Drinking habits

Drinking warm water: what it does – and what it doesn't

Drinking warm water hydrates just as well as cold: the body brings any liquid to operating temperature within minutes. That leaves the question of what else the popular morning ritual can do, and where it actually comes from.

Updated August 2026 · 6 min read

A glass of warm water after getting up is one of the most frequently recommended drinking rituals of all. It is credited with better digestion, better-looking skin, a boosted metabolism. The honest verdict is more sobering: for most of these promises there is no evidence, and the temperature changes nothing about water's most important job, supplying the body with fluid. Even so, there are good reasons why the ritual pays off for some.

What does drinking warm water actually do?

The digestive tract absorbs water whether it arrives at 15 or at 40 degrees. The body evens out the temperature within a short time, and the effort involved is tiny: bringing a quarter of a litre of fridge-cold water up to 37 degrees takes around seven kilocalories on paper. That is the equivalent of one bite of an apple.

For hydration, this means warm water is neither better nor worse than cold. What matters is the amount. The European Food Safety Authority (EFSA) gives a guide value for total water intake of 2.0 litres per day for women and 2.5 litres for men; around a fifth of that comes from solid food. To see what this means for your personal intake, use the water intake calculator.

Where does the warm morning water ritual come from?

The habit is far older than any wellness trend. In Ayurveda, the traditional Indian system of health, water that has been boiled and drunk warm has been recommended for centuries. In China, hot water remains the everyday drink to this day, on hand in trains and hotels alike. Both traditions attach their own ideas of digestibility and inner balance to it.

In the German-speaking world, morning water owes its popularity above all to Ayurveda guides and social media. That a practice is old and widespread, however, says nothing about whether it works. The specific effects attributed to warm water are not scientifically proven. That does not make the ritual worthless: a fixed morning habit ensures adequate drinking more reliably than any good resolution.

When is warm water the more pleasant choice?

Comfort is an entirely legitimate reason. In these situations, warm can be the better choice:

• In winter: many people find it hard to drink enough during the cold months. A warm glass noticeably lowers the hurdle.
• With a sensitive stomach: some find very cold water unpleasant on an empty stomach. Lukewarm is the gentler option.
• For drinking slowly: warm water is naturally taken in small sips instead of large amounts hastily gulped down.
• As a routine anchor: a fixed warm glass after getting up anchors drinking in your daily routine before the rush begins.

The last point in particular is underestimated. If you simply forget to drink during the day, you benefit from every fixed anchor – whatever the water temperature. You will find further strategies in the article on not drinking enough water.

Conversely, cold water has an advantage of its own: to many people, cool feels more thirst-quenching, which makes them drink it more willingly. That too is comfort, not physiology. Simply choose the temperature at which you reliably reach your amount.

“Detox”: what lies behind the term?

Hardly any word comes up as often in connection with warm water as “detox”. Physiologically, it is not defined. The original image comes from metalworking, where slag is a real residue; in the human body there are no comparable deposits that settle and would need to be flushed away. The German Nutrition Society (DGE) states that any scientific evidence for such “waste deposits” is lacking.

The breakdown products your metabolism actually leaves behind are disposed of around the clock by the liver and kidneys. Sufficient fluid supports the kidneys in this work, because urine needs water. Normal drinking in normal amounts is enough for that, and temperature plays no part in it.

How warm should the water be?

Lukewarm to pleasantly warm, so roughly 30 to 45 degrees. There is a clear upper limit: the International Agency for Research on Cancer (IARC) classifies drinks above 65 degrees as probably carcinogenic to the oesophagus. That applies to scalding-hot tea just as much as to scalding-hot water. So let boiled water stand for a few minutes before you drink.

In Switzerland, boiling is not a hygienic necessity anyway; tap and mineral water are strictly monitored. A tried-and-tested approach is the mixing method: two thirds cold water, one third boiling. If you heat hard water, you will occasionally see white flakes in the glass. That is precipitated limescale, in other words calcium carbonate, and it is harmless. More on this in the article on hard water.

Warm water is a feel-good ritual, not a remedy. Persistent digestive complaints or pain when swallowing should be assessed by a doctor.

If you prefer your mineral water gently warmed: careful heating changes nothing about the minerals. A litre from the Castels spring in Mels brings 87 mg of calcium, 35 mg of magnesium and 265 mg of sulphate, whether it lands in the glass cool or at 40 degrees. And the roughly twelve years this naturally alkaline mineral water with a pH of 8.0 has spent travelling through the rock strata of the Sardona Alps can be tasted at any temperature.

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