The Natural Hydration Council recommends that the average man and woman drink 2.5 and 2 litres of water each day, respectively. Unfortunately, it can be easy to neglect your body's hydration needs. That's when you become dehydrated – a state where your body doesn't have the amount of fluid required to function. Most day-to-day cases of dehydration are moderate and can be cured by increasing water or fluid intake. When dehydration becomes more serious, however, you'll notice it in your body's functions. Urination becomes dark and less frequent and you might get a headache. As dehydration becomes more serious, the NHS warns that you could experience unusual tiredness, confusion, dizziness that doesn't pass, a weak pulse, and even fits.
When you're not properly hydrated, your body works to conserve the fluid it does have. That's why one of the first signs of dehydration is decreased saliva production. Your tongue might feel dry and even swollen as your body reduces saliva production to conserve fluid. A dry, dehydrated tongue isn't a sign that your mouth is dehydrated; it's a sign that your entire body requires more fluids.