Older adults (who are less likely to drink enough fluids) and young children (who have higher energy needs and are more likely to deal with diarrhea and vomiting) also have a higher risk of becoming dehydrated, per the U.S. National Library of Medicine.
What are the symptoms of dehydration?
The signs and symptoms of dehydration can be pretty obvious or seemingly random. Here’s what you might experience when your body needs more fluids:
1. Muscle cramps
Your body likes to maintain an optimal balance of fluids to ensure different parts, from your joints to your intestines, function properly, Mark Conroy, M.D., an emergency medicine physician at The Ohio State University Wexner Medical Center, tells SELF.
“Your muscles also require a certain amount of water to function well,” Dr. Conroy explains. When you’re dehydrated, your body will “pull water out of that muscle tissue, along with electrolytes,” he says, which can lead to painful muscle cramps.
This is often due to a sodium deficit in the body. “Exertional heat cramping, or full-body cramping, may be related to sodium depletion and fluid loss especially in individuals who are ‘salty sweaters,’” Pritchett says. In this case, particularly for endurance exercise like long-distance running, sipping on an electrolyte sports drink (or even just having a salty snack with water) can be helpful to restore the natural mineral balance in the body.
2. Headache
The exact reason why dehydration sometimes causes a headache isn’t known. One theory is that dehydration alone doesn’t directly lead to headaches but may exacerbate underlying conditions like migraine.1 There’s also “potentially a slight, temporary contraction of the brain due to low hydration levels,” which doesn’t necessarily feel great, Dr. Khan says.
3. Low energy and fatigue
When you’re dehydrated, your blood vessels contract and your body tries to pull fluid to more centrally located organs, like your heart and brain, to keep them running properly, Dr. Conroy explains. This means the rest of your body may start to operate at a slower pace, making you feel sluggish and tired. “Fatigue is your body noticing it doesn’t have an optimal state,” Dr. Conroy says.
4. Dizziness
The low blood pressure that comes with dehydration can also make you feel woozy, Dr. Khan says. A lower level of electrolytes can also cause dizziness or a lightheaded feeling.
5. Dark and smelly urine
Under normal, well-hydrated circumstances, your urine should be a pale yellow with little-to-no odor.2 When you’re dehydrated, though, you’ll be able to tell (or shall we say smell) when you do go, as you’ll likely be peeing less than you normally would. “As you become dehydrated your body seeks to conserve fluids by reducing urine output and concentrating the urine,” Dr. Dark says. “Thus, it appears darker and in lower volume.”
6. Dry mouth, lips, or skin
Remember, dehydration shifts your body into survival mode, so it tries to shuttle water to the areas where it’s most needed, Dr. Khan says. “Water is diverted from nonvital organs such as the skin to more vital ones like the heart, brain, and kidneys,” she explains. As a result, places like your mouth and lips might start to feel really dry.
7. Bad breath
Saliva has bacteria-fighting properties, Dr. Wider explains. When you’re dehydrated, your saliva levels go down because your body is using fluids where it needs it the most, meaning your mouth’s ability to fight odor-causing germs may not be as efficient. If you notice that you suddenly have bad breath for no reason, try drinking more water regularly. Fixing the dry mouth alone may freshen things up.