Maintaining proper hydration is essential to overall good health. Without water, your cells can’t function, which is why humans can only survive a few days without fluids (1).

Unfortunately, many adults and kids don’t consume enough fluids, which can lead to chronic dehydration (2).

What’s more, conditions like diarrhea, vomiting, and excessive sweating can lead to acute or short-term dehydration (2, 3).

Dehydration can negatively affect many aspects of health and even be life threatening in severe cases, so it’s important to know the potential signs and symptoms of dehydration in both adults and kids.

This article covers 8 signs and symptoms of dehydration in adults, as well as explains the most common signs of dehydration in infants and kids.

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Here are 8 potential signs and symptoms of dehydration to watch out for.

Keep in mind that these symptoms could also indicate an underlying health condition unrelated to dehydration. If you’re experiencing one or more of these symptoms, it’s important to visit a healthcare professional for appropriate care.

1. Fatigue

If you’re dehydrated, you may feel more tired than usual (2).

This is because dehydration affects every aspect of health, including your sleep-wake cycles.

One study that included more than 26,000 Chinese and American adults found that shorter sleep duration was significantly associated with inadequate hydration, as well as that people who were adequately hydrated slept longer than those who were not (4).

Being dehydrated can likewise make you feel more fatigued during exercise.

One small study that included 14 male athletes found that acute dehydration of 3.2% body mass led to increased fatigue perception and also negatively affected exercise endurance (5).

2. Dark-colored urine and low urine output

If you’re not drinking enough fluids, your urine will be a darker color and you won’t pee very much.

In fact, looking at the color of your urine is considered a practical way to identify dehydration (6).

Darker-colored urine can occur when your body is conserving more water and not releasing it into urine. For this reason, the urine becomes more concentrated with waste products from the body, like sodium and urea (7).

The goal is not to have completely clear urine. Instead, the ideal urine color is a pale yellow, like the color of light straw.

Keep in mind that other factors can affect your urine color, including the use of medications and B vitamins, which can turn urine bright yellow.

3. Dry skin, decreased skin elasticity, and cracked lips

One of the most common signs of dehydration is dry skin and lips and decreased skin elasticity (8).

If you’re experiencing dry skin, dry mouth, and dry or cracking lips, dehydration may be contributing to these symptoms.

Keep in mind that dry skin and cracked lips can also be a sign of many other health conditions, so it’s important to get the right diagnosis, especially if you’re experiencing dry skin or cracked lips even when you’re drinking optimal amounts of water.

Healthcare professionals often use something called the skin turgor test to assess a person’s hydration status.

The skin turgor test involves grasping the skin on the lower arm or abdomen between two fingers and then releasing it after a few seconds.

Hydrated skin will rapidly return to its normal position, while dehydrated skin will remain in a “tented” position and take much longer to bounce back (9).

Decreased skin turgor is usually a sign of moderate to severe dehydration (9).

4. Headaches

When you’re not getting enough fluids, you may get frequent headaches.

Even though dehydration is strongly linked to headaches, researchers aren’t exactly sure how dehydration causes headaches.

One theory is that fluid depletion in the body leads to the stretching of blood channels in the brain, leading to headaches (10, 11).

However, researchers acknowledge that there are likely multiple mechanisms behind dehydration-related headaches, and that some people may be more susceptible to dehydration-related headaches than others (11).

Some studies show that increasing water intake may help reduce headache symptoms in people who experience migraine.

One study that included 256 women with migraine headaches showed that migraine severity, frequency, and duration were significantly lower in those who drank more water (12).

5. Light-headedness and dizziness

Dehydration may cause you to feel dizzy and light-headed, especially when you stand up (13).

Orthostatic hypotension is the medical term for a reduction in blood pressure when you stand or sit up (14).

Dehydration can lead to orthostatic hypotension. This is especially common among older adults, who are more at risk of developing dehydration and low blood volume (hypovolemia) (15).

Being dehydrated may cause you to feel dizzy and light-headed, especially when you stand or sit up quickly.

Severe dehydration may even lead to fainting in some cases, especially among older adults (16).

6. Heart palpitations

Being dehydrated may cause cardiac symptoms like palpitations, or a sensation of pounding, fluttering, or an irregular heartbeat (2).

Not drinking enough fluids can negatively affect overall health, including heart health.

According to one review, dehydration may impair heart function in several ways, including by negatively affecting blood vessel function and altering blood pressure regulation (17).

Dehydration can also compromise heart function in people who are performing intense exercise in the heat.

It does this by decreasing the amount of blood pumped out of the left ventricle of the heart and reducing cardiac output — the amount of blood the heart pumps per minute (18).

7. Low blood pressure

Low blood pressure is a sign of dehydration that only appears if a person is significantly dehydrated.

As mentioned above, dehydration impairs blood vessel function and blood pressure regulation. Dehydration causes low blood volume — that is, a low amount of fluid circulating within your capillaries, veins, arteries, and chambers of your heart (19).

When your blood volume decreases, your body compensates by increasing your pulse and respiratory rate, as well as by decreasing your blood pressure (19).

Low blood pressure is a sign of severe dehydration, and it can be dangerous. Severe dehydration could lead to significantly low blood pressure, shock, and even death (20).

8. Poor concentration and altered mental state

Not taking in enough fluids can take a toll on your brain and reduce your ability to concentrate.

