1. You have very concentrated and yellow urine.
One of the most common signs of dehydration is having pee that is darker than usual, according to Shapiro.
"You want your pee to be the color of lemonade, instead of dark yellow or even brown," the dietitian said.
The more water you have in your system, the lighter your urine will be. And so, if you're dehydrated, you don't have enough water to dilute whatever waste your body is eliminating.
But it's far more common to have darker yellow urine when dehydrated than brown, Shapiro added.
"Brown is more severe, when you're dehydrated in the dessert," she explained.
2. You've got a killer headache.
People suffer from headaches for a myriad of reasons.
And when you aren't drinking enough water, that can also cause your head to throb.
That's because your body uses water for energy. Therefore, not getting enough water can leave you feeling weak or tired.
"When you don't have enough, your body is working really hard to keep itself going. So you get a headache because your body is depleted," Shapiro said.
3. You're feeling extremely hungry.
Most of us equate feelings of hunger with the desire for food, but according to Shapiro, it can also be an indicator of dehydration.
"Sometimes we feel hungry when we're thirsty because our stomachs are empty, and we're mistaking that sensation for actually being hungry," Shapiro said.
If it's been four hours since you've eaten anything, that's a good sign that you're actually hungry.
Otherwise, the dietitian recommends drinking a glass of water before rushing to grab some food.
"If you don't feel hungry after, then you're probably just dehydrated," she said.
