 Dr. Bozzoli says signs of dehydration include headache, tiredness, dizziness, dry mouth, flushed skin, dark urine, and muscle cramps. In severe cases, dehydration can lead to heat stroke. If you're starting to feel thirsty, you're already probably about a liter or so dehydrated and behind. And so thirst is one of our first signals to trigger us that we need to try to catch up. For LifeBeat, I'm Marina Rockinger, Northwest News Radio.