Signs of Dehydration

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Signs of Dehydration

Dehydration happens when you lose more fluids than you are taking in, and your body doesn’t have enough fluids to work properly. Dehydration is associated with certain illnesses and even death, if not treated and corrected.

Why is staying hydrated so important?

We all know that we should be drinking a lot of water during the day. But why?

Water accounts for about 60% of body weight. Losing as little as 3% of body weight from fluid loss can cause dehydration, according to a 2018 article from the journal BMC Public Health. Water is vital for our existence, and we need it to:

  • Regulate body temperature
  • Digest food and get rid of waste
  • Lubricate and cushion joints
  • Protect the spinal cord and other vital tissues and organs

What causes dehydration?

Dehydration can occur for a number of reasons:

  • Diarrhea and vomiting
  • Sweating too much
  • Fever
  • Urinating too much

Illness, in general, is a prime cause of dehydration, especially if you have severe diarrhea and/or vomiting (this causes a large loss of water and electrolytes) or a fever (the higher the fever, the more fluids you lose).

Increased urination can also dehydrate you and may happen if you have undiagnosed or poorly controlled diabetes. It can also result from taking certain medications, such as diuretics, some types of antidepressants, and some types of sleeping pills. A class of diabetes medicine called SGLT2 inhibitors (brand names Farxiga, Jardiance, and Invokana) also cause increased urination. However, you can avoid becoming dehydrated if you take any of these medicines as long as you are drinking enough fluids.

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What are symptoms and signs of dehydration?

Typical symptoms and signs of dehydration in adults are:

  • Feeling very thirsty
  • Dry mouth
  • Not urinating or sweating as much as usual
  • Dark-colored urine
  • Feeling tired
  • Headache
  • Dry skin
  • Dizziness
  • Confusion

Severe dehydration can be life-threatening. If you have any of these symptoms, you need to get medical help right away:

  • Confusion
  • Fainting
  • Lack of urination
  • Rapid heartbeat
  • Rapid breathing
  • Shock

Are you at risk of dehydration?

Dehydration can happen to anyone, but some people are at higher risk:

Infants and children

They are most likely to have severe diarrhea and vomiting, and lose a higher amount of fluids from fevers due a higher surface area to volume area, according to the Mayo Clinic.

Older adults

Older adults tend to have a diminished sense of thirst, so they may not drink enough. Older adults who have dementia, diabetes, mobility problems, or who take certain medications are especially at risk of dehydration.

People with chronic illnesses

Diabetes, cystic fibrosis, and kidney problems can cause frequent urination or sweating, leading to dehydration.

People who exercise or work outdoors

Hot and humid weather increase the risk of dehydration.

How is dehydration treated?

The goal of treatment is to replace the fluids and electrolytes that you’ve lost. Mild cases of dehydration can be treated by drinking a lot of water. If you’ve been ill or sweating a lot, you may need to drink beverages that contain electrolytes, such as Gatorade, Propel Immune Support, and Pedialyte (no, it’s not just for kids!). Choose sugar-free or unflavored versions of electrolyte beverages if you have diabetes.

More severe cases of dehydration require an IV to replenish fluids and electrolytes.

How can you prevent dehydration?

The best way to avoid getting dehydrated is to drink enough water. The National Academies of Sciences, Engineering, and Medicine recommend that women drink about 11 cups of water daily, and men, about 15 cups daily. General tips for preventing dehydration include:

  • Drink water during the day. Keep a filled water bottle or a glass nearby to remind you to drink.
  • If you’re bored with water, give it some flavor without adding carbs. Squeeze lemon or lime juice into your water or add some sliced cucumbers or fresh herbs. You can also try sugar-free liquid water enhancers. Brands include MiO, Stur, and SweetLeaf. Seltzer water is another good option.
  • Make sure to drink frequently if you are outside in the heat, exercising, or when you’re sick, even if you aren’t thirsty.
  • Eat vegetables and fruits that are high in water, such as lettuce, cucumber, celery, melon, strawberries, and pineapple.
  • Sugar-free gelatin and popsicles also “count” as water and can be especially appealing when you are sick.
  • Use an app to remind you to drink water. Examples are Eight Glasses a Day, iHydrate, and Water Your Body.

Talk with your health care provider or dietitian about the amount of water that’s right for you, based on your age, level of activity, and certain medical conditions that you have (you may need to restrict your fluid intake if you have kidney disease or congestive heart failure, for example).

Want to learn more about staying hydrated? See “Staying Hydrated,” “Best Beverages for Staying Hydrated,” “Water Facts: Getting to Know H20,” and “What’s to Drink?”

Amy Campbell, MS, RD, LDN, CDCES

Amy Campbell, MS, RD, LDN, CDCES

Amy Campbell, MS, RD, LDN, CDCES on social media

A Registered Dietitian and Certified Diabetes Educator at Good Measures, LLC, where she is a CDE manager for a virtual diabetes program. Campbell is the author of Staying Healthy with Diabetes: Nutrition & Meal Planning, a co-author of 16 Myths of a Diabetic Diet, and has written for  publications including Diabetes Self-Management, Diabetes Spectrum, Clinical Diabetes, the Diabetes Research & Wellness Foundation’s newsletter,, and

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