Severe dehydration can lead to injury or fatal complications, and it requires an ER visit. Seizures, cardiac arrhythmia, or hypovolemic shock can occur because your blood volume is too low.
Yet it rarely comes to that. Most of the time, you can easily replenish your fluid stores and fend off dehydration when you drink water throughout the day. Thirst, dry mouth, and fatigue are all signs it’s time to reach for water or a sports drink that’s low in sugar and high in electrolytes. But other signs of dehydration aren’t always so obvious.
1. Bad Breath
Saliva has antibacterial properties, but dehydration can prevent your body from making enough saliva.
“If you’re not producing enough saliva, you can get bacterial overgrowth in the mouth, and one of the side effects of that is bad breath,” says John Higgins, MD, a professor of medicine at UT Health Houston’s McGovern Medical School and senior cardiologist at Lyndon B. Johnson Hospital.
It’s the same reason you may wake up with “morning breath”: Saliva production slows down during sleep leading to an unpleasant taste in the mouth as bacteria grow. So the next time you experience dry mouth and your breath smells less than fresh, it may be time to rehydrate.
2. Dry or Flushed Skin
“A lot of people think that people who get dehydrated are really sweaty, but in fact, as you go through various stages of dehydration, you get very dry skin,” Dr. Higgins says, adding that skin may appear flushed as well.
Another key skin-related symptom of dehydration is a loss of skin elasticity. This can cause skin to remain “tented” after being pinched, taking some time to return to its normal appearance. (More on that below.)
3. Muscle Cramps
When your body loses enough fluid, it’s unable to cool off adequately, leading to heat illness. One symptom to watch for is muscle cramps, which can happen during exercise, particularly in hot weather.
“The hotter you get, the more likely you are to get muscle cramps, and that’s from a pure heat effect on the muscles,” Higgins says. “As the muscles work harder and harder, they can seize up from the heat itself. Changes in the electrolytes, such as sodium and potassium, can lead to muscle cramping as well.”
Bear in mind that when it comes to rehydration after intense exercise, all drinks may not be created equal. A study of 86 athletes participating in a half-marathon found that those who rehydrated with a drink containing electrolytes were less likely to develop muscle cramps compared to participants who drank plain water.
Even in cooler weather, dehydration is possible if you don’t replace lost fluids by drinking small amounts of water while working out. Higgins says symptoms may be milder or come on slower, but dehydration carries the same risks, regardless of the temperature outside.
4. Fever and Chills
Other symptoms of heat illness include fever and chills. Excessive sweating combined with your skin feeling cool to the touch may be signs of heat exhaustion.
Fever can worsen dehydration. The higher the fever, the more severely dehydrated you may become. Unless your body temperature decreases, your skin will lose its cool clamminess and then become hot, flushed, and dry to the touch. At this point, it’s important that you cool yourself down immediately and see a medical professional, the Centers for Disease Control and Prevention (CDC) advises. Applying ice and cool, wet cloths, and moving to a cool area are short-term strategies until you can get medical attention.
Children and infants lose more of their body fluid to fever, and they are more likely to experience severe diarrhea and vomiting from illness. An infant or young child may also have other dehydration-related symptoms, such as a sunken spot on their head, no tears when they cry, or fewer wet diapers than normal. Any fever in an infant or toddler is cause for concern. Ask your pediatrician for advice on when to call the doctor in these circumstances.
Adults with a fever of 103 degrees F or higher should call their doctor. Seek emergency treatment right away if the fever is accompanied by persistent vomiting, confusion, difficulty breathing, chest pain, or seizures.
5. Food Cravings, Especially for Sweets
“When you’re dehydrated, it can be difficult for organs such as the liver, which uses water, to release glycogen [stored glucose] and other components of your energy stores, so you can actually get cravings for food,” Higgins says.
While you can crave anything from chocolate to a salty snack, cravings for sweets are more common because your body may be experiencing difficulty breaking down glycogen to release glucose into the bloodstream to use as fuel, he says.
6. Headaches
Even mild dehydration can cause a headache. Although various factors besides dehydration can cause headaches, drinking a full glass of water and continuing to sip more fluids during the day is a simple way to ease your pain if dehydration is the culprit.
Are You Dehydrated, or Is It Something Else?
If you’re thirsty, you’re already dehydrated. But lack of thirst doesn’t necessarily mean you’re well hydrated. Here are two other ways to check your hydration.
Try this skin test. Use two fingers to pinch up some skin on the back of your hand, and then let go. The skin should spring back to its normal position in less than a couple of seconds. Higgins says that if the skin returns to normal more slowly, you might be dehydrated.
Check your urine. If you’re well hydrated, your urine will be mostly clear with a tinge of yellow (the color of light lemonade before it hits the bowl). Amber or orange are the “warning” colors to watch for. If your pee is dark, start drinking fluids. (On the flip side, clear or transparent urine could mean you’re getting too much water.)
While it’s fairly straightforward to counter mild dehydration at home by drinking more water or drinks with electrolytes, severe dehydration requires immediate medical attention.
Call 911 or go to your local emergency room if you or a loved one experience the following symptoms:
Fever of 103 degrees F or higher
Muscle twitching
Rapid heartbeat
Nausea and vomiting
Dizziness or fainting
Confusion or hallucinations
Seizures
The Takeaway
Dehydration occurs when your body loses water and electrolytes, which can happen through sweating, illness, or simply not drinking enough fluids throughout the day.
Unusual signs of dehydration include bad breath, dry or flushed skin, muscle cramps, fever and chills, food cravings (especially for sweets), and headaches.
If you experience these signs of mild dehydration, start drinking water. If symptoms are more severe, including a fever, dizziness or faintness, confusion, or seizures, seek emergency medical care immediately.