11 Reasons You’re Still Dehydrated After Drinking Lots Of Water

You often hear the old adage “eight glasses of water a day” as a way to stay hydrated. But unfortunately, hydration isn’t quite as simple as refilling your Nalgene and getting a lot of H2O out. In fact, it’s possible to still feel thirsty and dehydrated, even if you’re someone who takes pride in the water drinking game.

If you drink a lot of water and still feel dehydrated, there may be another reason for this. “Dehydration usually means fluid loss in the body,” says Kelly Unger, certified personal trainer, nutritionist, and co-founder of Epic Fitness. While this is usually caused by not drinking enough, other factors such as certain diseases or excessive sweating can cause your body to become irritated.

Since dehydration is never a good feeling, it will be important to quench your thirst and identify the exact cause so that you can get yourself back on track. Some signs of dehydration to watch for include dry mouth, bad breath, excessive thirst, little or no frequent urination, and dark urine. And if you’re really dehydrated, you may feel dizzy, tired, or stop sweating altogether.

It can be confusing if you experience these signs even after drinking plenty of water, but drinking water isn’t all it takes to stay hydrated. Here are some of the reasons why you might feel dehydrated despite drinking enough water, according to experts.


You are missing electrolytes

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“You’re probably drinking enough water but still feeling dehydrated if you have an electrolyte imbalance,” says Dr. Natasha Trentacosta, MD, a sports medicine and orthopedic specialist at Cedars-Sinai Kerlan-Jobe Institute.

It says electrolytes like sodium, chloride, magnesium, and potassium are essential for delivering fluids to your cells. If you lose it due to excessive sweating at the gym, for example, it can really throw things off. She recommends focusing on drinks that contain a lot of salt, such as coconut water, and eating fruits and vegetables that contain a lot of fiber to combat these losses.


I drank a lot of water

Believe it or not, drinking a lot of water can also make you feel good due to the way it affects electrolytes. “Water consumption, especially in excess of it, can flush out electrolytes and fiber,” Trentacosta explains. The National Academies of Sciences, Engineering, and Medicine recommend drinking about 91 ounces, or 2.7 liters, per day.


Drink all your water at once

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Are you the type to drink three glasses of lemon water first thing in the morning? If so, it is important to make sure that you drink water throughout the day, rather than drinking it all in one sitting. “Your body will absorb more water throughout the day, not all at once,” says Scott Michael Schreiber, MD, a board-certified rehabilitation specialist.


It could be a sign of diabetes

If no amount of water quenches your thirst and you are urinating excessively, it is time to consult your doctor. “This may be the first sign of diabetes,” Trentacosta says. As the body tries to get rid of sugar, people with diabetes may urinate frequently, which can dehydrate them. And if you’re always thirsty and pee a lot, you might be worth getting tested for diabetes.


I’ve been sick lately

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Illness can make you feel dehydrated, says registered dietitian Kristen Gillespie, MS, RD, LD, whether you’re vomiting, have diarrhea, sweat heavily, or have dealt with all of the above. “Obviously increasing fluid intake is essential to combating fluid loss, but that is easier said than done, especially during illness,” she told Bustle. “It may be easier to tolerate keeping fluids on hand and sipping it throughout the day rather than trying to drink large amounts at one time.”

This is the moment when you might be tempted by drinks like Pedialyte or Gatorade. “Not only do they contain electrolytes, which are also lost through sweating and GI tract loss, but they are often more easily absorbed within the body,” Gillespie says.


You are taking some medicine

Some types of medications may make you more susceptible to dehydration. “Some medications intentionally flush water and electrolytes from the body,” says Trentacosta, citing diuretics, laxatives, antacids, and even blood pressure medications as examples. Since some of them may list dehydration as a side effect, check with your doctor to find out what they recommend regarding staying hydrated.


You live in a hot climate

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Even if you drink eight cups a day or more, this may not be enough for you, depending on your size and level of physical activity. “You may not actually get as much water as you think,” says Dr. Trentacosta. “The general recommendation is to drink about eight glasses of water per day, but this should be proportional to the individual’s weight and activity levels.”


You drink dehydrated liquids

Be mindful of what you drink besides the water. According to Gilspie, if you feel thirsty, you should try to increase your intake of hydrating fluids, such as water, tea and sports drinks, and reduce alcohol-containing drinks, as they may have a slight diuretic effect.

The same is true if you are a big fan of coffee and soda. “Many individuals use these products as one of their liquids,” Jaramillo says. “In fact, we should match each of these drinks consumed with an extra glass of water.” If you’re not a fan of plain water, Gillespie recommends submerging your own fruit or adding flavor to improve the taste.


You wear too many layers

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Another quick way to feel dehydrated? Make yourself sweat by wearing too many layers. “Sweating is your body’s way of trying to lower your body temperature,” Unger says. Make sure you don’t make your body work too hard by sitting in three jackets and a pile of blankets. It won’t necessarily make you dehydrated, but this should be considered if you can’t figure out why you’re always screaming at water.


You have a hormonal imbalance

You’re also more likely to have a hormonal imbalance, says board-certified clinical dietitian and functional medicine practitioner Filipa Bellette, Ph.D., especially if you have to urinate almost immediately after drinking a glass of water.

Billet points to a hormonal imbalance linked to stress in particular, noting that it can cause a mineral deficiency in the body. “If a person is deficient in minerals, they will not be able to absorb water into their cells, which means that they begin to urinate almost all the water they drink, leaving their body dehydrated despite how much water the person drinks,” she told Bustle.

These and other health issues are something you can test in your doctor’s office. If you can’t figure out why you’re feeling dehydrated and thirsty all the time, it’s a good idea to start ruling things out.


You always wait until you feel thirsty

“When you’re thirsty, you’re really heading down the path to dehydration,” Schreiber says, which is why you need to drink water throughout the day—and not just when you’re thirsty. “Your body will absorb more water throughout the day rather than in one dose,” he explains.

Since it’s hard to remember to drink water, especially if you’re busy or have an active job, Trentacosta suggests keeping track of how much water you drink throughout the day. Consider getting a water bottle that quantifies fluid amounts or using a water tracking app so you know for sure you have enough.

If you’re experiencing signs of chronic dehydration despite drinking plenty of water, talk to your doctor about what might happen and how to stay hydrated.

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Freund, b. (1996). Nutritional needs in cold environments and at heights: applications for military personnel in field operations. Institute of Medicine (US) Military Nutrition Research Committee; Marriott BM, Carlson SJ, editors. National Academies Press (USA); 1996. https://www.ncbi.nlm.nih.gov/books/NBK232870/

Gersh, J (2020). Fluid balance and hydration considerations for women: a review and prospective guidance. Med Sports. https://pubmed.ncbi.nlm.nih.gov/31641955/

Maughan, R.J. (1991). Fluid and electrolyte loss and replacement with exercise. Sports Science J. https://pubmed.ncbi.nlm.nih.gov/1895359/

Popkin, B.M., D’Anci, K.E., & Rosenberg, IH (2010). Water, water and health. Nutrition ReviewsAnd 68(8), 439-458. https://doi.org/10.1111/j.1753-4887.2010.00304.x.


Scott Michael Schreiber, DC, Board Certified Rehabilitation Specialist

Dr. Natasha Trentacosta, Specialist Sports Medicine and Orthopedics at Cedars-Sinai Kerlan-Jobe Institute

Sheena Jaramillo MS, RD, Registered Dietitian

Filipa Bellette, Ph.D., Clinical Dietitian and Board Certified Occupational Medicine Practitioner

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