The body contains about 60% water by drinking water. However, we are losing water continuously due mainly to urine and sweat. There are many different points of view about the amount of water that should be taken per day, but, as with most things, this depends on each person and various factors (both internal and external) that intervene in our need for Water.
How Much Water Should We Drink a Day?
Normally, health authorities recommend following the “8 × 8 rule”: 8 eight-ounce glasses (about 240 ml), which is roughly equivalent to 2 liters of water. However, there are other health gurus who think that we are always on the verge of dehydration and that we need to be sipping water throughout the day, even if we are not thirsty. Let’s see how water consumption affects the functioning of the body and brain and how easy it is to adapt water consumption to the needs of each person. If we drink more water, does it increase our energy levels and improve the functioning of our brain? Numerous studies states that if we do not stay hydrated during the day, our energy levels and the functioning of our brain may begin to decline. In a study of women, a loss of fluids of 1.36% after exercise affected mood and concentration, while increasing the frequency of headaches. Other studies show that mild dehydration (1-3% of body weight) caused by exercise or heat can negatively affect other aspects of brain function. However, it should be borne in mind that even if only 1% of our body weight actually represents a fairly significant amount. This occurs mainly when we sweat a lot, due to exercise or high temperatures. Mild dehydration can also negatively affect physical performance, causing a reduction in endurance.
In summary: Mild dehydration caused by exercise or heat can have negative effects on physical and mental performance.
Does Drinking a Lot of Water Help Us Lose Weight?
There are many claims that water consumption influences body weight: when we drink more water, metabolism increases and appetite is reduced. According to two studies, drinking 500 ml (17 oz) of water can temporarily increase the metabolism by 24-30%. Researchers estimate that drinking 2 l (68 oz) a day can increase energy expenditure by about 96 calories per day. If our goal is to burn calories, it is preferable to drink cold water, since the body will need to spend energy (calories) to heat the water to body temperature.
“Drinking water half an hour before meals can also reduce the amount of calories that people ingest throughout the day, especially the elderly”.
One study showed that people who are on a diet and drink 500 ml of water before meals lose 44% more weight, in a period of 12 weeks, than those who do not take that amount. Broadly speaking, it seems that drinking an adequate amount of water (especially before meals) can be very favorable for losing weight, especially when combined with a healthy diet.
In short: Drinking water can slightly and temporarily increase the metabolism. Also, if it is taken half an hour before meals, it can cause people to automatically eat fewer calories.
Can a Higher Intake of Water Help Us Prevent Health Problems?
There are certain health problems that can respond well to an increase in water intake:
- Constipation: Increasing water intake can help with constipation, a very common problem.
- Cancer: There are several studies that show that those who drink more water have a lower risk of bladder cancer and colon cancer (8, 9). Kidney stones: The increase in water intake seems to decrease the risk of kidney stones.
- Acne and skin hydration: According to numerous anecdotal reports, water helps hydrate the skin and reduce acne.
In summary: Increasing water consumption can help treat various health problems, such as constipation or kidney stones.
In Addition to Water, Can We Include Other Liquids in the Total?
Flowing water is not the only liquid that contributes to the water balance (entry and exit of liquids) of our body: there are other drinks and foods that also have a considerable influence. There is a myth that says that caffeinated drinks (such as coffee and tea) are not accounted for in the balance because caffeine is diuretic. However, several studies show that this is not true, since the diuretic effect of these drinks is very small. Most foods contain high amounts of water. Meat, fish, eggs and especially water-rich fruits and vegetables contain significant amounts of water. If you drink coffee or tea and eat water-rich foods, this is likely to be enough to maintain the water balance – as long as you don’t sweat much.
In summary: There are other drinks besides water that contribute to the water balance, including drinks with caffeine, such as coffee and tea. Most foods contain water.
Trust Your Thirst … It’s There for a Reason:
Maintaining the water balance is essential for our survival. For this reason, evolution has provided us with complex mechanisms to regulate the frequency and quantity of what we drink. When our total water content is below a certain level, thirst appears. This is controlled by mechanisms similar to processes such as breathing: we don’t have to consciously think about it. Probably, most people do not need to worry about water consumption: the instinct of thirst is very reliable and has managed to keep the human being alive for a long time. In fact, there is no real science behind the “8 × 8 rule”: it is completely arbitrary. Therefore, there are certain circumstances that may require an increase in water intake, that is, not only when we feel thirsty. The most important circumstance may be a high perspiration moment. For example, when we exercise or it’s hot (especially in a dry climate). When you sweat a lot, be sure to replace lost fluids with water. Athletes who exercise intensely for a long period may also need to replenish electrolytes, in addition to water. The need for water also increases during breastfeeding, as well as during some disease states such as vomiting or diarrhea. According to some studies, older people are likely to need to consciously monitor their water consumption, since the mechanisms that regulate thirst can begin to fail at an advanced age.
In short: Most people do not need to consciously think about water intake because the brain mechanism that regulates thirst is very effective. However, some circumstances require increasing water consumption.
How Much Water is Adequate?
Actually, nobody can tell you exactly how much water you need. As with most things, this depends on each individual. Some people may live better with more water than usual, while for others, this can only be the inconvenience of making more trips to the bathroom.
If you are thirsty, baby, and when you are satiated, stop. In periods of hot weather or exercise, drink enough water to compensate for fluid loss.