A writer from Verywell Mind decided to test the recommendation of drinking 13 glasses of water a day for a week.
The experiment revealed both mental and physical changes, along with several surprising effects along the way.
A simple goal

The author began the experiment because he normally does not drink enough water.
According to the Academy of Nutrition and Dietetics, an average man should drink about 13 glasses of water a day, so he wanted to see how it would affect him over the course of a week.
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A feeling of success

The experiment began on a Saturday morning, when he started the day with two glasses of water before coffee.
Throughout the rest of the day, he kept drinking water regularly, including while he was out running errands.
Late in the evening, he had reached the goal of 13 glasses and felt a clear sense of satisfaction at having achieved it.
A new habit

On the second day, he continued drinking water throughout the day. He drank water before grocery shopping, during exercise, and with dinner.
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By taking a glass of water every time he went into the kitchen, it became easier to reach his daily goal.
The first changes appeared on the third day

By Monday morning, he already noticed a difference. He felt less irritable than usual.
At the same time, he noticed that the color of his urine was lighter, which can be a sign of better hydration.
No headaches during work

On the fourth day, he began to feel both mentally and physically more refreshed. He went to the bathroom more often but felt less tired.
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He also noticed that he had not experienced headaches during the week, even though he normally often gets them after long workdays in front of a screen.
An unexpected improvement in mood

In the middle of the week, he noticed that he had been having a particularly good week mentally.
During a conversation with his therapist, he mentioned that he felt better than he had in a long time.
Only later did he consider that the increased water intake might have played a role.
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Less water was quickly noticeable

One busy day meant he drank slightly less water for a period.
On a warm day, he quickly began to feel the onset of a headache, which made him consider whether hydration might have a direct effect on his well-being.
Easier to choose healthier alternatives

Later in the week, he noticed that he ate fewer unhealthy snacks.
It seemed that regularly drinking water helped reduce the urge to buy snacks during the day.
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A natural part of everyday life

By the end of the week, it no longer felt like an experiment. Drinking 13 glasses of water had become a natural part of his daily routine.
Fluids through food

Part of the body’s water needs is actually covered through food and other drinks.
Around 20 percent of the necessary fluid intake normally comes from the diet without actively drinking more water.
The need for water varies

How much water a person should drink depends on several factors.
Age, activity level, health, as well as pregnancy or breastfeeding can influence how much fluid the body needs.
Too much water can also be harmful

Although hydration is important, it is also possible to drink too much water. This can lead to a condition called water intoxication, where the body’s chemical balance is disrupted.
Symptoms may include headache, nausea, confusion, and muscle weakness.
Small habits make it easier

If you want to increase your water intake, it can help to turn it into a fixed routine.
For example, you can drink a glass with every meal, alternate between water and other beverages, or add flavor to water with fruit or herbs.
Sources: Verywell Mind, and Academy of Nutrition and Dietetics.
