With excessive heat expected to continue, Angela Leppert Vander Molen, RN at Pella Regional Health Center, says that one of the biggest threats is dehydration. Vander Molen adds that we use so much fluid in our everyday activities, that symptoms often won’t show up until you are extremely dehydrated. Vander Molen continues by saying that if you start to experience excessive thirst, sleepiness, dry mouth, muscle weakness, headaches, or dizziness that you should call a doctor or 911.