Water is vital for good health and, really, it helps with everything. And since about 60% of the human body is water, according to the U.S. Geological Survey (USGS), it needs to maintain hydration levels to fuel cells and keep the brain and body functioning.
You probably already know that drinking water will help you stay hydrated, but certain foods can also help increase your hydration levels. These foods include those with a high water content, such as cucumbers, watermelon, bell peppers and tomatoes.
With that said, many of us aren't drinking nearly enough water daily—and may even be drinking dehydrating sources, like sugar-sweetened beverages and booze, which can strip the body of hydration.
So, what exactly happens to your body if you don't drink enough? Here are 10 unpleasant side effects you might experience.
Read more: How Much Water Should You Drink, by the Numbers
1. Low Energy
When dehydrated, you might notice your energy levels plummet, as water helps keep your mind alert and the body balanced, according to a 2019 review in Nutrients. If you're not drinking enough during the day, that afternoon slump will hit even harder, and you might feel too tired to continue with work or make it to your evening workout. Keep a water bottle on hand to remind you to consistently drink throughout the day.
2. Mental Fog
Your brain needs water since it's made up of about 73% water, per the USGS, and drinking enough keeps you mentally sharp, even long-term. The same 2019 review in Nutrients found that dehydration negatively affects working memory. Working memory allows us to remember information temporarily so that we can work without losing track of what we are doing. If you're feeling foggy and are spacing out, chug some water and see if it helps.
3. Increased Risk of Stroke
According to a 2020 study in the Journal of Clinical Neuroscience, being dehydrated can raise the risk of strokes and prolong recovery time, if you've had one. So, to keep your cardiovascular system in tip-top shape, pay attention to how much you're drinking. If your pee is dark yellow or you feel faint, drink some water pronto.
4. Moodiness
Dehydration can make you cranky, too. The 2019 review in Nutrients states that emotions, such as anger, hostility, confusion, depression and tension increase with as little as 1% dehydration. So, the next time you're feeling down or irritable, pour yourself a glass of water and take some time to just breathe and hydrate.
5. Overeating
Sometimes we confuse thirst with hunger, so drink up and see if that helps you distinguish what your body really needs. If you still feel hungry after that, then eat! It's important to listen to your body's cues and fuel it with what it needs.
6. Slower Metabolism
Water is needed for every single function in the body, so when you're dehydrated, your metabolism naturally slows down—and with it, so do your energy levels. Staying properly hydrated can give your body what it needs to function so you can feel your best.
7. Headaches
Since your brain needs water, when it's lacking, it can lead to headaches and fatigue, according to 2021 research in Current Pain and Headache Reports. So, before taking medication, have some water first and rest. That head pain might go away without you needing to take any other measures.
8. Skin Damage
Our skin needs water to stay healthy and look hydrated. The 2019 review in Nutrients states that people who drank the most water had skin that was greater in elasticity and was less dry and rough. Not drinking enough can increase the effects of aging. With insufficient water, collagen can crack, leading to fine lines and wrinkles. That's why people need moisturizing, hydrating products in a skin-care regimen to complement their water intake for that soft, supple look.
9. Weaker Workouts
When you're sweating, you're losing electrolytes and water, so it's important to drink before, during and after working out to replenish lost stores. As shown in a 2021 study in the Journal of Human Kinetics, not being hydrated enough can decrease strength, endurance and power—and consequently, performance. It's important to be well-hydrated prior to working out and to continue hydrating during and after exercise.
10. Weight Gain
A little weight gain is nothing to lose sleep over. That said, if it continues over time or is in the belly region in particular, it can put you at a greater risk for various chronic diseases, including diabetes, heart disease and more. Drinking water might help you lose weight, especially if you're drinking it in place of sugary beverages or other higher-calorie drinks, according to a 2019 review in Nutrición Hospitalaria. Water is filling, so it can help you feel less hungry in between meals and snacks—although you shouldn't drink water as a meal replacement.
The Bottom Line
Water is essential for many bodily processes to work properly and might even help improve your mood. If you're not crazy about plain water, try infusing flavor into it with flavor makers like cucumber, mint, citrus fruit or berries. Or try making our DIY Easy Flavored Ice Cubes, which not only add flavor but are beautiful to look at, too.
