Trust Your Thirst

some health gurus believe that you need to sip on water constantly throughout the day, even when you’re not thirsty.

As with most things, this depends on the individual. Many factors (both internal and external) ultimately affect your need for water.

This article takes a look at some water intake studies to separate fact from fiction and explains how to easily match water intake to your individual needs.

Many people claim that if you don’t stay hydrated throughout the day, your energy levels and brain function start to suffer.

And there are plenty of studies to support this.

One study in women showed that a fluid loss of 1.36% after exercise impaired mood and concentration and increased the frequency of headaches (1Trusted Source).

Other studies show that mild dehydration (1–3% of body weight) caused by exercise or heat can harm many other aspects of brain function (2Trusted Source, 3Trusted Source, 4).

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 (5Trusted Source, 6Trusted Source, 7Trusted Source).

SUMMARY

Mild dehydration caused by exercise or heat can have negative effects on both your physical and mental performance.

Does Drinking a Lot of Water Help You Lose Weight?

There are many claims that increased water intake may reduce body weight by increasing your metabolism and reducing your appetite.

According to two studies, drinking 17 ounces (500 ml) of water can temporarily boost metabolism by 24–30% (8Trusted Source).

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 (9Trusted Source):

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 (10Trusted Source, 11Trusted Source).

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 (12Trusted Source).

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.

Trust Your Thirst — It’s There for a Reason

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.

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 (23Trusted Source).

There really is no science behind the 8×8 rule. It is completely arbitrary (24Trusted Source).

That said, certain circumstances may call for increased water intake.

The most important one may be during times of increased sweating. This includes exercise and hot weather, especially in a dry climate.

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, as well as several disease states like vomiting and diarrhoea.

Furthermore, older people may need to consciously watch their water intake because the thirst mechanisms can start to malfunction in old age (25Trusted Source).

SUMMARY

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.