About 60% of our bodies are water. We often lose water mainly through urine and sweat.
There are many different opinions about the amount of water we should drink every day.
Health authorities often recommend eight glasses (each weighs 8 ounces), equivalent to about 2 liters, or half a gallon. This is called an easy to remember 8 × 8 rule.
However, there are other health professionals who think that we are always at risk of dehydration and need to drink water continuously throughout the day. even if not thirsty.
This largely depends on each individual and there are many factors (both inside and outside) that affect our water needs.
I want to look at some of the studies on how much water intake and how it affects the function of the body and brain, then explain how to easily make the intake of drinking water in accordance with the needs. personal.
Can water help increase energy and improve brain function?
Many people think that if we don't drink enough water throughout the day, the energy level and brain function can start to get worse.
There are many studies supporting this idea.
A study in women showed that losing 1.36% of water after exercise both depressed mood and concentration, while increasing the frequency of headache .
There are other studies that show that Mild (1-3% of body weight) due to exercise or high temperature can negatively affect many other aspects of brain function .
However, remember that just losing 1% of your body weight is really significant. This happens mainly when you sweat a lot, such as during exercise or due to high temperatures.
Mild water loss can also negatively affect physical activity, leading to reduced durability .
Key thing: Mild dehydration due to exercise or high temperature can have negative effects both physically and mentally.
Does drinking plenty of water help you lose weight?
There are many claims about drinking water that affect body weight, that drinking lots of water can increase metabolism and reduce appetite .
According to two studies, drinking 500ml of water (17 oz) may temporarily accelerate the 24-30% metabolism .
The top graph below shows how 500 ml of water helps increase metabolism (EE - Energy Cost). You can see the effect has decreased before reaching the 90-minute mark :
Researchers estimate that drinking 2 liters a day can increase energy consumption by about 96 calories .
It may be best to drink water cold because then the body needs to consume energy (calories) to heat the water to equal body temperature.
Drinking water about half an hour before a meal can also reduce calorie consumption, especially in the elderly .
One study showed that dieters took 500ml of water before a meal weight loss 44% more in 12 weeks than those who don't drink .
In general, it seems that drinking enough water (especially before meals) can help significantly lose weight, especially when combined with a healthy diet.
Key thing: Drinking water may temporarily increase your metabolism and drink about half an hour before a meal can make us automatically eat less calories.
Does drinking more water help prevent health problems?
Some health problems can be improved by increasing the amount of drinking water:
- Constipation: Drinking plenty of water can help improve constipation which is a common problem .
- Cancer: There are some studies that show that people who drink a lot of water are at lower risk of developing bladder and colorectal cancer, while others do not see any effect .
- Kidney stones: Increasing the amount of drinking water reduces the risk of kidney stones .
- Acne and dry skin: There are many sideline reports on water that help hydrate the skin and reduce it But I didn't find any research to confirm or reject this.
Key thing: Drinking more water can help solve some health problems like constipation and kidney stones.
Are other liquids included in the total amount of water?
Filtered water is not the only ingredient that contributes to body fluid, other drinks and foods can also have a significant impact.
One thing that is still transmitted is that caffeinated drinks (like the coffee or tea) is not counted because caffeine is a diuretic.
However, studies show that this is not true, because the diuretic effect of these drinks is very faint .
Most types food also contains plenty of water. Fish, egg , especially fruit with lots of water and vegetables contain a significant amount of water.
If you drink coffee or tea and eat foods that are high in water, it is possible just like that It is enough to maintain fluid balance as long as you don't sweat much.
Key thing: Other drinks you drink also contribute to body fluid balance, including caffeinated beverages like coffee and tea. Most foods also contain water.
Trust your thirst. You are thirsty for a reason
Maintaining water balance is essential for our survival. So evolution has provided us with complex mechanisms to regulate when and how much we should drink.
When our total water drops below a certain level, we will start to feel thirsty. This is controlled by the same mechanisms as breathing, We don't need to consider that too mechanically .
For most people, there is probably no need to worry about water intake. The thirsty instinct is very reliable and has looked after so that we humans have been living for a long time .
There is really no scientific basis behind the 8 × 8 rule. This entirely depends on the individual . However, there are some situations where it may be necessary to increase the amount of drinking water ... that is to drink even if not thirsty.
The most important case may be during sweating due to exercise, as well as hot weather (especially in a dry climate).
If you perspire a lot, make sure you replenish your lost water. Athletes who exercise for a very long time, high intensity may also need to add electrolytes in parallel with the water.
Water demand also increased during breastfeeding, as well as a number of conditions such as vomiting and diarrhea.
Older people may need to pay attention to monitoring the intake of drinking water because some studies show that thirst mechanisms may start to deviate when they get older .
Key thing: Most people do not need to think too much about drinking water because the thirst in the brain works very well. However, certain cases need to drink more.
How much water is best?
After careful consideration, no one can say exactly how much water we need. This depends mainly on each person.
Through an autonomous experiment, some people may perform better when drinking more water than usual, while for others it is only inconvenient to have to go to the toilet more often.
However, I am not sure whether the small benefits of being provided with enough "optimal" water should have been over thinking about it. Life is inherently complicated enough.
If you want everything to be simple (this is always a good idea) then 90% of us should apply these principles:
- Thirsty, drink.
- No more thirst, then stop.
- When it's hot and practice a lot, drink enough water to make up for the lost water.
- That's it.