Glass of water
8 Signs You're Not Drinking Enough Water

Fact Checked by Brett Melanson, PhD

We’ve all heard the classic “drink 8 glasses of water a day” as a standard measure of how much water we should be drinking daily.

But what happens when we don’t get enough water in our bodies?

Here, you’ll find 8 signs that are often experienced by people who are dehydrated and often indicate that you need to drink more water.

1. You’re Thirsty

It might be obvious, but it’s a telltale sign that you are clearly not drinking enough water.

The problem is, when we become stressed or are active, we often forget that these kinds of things can actually cause our bodies to use more water, resulting in states of dehydration (1).

This is because both stress (2,3) and exercise (4) are things that demand a lot of energy, and water is required by our cells to make this kind of energy (5).

Main point: When you feel thirsty, it’s a good sign you haven’t had enough water to drink. Remember to increase your water intake if you are stressed or are active.

2. Constipation

Crazy to think, but even your bowels need water to function properly (6).

You see, your intestines need water to keep the digestive environment lubricated and capable of moving digested food towards your colon (and the exit, of course) (7).

So, when you’re not drinking enough water, your intestines begin to struggle with moving all of that digested food towards the exit and can cause a build-up, otherwise known as constipation.

Want to feel regular? Start by drinking more water!

Main point: Dehydration can strain the intestines and colon from moving stools toward the exit, causing constipation. Drink more fluids to avoid this!

3. The Colour Of Your Urine

This is often pointed out throughout life, but when the urine is clear, so is your level of hydration (most of the time).

If your urine is a yellowish to amber colour, there is a good chance you’re not getting enough water. Adequate water intake is reflected by a lighter yellow to clear appearance of urine (8).

Things like alcohol can actually dehydrate us quickly but cause our urine to turn clear. This is because of a hormone that is released after alcohol consumption called vasopressin, which causes the body to increase the amount of water it gets rid of (9).

So, next time you’re feeling thirsty, try and grab some water instead of that beer.

Main point: The colour of your urine can tell you just how much water you’re getting. Clear urine is good (but not if you’ve been drinking a lot of alcohol). On the other hand, yellow urine can be a sign that you need to increase your water intake.

4. Feeling Tired and Moody

That’s right, being dehydrated can make you feel tired and grumpy.

In fact, when researchers caused dehydration in women, it caused them to become more moody, but this effect was not as obvious in men (10).

However, in a randomized controlled trial (a gold standard in science), scientists found that even mild dehydration caused dramatic changes in cognitive functions like working memory and attention, and increased feelings of anxiety and tiredness (11).

So, if you’re feeling cloudy, moody, or a little tired, why not grab a glass of water?

Main point: There is evidence that not drinking enough water can impact mood and the ability to think. So, if you’re trying to focus on a task, make sure you’re drinking enough water to help.

5. The Look and Feel of Your Skin

Your skin cells are much like many other cells in the body in that they require water to survive (12).

When we increase our body temperature, we begin to sweat. Sweat is comprised of electrolytes and water and is a natural response of the body and skin to cool ourselves down (13).

However, in extreme cases of dehydration, the body may not actually be able to produce sweat because there just isn’t enough water to make it with.

This can be a cause of concern, especially for individuals who work in hot, humid climates, or those who are physically active for long periods such as marathon runners.

Luckily, our skin can provide us with early warning signs that we are not getting enough water. These include (14):

  • Cracking of the skin or lips
  • Rough or flaking skin
  • Feeling flushed or appearing more red than usual
  • Having skin that feels cold and clammy

Main point: The skin is a great indicator of hydration levels—keep an eye out for the indications mentioned above and make sure you drink enough water to allow your body to cool down during times of exercise or when working in hot environments.

6. Dry Mouth

In addition to feeling thirsty, dehydration can make your mouth feel dry (15).

This is because the mouth constantly lubricates the internal environment with saliva, which is highly composed of water (16).

Dry mouth can also result from a variety of other medical conditions, however, so if drinking a glass of water doesn’t help your dry mouth, it is best to seek out professional medical advice to see why you’re experiencing this.

Main point:  A lack of water intake can reduce the ability of the mouth to produce saliva. Saliva helps keep the mouth lubricated and is largely composed of water. So, if you’re experiencing dry mouth and are thirsty, there is a good chance you are dehydrated.

7. Headaches

Not only can dehydration affect your cognitive function and mood, it can also cause you to experience headaches. 

One study looked at the effects of dehydration caused by exercise and found that even becoming dehydrated by 1.36% caused problems in concentration, task difficulty and headaches! (17

This means that even moderate exercise can put you at risk of dehydration if you don’t drink enough water.

Main point: Water is extremely important for our overall health and may be a cause of those headaches you’ve been experiencing. Try increasing your water intake each day to see if this helps.

8. Effects on the Heart

In addition to your skin, organs, and just about everything else in your body, your blood is also composed of water.

This means that low water intake can affect how blood gets around your body.

This is suggested to cause fluctuations in your blood pressure as well as your heart beat (18), and may be why some people who experience dehydration also experience heart flutters (or palpitations) (19)

Main point: Just like every other cell in your body, your blood is made up of cells, which also must have adequate water to survive. Staying hydrated can prevent possible drops in blood pressure and heart flutters that may result from dehydration.

Drink Up!

Hopefully, after reading through these telltale signs of dehydration, you can now keep your body in check with adequate fluids and efficiently prepare for scenarios that require increased energy demand, like exercise or stressful work environments.

As always, you should discuss any changes to your diet or lifestyle with a healthcare professional, especially in the context of dehydration. Many symptoms of dehydration can be a symptom of another underlying medical condition and should always be checked with a professional healthcare provider if it persists.


Fact Checked by Brett Melanson, PhD