Latest research! Not everyone needs eight glasses of water a day

From childhood to adulthood

Always hear people say

Each person should drink 8 glasses of water (about 2 liters) every day

Recently, a new study refuted this claim.

In fact, human drinking water needs vary greatly

1

How do scientists measure how much water a person needs in a day?

The study, published in the journal Science on November 24, measured the water intake of more than 5,600 people in 26 countries. The participants ranged in age from 8 days to 96 years old. They drank a certain amount of water containing traceable hydrogen and oxygen isotopes. The researchers found that the average amount of water people drank per day was between 1 liter and 6 liters.

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In addition, the researchers collected and analyzed data from the participants, comparing environmental factors such as temperature, humidity, and altitude of the participants' locations with measured water turnover, energy expenditure, weight, gender, age, and more.

All things being equal, the difference between men and women is about half a litre of water turnover. The results estimate that a 20-year-old, 70kg, non-athletic male living at sea level in a developed country with an average temperature of 10 degrees Celsius and a relative humidity of 50% will absorb and lose about 3.2 litres of water per day. A woman of the same age and activity level, weighing 60kg and living in the same place, would need to consume 2.7 litres of water.

At the same time, if a person doubles their energy consumption, they will use about 1 liter more water per day. For a 50 kg increase in weight, water consumption will increase by 0.7 liters. For every 50% increase in humidity, water consumption will increase by 0.3 liters. Athletes consume about 1 liter more water than non-athletes.

2

Come and calculate how much water you need!

In this study, scientists from nearly 100 teams conducted joint experiments and came up with the world's first "water drinking formula" for the entire human life cycle. Based on this formula, everyone can accurately calculate how much water they should drink every day.

Among them, PAL is the physical activity level, which is equal to the total energy expenditure (TEE) of the human body in 24 hours divided by the basal metabolic rate (BMR) of the human body in 24 hours. HDI stands for the Human Development Index, which reflects the degree of social progress in different places. For this formula, the HDI value of developed countries is 0, the HDI value of middle-class countries is 1, and the HDI value of backward countries is 2. In addition, the Athlete Status value of non-athletes is 0, and that of athletes is 1.

The researchers used this formula to calculate that, on average, men aged 20 to 35 consume 4.2 liters of water per day, while women aged 30 to 60 consume 3.3 liters of water. And from the age of 60, the demand for water decreases with age. By the age of 90, the water demand has dropped to about 2.5 liters.

3

Drink water scientifically, and pay attention to these!

As the saying goes, "Food is the first necessity of life, and water is the first necessity of life." Drinking enough water every day plays a vital role in the health of human skin, blood vessels, and intestines. Here are some tips for daily scientific drinking of water:

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1. Don’t wait until you are thirsty to drink water. Thirst is a sign of dehydration in the body. When you feel thirsty, it means that your cells are already dehydrated.

2. Do not drink a lot of water before eating. This may dilute the digestive juices and reduce the concentration of gastric acid, which may cause indigestion, acute gastroenteritis and diarrhea.

3. When drinking water, the water temperature should be between 25℃ and 40℃, and it is best not to exceed 65℃.

4. Don’t drink a lot of water after exercise! If you drink a lot of water after exercise, the sodium ion content will become low. This phenomenon is called "dilutional hyponatremia", also known as water intoxication. After exercise, the organs of the human body are in a state of fatigue. Sudden large amounts of water intake will significantly increase the burden on the heart, which is not good for the functions of many organs, especially the heart.

5. After high-intensity exercise, you need to drink appropriate amounts of water containing electrolytes, such as salt and sugar, to replenish the salt and sugar lost by the body.

END

Source: Popular Science China, China Science Network, The Paper

Compiled by: Dong Xiaoxian

Editor: Guru