Some studies have shown that dehydration can be detrimental to short-term memory, concentration, and mood.

A small study including 12 men found that abstaining from drinking water for 36 hours led to higher error rates on tests and negatively affected energy, mood, attention, and memory. Rehydration with water alleviated these symptoms (21).

Many other studies have also shown that dehydration can negatively affect mood and cognitive performance in both men and women (22, 23).

Severe dehydration can lead to an altered mental state, which can seem like confusion and anger (24).

Summary

Many signs and symptoms may indicate dehydration in adults, including dark-colored urine, decreased urination, headaches, fatigue, dry skin, and light-headedness.

A dehydrated infant or child may not show the same signs of dehydration that adults do, making it hard for parents and caregivers to identify potential dehydration.

Infants and kids are more susceptible to dehydration caused by diarrhea, fever, and vomiting. This is because kids have a higher metabolic rate and lose more water on a daily basis than adults do (25).

Plus, babies and younger children depend on caregivers for hydration (25).

Signs of mild to moderate dehydration in babies and young children may include (25, 26):

  • less frequent urination (fewer than six wet diapers a day for babies)
  • playing less frequently
  • fewer tears when crying
  • a dry tongue and lips
  • the fontanelle or soft spot on the infant’s head is sunken
  • diarrhea or constipation, depending on the cause of fluid loss

In addition to the signs and symptoms above, kids with severe dehydration may show:

  • extreme agitation
  • extreme fatigue
  • sunken eyes
  • a cold feeling, discolored hands and feet
  • wrinkled skin
  • minimal urination (less than twice per day)
  • low blood pressure
  • an increased heart rate
  • an altered mental status

Although mild to moderate dehydration is common in children who are sick, any kind of dehydration can be extremely dangerous to your child’s health if not treated quickly. Severe dehydration can be life threatening.

If your child is showing signs of dehydration, contact their pediatrician for advice. They may suggest that you bring your child to a healthcare facility where they can be appropriately treated and monitored.

Summary

Babies and kids may not show the same signs of dehydration that adults do. If your baby or child is showing signs of dehydration, contact their doctor for advice.

There are many potential causes of dehydration, including vomiting, diarrhea, excessive sweating, medication use, and more (2).

For example, it’s common to become dehydrated when you’re experiencing symptoms like diarrhea, vomiting, and high fever.

If you or your child is ill, it’s important to replace lost fluids with water or other beverages like electrolyte drinks. Consuming foods that are high in fluids, such as soups and fruits, can also help prevent dehydration.

For people who are experiencing chronic dehydration, increasing fluid intake is essential. If you’re experiencing symptoms of dehydration like dry skin, headaches, fatigue, and dark-colored urine, try increasing your overall fluid intake.

Most people can meet their fluid needs by drinking water, but fluids like coffee, tea, and sparkling water also count toward your total fluid intake, as do foods like fruits and veggies.

Hydration needs vary widely and depend on factors like activity levels, body weight, pregnancy and breastfeeding status, and the environment.

People who live in hot climates typically need more water, as do pregnant and breastfeeding people. Highly active people, like athletes and those with physically demanding jobs, also require more water than the average person (27).

For many people, quenching your thirst is a smart way to ensure you’re getting enough water.

However, how thirsty you feel may not be a reliable indicator of your hydration needs. This may be the case if you have increased hydration needs, as athletes do, or if you’re an older person who has decreased thirst (28).

Although hydration needs vary, water recommendations from the Institute of Medicine (IOM) and the European Food Safety Authority (EFSA) generally range from (29):

  • Adult women: 67–91 ounces (2–2.7 liters) per day
  • Adult men: 84–125 ounces (2.5–3.7 liters) per day

You can use methods like looking at the color of your urine to make sure you’re properly hydrated.

Seek help for severe dehydration from a healthcare professional

You can usually manage your mild dehydration by increasing your fluid intake. However, it’s important to note that severe dehydration can be life threatening and should be treated by a healthcare professional.

If you or a loved one is experiencing signs of severe dehydration, contact a healthcare professional immediately. This is especially important for infants, children, and older adults, who are more susceptible to dehydration.

Risk factors for severe dehydration included prolonged diarrhea or vomiting, extreme exercise, laxative use, burns, and certain medical conditions (2).

Severe dehydration requires immediate medical attention and can’t be treated at home.

Summary

Hydration needs vary depending on a number of factors, including your activity levels, age, and body weight. Drinking plenty of fluids on a daily basis is the best way to prevent dehydration. Severe dehydration must be treated by a healthcare professional.

Dehydration is quite common and can be caused by factors like illness, medication use, extreme exercise, or simply insufficient fluid intake.

Signs and symptoms of dehydration include dark-colored urine, decreased urination, headaches, fatigue, dry skin, decreased skin turgor, and poor concentration.

Make sure you’re getting enough fluids every day by drinking plenty of water or other fluids. If you’re concerned that you or a loved one may be severely dehydrated, contact a healthcare professional for help right away.

Just one thing

Try this today: If you’re not a fan of plain water, you can make it more appetizing by infusing it with fresh fruit, lemon juice, or mint.

You could also try adding a bag of herbal tea, like hibiscus or mint tea, to your water and letting it sit for 10 minutes to infuse flavor into your drink. I love using a splash of tart cherry juice to add a kick of flavor to my water.