirst.

How much should you drink each day?

The UK's National Health Service (NHS) recommends six to eight cups or glasses of fluid daily as a general guide.

Dutch advice recommends at least 1.4 liters of drinks daily for adult women and 1.4 to 1.8 liters for adult men, depending on individual needs and assuming an appropriate diet.

An intake of roughly 1.5 to 2 liters of drinks is therefore a useful everyday reference for many adults, although it isn't a fixed target for everyone.

And here's something many people overlook: it doesn't all have to come from water.

Tea, coffee, milk, and other suitable drinks contribute to your fluid intake. Foods containing plenty of water, including soup, fruit and vegetables, also help keep you hydrated.

Small drinking habits that make a difference

Drinking enough becomes easier when you spread it throughout the day.

Try having a glass of water with breakfast, tea during the morning, another drink with lunch, and water during the afternoon. A warm bowl of soup can contribute additional fluid on a cold day.

Keep a glass or bottle within reach when reading, watching television, or working around the house. Seeing it can remind you to take a few sips.

If frequent nighttime bathroom visits bother you, it may help to drink more earlier in the day rather than saving most of your drinks for the evening.

You can also look at your urine. The NHS says it should generally be a clear, pale yellow color. Dark yellow urine or urinating less frequently can suggest dehydration, although urine color alone isn't a reliable test, particularly in frail older adults.

When drinking more isn't the right advice

Important: People with heart failure, kidney disease, or a prescribed fluid restriction shouldn't automatically increase their water intake. Certain medications, including diuretics, can also affect fluid balance.

If this applies to you, follow the amount recommended by your doctor rather than a general drinking guideline.

For most otherwise healthy adults, the message is simple: don't wait until you're very thirsty. A few small drinks throughout the day can be easier to manage than trying to make up for everything in the evening.