Other studies show that mild dehydration (1–3% of body weight) caused by exercise or heat can harm many other aspects of brain function (
体育投注网址Keep in mind that just 1% of body weight is a fairly significant amount. This happens primarily when you’re sweating a lot.
Mild dehydration can also negatively affect physical performance, leading to reduced endurance (
体育投注网址Mild dehydration caused by exercise or heat can have negative effects on both your physical and mental performance.
The image below shows this effect. The top line shows how 17 ounces (500 ml) of water increased metabolism. Notice how this effect decreases before the 90-minute mark (
体育投注网址The researchers estimated that drinking 68 ounces (2 liters) in one day increased energy expenditure by about 96 calories per day.
体育投注网址Additionally, it may be beneficial to drink cold water because your body will need to expend more calories to heat the water to body temperature.
Drinking water about a half hour before meals can also reduce the number of calories you end up consuming, especially in older individuals (
One study showed that dieters who drank 17 ounces (500 ml) of water before each meal lost 44% more weight over 12 weeks, compared to those who didn’t (
Overall, it seems that drinking adequate amounts of water, particularly before meals, may have a significant weight loss benefit, especially when combined with a healthy diet.
What’s more, adequate water intake has a number of other health benefits.
体育投注网址Drinking water can cause mild, temporary increases in metabolism, and drinking it about a half hour before each meal can make you automatically eat fewer calories. Both of these effects contribute to weight loss.
体育投注网址Several health problems supposedly respond well to increased water intake:
Drinking more water may help with some health problems, such as constipation and kidney stones, but more studies are needed.
Plain water is not the only drink that contributes to your fluid balance. Other drinks and foods can have a significant effect.
One myth is that caffeinated drinks, such as coffee体育投注网址 or tea, don’t help you hydrate because caffeine is a diuretic.
In fact, studies show that the diuretic effect of these beverages is very weak (
体育投注网址Most foods are also loaded with water. Meat, fish, eggs and especially fruits and vegetables all contain significant amounts of water.
体育投注网址Together, coffee or tea and water-rich foods can help maintain your fluid balance.
体育投注网址Other beverages can contribute to fluid balance, including coffee and tea. Most foods also contain water.
Maintaining water balance is essential for your survival.
For this reason, your body has a sophisticated system for regulating when and how much you drink.
When your total water content goes below a certain level, thirst kicks in.
体育投注网址This is controlled by mechanisms similar to breathing — you don’t need to consciously think about it.
For the majority of people, there probably isn’t any need to worry about water intake. The thirst instinct is very reliable (
There really is no science behind the 8×8 rule. It is completely arbitrary (
That said, certain circumstances may call for increased water intake.
体育投注网址The most important one may be during times of increased sweating. This includes exercise and hot weather, especially in a dry climate.
体育投注网址If you’re sweating a lot, make sure to replenish the lost fluid with water. Athletes doing very long, intense exercises may also need to replenish electrolytes along with water.
Your water need also increases during breastfeeding体育投注网址, as well as several disease states like vomiting and diarrhea.
Furthermore, older people may need to consciously watch their water intake because the thirst mechanisms can start to malfunction in old age (
Most people don’t need to consciously think about their water intake, as the thirst mechanism in the brain is very effective. However, certain circumstances do call for increased attention to water intake.
At the end of the day, no one can tell you exactly how much water you need. This depends on the individual.
体育投注网址Try experimenting to see what works best for you. Some people may function better with more water than usual, while for others it only results in more frequent trips to the bathroom.
If you want to keep things simple, these guidelines should apply to the majority of people: