The signs and symptoms you may experience with dehydration are not always a reliable indicator of early onset of dehydration, however many adults and in particular seniors, do not feel thirsty until they are already dehydrated. That is why it is so important to continuously increase your water intake throughout the day and during warmer to hot climate or when you are feeling ill. A few signs and symptoms of severe dehydration can be different with age, however the most common are: Infant or young child • Dry mouth and tongue • No tears when crying • No wet diapers for three hours • Sunken eyes and cheeks • Sunken soft spot-on top of the skull • Listlessness or irritability Adult • Extreme thirst • Less frequent need to urinate • Dark-colored urine • Tired • Dizzy • Confused