Get full access to Outside Learn, our online education hub featuring in-depth fitness and nutrition courses and more than 2,000 instructional videos when you sign up for Outside+.
You already know what it feels like to be thirsty. It can come on strong after a particularly sweaty soccer game or a day of running errands without your trusty water bottle. But some symptoms of dehydration are subtler — or even a little bit weird.
Dehydration is losing more fluid than you take in. Thankfully, early signs you’re dehydrated start off mild and go away once you find that water bottle and take a few gulps.
“When you start experiencing infrequent urination, dark yellow urine, headaches, muscle cramps or feeling hot with skin cool to the touch, these are all mild signals, and your body is letting you know you need water,” says Jay Woody, M.D., emergency room physician at Legacy ER & Urgent Care. “Most people can get rid of these symptoms simply by drinking water and rehydrating the body.”
It’s important to know that dehydration can hit women more often because women have a lower percentage of water for their bodyweight than men. This can lead to women becoming more symptomatic than men at similar losses of body fluid, explains Natasha Trentacosta, M.D., sports medicine specialist and orthopedic surgeon at Cedars-Sinai Kerlan-Jobe Institute.
But here are some of the more unusual signs you’re dehydrated to keep an eye out for:
1. You’re itchy
“Loss of water from the cells of the skin results in the shrinkage of skin cells,” says dermatologist Ahmad Chaudhry, M.D. In addition to skin feeling dry to the touch, it could become itchy and flakey.
2. Your breath stinks
When you’re dehydrated, less saliva is produced, says dietitian Paula Doebrich, RDN, MPH. Since the main role of saliva is to rinse bacteria out of the mouth, this can eventually lead to bad breath.
3. Your eyes look different
Dehydration also affects your eyes, says ophthalmologist Angelique J. Pillar, M.D. In addition to your eyes feeling dry, you might start to notice dark circles under your eyes or sunken or hollow eyes.
4. Your muscles are cramping
5. You’re constipated
Water is needed for proper digestive function, says Paula Doebrich, RDN, MPH. “When you are dehydrated, the intestines aren’t able to add enough water to the stool,” she says. “As a result, you may have a hard time going to the bathroom.”
6. You’re craving something sweet
When you’re dehydrated, you might find yourself craving sweets. This is especially common when you’re already dehydrated and then do intense exercise, Doebrich says. Once energy stores are depleted, the body may signal to correct the deficit — and the fastest way to do that is with sugar. Make sure to hydrate properly after a workout.
“Keep in mind that those cravings are not always bad,” Doebrich says. “In some cases, especially if dehydration is due to physical activity, intake of an isotonic sports beverage containing carbohydrates is actually a good way to rehydrate.”
7. Your workout was a bust
Exercise performance suffers when your body isn’t adequately hydrated. But that doesn’t mean you should guzzle water and get back out there. Instead, replenish lost fluid slowly.
8. You’re anxious
“Dehydration causes your blood vessels to constrict and your heart rate can rise. These can mimic feelings of anxiety,” says neurologist Santoshi Billakota, M.D.
9. You’re crabby
More signs you’re dehydrated include irritability, mental fog and slow cognition. If you find yourself in a sour mood or feel like your brain is operating in slow motion, you might just need to find a drink. Sip something with electrolytes in particular, Billakota says.
10. Your vision changes
Dehydration can cause eye strain that makes your vision distorted, Pillar says. Blurred vision and eye floaters, or spots in your vision, are also common.
“It’s important to recognize such symptoms and drink more water, given the risk of chronic vision and eye conditions directly resulting from dehydration,” Pillar says. “Make an appointment for an eye exam if you start drinking water and still have these issues.”
11. Your skin doesn’t bounce back
A quick test of your hydration status is to pinch the skin of your abdomen in front of your sternum. If it doesn’t bounce back quickly, you need water stat, Chaudhry says. Signs of frequent dehydration can include wrinkles and fine lines appearing on the skin.
12. You have a headache
“Headaches are a very common early sign of dehydration in women,” Trentacosta says. When the body loses water, it loses water from the brain, as well, causing it to temporarily shrink. The pain you feel is the nerve endings being stretched. Avoid this with a nonboring hydrating drink.
How much water should you drink?
Everyone’s hydration needs vary based on factors like body size and activity level. The general rule is to drink eight glasses of water each day from 8-ounce glasses for a total of 64 ounces, Woody says. You also can fill your 16-ounce water bottle four times.
When signs you’re dehydrated get more severe, you might experience dizziness, mental confusion, rapid heartbeat, seizures, and the inability to cry, urinate or sweat.
“At this point, it’s not only essential to get liquids into your body, but you also might need to see a medical professional who can help administer the proper care to make a full recovery,” Woody says.