A calculation formula that can accurately predict the amount of water lost from the human body in a day has been found
Part of the human body is made up of water. Previous research has shown that the proportion (body water content) is about 60% for infants, about 53% for ordinary men, and about 45% for ordinary women, but how much of that is consumed per day? The exact number of losses was not known. Recently, researchers at the National Institute of Biomedical Innovation, Health and Nutrition and other institutions have come up with a calculation formula that accurately predicts how much water goes in and out of the human body (water turnover). I did.
Variation in human water turnover associated with environmental and lifestyle factors | Science
The world's first formula to predict the amount of water turnover in the human body has been invented - Based on the results of an international joint survey of 5,604 people in 23 countries - | National Institute of Biomedical Innovation, Health and Nutrition
Predicting the amount of water turnover in the human body – Waseda University
https://www.waseda.jp/top/news/85759
The research was conducted by Yosuke Yamada, director of the Exercise Guidelines Laboratory, Physical Activity Research Department, National Institute of Biomedical Innovation, Health and Nutrition (NIBIOHN), as well as Waseda University, Kyoto University of Advanced Science, the University of Tsukuba, as well as China, the United Kingdom, the United States, and Canada. This work was carried out jointly by researchers from research institutions such as .
The research team focused on the change in the stable isotope value of water (H₂) in the body, which increases slightly due to drinking water and then returns to its original value within a few months. By using a stable isotope ratio mass spectrometer that can accurately detect changes, we devised a method to measure body water content and water turnover rate. Measurements were conducted on a total of 5,604 men and women, including the elderly.
The results showed that, on average, infants lose about 25% of their body water per day, and adults lose about 10% of their body water per day. The following is a graph of the average value of water turnover rate by age, showing that the older you get, the lower the water turnover rate is. There were almost no differences by gender. However, this is just an average value, and when comparing individual values, some people had a daily water turnover rate of only 5%, while others had a daily water turnover rate of 20%.
In terms of volume, men between the ages of 20 and 35 have the highest turnover of water, averaging 4.2 liters per day. By the age of 90, this decreases to an average of 2.5 liters a day. For women, the value was highest between the ages of 30 and 60, with an average of 3.3 liters per day, and by the age of 90, it decreased to an average of 2.5 liters per day, similar to men.
In addition, water turnover showed high values when the temperature was high or when living near the equator, and high values were also found when living in extremely cold places or in the Arctic Circle. . In addition, water turnover was higher on average in hot summer than in spring, and water turnover also increased in late pregnancy as the fetus grew and body water content increased. Furthermore, developing countries, countries with a lot of manual labor, people who do a lot of physical activity on a daily basis, and athletes also have higher water turnover values.
The following formula was derived to clarify the influence of these factors.
Water turnover (ml/day) = [1076 x physical activity level] + [14.34 x body weight (kg)] + [374.9 x sex] + [5.823 x average daily humidity (%)] + [1070 x athlete ] + [104.6 × Human Development Index (HDI)] + [0.4726 × altitude (m)] - [0.3529 × age squared] + [24.78 × age (years)] + [1.865 × average temperature squared] - [19.66 ×Average temperature (℃)] -713.1
・Physical activity level: 1.5 for sedentary, 1.75 for average, 2.0 for high
・Gender: 0 female, 1 male
・Athletes: 0 non-athletes, 1 athlete
・HDI: 0 developed countries, 1 intermediate country, 2 developing countries
Note that just because men between the ages of 20 and 35 lose an average of 4.2 liters of water a day, it doesn't mean they should drink 4.2 liters of water a day. . This is because water enters the body through water produced during energy metabolism in the body, from exhaled air, and because the food itself contains water. If you are taking in water, you are taking in about 1.8 liters of water, so the amount of fluid you need to rehydrate is about 1.8 liters. For women in their 20s, it is approximately 1.4 liters.
Furthermore, further research is required regarding the relationship with the risk of disease and death.
・Continued
A website that allows you to easily and accurately calculate the amount of water lost from the human body in a day has appeared - GIGAZINE
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