7 things that can happen to your body when you don't drink enough fluids.

You know the drill: keeping yourself hydrated is important. The humble H2O is necessary for a long list of bodily processes, including digestion, the dissolving of nutrients, waste elimination and thermoregulation.

While the amount of fluids we should each be drinking is dependent on a number of variables, the Nutrient Reference Values daily recommended intake is 2.6L for men and 2.1L for women — this can be derived from water, food sources, and other beverages.

RELATED: It’s a lot more fun than regular water, but is sparkling water bad for your teeth?

Hitting this target will not only make you immediately feel more virtuous (no judgement here, don’t worry) but it can also fend off a number of unpleasant physiological symptoms. Here are just some of the things that can happen when you don’t get enough water:

1. You could feel ravenously hungry

This might come as a surprise, but sometimes hunger isn’t hunger at all. Don’t worry, we’re not accusing you of looking for excuses to stick your head in a box of Shapes; when you drop the ball on your fluid intake your body can sometimes get a bit confused.

"Many people may misinterpret a thirst cue as a hunger cue. Always check if you are feeling hungry and if you are due to eat a meal, or if you are actually needing to drink some water," advises Geraldine Georgeou, Accredited Practising Dietitian and Director of Designer Diets.

RELATED: 5 possible reasons why you're constantly hungry.

"[Y]ou’re reaching for energy, but really you’re sluggish and lethargic because your body is searching for more water,” adds health coach Kirsty Welsh.

2. You might feel physically weaker

Hitting the water bottle at the gym helps to restore the fluid you lose through sweating, but that's not the only reason it's important. It could actually impact how well your muscles work, which is a bit awkward if you're in the middle of a strength training session.

"Muscles need to be hydrated or they can lose strength, so for better energy keep your fluid intake up while working out," Georgeou says.

3. You could throw out your fluid balance

This one mightn't be immediately obvious to you, but it could have a domino effect on your body's processes.

"Approximately 60 percent of the body is made up of water. Drinking enough water maintains the body’s fluid balance, which helps transport nutrients in the body, regulate body temperature, digest food, and more," Georgeou explains. (Post continues after gallery.)

4. You might feel tired...

Desperate for sleep, even though you got a solid seven hours of it last night? Pour yourself a glass (of H2O, not wine). Georgeou says one of the most common signs of dehydration is fatigue, adding that water can "help fight those feelings of 'tired eyes'".

RELATED: 7 reasons why you might be tired all the time.

It seems a lot of people don't realise the difference water can make. Earlier this year, it was reported many patients were making GP appointments for symptoms that would be resolved if they were consuming more fluids.

"Many of my patients do not drink enough fluid each day and only believe they are dehydrated when they start to feel thirsty... Yet other symptoms of dehydration appear before this, including fatigue and tiredness, headaches and poor concentration," Dr Roger Henderson told the Daily Mail.

5. ...and cranky

A small study in 2012 found when women were mildly dehydrated, their mood was significantly affected — as was their concentration.

So that's a fairly likely explanation for the notorious slump that tends to stake its claim around 3pm on work days. If you find yourself feeling like a total space cadet or grumpier than usual (or both!) a drink could help get you back on track. (Post continues after video.)

6. You could suffer from constipation

Water and your digestive system are pretty close mates, so if you keep them apart from one another for too long things can start to get a bit... strained. Ahem.

RELATED: How to deal with constipation. Yes, we're going there.

"Consuming adequate fluid can help reduce constipation. The bowel needs to stay hydrated to assist bowel regularity," Georgeou says.

7. You could contract a UTI

Sorry to end this article on a bit of a downer, but this is an important one to mention: if you're not taking in enough fluids, you put yourself at greater risk of a nasty, eye-watering urinary tract infection. And there's a simple explanation as to why this is.

"Drinking lots of water means you need to pee more, which helps flush out those [bacterial] bugs," says Dr Evelyn Lewin.

RELATED: 5 clever ways to avoid a dreaded urinary tract infection.

Seriously, if that's not enough to convince you, nothing will.

Have you ever experienced these side effects?